The Pediatric and Perinatal Autopsy Manual with DVD-ROM [1 ed.] 1107646073, 9781107646070

Table of contents :
Cover
Half-title page
Title page
Copyright page
Contents
Contributors
Foreword
Preface
Acknowledgments
Chapter 1 Perinatal autopsy, techniques, and classifications
The perinatal autopsy
Classification of perinatal deaths
References
Chapter 2 Placental examination
Introduction
Placental anatomical and functional structure
Indications for placental examination
Examination of the placenta
Gross examination
Microscopic examination
Pathology of the placenta
Placental abruption or retroplacental hematoma
Characteristic pathologic findings in specific disorders
The placenta in the medico-legal arena
Summary
Acknowledgment
References
Chapter 3 The fetus less than 15 weeks gestation
Background
Terminology
Causes of early miscarriage (abortion)
Autopsy objectives
Practical issues
Standard protocol
External examination
Internal examination
Microscopic examination
Clinical situations requiring additional investigations
Conclusion
References
Chapter 4 Stillbirth and intrauterine growth restriction
Introduction
Pathology and interpretation
Intrauterine growth restriction
The concept of optimal growth
Small for gestational age vs. growth restriction
Pattern of growth restriction “symmetrical vs. asymmetrical”
IUGR as a category in stillbirth classification systems
Post mortem assessment of growth
External assessment
Maceration
Internal examination
Histological examination
Placenta
Ancillary investigations
The autopsy summary
Causes of growth restriction
The combined macrosomic and growth-restricted fetus
The future
Summary approach to the examination of the stillbirth
References
Chapter 5 Hydrops fetalis
Introduction
Principal causes of HF
Specific causes of HF
Results of in utero treatment of HF
The placenta in HF
Practical tips for autopsy of HF
Summary
References
Chapter 6 Pathology of twinning and higher multiple pregnancy
Introduction
Pathological examination of the twin and higher multiple placenta
Complications of twinning
Conclusion
References
Chapter 7 Is this a syndrome? Patterns in genetic conditions
Introduction
Patterns of inheritance
Clinical approach
Examination
Head
Face
Neck
Hands
Feet
Heart
Lungs
Gastrointestinal tract
Kidneys and urinary tract
Spine
Central nervous system
Genitalia
Skeleton
Minor congenital anomalies
Syndromal associations
Genetic counseling
Genetic resources
References
Chapter 8 The metabolic disease autopsy
Introduction
Clinical presentation
Gross autopsy findings
Microscopic autopsy findings
General approach
Disease groups
Investigations and analysis
Conclusion
Appendix: common abbreviations used in this chapter
References
Chapter 9 The abnormal heart
Introduction
Before the incision
Autopsy technique
Evidence of cardiac disease
Examination of the arrangement of the organs (situs)
Examination of the external features of the heart
Dissection of veins and arteries
Dissection of the heart
Microscopic examination of the fetal and pediatric heart
Structural abnormalities of the heart and great vessels: congenital heart disease
Anomalies of position and situs
Anomalies of the atria
Anomalies of the atrioventricular connections
Anomalies of the ventricles
Anomalies of the ventriculoarterial connections
Anomalies of the great arteries and coronary arteries
Anomalies of the pulmonary veins
Anomalies of the venae cavae
Complications of congenital heart disease
Pathology of the normally formed heart
Conclusion
References
Chapter 10 Central nervous system
Introduction
Autopsy examination and removal of the brain
The autopsy
Normal brain development
Cellular reactions
White matter damage
Hemorrhages
Strokes
Infections
Primary perivascular inflammation
Trauma
Metabolic diseases
CNS malformations
Microcephaly/megalencephaly
Holoprosencephaly
Other ventral forebrain malformations
Corpus callosum anomalies
Hydrocephalus
Lissencephaly
Brainstem and cerebellum malformations
Abnormalities of meninges, choroid plexus, blood vessels, and phacomatosis
Neurodegenerative diseases
Neural tube defects
References
Chapter 11 Significant congenital abnormalities of the respiratory, digestive, and renal systems
Introduction
Respiratory system anomalies
Digestive system anomalies
Kidney and urinary tract
References
Chapter 12 Skeletal dysplasias
Introduction
Basic autopsy approach
Common lethal skeletal dysplasias
Dysostoses (Table 12.6)
Limb hypoplasia/reduction defects
Examples of non-genetic disorders with limb involvement often confused with skeletal dysplasias
Summary
References
Chapter 13 Congenital tumors
Introduction
Incidence of congenital tumors
Germ cell tumors
Neuroblastoma
Congenital renal tumors
Soft tissue tumors
Tumors of skeletal muscle origin
Neural tumors
Congenital hepatic tumors
Congenital cardiac tumors
Congenital brain tumors
Congenital hematolymphoid neoplasms
References
Chapter 14 Complications of prematurity
Introduction
General approach to the post mortem examination of the premature infant
Respiratory system
Gastrointestinal system
Liver
Infection
Complications of catheterization
Central nervous system
References
Chapter 15 Intrapartum and neonatal death
Introduction
Intrapartum asphyxia
Diagnosis
Intrapartum assessment
Postpartum assessment
Pathophysiology of intrapartum asphyxia
Causes of intrapartum asphyxia
Post mortem findings
Late deaths
Intrapartum trauma
Type of injuries in intrapartum trauma
Intrapartum trauma versus intrapartum asphyxia
Neonatal infections
The neonatal immune system
Bacterial infections
Viral infections
Investigations
Aseptic technique
References
Chapter 16 Sudden unexpected death in infancy
Definition
Explained SUDI
Unexplained SUDI or SIDS
Risk factors for SIDS
Triple risk hypothesis
The home visit
Role of the autopsy
Autopsy procedure
Classification systems
References
Chapter 17 Infections and malnutrition
Overview of congenital infections with description of the most frequent conditions
What to consider depending on location and age
Timing of the infection
Infections in different organs and systems
Interaction between malnutritionand infection [53]
References
Chapter 18 Role of MRI and radiology in post mortems
Introduction
Conventional radiography
Fetal radiography
Pediatric radiology
Forensic radiography in suspected non-accidental injury (NAI): skeletal, visceral, and craniospinal
Underlying bone disease?
Anthropomorphic radiography
Post mortem magnetic resonance imaging
The fetal and neonatal central nervous system
Fetal heart
Genitourinary tract
Gastrointestinal tract/abdomen
Organ weight
Acceptance of imaging
MRI sequences
The future
References
Recommended further reading
Chapter 19 The forensic post mortem
Introduction to forensic death investigation
What is death investigation?
Challenges to the death investigation
What hurts and kills children?
Consultations
Case timeline
The investigation
Case report
What is a case file?
Death investigation
Scene investigation
Timeline analysis
Case type
Analysis
The pediatric forensic post mortem
Elements of the pediatric medico-legal autopsy
Documentation
The autopsy report: protocol/documentation/interpretation (Tables 19.8–19.9)
Appendices
References
Chapter 20 Appendix tables
Index

Citation preview

The Pediatric and Perinatal Autopsy Manual

The Pediatric and Perinatal Autopsy Manual Edited by

Marta C. Cohen Consultant Paediatric and Perinatal Histopathologist, Sheffield Children’s Hospital; Honorary Senior Lecturer, University of Sheffield, UK

Irene Scheimberg Consultant Paediatric and Perinatal Pathologist, Royal London Hospital, Barts Health NHS Trust; Honorary Senior Lecturer, Barts Medical School, Queen Mary University, London, UK

The Edinburgh Building, Cambridge CB2 8RU, UK Cambridge University Press is part of the University of Cambridge. It furthers the University’s mission by disseminating knowledge in the pursuit of education, learning, and research at the highest international levels of excellence. www.cambridge.org Information on this title: www.cambridge.org/9781107646070 © Cambridge University Press 2014 This publication is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published 2014 Printed and bound in the United Kingdom by Bell and Bain Ltd A catalogue record for this publication is available from the British Library Library of Congress Cataloguing in Publication data The pediatric and perinatal autopsy manual / edited by Marta C. Cohen, Irene Scheimberg. p. ; cm. Includes bibliographical references and index. ISBN 978-1-107-64607-0 I. Cohen, Marta C., 1961– editor of compilation. II. Scheimberg, Irene, editor of compilation. [DNLM: 1. Autopsy. 2. Child. 3. Fetal Death – pathology. 4. Infant, Newborn. 5. Stillbirth. QZ 35] RJ49 618.920 00759–dc23 2013036995 ISBN 978-1-107-64607-0 Mixed Media ISBN 978-1-107-64148-8 Paperback ISBN 978-1-107-68507-9 CD-ROM Additional resources for this publication at www.cambridge.org/9781107646070 Cambridge University Press has no responsibility for the persistence or accuracy of URLs for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate.

