14
Fetal, Perinatal, and Infant Autopsies
350
Although many pathologists feel less confident about performing “baby”
post mortems, these are in fact comprising an increasingly high proportion of the autopsy workload. Contrary to popular belief, they are not more dif- ficult than adult autopsies, but do require a number of extra techniques to be performed routinely. This chapter aims to cover the basic techniques required for fetal, perinatal, and infant post mortems.
The chapter is organised in much the same way as the rest of the book, and includes:
• Aspects to consider before the post mortem
• External examination
• Evisceration and block dissection
• Organ dissection in systems
• Special techniques used in perinatal and infant autopsies
• Taking samples for ancillary investigations, including histology
• Examination of the placenta
• Estimation of gestational age and growth
• Demonstration of post mortem findings
• Determining the cause of death
• Writing the report
Although it has been impossible to be fully comprehensive, the chapter covers all techniques that are likely to be necessary outside of a special paediatric pathology centre. Post mortem examinations of children older than 2 years of age do not differ greatly from adult autopsies and are not considered further.
Introduction
The age at which a fetus becomes legally viable is defined either by the ges-
tational age or by the body weight, and varies from country to country. In
the United Kingdom, a gestational age of 24 weeks is the lower limit of legal
viability, regardless of body weight at birth. Obviously all fetuses who have shown “signs of life” are also considered legally viable, regardless of their body weight or gestation, although the survival rate of fetuses under 24 weeks is low. Although technically post mortem examinations can be con- ducted only on legally viable fetuses, most pathologists would perform peri- natal post mortems on fetuses of a gestational age greater than about 16 weeks or a body weight greater than 400 g. Although such nonviable fetuses are actually surgical specimens and therefore written consent is not legally required, it is considered good practice to obtain consent for a post mortem in the usual way. For fetuses between 400 g and 25 g a “mini-post mortem”
can be performed and below 25 g a longitudinal sectioning method can be employed. Examination of the placenta is also an essential part of the autopsy of a perinatal case. Most perinatal and neonatal autopsies are hospital cases; however, infant post mortems may be medico–legal cases if the cause of death is not known.
Performance of Post Mortems
In many countries, including the United Kingdom, perinatal and paediatric pathology is a specialised branch of histopathology, requiring further formal training and often an examination before one is eligible to practise.
Unfortunately, there is currently a worldwide shortfall in the number of histopathologists in general, and perinatal and paediatric pathologists in particular, although this shortage is most acute in the United Kingdom.
This has led to more and more perinatal post mortems being performed by general histopathologists. A recent report into fetal and perinatal pathol- ogy in the United Kingdom [1] has reiterated the importance of perinatal and paediatric pathology as a separate discipline, but until more such pathologists can be trained, has recognised the need for uncomplicated perinatal post mortems to be performed by nonspecialised pathologists.
It recommends that in each unit without a specialised pathologist one
of the general pathologists act as a “lead pathologist” who is responsible
for implementing appropriate protocols, attending mortality meetings,
auditing quality of the post mortem service, and participating in con-
tinuing medical education on this subject. It is suggested that such “lead
pathologists” should have access to at least 50 perinatal cases per year to
maintain an appropriate level of expertise, which in many U.K. hospitals
means that, in practice, only one general histopathologist should be
performing all of the perinatal post mortem work per hospital. Post
mortems on infants and young children should be performed by specialised
perinatal and paediatric pathologists. If nonaccidental injury is strongly
suspected, the case should be treated as a suspicious death and the
post mortem examination performed by either by a perinatal and paedi-
atric pathologist with a forensic interest or in partnership with a forensic
pathologist [2].
Consent
As discussed in Chapter 1 (see p. 18), the United Kingdom has recently had to deal with issues surrounding the retention of whole organs at post mortem in perinatal cases. This began with the Royal Liverpool Children’s Hospital inquiry [3], and has since led to similar inquiries elsewhere in the United Kingdom [4,5]. A Retained Organs Commission was formed by the Department of Health in 2001 as a Special Health Authority within the NHS (National Health Service). Their aims are to deal sensitively and comprehensively with the organs and tissues that have already been retained and to guide future legislation to prevent similar events occurring again, in the hopes that this will restore public confidence in the post mortem system. This has led to significant changes in post mortem consent procedures, in both adult and fetal/perinatal cases. Now most countries have adopted a new and much more detailed consent form (see Fig. 14.1 for the form currently used in the United Kingdom for fetal and perinatal post mortems). Any ancillary investigation in a hospital post mortem needs specific consent from the next of kin. Furthermore, the next of kin must also be asked whether any organs or tissues removed can be kept by the pathologist for storage or later disposal or must be returned to the body. In the latter case, this may lead to a delay in funeral arrangements, and this must also be discussed with the relatives. Separate further consent is required for all purposes other than diagnosis, for example, for teaching and/or research. The next of kin can also limit both the examination and sampling by specifying which parts of the body/organs are not to be exam- ined or used. In addition, of course, the use of human tissue for research would also have to be approved by the appropriate regulatory authority, for example, a research ethics committee in the United Kingdom or an insti- tutional review board in the United States. In the United Kingdom, a new Human Tissue Bill is currently going through Parliament [6] and is intended to replace the previous Human Tissue Act of 1961 [7]. This will require written consent for diagnosis on all tissue or fluid specimens, and is likely to require separate permission for nondiagnostic usage, such as teaching or research. Although, at least in the United Kingdom, such consent is already in use for post mortem tissue, the bill as it is currently written requires any nondiagnostic usage to be specified. This may mean that retrospective research on stored tissue will no longer be possible without further consent, and this is likely to impinge on any future research that uses post mortem tissue.