................................................................................................. Every effort has been made in preparing this book to provide accurate and up-to-date information which is in accord with accepted standards and practice at the time of publication. Although case histories are drawn from actual cases, every effort has been made to disguise the identities of the individuals involved. Nevertheless, the authors, editors, and publishers can make no warranties that the information contained herein is totally free from error, not least because clinical standards are constantly changing through research and regulation. The authors, editors and publishers, therefore disclaim all liability for direct or consequential damages resulting from the use of material contained in this book. Readers are strongly advised to pay careful attention to information provided by the manufacturer of any drugs or equipment that they plan to use.

Contents List of contributors page vi Foreword ix Preface xi Acknowledgments xii

1. Perinatal autopsy, techniques, and classifications 1 Mudher Al-Adnani

12. Skeletal dysplasias 235 Josephine Wyatt-Ashmead, Anastasia E. Konstantinidou, and Amaka C. Offiah

2. Placental examination 17 Beverly Rogers and Carlos Abramowsky

13. Congenital tumors 262 Sarangarajan Ranganathan

3. The fetus less than 15 weeks gestation L. Cesar Peres and Christina Vogt

47

14. Complications of prematurity 284 Stephen Gould and Nicholas Smith

4. Stillbirth and intrauterine growth restriction 62 Adrian Charles and Yee T. Khong

15. Intrapartum and neonatal death 298 Irene Scheimberg, Susan Arbuckle, and Samantha Holden

5. Hydrops fetalis 83 Geoffrey A. Machin

16. Sudden unexpected death in infancy 319 Chitralekha Sethuraman, Robert Coombs, and Marta C. Cohen

6. Pathology of twinning and higher multiple pregnancy 93 Phil Cox

17. Infections and malnutrition 330 Ronald O. C. Kaschula and Helen C. Wainwright

7. Is this a syndrome? Patterns in genetic conditions 105 Meena Balasubramanian

18. Role of MRI and radiology in post mortems 362 Alan Sprigg and Elspeth H. Whitby

8. The metabolic disease autopsy Kevin Bove and Simon Olpin

19. The forensic post mortem Janice Ophoven

120

9. The abnormal heart 139 Glenn P. Taylor, Mary N. Sheppard, and S. Yen Ho

376

20. Appendix tables 409 Irene Scheimberg, L. Cesar Peres, and Marta C. Cohen

10. Central nervous system 173 Waney Squier and Férechté Encha-Razavi 11. Significant congenital abnormalities of the respiratory, digestive, and renal systems 205 Linda R. Margraf, Ana M. Gomez, and Carlos A. Galliani

Index

422

v

Contributors

Carlos Abramowsky Professor of Pathology and Laboratory Medicine and Professor of Pediatrics, Emory University School of Medicine, and Staff Pathologist, Children’s Healthcare of Atlanta, Atlanta, GA, USA Mudher Al-Adnani Consultant Paediatric and Perinatal Pathologist, Sheffield Children’s Hospital, Sheffield, UK Susan Arbuckle Staff Histopathologist and Head of Department, Department of Histopathology, The Children’s Hospital at Westmead, Sydney, New South Wales, Australia Meena Balasubramanian Consultant Clinical Geneticist, Sheffield Clinical Genetics Service, Sheffield Children’s NHS Foundation Trust, and Honorary Senior Lecturer, Department of Human Metabolism, University of Sheffield, Sheffield, UK Kevin Bove Professor of Pathology, University of Cincinnati College of Medicine, and Staff Pathologist, Children’s Hospital Medical Center, Cincinnati, OH, USA Adrian Charles School of Pathology and Laboratory Medicine, University of Western Australia, Crawley; Department of Histopathology, Princess Margaret Hospital for Children, Subiaco, Perth, Australia

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Marta C. Cohen Consultant Paediatric and Perinatal Histopathologist, Sheffield Children’s Hospital; Honorary Senior Lecturer, University of Sheffield, UK

Robert Coombs Consultant Neonatologist, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK Phil Cox Consultant Perinatal Pathologist, Birmingham Women’s Hospital, Birmingham, UK Férechté Encha-Razavi Service d’Histologie-Embryologie-Cytogénétique, Hôpital Necker-Enfants Malades, Paris, France Carlos A. Galliani Department of Pathology, Cook Children’s Medical Center, Fort Worth, TX, USA Ana M. Gomez Department of Pathology, Cook Children’s Medical Center, Fort Worth, TX, USA Stephen Gould Consultant Paediatric Pathologist, Oxford University Hospitals NHS Foundation Trust, Oxford, UK S. Yen Ho Professor of Cardiac Morphology, Royal Brompton Hospital, London, UK Samantha Holden Consultant Histopathologist, Department of Cellular Pathology, Southampton General Hospital, Southampton, UK Ronald O. C. Kaschula Division of forensic Medicine and Toxicology, University of Cape Town, Cape Town, South Africa Yee T. Khong Professor, Departments of Pathology and Obstetrics and Gynaecology, University of Adelaide, Adelaide, Australia

List of contributors

Anastasia E. Konstantinidou Associate Professor of Pathology, University of Athens Medical School, Athens, Greece Geoffrey A. Machin Emeritus Professor of Pediatric Pathology, University of Alberta, Edmonton, Alberta, Canada Linda R. Margraf Department of Pathology, Cook Children’s Medical Center, Fort Worth, TX, USA Amaka C. Offiah HEFCE Clinical Senior Lecturer, Honorary Consultant Radiologist, University of Sheffield and Sheffield Children’s NHS Foundation Trust, Sheffield, UK Simon Olpin Consultant Clinical Scientist in Inherited Metabolic Disease, Department of Clinical Chemistry, Sheffield Children’s Hospital, Sheffield, UK Janice Ophoven Ophoven MD and Associates, Woodbury, MN, USA L. Cesar Peres Consultant Histopathologist, Department of Histopathology, Sheffield Children’s Hospital NHS Foundation Trust, Sheffield, UK Sarangarajan Ranganathan Director, Anatomic Pathology, Children’s Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Department of Pathology, Pittsburgh, PA, USA Beverly Rogers Chief of Pathology, Children’s Healthcare of Atlanta, Adjunct Professor of Pathology and Pediatrics, Emory University School of Medicine, Atlanta, GA, USA Irene Scheimberg Consultant Paediatric and Perinatal Pathologist, Royal London Hospital, Barts Health NHS Trust; Honorary Senior Lecturer, Barts Medical School, Queen Mary University, London, UK Chitralekha Sethuraman Consultant Histopathologist, Sheffield Children’s Hospital NHS Foundation Trust, Sheffield, UK

Mary N. Sheppard Consultant Histopathologist and Director, Imperial Unit of Cardiovascular Pathology, Royal Brompton and Harefield NHS Foundation Trust, London, UK Nicholas Smith Clinical Associate Professor and Senior Specialist Pathologist, Princess Margaret Hospital for Sick Children, Perth, Australia Alan Sprigg Consultant Paediatric Pathologist, Sheffield Children’s Hospital, Sheffield, UK Waney Squier Neuropathology Department, Oxford University John Radcliffe Hospital, Oxford, UK Glenn P. Taylor Head, Division of Pathology, Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, ON, Canada Christina Vogt Department of Pathology and Medical Genetics, St. Olavs Hospital, Trondheim University Hospital, and Department of Laboratory Medicine, Children’s and Women’s Health, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway Helen C. Wainwright Associate Professor, Division of Anatomical Pathology, University of Cape Town Faculty of Health Sciences, Cape Town, and Principal Pathologist, National Health Laboratory Service, D7 Groote Schuur Hospital, Cape Town, South Africa Elspeth H. Whitby Senior Lecturer and Honorary Consultant Radiologist, University of Sheffield and Sheffield Teaching Hospitals Foundation Trust, Sheffield, UK Josephine Wyatt-Ashmead Department of Cellular Pathology, Hammersmith Hospital, Imperial College Healthcare, London, UK

vii

Foreword

Marta Cohen and Irene Scheimberg, pediatric pathologists of international repute, have recruited a distinguished panel of authors for this book. Their assignment is to provide general pathologists with up-to-date information on perinatal and pediatric pathology. As a manual, it emphasizes techniques for examining pediatric postmortem and surgical specimens, including histopathology. But this is much more than a procedure manual. The book is brim full of current information about common and obscure pediatric disease. Chapter by chapter, the assembled experts have laid out detailed approaches to perinatal and pediatric specimens. The descriptions of dissections are so cogent they could well be read aloud to an inexperienced prosector while he or she conducts an examination. Even experienced pediatric pathologists will find techniques and methods that they had not considered or, perhaps, not even known. In a volume of 436 pages, the authors have wisely emphasized the approach to specific problem areas. These include immature fetuses and infants, growth restriction, excessive body growth, sudden unexpected death in early life, pediatric infectious diseases, problems related to pediatric intensive care, etc. Pertinent information is provided on pathologic anatomy, histopathology, chemistry, microbiology, and molecular

genetics. An entire chapter on pediatric radiology is a feature not usually found in pathology textbooks. Still another special chapter deals with perinatal and pediatric forensic pathology. Photographs of actual dissections provide exquisite detail that complements the text. Other color illustrations add appreciably to both the appeal and the teaching value of the book. Tables with classifications and algorithms enhance the information in each chapter. And the relatively brief reference lists are a pleasant departure from the massive multipage bibliographies found in most modern textbooks of pediatric pathology. The value of thorough perinatal and pediatric autopsies and other pathologic examinations extends beyond providing diagnoses for the attending physicians. These examinations instruct interns, residents, nurses, other care givers, and the public at large. Most significantly, as pointed out in this book, such examinations provide definitive information for patients’ families. While this work is intended to meet the needs of general pathologists, it will be welcomed by trainees in pediatric pathology, and will likely find an appreciative audience in every pathology department. Don B. Singer J. Bruce Beckwith

ix

Preface

The Pediatric and Perinatal Autopsy Manual has been written for general pathologists that have to perform pediatric and perinatal autopsies during the course of their mainly “adult” work. Babies and children aren’t simply “small adults.” The incidence, rarity, and peculiarity of many diseases and conditions is such that it justifies the need for a separate subspecialty of pathology addressing all conditions of unborn babies, infants, and children up to the age of 16 years. The autopsy caseload of this age group is extremely rich and varied, to the point that some cases are unique. This is down to the peculiar genetic and developmental abnormalities that characterize this period. However, the practice of pediatric and perinatal pathology is not always carried out in specialist centers where experts in this discipline are available. This is true in many countries around the world where there are few exclusively pediatric hospitals. Referral centers may be far away and it is not always possible to send these cases for specialist post mortem. In these circumstances, the pediatric and perinatal autopsies, as well as the placental examinations, are carried out by general pathologists. The Pediatric and Perinatal Autopsy Manual is also aimed at trainee pediatric pathologists and forensic pathologists who have to perform pediatric autopsies. It is designed and written as a practical bench-book, where each chapter is written by experts in the relevant field. A key feature of the book is that chapters are organized by types of autopsy rather than by organ system. This is because we anticipated that the reader will want to find answers to practical questions posed around the complex diseases and conditions that can affect the fetus and/or the placenta, the newborn, the infant, or the child. Thus, the book begins with a detailed explanation of how to perform a pediatric post mortem. A separate chapter deals with the small and frequently macerated fetus. Other categories, such

as stillbirths and intrauterine growth restriction, are also dealt with separately. Premature infants present their own problems and a chapter is devoted to the particular problems of premature babies, while intrapartum and neonatal deaths are also described separately. No book on perinatal pathology is complete without a chapter on placental diseases and we have one that is concise and comprehensive. Infections and nutritional problems are prevalent in many countries and a chapter is dedicated to these subjects. Useful algorithms and clues to metabolic and genetic autopsies are presented. Some specific problems such as hydrops or systemic conditions requiring more detailed description have their own chapters. Autopsies on sudden unexpected death in infancy are performed in many countries by forensic pathologists. We hope that this particular chapter, together with relevant information present in the other chapters, will be useful to them. Finally, a forensic chapter should be useful not only for forensic pathologists, but also for any pathologist encountering unexpected suspicious findings during an initially non-suspicious post mortem. We tried to describe the most common and important conditions that may be found in a pediatric or perinatal autopsy, providing a guide to those performing these post mortems. As such, this book does not pretend to have an in-depth understanding of each condition. There are good books that cover this particular aspect. However, each chapter contains good references for the interested pathologist. We are grateful to our colleagues and friends who agreed to co-author the 20 chapters that constitute The Pediatric and Perinatal Autopsy Manual. We are indebted to them for their skillful contribution, thoughtful advice, and enduring patience, which helped us shape the book that we initially envisioned two years ago.

xi

Acknowledgments

To my parents, Elsa and Ramon Cohen, who as pediatricians nurtured and encouraged my love for pediatric medicine. I also dedicate the book to Roc Kaschula, my mentor during my time as a young trainee in Cape Town, South Africa, whose inspiration, careful guidance, and continuous friendship have influenced all my accomplishments. Marta C. Cohen

xii

To my wonderful parents Rosa and Augusto, excellent clinicians in their own fields and even better parents, and to Fernando Paradinas, whose knowledge and love of pathology inspired me to pursue this exciting career path. Irene Scheimberg Sincere thanks are due to our families: our spouses and children, who provided the necessary emotional support whilst deprived of invaluable family-time during weekends and holidays.

Chapter

1

Perinatal autopsy, techniques, and classifications Mudher Al-Adnani

The perinatal autopsy

Autopsy protocol

The value of the perinatal autopsy

Clinical information

The perinatal autopsy can provide important information to the family, the clinician, and society [1–3]. When the parents give their consent for a post mortem examination on their baby, they are hoping to know why and how their baby died. It is quite reassuring to the parents to know that whatever has gone wrong, it did not happen because they did something wrong, and that there was nothing they could have done to prevent it. In cases where the pregnancy was terminated due to malformations, the post mortem can confirm, modify, or exclude a prenatal diagnosis, i.e., it serves as an audit tool for both diagnosis and diagnostic techniques. In all cases, whether it was a miscarriage, a stillbirth or a termination of pregnancy due to fetal malformations, the information obtained from the autopsy can help both the parents and the clinicians to plan for future pregnancies, and help the clinicians to counsel the parents about possible recurrence risks. In cases of neonatal deaths, the perinatal autopsy can provide the neonatologists with information about the accuracy of their diagnoses and any conditions that were not recognized. It can also provide information about the effects of various treatments and drugs on the tissues and organs. The autopsy is an important teaching tool for a variety of health professionals involved in the care of women and their babies. This includes pathologists, pediatricians, neonatologists, obstetricians, midwives, nurses, and bereavement officers. The perinatal autopsy provides information that can be used to promote public health. Accurate information on causes of death is essential for national perinatal mortality data and health service planning.

Adequate clinical information is essential for any post mortem examination [1–4]. This is because having the appropriate information helps the pathologist to decide the best approach to perform the examination, e.g., method of evisceration and removal of the brain, and what ancillary investigations are necessary. In addition, knowing what investigations have been carried out during pregnancy or after delivery would help prevent unnecessary duplication. Having the mother’s (and baby’s) clinical notes would be the ideal situation. However, this may not be possible since, quite often, babies are sent to different hospitals for post mortem examination. The alternative is an appropriately completed autopsy request form. Such a form should contain information about the mother’s past medical history, including any conditions that may affect pregnancy outcome, e.g., chronic hypertension and diabetes. History of previous pregnancies and their outcome is essential. For the index pregnancy, the gestation based on the mother’s last menstrual period, as well as any revisions using ultrasound scans, should be stated. Any pregnancy complications such as pre-eclampsia, gestational diabetes, pyrexia, and antepartum hemorrhage should be included. Investigations undertaken during pregnancy and their results are essential. If the mother’s clinical notes are not available, a copy of any abnormal scan reports is essential, especially if the pregnancy had been terminated due to fetal anomalies. The form should include time and date of delivery, mode of delivery, and birth weight. For live births, the condition of the baby at birth, postnatal progress, including any medical procedures, and clinical cause of death should be included.

The Pediatric and Perinatal Autopsy Manual, ed. Marta C. Cohen and Irene Scheimberg. Published by Cambridge University Press. © Cambridge University Press 2014.

1

Chapter 1: Perinatal autopsy, techniques, and classifications

foot length is considered the most reliable to assess gestation in cases where the fetus is macerated. Other optional measurements include chest and abdominal circumferences (at the level of the nipples and umbilicus, respectively). The chest circumference may be of value in cases of skeletal dysplasia. All major organs (thymus, heart, lungs, liver, spleen, pancreas, adrenals, kidneys, and brain), as well as the placenta, should be weighed and compared with expected values for gestation.

Radiology

Figure 1.1 Instruments used in the perinatal autopsy.

Equipment The perinatal post mortem requires a fully equipped mortuary with abundant light and suitably sized tables and benches. Advanced photography equipment (cameras and stands) that allow photographing small fetuses and organs are invaluable for a perinatal pathologist. If this is not available, a modern small camera with a good macro function should suffice. Radiographic equipment, usually in the form of a Faxitron, is also essential (see Chapter 18). Autopsy examination of fetuses and neonates requires accurate weighing scales. An electronic balance with a digital display is ideal to record weights to the nearest 0.1 g. Measuring the body and foot lengths can be performed using a metric ruler with calipers, or a fixed board with a fixed end and movable foot. A string or tape can be used for circumferential measurements. Dissection of small babies and fetuses requires blades, scissors, forceps, and probes of various sizes (Figure 1.1). Appropriately sized bowls and brushes are useful to handle small and soft brains. A mounted magnifying glass or a dissecting microscope may be needed for the examination of small fetuses and organs.