In medico–legal post mortems, ancillary investigations are permitted only
if they are required to establish the cause of death, and it is the duty of the
pathologist to see that such investigations are completed. Specific consent
is required from the coroner or equivalent, and they are also responsible
for setting a time limit for sample retention, in discussion with the pathol-
ogist. As for hospital cases, relatives must be consulted as to whether they
Figure 14.1. The consent form used throughout the United Kingdom for a hospi- tal post mortem examination on a baby or child. (Reprinted with permission from the Department of Health, London; HMSO, 2003.)
Figure 14.1. Continued
Figure 14.1. Continued
Figure 14.1. Continued
Figure 14.1. Continued
Figure 14.1. Continued
would like the samples returned to the body or disposed of, although in this context they have no legal say in the undertaking of the investigation itself, as it is necessary to establish the cause of death. These issues are legally enshrined in the United Kingdom under the Coroner’s Rules and later Coroner’s Act [8,9]. The recent changes in hospital post mortem consent, however, have led to most coroners or equivalents requiring additional consent from the next of kin, even though this is not strictly speaking nec- essary in law at the present time. This consent may be sought by coroners or equivalents, or they may ask the pathologist or clinician concerned to obtain consent themselves. If ancillary investigations are desired by the pathologist or clinician, but are not necessary to identify the cause of death, then by law the coroner or equivalent can refuse consent but is unable to give it, and therefore consent must be sought from the relatives in exactly the same way as in a hospital post mortem. There has been a recent review of the Coronial service in the United Kingdom [10] which is likely to lead to a new Coroner’s Act in the next few years. It is anticipated that the service will undergo significant changes, particularly around issues of death certification, and this will inevitably have implications for medico–legal post mortem work in the future.
Definitions
Embryo 1 to 8 weeks gestation Fetus 8 weeks gestation to term
Stillbirth Intrauterine/intrapartum fetal death after the age of legal viability, i.e., born with no “signs of life”
Figure 14.1. Continued
Perinatal Stillbirths + neonates in first week after birth Early neonatal First week after birth
Neonatal First month after birth Post perinatal Between 1 week and 1 year Post neonatal Between 28 days and 1 year
Infant From 1 week of age to 2 years of age
Preterm <37 weeks gestation or weight less than <2500g at birth
Term 37 to 41 weeks of gestation Post term >42 weeks of gestation
Small for dates Weight at birth <10
thcentile expected for gestational age
Very low birth Weight at birth <1500g weight
Premature Preterm, small for dates and very low birth weight Intrauterine Weight/other parameters <10
thcentile expected for
growth gestational age
retardation
Before the Post Mortem
As with all post mortems, the clinical details must be obtained wherever possible, usually from the mother’s and (if liveborn) the baby’s hospital notes. Such information should include:
• Mother’s age, parity, and ethnic origin
• Family history, including hereditary disease and multiple pregnancies
• Gestational age at birth
• Data on any relevant maternal illnesses
• Details of previous pregnancies
• Full details of the present pregnancy, including LMP (last menstrual period) and EDD (estimated date of delivery) by dates and scans
• Full details of labour and mode of delivery In addition, if liveborn:
• Birthweight
• State of infant at birth
• Any resuscitation measures
• Neonatal course In addition, if an infant:
• Details of any childhood illnesses and vaccinations
• Details of the death and the preceding events
In addition, if a termination of pregnancy (TOP) for fetal abnormality:
• A copy of the scan report for comparison with the post mortem findings Although the basic autopsy varies little, there are various special investi- gations that may or may not be necessary, depending on the particular case.
These include photography, whole body X-ray films, bacteriology, virology, metabolic studies, and chromosome analysis. At least some of these are per- formed in each case, and exactly which to carry out is best decided before the post mortem is started to avoid poor technique. It is best to follow standard guidelines or protocols methodically in each case, whether they be national or have been produced locally as required. In this way, all neces- sary data will be available for retrospective analysis and mistakes of omis- sion will be avoided. Figure 14.2 is an algorithm of perinatal post mortem procedures.
Whole-Body Radiography
This is particularly useful in the investigation of the following conditions, although in many departments it is done routinely in all cases. Two views are usually obtained, an AP (anteroposterior) and lateral.
• Chondrodysplasias
• Osteogenesis imperfecta
• Skeletal trauma
• Skeletal anomalies
• Gas—pneumothorax, necrotising enterocolitis
• Abnormal calcifications
• Estimation of gestational age via ossification centres (see p. 409)
Case Examples
Some case examples follow, with lists of the appropriate special investiga- tions. If such investigations were performed during life, however, it is not always necessary to repeat them at post mortem, although as discussed on p. 326 repeat bacteriological analysis is always useful in septic deaths to identify or confirm the origin of the sepsis.