Procedure

A Faxitron whole-body radiograph is a useful investigation in the perinatal autopsy. Antero-posterior and lateral views are the basic requirements. Further images of individual sites, e.g., limbs or chest, can be obtained as required. A high-quality radiograph is essential for the investigation of skeletal dysplasia. It can also be used to assess gestational age and detect soft tissue calcification. In some centers, post mortem MRI is increasingly used as an adjunct to the post mortem examination, especially in cases of termination of pregnancy due to brain malformations. MRI is very useful in imaging the soft brain before the skull is opened, especially in macerated fetuses [5,6]. For further information please refer to Chapter 18.

Photography The minimum requirements are anterior, posterior, and lateral images. Further images of dysmorphic features and any other abnormalities detected on external and internal examinations are obtained as required. A photographic record of any abnormality is more reproducible and more accurate than any written description. Clear photographs are not only useful for the pathologist, but also for clinical geneticists, and if a second opinion is required on difficult cases. They can also be used to demonstrate the various abnormalities in perinatal mortality meetings and for training and teaching purposes. Some centers provide photographs for families if requested.

Weights and measurements

2

The body weight and external measurements should be accurately recorded and compared with appropriate gestation-related normal values (see Chapter 20). Standard measurements include crown–rump, crown–heel, head circumference, and foot length. These should be recorded to the nearest 0.5 cm. The

External examination Similar to the neonatal check carried out on newborn babies before they are discharged from hospital, the external examination is a “tip to toe” check looking for any abnormalities in the baby or fetus. Assessing skin color and the presence or absence of skin slippage, and

Chapter 1: Perinatal autopsy, techniques, and classifications

Table 1.1 External features of maceration and approximate timing of fetal death

Timing

Gross skin findings

≥ 6 hours

Skin desquamation ≥1 cm

≥ 12 hours

Skin desquamation of face, back, or abdomen

≥ 18 hours

Skin desquamation ≥ 5% of body surface

≥ 18 hours

Skin desquamation involving two or more body regions

≥ 24 hours

Skin color brown or tan

≥ 2 weeks

Mummification

Source: Data from D. Genest and D. B. Singer.[7].

Figure 1.2 Hypercoiled umbilical cord with stricture at the fetal end.

its extent if present, allows the pathologist to assess the degree of maceration and gives clues about the time of death [7] (Table 1.1). It has to be said, however, that this may not be reliable in very small fetuses. Skin color also helps in assessing/confirming gestation of the baby, as very pre-term babies have bright pink skin while post-term babies can have dry, wrinkled skin. Pale skin can indicate fetal anemia, and in near-term or term babies it raises the possibility of feto-maternal hemorrhage; the pathologist can alert the clinician or the laboratory to carry out a Kleihauer test (if not already done) while the opportunity is still there. Other features that can be assessed include bruising, petechial hemorrhages, edema, and jaundice in neonatal deaths. Together with the given gestation on the post mortem request form, body weight, and external measurements, the fetal growth can be assessed to determine if the fetus is appropriately grown for gestation or if the fetus is small or large for gestation. Small for gestational age or growth-restricted babies can look “tall and thin” with a large head and have thin thighs compared to what might be expected in appropriately grown babies. This would be more obvious in near-term or term babies. Growth-restricted babies may also have dry skin, even if they are pre-term. The fetus is then examined, looking for dysmorphic features. These can give clues to a specific diagnosis, e.g., Down’s syndrome, and to possible internal malformations, thus allowing the pathologist to decide the approach to be taken for the rest of the examination. The pathologist can also decide what ancillary investigations may need to be carried out, e.g., cytogenetics. Other abnormalities that can be seen include abnormalities of posture, such as positional talipes,

arthrogryposis, amputated limbs, neural tube defects, and abdominal wall defects. The attached umbilical cord can also provide useful information, especially if the placenta is not submitted for examination. The umbilical cord should be measured (length and diameter) and the number of vessels recorded. Abnormalities such as hypercoiling and strictures at the fetal end (Figure 1.2) should be assessed as these might give important clues in miscarriages and stillbirths. Any injuries related to delivery, such as abdominal wall defects, should be carefully recorded, even in miscarriages and stillbirths, and these should be differentiated from true malformations. It is not uncommon that parents want to see photographs of their babies and it is critically important that any birthrelated injuries are documented to prevent any potential complaints against the mortuary staff or the pathologist. In addition, cases of possible birth trauma in intrapartum or neonatal deaths are likely to be investigated by the coroner or medical examiner. Therefore, careful and accurate documentation of any injuries cannot be overemphasized. In cases of neonatal death, sites of venepuncture, drains, catheters, and surgical incisions should be noted. All drainage tubes, central lines, and umbilical arterial and venous catheters should be left in situ until the position of the tip is checked internally.

Internal examination Initial incisions The incision used to open the body can be done in many ways. This depends on the size of the fetus or

3

Chapter 1: Perinatal autopsy, techniques, and classifications

baby, potential malformations predicted from the clinical information provided and/or external examination, and, to a lesser extent, personal preferences. A single straight midline incision from the sternal notch to the symphysis pubis is usually adequate for small fetuses. A T-, Y-, or inverted Y-shaped incision can be used for bigger babies. In a T incision, an incision is made from one shoulder tip to the other. A vertical incision is then made from the sternal notch down to the symphysis pubis (Figure 1.3). A Y-incision would be preferable if the neck is going to be dissected. Each limb of the Y represents an incision that runs from just behind the ear along the sternocleidomastoid muscle to the sternal notch. A vertical incision is then made from there to the symphysis pubis. An inverted Y-incision is useful for good exposure of the bladder and umbilical arteries. A vertical incision is made from the sternal notch to just above the umbilicus. The limbs of the Y represent two incisions from just above the umbilicus to the groin. One limb of the Y

4 Figure 1.3 T-shaped initial incision of the chest and abdomen.

can be continued to the thigh or knee if a limb muscle is going to be sampled or the femur needs to be removed. If the body is likely to be viewed after the autopsy, a T-shaped incision would be preferable. The thorax On dissecting the skin and subcutaneous fat from the rib cage, the amount of subcutaneous fat can be assessed. This will give additional information regarding the fetal state of nutrition. An average-term baby should have a subcutaneous fat thickness of approximately 5 mm. A growth-restricted baby might have subcutaneous fat thickness as little as 2 mm, while a macrosomic baby might have subcutaneous fat thickness as high as 10 mm. The volume of muscle on the chest can also be noted as poor muscle volume raises the possibility of myopathic or neuropathic disorders. This should prompt careful examination of the nervous system, sampling of limb muscles, and taking muscle samples for freezing and electron microscopy. The shape of the thoracic cage can then be inspected. A narrow bell-shaped chest can be a feature of skeletal dysplasia and may suggest the possibility of pulmonary hypoplasia. In neonatal deaths the possibility of pneumothorax should be excluded. This can be done by immersing the body in water and inserting a cannula into each pleural cavity through the sixth intercostal space in the mid-axillary line. If a pneumothorax is present, gas bubbles will emerge from the cannula when the trocar part is removed. The thoracic cavity can be accessed by cutting through the sternoclavicular joints and rib cartilages, approximately 5 mm medial to the costochondral junction on each side, and removing the sternum. The thoracic contents should be examined in situ to confirm position and appearance of the organs and their relationships. The presence of any spaceoccupying abnormality, e.g., effusion, abdominal organs through a diaphragmatic hernia or tumor, should be recorded. Samples from the lung or effusion, if present, can be taken for microbiology at this stage. The position of the tips of any chest drains should be located and any lung or heart damage excluded. The thymus is a large bilobed organ overlying the superior aspect of the heart and the roots of the great vessels. It can extend into the neck for a variable distance. The thymus shrinks with longstanding stress of any cause. Therefore, growth-restricted fetuses or neonates who have been in the intensive care units can have a very small thymus. This should not be confused

Chapter 1: Perinatal autopsy, techniques, and classifications

with cases of Di George syndrome, where the thymus is usually absent. The thymus should be carefully dissected off the pericardium without damaging the innominate vein, which runs behind it. Petechial hemorrhages secondary to hypoxia may be present. The pericardium is opened, noting the presence of any effusion or blood. It can then be completely removed by dissecting it off the roots of the great vessels and sides of the atria, taking care not to damage the pulmonary veins at the back. This will expose the heart and great vessels; the exterior of the heart and its connections can be examined in situ. The presence or absence of epicardial petechiae should be noted. The position, shape, and size of the heart can be checked. The presence and position of the superior and inferior vena cavae should be confirmed. If the innominate vein behind (and sometimes in front of) the thymus is not identified, the presence of a persistent left superior vena cava should be ascertained. The pulmonary veins should be inspected to confirm their drainage into the left atrium. The atria and their appendages can be checked to determine atrial situs. In fetuses and early neonatal deaths, the right and left ventricle should be more-or-less equal in size. The ascending aorta and pulmonary artery should also be equal in diameter, with the pulmonary artery crossing in front of the aorta. The aortic arch and its branches and the ductus arteriosus are then checked. If all of the above are normal, then a significant cardiac malformation is unlikely to be present (see also Chapter 9). Dissection of the heart can be carried out in situ, or after removing it en-bloc with other organs. Some pathologists prefer to examine the heart in situ if all of the above external inspection is normal. This is because the heart would still be in its natural position and with natural connections, and therefore more stable and easier to examine. If there is any suspicion of congenital heart disease, the heart should be photographed, removed en-bloc, and examined after fixation. This can be done after as little as 2–3 hours if the body has to be released back to the family as a matter of urgency. Otherwise, the examination can be left until the following day. Some pathologists, on the other hand, prefer to examine the heart in the fresh state [2].