Isoimmunization
• Blood for haematological examination (e.g., grouping, Coombs’ test, and testing against maternal serum)
Nonimmunological Hydrops
• Arrange blood sample from mother for Kleihauer test
• Photography
Figure14.2.A representation of the perinatal post mortem as a sorting process.HMD,Hyaline membrane disease; IVH,intraventricular haemorrhage;NND,neonatal death;SB,stillbirth.(Reprinted with permission from Wigglesworth JS.Perinatal pathology.Philadelphia:WB Saunders,1996;p.39).
• Whole-body radiography
• Blood and bronchial/tracheal swab or lung for bacteriology
• Placenta for bacteriology
• Lung or bronchial/tracheal swab for virology
• Comprehensive histology
• Blood for haematological investigation (e.g., grouping, Coombs’ test, and testing against maternal serum)
• Blood for viral serology [e.g., TORCH (toxoplasmosis–rubella–
cytomegalovirus–herpes virus)] test and B19 (parvovirus)
• Tissue for cytogenetics
• Retention of liver sample frozen
Multiple Malformation/Dysmorphic Facies
• Photography
• Whole body X-ray films
• Tissue for cytogenetics
• Blood and tracheal/bronchial swab or lung for bacteriology
• Placenta for bacteriology Skeletal Dysplasia
• Whole body X-ray films
• Photography
• Histology sample from trachea and epiphysis of a long bone
• Tissue for cytogenetics/fibroblast culture Twins
• Assessment of zygosity via pattern of placentation
• If vital, assessment of zygosity via haematological investigation (e.g., blood group or DNA analysis)
• If monochorionic, assessment of possible twin to twin transfusion (by examination of vascular communications in the placenta, using barium injection into umbilical cord of donor twin if necessary)
Suspected Infected Baby
• Blood sample for bacteriology
• Bronchial/tracheal swab or lung sample for bacteriology and virology
• Heart and spleen samples and cerebrospinal fluid (CSF) for bacteriology and virology
• Placental sample for bacteriology if stillbirth or perinatal death Stillbirth
• Assessment of interval between intrauterine death (IUD) and delivery, i.e., degree of maceration
• Infection screen (as for infected baby)
Genetic Metabolic Disease
• Whole body X-ray films
• Tissue for cytogenetics/fibroblast culture
• Retention of urine, CSF, and plasma for biochemistry
• Blood sample for haematology (smear to assess presence of vacuolated lymphocytes)
• Comprehensive histology, including bone marrow and fat stains on frozen sections
• Samples of liver, kidney, brain, and placenta for electron microscopy
• Retention of frozen samples of skin, placenta, muscle, brain, liver, spleen, and kidney
Preterm Infant
• Infection screen (as for infected baby) IUGR (Intrauterine Growth Retardation)
• Infection screen (as for infected baby)
• Tissue for cytogenetics
SUDI (Sudden Unexpected Death in Infancy)
• Photography
• Whole body X-ray film
• Vitreous humor sample for urea/electrolytes/osmolality
• Samples of blood, CSF, intestinal contents, and bronchial/tracheal swab or lung for bacteriology
• Samples of heart, intestinal contents and lung or bronchial/tracheal swab for virology
• Immunofluorescence for RSV (respiratory syncytial virus) on a tracheal tissue block
• Refrigerate stomach contents, serum, and urine for potential toxicology
• Freeze samples of skin, liver, muscle, spleen, kidney, and brain for possi- ble enzyme studies
• Comprehensive tissue for histology and possible electron microscopy (including fat stains on a frozen section of liver)
• Skin for tissue culture
• Blood for haematology (smear to look for toxic lymphocytes)
• Examination of middle ear for sepsis Fetal Anomaly Not Diagnosed Prenatally
• Photography
• X-ray film
• Tissue for cytogenetics/fibroblast culture
Neonatal Death
• Whole body X-ray film (for diagnosis of pneumothorax)
• Infection screen (as for infected baby)
External Examination
A careful external examination should be made to assess any external abnormality. In perinatal cases, the shape of the head, the facies, the palate, the number of digits, the external genitalia, the patency of the anus, and the continuity of the spinal column should be assessed. A probe should be passed through each nasal orifice to exclude posterior choanal atresia and into each external ear to ensure patency. The eyes should be examined for evidence of icterus and conjunctival haemorrhage.
Evidence of external trauma should also be looked for, particularly with reference to the obstetric and neonatal history. All bruises, needle punc- tures, forcep blade marks, surgical incisions, and so forth should be noted.
Any tubes or catheters should be left in situ for later examination. It is often easiest to cut these flush with the skin. This allows later dissection to assess their siting and provides a means of resetting the site (by placing cut end flush with skin again) if they are inadvertently moved during examination.
The apparent state of nutrition and any evidence of cyanosis, pallor, jaundice, oedema, and meconium staining should be assessed. A search for petechial haemorrhages should also be made, both on the skin (particularly of the head and upper chest) and on the conjunctiva and mucous mem- branes of the oral cavity.
The shape of the thoracic cavity should also be assessed; a narrow cavity often indicates pulmonary hypoplasia. Interstitial emphysema should be sought in cases of neonatal death. The umbilicus should also be closely inspected.