Evisceration Evisceration can be carried out in several ways. The most important aspect is that organs should not be removed individually. The organs can be removed in one (Rokitanski), two, three, or four blocks, depending

on the potential abnormalities that might be identified and personal preferences. The author prefers the method adopted by Wigglesworth [1,2], which includes removal of the viscera in four blocks: neck structures (with or without the tongue) and thoracic organs; small and large intestines; upper abdominal organs; and the urogenital organs. If there is a possibility of anomalous venous drainage, the neck and thoracic organs should be removed in continuity with the upper abdominal organs.

Neck and thoracic organs After removing the sternum, the neck structures can be dissected as far as the top of the larynx. These can then be brought down together with the thoracic organs by gentle traction and separation from the prevertebral fascia. The esophagus and blood vessels are then cut at the level of the diaphragm in order to free this organ block. Some pathologists prefer to remove all the neck structures, including the tongue. Others, including the author, do not advocate removing the tongue in the routine perinatal post mortem unless there is a specific indication, such as possible upper airway obstruction or malformation. Leaving the tongue in situ allows better cosmetic result after reconstruction, especially if the family wants to view the body after the post mortem examination. This organ block is dissected from the back by opening the posterior wall of the esophagus. This allows the identification of possible esophageal atresia and tracheo-esophageal fistula. The esophagus can then be dissected away from the posterior wall of the trachea. The larynx and trachea are then opened down their posterior wall as far as the two main bronchi. The lungs are examined, checking size, lobation, and the presence of pleural petechiae. In the perinatal autopsy it is rarely possible to identify specific pathology in the lungs macroscopically since the lungs nearly always appear airless and congested. The diaphragm is then examined and checked for completeness.

Examination of the heart Whether the heart is examined fresh or fixed, it should be opened following the flow of blood through the heart and assessing the morphology of the chambers and arterial trunks (sequential segmental analysis) [8,9]. There are circumstances, however, in which the heart may be opened differently. For detailed examination of the abnormal heart, see Chapter 9.

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Chapter 1: Perinatal autopsy, techniques, and classifications

6

The heart is placed in the anatomical position while it is still attached to the lungs. The right atrium is opened by cutting between the opening of the superior and inferior vena cavae along the right border of the heart. The oval fossa and opening of the coronary sinus can then be identified. The foramen ovale should be largely covered by a membrane, but it should be still probe patent. In small fetuses the membrane covering the foramen ovale is very thin and may appear absent on first impressions. Any septal defects should be noted and their site and size documented. The tricuspid valve can be inspected, looking for atresia, stenosis, or dilatation. The right ventricle can then be opened by cutting down the right lateral border of the heart to the apex along the posterior coronary artery, and then upwards along the outflow tract through the pulmonary valve and into the pulmonary artery. The cut can be continued through the ductus arteriosus, thus confirming its presence and patency at this stage, or it can be done after examining the pulmonary valve and arteries. The tricuspid valve is examined, looking for abnormalities of cusp number and morphology. The trabecular morphology of the right ventricle is then confirmed and any defects in the ventricular septum can be assessed. The pulmonary valve is examined looking at the number and morphology of the cusps and any pulmonary outflow obstruction. The main pulmonary truck and the right and left pulmonary arteries are inspected, and the presence and patency of the ductus arteriosus assessed, if not already done. The next step is to open the left atrium between the pulmonary veins. The mitral valve can be inspected looking for atresia, stenosis, or dilatation. The left ventricle can then be opened by cutting down the left lateral border of the heart to the apex, and then upwards along the outflow tract, following the interventricular septum using the left anterior descending coronary artery as a guide. To open the aorta, the prosector will have to cut through the aortic valve and pulmonary trunk. Therefore, the aortic valve needs to be inspected for possible atresia or stenosis before this is done. The mitral valve is examined looking for abnormalities of cusp number and morphology. The trabecular pattern of the left ventricle is noted. The interventricular septum is inspected again from the left side since it is easier to identify small septal defects, which may have been obscured by the coarse trabeculations of the right ventricle. The aortic valve is then examined, looking at the number and morphology of the cusps and any outflow obstruction.

In larger fetuses and neonatal deaths the coronary artery ostia should be identified and their origin ascertained. The aortic arch and its branches are then inspected, looking for possible coarctation, especially in the pre-ductal area.

The abdominal cavity It is useful to start by inspecting the peritoneal cavity and its contents before any dissection, especially in the macerated fetus. The presence of ascites or hemorrhage can be checked. The appendix and cecum should be located in the right side of the abdomen to exclude intestinal malrotation. The gonads can be located at this stage, before removing the intestines, to confirm the sex of the baby, especially in the very small fetus where the external genitalia may be difficult to assess. The presence and position of the umbilical arteries, umbilical vein, liver, stomach, spleen, and pancreas can be assessed. The intestines can then be removed by cutting through the fourth part of the duodenum as it emerges from the retroperitoneum behind the transverse colon and just below the stomach. The intestines are gently pulled and the mesentery divided all the way down to the rectum. This procedure allows any abnormalities such as atresias, duplications, infarctions, or enterocolitis to be identified. The upper abdominal organs can then be removed in one block by cutting the diaphragm along its peripheral insertions and gently separating the liver, pancreas, and spleen from the fascia covering the adrenal glands and aorta. The various organs can then be separated and examined. The abdominal parts of the inferior vena cava and aorta are opened in situ. If the baby had umbilical vein and/or artery catheters inserted, the position of the tips and any thrombus should be noted. The position and patency of the renal arteries can then be checked. The adrenals and urinary tract are then inspected. If there is no evidence of obstruction, i.e., enlarged bladder, dilated tortuous ureters, or hydronephrotic kidneys, the adrenals and kidneys can be removed individually. Otherwise, the whole urinary tract should be removed in continuity. In neonatal deaths the adrenals and kidneys can be checked for hemorrhage or infarction. The internal genitalia are inspected. The uterus can be checked for malformations such as bicornuate uterus. The appearance of the fallopian tubes and ovaries is noted. In most fetuses the testes will be in the abdomen, but in larger babies or neonates they may be in

Chapter 1: Perinatal autopsy, techniques, and classifications

the inguinal canal or scrotum. A sample from the psoas muscle can be taken for histology and freezing. If using the Rokitanski method, all the organs are removed in one block after removing the intestines, and the dissection proceeds in a similar way as that described above, separating the organs into three blocks: thoracic, abdominal, and genitourinary.

The head The scalp is inspected externally, looking for edema, caput, and bruising. The presence of localized swelling/mass may suggest an underlying encephalocoele. The head may be visibly enlarged in cases of severe hydrocephalus that have not been terminated early in pregnancy. In intrapartum and neonatal deaths, any bruising, hematomas, and ventouse or forceps marks should be carefully documented. The scalp is reflected by making an incision starting behind one ear and cutting posterior to the crown of the head toward the other ear. The incision can then be extended toward the neck and down the center of the back of the neck to form the shape of a “question mark” (Figure 1.4). This incision allows adequate

Figure 1.4 A “question mark” scalp incision.

access to the brain and cervical spinal cord and, at the same time, satisfactory reconstruction of the head. The scalp flaps are then reflected forwards and backwards and the inner aspect is examined for the presence of edema and hemorrhage. After instrumental deliveries, subgaleal or subaponeurotic hemorrhage may be present. The size of the anterior fontanelle and width of the sutures is then noted. The appearance and shape of the skull bones and the presence of any defects are documented, including position, size, and any protruding tissues. If there are any fractures, their position, extent, and appearance should be noted. In some skeletal dysplasias, the skull bones may be very thin and even soft. Severe craniotabes in rickets may present with a completely fibrous and pliable calvarium. The posterior flap of the scalp is reflected to expose the occipital bone and cervical vertebrae. After removing the soft tissues and muscle, the posterior aspect of the atlas will become visible. This can be carefully removed by cutting the bone on either side, thus exposing the upper spinal canal (Figure 1.5). A small sterile needle can then be carefully inserted into the canal to obtain a sample of the cerebrospinal fluid (CSF), if required. Alternatively, the dura can be incised and the CSF obtained using a sterile pipette. The cervical vertebral laminae can then be removed as far down as desired to obtain an adequate length of cervical spinal cord (approximately 5 cm is adequate for routine examination). The cord can then be divided and separated from the nerve roots and dura. The incision in the dural covering of the cord can be extended upwards till the foramen magnum. This would expose any downward displacement of the cerebellum in cases of spina bifida and brain swelling. The cranial cavity is then opened by making parallel incisions in the anterior fontanelle away from the midline. This is to ensure that the sagittal sinus is not damaged. The incisions are then extended forwards and backwards on either side of the midline. The frontoparietal and parieto-occipital sutures are then cut on each side. Care should be taken in all these steps that the scissor point is kept up against the bone to avoid damaging the brain. The frontal and parietal bones can then be opened in order to expose the brain. The cerebral gyral pattern is inspected and compared with what is expected for gestation. The normal gyral pattern is maintained in macerated stillbirths and growth-restricted babies and can be used to estimate gestation and the time of death. The gyri may

7

Chapter 1: Perinatal autopsy, techniques, and classifications

(c)

(a)

*

(b)

Figure 1.5 Sampling the cerebrospinal fluid (CSF). (a) After reflecting the skin, the skeletal muscle at the back of the neck is removed to expose the atlas (asterisk). The bone is cut using a suitably sized bone cutter. (b) The top of the spinal canal is exposed after removing the posterior aspect of the atlas. (c) The CSF is sampled using a sterile needle.

8

be flattened in cases of severe hydrocephalus, and in case of edema in neonates. The gyral pattern may be abnormal in certain malformations. The presence, site, and size of any subdural or subarachnoid hemorrhage should be documented. The brain is then taken out underwater (or saline, if available). This technique is useful in all perinatal post mortems, especially small and macerated fetuses, because the water will support the brain and free the prosector’s hands to separate the brain from the dura.

Depending on the size of the fetus, the entire body can be submerged under water if the fetus is small, or only the head can be tipped backwards so that the weight of the brain is supported by the water as it falls backwards from the cranial cavity. After opening the skull bones, the sagittal sinus is divided anteriorly and lifted backwards. The head of the fetus is tilted backwards until the frontal lobes begin to fall away from the frontal bones. The brain can be gently teased backwards using the scalpel blade or a brush until the olfactory bulbs

Chapter 1: Perinatal autopsy, techniques, and classifications

and optic chiasma appear. These can be divided, allowing the brain to fall further backwards. This will gradually expose the front of the brainstem and the cranial nerves can be divided from the pons and medulla. When the tentorium appears it can be separated from the occipital bone by cutting it as close to the bone as possible. This will allow the cerebellum to fall backwards. With further tilting of the head backwards, the entire brain will fall onto the occipital bone and into the water. The dura can be inspected for any hemorrhage and tears, especially in the posterior falx and tentorium, which can be damaged during delivery. Very macerated brains can be removed with the dural coverings intact in order to preserve as much as possible of the brain. The brain, with its coverings, is then fixed prior to examination. If the brain is fixed within the dura, the weight of the dura should be subtracted from the total weight before comparing with appropriate tables. In cases of suspected hydrocephalus or posterior fossa abnormalities such as Dandy–Walker malformation, the brain should be removed using the posterior fossa approach (Figure 1.6). After reflecting the scalp, the occipital bone is carefully removed by cutting the sutures around it. The bone is then carefully lifted and separated from the underlying dura. This is to ensure that the cerebellum and potential underlying structures such as a Dandy– Walker cyst are preserved. The laminae of the upper cervical vertebrae can then be cut on either side to expose the upper cervical spine. The presence of an Arnold–Chiari malformation would be confirmed after this step. The contents of the posterior fossa and upper cervical spine are inspected and photographed before removal of the brain is attempted. This is particularly important when the fetus is macerated and if a cyst is present, as it is quite likely that any abnormality would be lost as the brain is removed. The cervical spinal cord is then divided and brain can be taken out using the method described above. The fetal and neonatal brains should be fixed prior to examination, unless the family explicitly states that they want the brain to be returned to the body immediately after the post mortem examination. Babies’ brains are soft due to higher water content and incomplete myelination. If they are cut in the fresh state, they will simply collapse and much useful information will be lost. For example, it would be extremely difficult to

Figure 1.6 Opening the skull using the posterior approach to view the contents of the posterior fossa and cervical spine.

diagnose or differentiate between severe hydrocephalus and holoprosencephaly (Figure 1.7). In addition, the presence and extent of any intraventricular hemorrhage would be impossible to ascertain. A fresh brain would have to be cut in thick slices and focal abnormalities may be missed. A rough guide for the minimum length of fixation is 2–3 days for fetuses of around 20 weeks gestation and 5–6 days for term babies and neonates. The brain can be fixed in 10% or 20% formaldehyde following department protocols.

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Chapter 1: Perinatal autopsy, techniques, and classifications

Figure 1.7 A case of alobar holoprosencephaly. This would be difficult to diagnose/confirm in a fresh non-fixed brain.

After fixation the brain is inspected further and any abnormalities noted on the initial inspection can be confirmed. The cerebellum and brainstem can then be detached by an incision across the junction of the upper pons and midbrain. This allows the presence and patency of the aqueduct to be confirmed. The forebrain and hindbrain can then be weighed if required. The cerebellum is separated from the pons and medulla and the presence and completion of the vermis is confirmed. The cerebellar hemispheres are then divided to reveal the dentate nucleus. The pons and medulla are serially sliced and sampled. The cerebrum is sliced coronally from the basal aspect, starting at the level of the mammillary bodies. Each slice should be no more than 1 cm thick.

The spinal cord

10

The spinal cord in fetuses and neonates can be removed by an anterior or a posterior approach. The anterior approach is convenient as it does not involve making extra incisions in the body and the vertebral column is easily accessible after evisceration. An intervertebral disc in the lower lumbar region is divided in the coronal plane. The vertebral pedicles on each side are then divided using a small bone cutter until the vertebral bodies can be lifted to expose the spinal cord. The pedicles are divided on each side in turn up to the top of the cervical spine. It is useful for subsequent reconstruction to leave the vertebral bodies attached to the top of the spine. The filum terminale is then divided and elevated with forceps and the spinal

Figure 1.8 Brain removed in continuity with the spinal cord in a case of spina bifida.

nerve roots divided on either side, taking care not to cut the dura. This protects the spinal cord and makes handling easier. As the brain has already been removed, the spinal cord will be freed once all the spinal nerve roots have been cut. In cases of spina bifida and Chiari malformation, the spinal cord can be removed in continuity with the brain using the posterior approach. The skull is opened using the posterior fossa approach as above. The skin incision already made on the back of the neck is extended down the entire spine. The vertebral laminae are then cut on either side to expose the spinal cord. This can be freed and the brain removed as above, with the cord attached (Figure 1.8).

Bones In routine perinatal post mortem examinations, the anterior aspect of the fifth or sixth rib, including the adjacent costochondral junction, should be taken for histological examination. This allows the assessment

Chapter 1: Perinatal autopsy, techniques, and classifications

of the bone, growth plate, and bone marrow (if not autolyzed). In cases of skeletal dysplasia, examination of other bones, in addition to the rib, will be required. Two to three vertebral bodies and a humerus or femur are usually examined. The vertebrae can be removed after evisceration as described for removing the spinal cord. The femur can be removed by making an incision along the lateral aspect of the thigh. The muscles can be divided longitudinally to expose the hip joint and the femur. The hip joint capsule can then be incised and the femoral head mobilized by cutting the ligament of the head of the femur. The proximal end of the bone is then grasped and the muscle dissected away from the bone. The knee joint capsule is then opened and knee joint ligaments divided. The femur can then be removed, fixed in formalin, and decalcified. A small piece of a thin catheter or a matchstick can be used to reconstruct the leg.

Skeletal muscle In cases of arthrogryposis, skeletal muscles from various limbs, in addition to the psoas muscle, will need to be examined. In small fetuses the triceps and thigh muscles from both upper and lower limbs can be sampled by making a small incision on the lateral aspect of the limb. The muscle is then sent for histology, freezing, biochemical analysis, and possible electron microscopy.