Estimating the Degree of Maceration
In the case of stillbirths, it is important to note whether the body is fresh or macerated, and if maceration is present, the degree must be assessed to aid estimation of the time interval between IUD and delivery. There is a classification system to aid the estimation of the degree of maceration, but the changes are also affected by the ambient temperature during body storage [11]:
12 hours Skin slippage 24 hours Skin blebs
48 hours Skin sloughing and haemolysis of organs
5 days Liquefied brain, overlapping of sutures, collapse of calvarium
7 days Laxity and dislocation of joints
External Measurements
The following careful measurements should be made with a ruler and a length of string, and compared to tables of normal values (see Tables 14.1 to 14.5) to aid assessment of gestational age and allow assessment of growth retardation (see p. 408).
Essential
• Body weight
• Crown–rump length (sitting height)
• Crown–heel length (standing height)
• Foot length
• Head circumference Helpful
• Abdominal girth (at the level of the umbilicus)
• Chest circumference (at the level of the nipples)
If any abnormality is suspected, whole-body radiography and photography is advisable.
Case Examples
Some examples of major syndromes and their associated external abnor- malities follow, although are by no means comprehensive:
Oligohydramnios (from whatever cause)
• Low-set ears, a “parrot” nose, and prominent epicanthic folds
• Large, spade-like (“washer-woman’s”) hands
• Lower limbs often show distortion, hip dislocation, and talipes
• Associated internal abnormalities include renal anomalies and pul- monary hypoplasia
Trisomy 13
• Moderate microcephaly with a sloping forehead
• Eye defects including microopthalmos or coloboma
• Cleft lip or palate
• Often a capillary haemangioma over the forehead and localised scalp defects may be present over the parieto-occipital region
• Ears may be abnormally formed and low-set
• Frequently loose skin over the back of the neck
• Polydactyly is common and there are often simian creases and prominent
heels (rocker-bottom foot)
• Common internal anomalies usually involve the central nervous system (CNS), heart, and kidneys
Trisomy 18
• Often produces severe growth retardation
• Head characteristically has a prominent occiput and a narrow bifrontal diameter
• Ears are low-set and deformed, the palpebral fissures are small, the mouth is small, and there is micrognathia
• Hands are often clenched, with the index finger overlapping the fourth, and the hallux is often short and dorsiflexed
• A small pelvis may also be present, with limited adduction of the hip joints
• Common internal abnormalities include ventricular septal defect and both CNS and renal anomalies
Trisomy 21
• Brachycephaly with a flatter than normal occiput and slight microcephaly
• Face is also relatively flat with a small nose, a low nasal bridge, and inner epicanthic folds
• Palpebral fissures slant upward from inner to outer canthus
• Ears are small with overfolding of an angulated upper helix
• May be excess skin on the back of the neck and the neck itself may be short
• Hands have short metacarpals and phalanges with hypoplasia of the midphalanx of the fifth finger which often also shows clinodactyly
• This short fifth finger may have a single crease and there is often a single transverse palmar crease
• May also be a wide gap between first and second toes, with a marked plantar crease