The placenta Examination of the placenta is an essential part of the perinatal post mortem. In fact, the post mortem examination is incomplete without the placenta, especially in miscarriages, stillbirths, and early neonatal deaths. Placental examination is discussed in detail in Chapter 2.

Reconstruction of the body Agreeing to a post mortem examination on their baby is a difficult decision for the family. Therefore, every effort should be made to preserve the body and return it to the family in a presentable condition, as many families will want to view the body after the post mortem examination. Reconstruction starts even before the post mortem examination has taken place. The body should be adequately refrigerated (at 4 °C) to prevent decomposition and delay post mortem skin changes. After the post mortem is carried out, the organs will be returned

to the body and the incisions sutured or glued, depending on the size of the fetus. The body is then washed, hair dried (if applicable), and dressed. Any other belongings, e.g., toys or teddy bears, will then be returned to the referring hospital or family together with the body (Figure 1.9).

Histology With the exception of malformations, the macroscopic appearance of fetal organs in most perinatal post mortems does not give specific information. For example, it is impossible to differentiate between maceration, congestion, and inflammation in the lungs of a macerated stillbirth. Therefore, histological examination of fetal organs is an essential part of the post mortem examination. Apart from identifying a cause or mechanism of death, assessing maturation of the various tissues can give clues about the approximate gestation of the fetus. In addition, in cases where there is a question of whether a fetus is growth restricted or has been dead for a long period in utero, assessing tissue maturation would help to decide between the two possibilities. Diagnosing viral infections such as cytomegalovirus is always possible, even in the most macerated babies. Table 1.2 shows the routine histology samples required in a perinatal post mortem examination, in addition to the placenta.

Ancillary investigations Cytogenetics There is a debate about which perinatal post mortem cases should have a chromosomal analysis, mainly because most departments do not have the resources to test every case. Babies with malformations and very small fetuses where dysmorphic features may not be apparent should have chromosomal analysis. The yield from normally formed stillbirths and neonatal deaths is low [10], and therefore should not be carried out routinely. There is a 48–72 hour window for samples to be taken from the baby (usually skin from the chest at the main incision site or the axilla) using a sterile technique. In macerated fetuses, sampling the placenta may provide a better chance of obtaining a result. If routine culture fails, some laboratories can use fluorescence in situ hybridization (FISH) analysis to look for certain chromosomal aneuploidies on paraffin sections from fetal tissues.

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Chapter 1: Perinatal autopsy, techniques, and classifications

Table 1.2 Routine histology samples in a perinatal post mortem examination Brain (at least cortex, thalamus/basal ganglia, hippocampus, midbrain, pons, medulla, and cerebellum) Thymus Thyroid and trachea Lungs (one sample from each lobe in bigger babies) Heart (one sample from right and left ventricular myocardium) Small and large intestines Stomach

Microbiology There are many studies in the literature investigating the value of microbiological studies (both bacteriology and virology) in the perinatal post mortem, with varying results. In our unit we are very selective in carrying out microbiological studies, with the exception being neonatal deaths and in cases where a specific possibility was raised in the post mortem request form, e.g., mother is group B streptococcus positive. In such cases a blood culture (from the heart) and lung and/or splenic swabs can be obtained.

Liver (one sample from each lobe) Pancreas

Frozen tissue

Spleen

Retention of small unfixed frozen tissue samples may be very useful if further investigations need to be carried out, e.g., molecular genetics or microbiological studies. In some departments a frozen tissue sample from all perinatal post mortem cases is kept in case it is needed. If the family agrees, those are kept indefinitely for possible use in research, audit, and quality control.

Adrenals Kidneys Gonad Skeletal muscle (psoas) Costochondral junction

(a)

(b)

(c)

12

Figure 1.9 Reconstruction of the body after a post mortem examination. (a) and (b) The body and scalp incisions are sutured. (c) The body is washed and dressed, and united with any personal belongings brought by the family.

Chapter 1: Perinatal autopsy, techniques, and classifications

Otherwise, the samples will be either disposed of or put into paraffin blocks and returned to the family after the case is reported, depending on parental wishes.

Metabolic investigations These can be carried out in neonatal death cases if there is a suspicion of a metabolic disorder. Ideally, samples for metabolic studies should be taken prior to or as soon as possible after death. Samples that may be required will depend on the suspected disorder, but skin for fibroblast culture, blood spots on a Guthrie card, urine, and CSF would be a useful starting point. Heart, liver, kidney, skeletal muscle, and possibly brain samples can be snap frozen and kept for possible investigations. A skeletal muscle sample can also be taken and stored in gluteraldehyde for possible electron microscopy. Prior discussion with metabolic disease specialists and/or chemical pathology colleagues is invaluable in deciding on the timing of sampling, samples required, transport media, etc.

Classification of perinatal deaths Introduction The aim of classifying perinatal deaths is to derive strategies to understand the reason for, and ultimately prevent, perinatal mortality [11]. More specific purposes of classifying perinatal death include aiding parental counseling, improving practice, education, research, health service planning, and policy development. Good classification systems allow regional, national, and international comparisons for epidemiological, clinical practice and prevention strategies. A good pregnancy outcome is the result of complex interactions between the mother, the placenta, and the fetus; often, there are multiple factors that contribute to perinatal mortality, rather than a single defined cause. This has made accurate classification of perinatal deaths an extremely difficult process. More than 30 classification systems for perinatal mortality have been introduced since the 1950s [1,2,12–14]. Different systems were designed with varying aims, approaches, definitions, and levels of complexity. No single system is perfect and comparing different systems is difficult. The proportion of

unexplained stillbirths range from 7% to 82%, depending on the classification system used [12]. A good classification system must be easy to use by clinicians and pathologists, have clear uniform definitions, take into account clinical factors and autopsy findings, including placental examination, has to have a low inter-observer variability, be easy to expand in terms of subclassification with scientific developments, explain the underlying cause of death while taking into account factors that may have contributed to death, be suitable for stillbirths as well as neonatal deaths, and result in a high percentage of classifiable causes and a low percentage of unexplained cases [12,15].

Current classification systems Two of the oldest, and often cited, classification systems, the Aberdeen classification and Wigglesworth classification, are simple to use. However, they classify perinatal death from the clinical point of view and do not require autopsy findings, including placental examination. As a result, they have a high proportion of unexplained deaths (as high as twothirds) [14]. More recent classification systems such as the Relevant Condition at Death (ReCoDe) and Tulip adopted a different approach, integrating both clinical and autopsy findings, including placental findings. The ReCoDe system is a hierarchical classification that identifies the relevant condition at the time of death (Table 1.3). It does not address the underlying cause or mechanism of death, i.e., it identifies what went wrong, not necessarily why. The system allows more than one diagnosis to be included. The Tulip classification allows classification of underlying causes and mechanisms of perinatal mortality (Tables 1.4 and 1.5). The cause of death is defined as the initial pathophysiological entity initiating the chain of events that has irreversibly led to death. The mechanism of death is defined as the organ failure that is not compatible with life, initiated by the cause of death. Both the ReCoDe and Tulip classification systems are more complex than earlier classifications, but they have a lower percentage of unexplained deaths (15% and 11%, respectively). They also have a useful subcategory distinguishing between unexplained deaths “despite thorough investigation” and unexplained deaths because “important information

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Chapter 1: Perinatal autopsy, techniques, and classifications

Table 1.3 Relevant condition at death (ReCoDe) classification

Table 1.3 (cont.)

Group A: fetus

Group H: trauma

Lethal congenital anomaly

External

Infection

Iatrogenic

Non-immune hydrops

Group I: unclassified

Isoimmunization

No relevant condition identified

Feto-maternal hemorrhage Twin–twin transfusion Fetal growth restriction* Group B: umbilical cord

No information available * 30 neutrophils per high-power field in the chorionic plate, three or more subchorionic micro abscesses (masses of neutrophils at least 10 × 20 cells) in either the membranes or the chorionic plate, or an extensive, thick (more than ten cells wide), continuous band of neutrophils occupying more than half of the subchorionic fibrin or one revolution of the membrane roll. Severe necrotizing chorioamnionitis