• Pelvis is usually hypoplastic with an outward flaring of the iliac wings and a shallow acetabular angle
• Most common internal abnormalities are cardiac and gastrointestinal anomalies
Triploidy
• Variable degree of growth retardation with microophthalmi, colobomata, and low-set malformed ears
• May also be hypertelorism and micrognathia
• Syndactyly of third and fourth fingers, a single transverse palmar crease and talipes are also common
• Internal abnormalities include CNS, cardiac, and renal anomalies
Table14.1.Means and standard deviations of weight and measurements of liveborn infants GestationBodyCrown-Crown-Toe-BrainThymusHeartLungsSpleenLiverKidneysAdrenalsPancreas (weeks)weightrumpheelheel(g)(g)(g)(g)(g)(g)(g)(g)(g) (g)(cm)(cm)(cm) 2038118.325.63.6490.82.811.50.722.43.71.80.5 ±104±2.2±2.2±0.7±15±2.3±1.0±2.9±0.3±8.0±1.3±1.0±0.5 2142619.126.73.85713.212.90.724.14.220.5 ±66±1.2±1.7±0.1±8±0.3±0.4±2.8±0.2±4.2±0.7±0.5 224732027.84651.23.514.40.825.44.720.6 ±63±1.3±1.6±0.4±13±0.3±0.6±4.3±0.4±5.2±1.5±0.6±0.3 2352420.828.94.2741.43.915.90.826.65.32.10.7 ±116±1.9±3.0±0.5±11±0.7±1.3±4.9±0.4±8.0±1.8±0.8±0.4 2458421.6304.4831.54.217.40.92862.20.8 ±92±1.4±1.7±0.3±15±0.7±1.0±5.9±0.5±7.1±1.8±0.8±0.5 2565522.531.14.6941.84.7191.129.76.82.20.9 ±106±1.6±2.0±0.4±25±1.2±1.2±5.3±1.6±9.8±1.9±1.4±0.3 2673923.332.24.810525.220.61.332.17.62.41 ±181±1.9±2.4±0.7±21±1.1±1.3±6.3±0.7±10.9±2.5±1.1±0.5 2783624.233.451182.35.822.11.735.18.62.51.2 ±197±2.5±3.5±0.5±21±1.2±1.9±9.7±1.0±13.3±3.0±1.1±0.5 289492534.55.21322.66.523.72.138.99.72.71.4 ±190±1.7±2.3±0.6±29±1.5±1.9±10.0±0.8±12.76±12.0±1.2±0.5 29107725.935.65.414737.225.32.643.510.931.5 ±449±2.8±4.4±0.8±49±1.9±2.7±12.6±0.9±15.8±4.4±1.2±1.0 30121926.736.75.71633.58.126.93.349.112.33.31.7 ±431±3.3±4.2±0.7±38±2.6±2.6±20.3±2.0±18.8±8.5±2.7±1.0 31137527.637.85.91804928.5455.413.73.71.8 ±281±3.8±3.1±0.7±34±3.4±2.8±13.2±1.2±17.3±5.2±1.3±0.6
32154328.438.96.11984.710.130.24.762.515.24.12 ±519±9.5±5.7±1.1±48±3.6±4.4±19.0±5.4±30.0±7.4±1.7±0.8 33154328.438.96.11984.710.130.24.762.515.24.12 ±519±9.5±5.7±1.1±48±3.6±4.4±19.0±5.4±30.0±7.4±1.7±0.8 34190530.141.16.52376.112.433.56.478.718.55.12.3 ±625±4.3±4.0±0.6±53±3.8±2.8±16.5±3.0±30.2±9.3±2.2±1.1 35209330.942.36.72576.913.735.27.287.420.15.62.5 ±309±2.0±2.9±0.4±45±4.5±3.6±20.5±5.2±30.6±10.9±2.8±0.6 36228031.843.46.92787.71536.98.196.321.76.12.6 ±615±3.9±5.9±1.1±96±5.0±5.1±17.5±3.1±33.7±6.8±3.1±0.7 37246232.644.57.12988.416.438.78.8105.123.36.62.8 ±821±5.0±7.0±1.2±70±5.6±5.7±22.9±6.4±33.7±9.9±3.3±0.9 38263433.545.67.3318917.740.69.5113.524.87.13 ±534±3.2±5.1±0.8±106±2.8±5.4±17.1±3.5±34.7±7.2±2.9±1.1 39278934.346.77.53379.419.142.610.1121326.17.43.3 ±520±1.9±4.4±0.5±91±2.5±2.8±14.9±3.5±39.2±4.9±2.5±0.5 40292235.247.87.73569.520.444.610.4127.927.37.73.6 ±450±2.8±4.2±0.8±79±5.0±5.6±22.7±3.3±35.8±11.5±3.0±1.3 4130253648.97.93729.121.746.810.5133.128.17.83.9 ±600±3.1±5.4±0.8±65±4.8±10.9±26.2±4.5±55.7±12.7±2.8±1.5 42309136.9508.13878.122.949.110.3136.428.77.84.3 ±617±2.4±3.8±1.1±61±3.8±6.2±14.6±3.6±38.9±9.7±3.2±1.9 Complied in 1988 by CJ Sung and DB Singer with 1975–1984 data from Woman and Infant’s Hospital,Providence,Rhode Island (with permission from Singer DB,Sung CJ,Wingglesworth JS.Textbook of fetal and perinatal pathology,edition 2.Editors Wigglesworth JS and Singer DB.Blackwell Scientific Publications,1998;28)
Table14.2.Means and standard deviations of weight and measurements of stillborn infants GestationBodyCrown-Crown-Toe-BrainThymusHeartLungsSpleenLiverKidneysAdrenalsPancreas (weeks)weightrumpheelheel(g)(g)(g)(g)(g)(g)(g)(g)(g) (g)(cm)(cm)(cm) 2031318.024.93.3410.42.47.10.3172.71.30.5 ±139±2.0±2.3±0.6±24±0.3±1.0±3.0±1.0±9±2.9±0.6±0.1 2135318.926.23.5480.52.67.90.4183.11.40.5 ±125±4.8±3.6±0.6±18±0.3±0.9±3.8±0.6±7±1.3±0.7±0.4 2239819.827.43.8550.62.88.70.5193.51.40.6 ±117±9.6±2.5±0.4±15±0.4±0.9±3.1±0.4±10±0.8±0.6±0.5 2345020.628.74640.839.50.7214.11.50.7 ±118±2.3±3.3±0.5±18±0.5±1.4±5.7±0.5±7±1.7±0.8±0.3 2451021.529.94.2740.93.310.50.9224.61.50.7 ±179±3.1±4.3±0.8±25±0.7±1.8±5.6±0.7±8±2.4±0.8±0.3 2558122.331.14.4851.13.711.61.2245.31.60.8 ±178±4.0±6.5±0.8±31±0.8±1.3±4.9±0.4±35±2.4±0.8±0.7 2666323.232.44.7981.44.212.91.5266.11.70.8 ±227±4.1±5.3±0.9±37±1.4±2.2±8.7±1.1±16±3.6±0.9±0.7 2775824.133.64.91121.74.814.41.92971.90.9 ±227±2.9±3.2±1.4±37±1.1±3.6±9.7±1.0±24±3.1±1.5±0.3 2886424.934.95.112725.416.12.3327.92.11 ±247±2.2±5.6±1.2±39±2.1±2.6±7.0±1.1±32±2.5±1.6±0.3 2998425.836.15.31432.46.2182.73692.41.1 ±511±4.1±5.9±1.2±57±2.6±2.4±13.6±2.0±23±4.5±1.2±1.2 30111526.637.35.61602.8720.13.14010.12.71.2 ±329±2.4±3.6±0.7±72±4.1±2.8±8.6±1.5±22±6.0±1.3±0.2 31125927.538.65.81783.2822.53.64611.331.4 ±588±3.0±2.7±0.7±32±1.9±3.1±10.1±4.0±38±4.1±1.8±1.4
32141328.439.861963.79.1254.25212.63.51.6 ±623±2.8±5.4±0.6±92±2.2±4.1±10.7±2.4±32±8.0±1.8±0.6 33157829.241.16.22164.310.227.84.75813.93.91.8 ±254±3.5±3.1±0.4±51±1.5±2.0±5.8±2.3±17±3.5±1.4±0.8 34175030.142.36.52364.811.430.75.56615.34.42 ±494±3.5±4.3±0.8±42±5.6±3.2±15.2±2.5±22±5.1±1.3±0.5 35193030.943.56.72565.412.633.75.97416.74.92.3 ±865±3.9±5.8±0.9±70±3.4±5.3±14.3±6.8±46±7.1±1.9±0.7 36211431.844.86.92776.113.936.76.58218.15.42.6 ±616±4.0±7.2±0.8±94±4.1±5.8±16.8±2.9±36±6.3±2.4±2.6 37230032.7467.22976.715.139.87.29119.45.82.9 ±647±5.1±7.9±0.9±69±3.9±9.9±11.1±6.3±57±9.7±6.2±3.1 38248533.547.37.43177.416.442.97.810020.86.33.2 ±579±2.6±3.9±0.8±83±6.1±4.4±15.7±5.9±44±6.0±2.1±1.6 39266734.448.57.63378.117.545.88.5109226.73.5 ±596±3.7±4.9±0.5±132±4.7±3.9±15.2±4.5±53±5.8±5.3±1.9 40284235.249.77.83558.918.648.69.211823.173.9 ±482±6.4±3.2±0.7±57±4.3±12.9±19.4±4.1±49±8.6±2.9±1.7 41300636.1518.13739.619.551.19.912624.17.14.2 ±761±3.7±5.4±0.8±141±5.6±4.9±17.0±4.5±53±10.5±3.0 42315636.952.28.338910.420.353.210.613524.97.24.5 ±678±2.0±3.0±0.5±36±5.0±4.5±10.1±3.7±54±8.1±2.9±2.3 Complied in 1988 by CJ Sung and DB Singer with 1975–1984 data from Woman and Infant’s Hospital,Providence,Rhode Island (with permission from Singer DB,Sung CJ,Wingglesworth JS.Textbook of fetal and perinatal pathology,edition 2.Editors Wigglesworth JS and Singer DB.Blackwell Scientific Publications,1998;29)
Table14.3.Weight,Length,and Organ Weights in Fetuses from 9 to 20 Weeks of Development DevelopmentalWeightCrown-RumpHeartLungsLiverKidneysAdrenalsBrainNo.of Age (days)(g)Length (cm)(g)(g)(g)(g)(g)(g)Cases 631130.10.10.20.10.11.230 671340.20.30.70.10.11.527 711560.20.40.80.10.12.615 732070.30.41.10.20.14.321 762570.40.71.10.20.24.814 793080.41.01.30.20.25.415 843590.51.42.00.30.26.214 894590.51.92.50.40.47.422 9050100.51.93.00.50.58.523 9160100.52.53.40.60.61021 9270110.63.03.60.80.61124 9680110.73.04.30.80.6127 10090120.93.04.70.90.71415 105100121.13.95.61.40.71728 109125131.34.17.41.40.72321 115150141.45.39.21.40.82320 117175141.45.6111.80.82327 118200151.77.2122.21.13339 124250162.29.1152.71.23937 130300172.410173.11.54643 133350182.911213.82.05431 143400183.411234.22.26132 From Valdés-Dapena M,Kalousek DK,Huff DS:Perinatal,fetal and embryonic autopsy.In Gilbert-Barness E (ed):Potter’s Pathology of the Fetus and Infant.St.Louis:Mosby,1997,pp 483–524.