Chapter 2: Placental examination

shows features of both necrotizing and severe acute chorioamnionitis. Multiple grading systems have been proposed, and there is no single system that is used widely. However, fetal infection is more likely, particularly when pre-term, in the presence of “severe” acute chorioamnionitis and fetal vasculitis compared to less severe forms. Some placental pathologists will identify the inflammation as “early” or “late.” In our opinion there is no way to determine that a small amount of inflammation connotes an earlier response to amniotic fluid infection compared to a large amount of inflammation – this depends on the type of organism as well as the bacterial burden. For this reason we avoid the use of the terms early and late. One common question is what diagnosis should be rendered when neutrophils are only present in the chorion. The authors choose to call this acute chorioamnionitis for two reasons: The first is that obstetricians typically are more familiar with the term acute chorioamnionitis than acute chorionitis; the second is that, if you look hard enough and take enough sections, there will eventually be a neutrophil in the amnion. The fetal response to bacterial organisms in the amniotic fluid is reflected by neutrophils, and occasional eosinophils, particularly in the pre-term infant, emanating from fetal vessels in either the chorionic plate or umbilical cord. Chorionic plate vasculitis is manifest by neutrophils extending from the vascular lumen through the vessel wall toward the amniotic fluid. For this reason, the inflammation is asymmetric; that is, it is more prominent on the side by the amniotic fluid rather than the side of the vessel by the placental parenchyma (Figure 2.8, inset). It, too, can be defined as “severe” if the neutrophils within the wall are confluent and associated with attenuation and/or degeneration of the vascular smooth muscle cells, on the side of the vessel facing the amniotic cavity. Severe acute inflammatory lesions in the chorionic plate vessels, especially when associated with fresh fibrin thrombi, are an independent predictor of neurologic impairment at term, so they should be noted as a specific category separate from simple acute chorionic plate vasculitis (Figure 2.9). Inflammation in the umbilical cord may be diagnosed as funisitis, regardless of location in the cord, or may be separated into vasculitis, which means inflammation within the vessel wall, and funisitis,

Figure 2.9 A chorionic plate vessel contains intense suppurating inflammation in the vascular wall, and a fresh fibrin thrombus attached to the endothelium.

which means inflammation into Wharton jelly. Umbilical vasculitis is defined as neutrophils, with or without eosinophils, in the walls of the umbilical vessels. The cells often appear to be migrating toward the surface of the cord, similar to the asymmetric appearance of inflammation in chorionic plate vasculitis. The number of involved vessels may be included within the diagnostic line. The modifying term “severe” can be included if the neutrophils within the wall are confluent and associated with attenuation and/or degeneration of the vascular smooth muscle cells, on the side of the vessel facing the amniotic cavity. Funisitis is diagnosed when neutrophils extend from the vessel wall into the Wharton jelly. The modifier “necrotizing” should be included if neutrophils, cellular debris, and eosinophilic precipitate are arranged in a concentric band or arc around one or more umbilical vessels [8]. Mineralization may also be present, which may render the term “calcific” appropriate. These findings are associated with congenital syphilis, candidiasis and severe bacterial infection. They might have been noted in the gross examination as a dilated vein or perivascular white lines on the cut surface of the cord. Peripheral funisitis is a category of funisitis in which scattered, punctate micro abscesses are seen on the surface of the umbilical cord, typically associated with Candida spp. [9] (Figure 2.10). Fungal stains should be performed if fungal organisms are not seen on hematoxylin and eosin (H&E) staining. Rarely, peripheral funisitis may be seen in association with bacterial organisms.

29

Chapter 2: Placental examination

Figure 2.10 Peripheral funisitis is characteristic of Candida infection. An intense inflammatory response is present at the periphery of the cord, known as peripheral funisitis. The inset shows characteristic pseudohyphae.

Uncommon inflammatory lesions containing suppurating inflammation The most common place to find acute inflammation in the placenta is the fetal membranes, chorionic plate, and within the walls and adjacent to large fetal vessels. However, inflammation may also be found within the villi, termed acute villitis. Acute villitis is associated with fetal sepsis in the severely pre-term fetus, and may be associated with bacteria in the fetal vessels in the setting of pre-term fetal demise. In addition, acute villitis is a feature of congenital syphilis (see below) and has been described in bacterial infection with other spirochetes and uncommon bacteria, as well as a component, albeit rarely, of chronic villitis of unknown etiology. Acute villitis may also be a minor component of acute intervillositis, with or without micro abscesses. This finding is most commonly seen with Listeria monocytogenes infections, and Gram stains should be obtained. Other organisms rarely associated with this picture include Campylobacter fetus, Chlamydia psittacae, Francisella tularensis, Mycobacterium tuberculosis, and Coccidiodes immitis. Subacute chorioamnionitis is a mixed infiltrate of mononuclear cells and degenerating neutrophils seen in the chorionic plate, predominantly in the upper portion of the plate. It is a unique entity and has been associated with bronchopulmonary dysplasia [10]. For effects of these inflammations in the newborn see Chapter 17.

Chronic inflammatory lesions 30

Chronic inflammation in the placenta is common, but often undiagnosed. While a small focus of chronic

villitis is typically not of importance, unless having an infectious etiology, more extensive chronic villitis may portend fetal growth restriction, neurologic impairment, fetal demise, and the potential for recurrence. Non-infectious chronic villitis is typically a “third trimester” lesion, occurring most commonly after 35 weeks gestation. If chronic villitis is seen in placentas from earlier gestations, infection becomes a greater possibility. Chronic villitis is exemplified by a lymphocytic, plasmacytic, and/or histiocytic infiltrate within the stroma of the terminal villi [11]. Chronic villitis occurs in approximately 15% of placentas sent for pathologic evaluation. Approximately 5% of cases of chronic villitis can be attributed to infections (cytomegalovirus, T. gondii, T. pallidum). Ninety-five percent of placentas with chronic villitis have no defined infectious origin and are therefore called “villitis of undetermined etiology” (VUE). The lymphohistiocytic infiltrate in VUE consists of maternal cells and the lymphocytes are predominantly maternal CD8+ cells. At a low power (4×–10× objective), chronic villitis will hopefully catch the observer’s eye in that the villi involved by the villitis appear more “blue” than “red” (Figure 2.11a). This is because the small capillaries are constricted and there are increased numbers of nuclei because of the inflammatory infiltrate. Chronic villitis/ intervillitis has the appearance of something “sticking” to the villi. One can see intervillous monocytes and lymphocytes destroying the trophoblast on the periphery of the villi. Fibrin is deposited in these areas and some call this “inflammatory fibrin” to differentiate it from the perivillous fibrinoid, which is not associated with inflammation. Chronic villitis can be graded. One grading scheme is listed below, taken from Placental Pathology [1]. Focal: one cluster of ≤10 affected villi Multifocal: >1 cluster of ≤10 affected villi Patchy: cluster of >10 affected villi, involving ≤25% of all terminal villi Diffuse: clusters of >10 affected villi, involving >25% of all terminal villi Using this grading scheme, chronic villitis was divided into low-grade (focal and multifocal) and high-grade (patchy and diffuse), as suggested by Redline and compared to fetal and placental weight at birth, cord pH G (p.K329E) mutation accounts for 85% of this disease in most of Western Europe, although numerous other mutations have been described.

Medium chain acyl-CoA dehydrogenase deficiency Medium chain acyl-CoA dehydrogenase deficiency (MCADD) was first described in the early 1980s and is the commonest fatty acid oxidation defect occurring in central Europe, but is also present in other populations throughout the world. The first crisis is fatal in up to 25% of cases, patients classically presenting with hypoketotic hypoglycemia [8,10]. However, a significant percentage of genetically predisposed patients remain asymptomatic throughout life. The disease is primarily of hepatic fatty acid oxidation. Clinically, patients may present with lethargy, emesis, encephalopathy, respiratory arrest, hepatomegaly, seizures, apnea, and cardiac arrest. Although hypoglycemia with “inappropriate” hypoketosis is usually the major presenting biochemical feature, some patients may present with hypotonia and reduced consciousness while still maintaining blood glucose concentration within the normal range. Patients presenting in crisis may often have detectable ketones in their urine. Rarely, MCADD patients may present in crisis with “paradoxically” gross ketosis. Some patients presenting initially as SIDS (sudden infant death syndrome) have subsequently on biochemical testing been shown to have MCADD [10] (Figure 8.2). Babies can present within the first few days of life as a sudden death. Mean age at presentation in Europe is 13 months, presentation after the age of five

Other fatty acid oxidation defects Following the description of MCADD there has been considerable growth in our knowledge of previously undescribed FAODs, with some 17 or so defects that directly or indirectly affect fatty acid oxidation having now been reported. This group of disorders is now widely recognized as being an important cause of acute metabolic decompensation and sudden death in the neonatal period, infancy, and early childhood [2,4,18]. Two main types of presentation are most commonly observed. The first is characterized by hypoketotic hypoglycemia after a period of prolonged fasting. Patients may present acutely with a life-threatening illness, which may rapidly proceed to coma and death in the newborn period (Figure 8.3), or later in childhood during intercurrent infections, surgery, or other catabolic stress, having apparently

Post mortem sample (DBS) PM041213032 1 (2.010) Sm (SG, 2x0.75); Sb (0,40.00) 100 260.4 2614177

13-Dec-2004 Parents of 85ES+ 2.61e6

218.3 2253057

C8 ~ 8.4 μm/L (PM