Table14.4.Means and Standard Deviations of Body Length and Weights of Organs of Male Infants,1 to 12 Months AgeBodyHeartLungs,LiverPancreasKidneys,AdrenalThymusSpleenBrainNo.of (mo)Length(g)Combined(g)(g)CombinedGlands,(g)(g)(g)Cases (cm)(g)(g)Combined (g) 151.4 ±3.223 ±764 ±21140 ±406.2 ±3.634 ±95.1 ±1.77.8 ±5.312 ±4460 ±4756 254.0 ±2.927 ±774 ±26100 ±467.2 ±4.439 ±95.0 ±1.69.4 ±4.415 ±5506 ±6753 357.7 ±2.930 ±789 ±23179 ±417.7 ±3.145 ±105.0 ±1.310 ±516 ±5567 ±8143 460.4 ±4.131 ±796 ±27195 ±4111 ±547 ±124.9 ±2.010 ±617 ±5620 ±7142 562.0 ±3.135 ±593 ±18228 ±4711 ±454 ±115.3 ±1.912 ±718 ±7746 ±9140 664.2 ±3.940 ±8115 ±31259 ±5811 ±562 ±145.2 ±2.010 ±620 ±7762 ±7347 766.7 ±5.043 ±8118 ±33276 ±5412 ±669 ±145.5 ±2.112 ±923 ±10767 ±3227 868.2 ±3.444 ±8104 ±32285 ±5713 ±766 ±145.4 ±2.310 ±620 ±7774 ±9527 969.4 ±4.245 ±7109 ±33288 ±4716 ±767 ±165.4 ±2.010 ±422 ±5820 ±4925 1069.7 ±5.946 ±6110 ±34300 ±6914 ±672 ±175.7 ±2.19 ±524 ±11850 ±9620 1170.5 ±4.348 ±7130 ±31305 ±8116 ±376 ±196.1 ±1.819 ±428 ±10875 ±8916 1273.8 ±4.150 ±6116 ±23325 ±3914 ±676 ±136.3 ±2.212 ±528 ±7954 ±3519 From Schulz DM,Giordano DA,Schulz DH:Weights of organs of fetuses and infants.Arch Pathol 1962;74:244–250.
Table14.5.Means and Standard Deviations of Body Length and Weights of Organs of Female Infants,1 to 12 Months AgeBodyHeartLungs,LiverPancreasKidneys,AdrenalThymusSpleenBrainNo.of (mo)Length(g)Combined(g)(g)CombinedGlands,(g)(g)(g)Cases (cm)(g)(g)Combined (g) 151.9 ±4.521 ±564 ±27139 ±315.0 ±1.831 ±84.8 ±1.96.6 ±4.911 ±4433 ±5928 254.0 ±3.726 ±674 ±23159 ±317.1 ±2.936 ±104.7 ±1.45.8 ±4.714 ±5490 ±5139 357.0 ±3.728 ±481 ±14183 ±398.5 ±3.242 ±124.8 ±1.49.7 ±6.915 ±5525 ±8936 459.0 ±3.730 ±691 ±24204 ±499.0 ±3.050 ±114.6 ±2.19.0 ±7.317 ±5595 ±8029 562.2 ±3.336 ±5102 ±22227 ±3811 ±352 ±134.8 ±2.213 ±519 ±5725 ±6224 663.0 ±3.037 ±7111 ±30242 ±5811 ±458 ±204.6 ±1.610 ±618 ±8730 ±8523 765.4 ±4.240 ±9111 ±38272 ±5110 ±365 ±145.5 ±2.210 ±822 ±8750 ±9221 860.5 ±4.541 ±7109 ±35276 ±5411 ±560 ±135.3 ±2.38 ±520 ±9770 ±9624 968.3 ±4.741 ±5105 ±28288 ±6714 ±562 ±105.4 ±1.59 ±518 ±6810 ±8215 1067.5 ±4.243 ±7105 ±21284 ±4813 ±666 ±100.7 ±1.712 ±725 ±11830 ±11714 1170.5 ±3.144 ±8125 ±31292 ±3614 ±768 ±146.2 ±2.015 ±823 ±9875 ±6418 1271.5 ±4.749 ±6115 ±34315 ±3815 ±872 ±196.0 ±1.411 ±827 ±9886 ±6415 From Schulz DM,Giordano DA,Schulz DH:Weights of organs of fetuses and infants.Arch Pathol 1962;74:244–250.
Turner’s Syndrome
• Usually a small stature, a low posterior hairline, and a short neck with webbing or loose skin folds
• Anomalous ears, a narrow maxilla, a broad chest with widely spaced nipples, cubitus valgus, and lymphoedema
• Internal abnormalities include ovarian dysgenesis and renal and cardiac anomalies
Meckel–Gruber Syndrome
• A posterior encephalocoele and polydactyly
• Seen in association with renal anomalies Zellweger Syndrome (a Peroxisomal Disorder)
• A large fontanelle, a high forehead with shallow supraorbital ridges and a flat occiput
• Limb contractures with camptodactyly and simian creases may also be present
• Associated internal abnormalities include CNS, liver, and renal anom- alies with excess iron storage
Beckwith–Wiedemann Syndrome
• Macrosomia, with a particularly large tongue
• Many also show a small omphalocoele and a particular crease pattern to the ear lobes
• Associated internal abnormalities are numerous and include renal, adrenal, and pancreatic anomalies
Mercury Poisoning (Minamata Disease)
• Growth retardation, microcephaly, and limb deformities Androgenic Steroids
• Female virulization of the external genitalia Anticonvulsants
• Produce oral clefts and skeletal and digital anomalies
• Associated internal abnormalities include cardiac and CNS anomalies Warfarin
• Nasal hypoplasia and skeletal anomalies
• Internal abnormalities include optic atrophy
Fetal Alcohol Syndrome
• Microcephaly, short palpebral fissures, and maxillary hypoplasia
• Joint anomalies
• Growth retardation
Rubella Infection During the First Trimester
• Growth retardation
• Microcephaly, microopthalmia, and cataracts
• Also see osteolytic lesions of bone metaphyses
• Associated internal abnormalities including cardiac, CNS, and hepatosplenic anomalies
Evisceration and Block Dissection
It is essential to have a selection of small forceps, scissors, and probes, in addition to a scalpel. A pair of scales accurate at low weights is also neces- sary. Although any of the methods described in Chapter 2 can be used to eviscerate a baby, the most common would be the method of Letulle, in which all organs are removed en bloc. Alternatively, the method of Ghon can be used, which removes the organs in functional “blocks” for later dis- section. The former technique has the advantage of keeping continuity if malformations are suspected. Despite the much smaller scale, the actual technique is much the same as that for an adult, with the exception that some of the organ dissection is best done in situ, as anomalies are easier to identify when organs and vessels retain their continuity. In this way, the techniques used are modified using some of the methods from the eviscer- ation and dissection techniques of Virchow and Rokitansky.
The previous practice of fixing and keeping the whole organ blocks for later dissection is no longer acceptable and should not be done unless there are good diagnostic reasons to do so, and appropriate consent has been obtained.
Initial Stages of Evisceration
Several incisions are possible; however, the best involves an inverted Y, with
a central cut from below the chin to just above the umbilicus and then two
branches, one down to each inguinal fossa. This allows good exposure of
the umbilical arteries. A straight incision as in the adult can be used in a
postnatal case, but in a perinatal case will destroy the umbilical vessels. If
the body is to be viewed after autopsy, it is desirable to avoid any incision
in the neck, in which case the incision can be stopped at the sternal notch
and an adjoining horizontal incision made to allow removal of the neck
organs, although this is a time-consuming process from such an incision (see Fig. 14.3).
The skin and musculature should then be dissected from the thoracic cage and the upper chest and neck. This is more difficult than in the adult, as the skin is more delicate and the amount of subcutaneous tissue less. Then any pneumothorax should be identified, and is particularly likely following ventilation difficulties or the insertion of thoracic lines. The examination is performed in a similar manner to that described in the adult on p. 70. In a baby, however, it is often easier to immerse the entire body in water. An incision into the heart at the same time will also reveal any intracardiac air caused by air embolism.
Alternatively, a needle and syringe containing sterile saline can be used. If this is inserted through the chest wall, any air will escape into the syringe and be seen as bubbles. This method has the advantage of not contaminating the chest cavity prior to any sampling for microbiology.
Of course, a whole body X-ray film will also identify any pneumothorax.
Clues may also be apparent when dissecting the skin and musculature from the chest wall, as the side of the chest with a pneumothorax can appear pale.
Pneumothorax is almost invariably associated with a bulging mediastinum and interstitial emphysema.
Figure 14.3. A diagram illustrating the possible skin incisions during evisceration.
When dissecting skin and musculature off the thoracic cage the amount of subcutaneous fat and the development of the underlying musculature should be assessed. The abdominal cavity can then be opened. If an inverted Y has been used, the umbilicus will be avoided. If not, the incision should extend around the left of the umbilicus. When dissecting the abdominal wall, the umbilical vein should be opened and examined for any evidence of thrombus or bleeding sites. The number of arteries should be noted and the arteries themselves traced to their origin in the aorta. The umbili- cal vessels can then be ligated and transected. The peritoneal cavity can then be examined for any evidence of ascites, haemorrhage, or meconium.
From the abdomen, a finger should be placed inside to assess the level of the diaphragm, before the thorax is opened. The sternoclavicular joints should then be cut with a pair of scissors, following which the ribs can be similarly cut on both sides at the costochondral junction. The sternum and central portion of the ribs can now be removed to expose the thoracic contents. The pleural cavities should be inspected for petechial haemor- rhages and fluid. Lastly, the tongue and neck organs need to be freed, again in the same way as in an adult (see p. 75). This is accomplished by freeing the tongue and the floor of the mouth by incising with a scalpel around the inside of the mandible. This incision is then extended posteri- orly, to separate the hard and soft palate. The tongue can then be held with forceps, and the posterior attachments of the pharnyx and neck freed with a scalpel, from above downwards. The thoracic, abdominal, and neck organs can then be closely examined and even dissected in situ before further evisceration.
Alternatively, some pathologists prefer to leave the tongue in situ, as this produces a better cosmetic result. This can be achieved by using a scalpel to transect the pharynx at a level just above the hyoid bone, incising down to the vertebral bodies below. This releases the posterior part of the tongue, the remainder of the pharynx, the epiglottis, and the upper oesophagus. The neck structures apart from the anterior tongue can then be removed as before.
The initial stages of evisceration are summarised as follows:
• Make an inverted Y incision.
• Dissect skin and musculature from the abdominal wall.
• Check for pneumothorax.
• Open and examine the abdominal cavity.
• Open the umbilical vein.
• Identify and trace umbilical arteries.
• Ligate and transect umbilical vessels.
• Assess the level of the diaphragm.
• Cut sternoclavicular joints.
• Cut ribs at costochondral junctions.
• Expose and examine the thoracic cavity.
• Free the tongue and floor of the mouth.
• Free posterior attachments of the pharynx and neck.
Method of Letulle (Evisceration and Dissection in a Single Block)
The viscera can be removed in one block, in exactly the same way as in an adult (see p. 82). This has the advantage of retaining continuity in the case of any anomalies and does not have the disadvantage that it has in the adult, as the whole block is obviously still small enough to be easily handled.
Before removal, a detailed examination of the thoracic and abdominal organs should be made and any samples taken for microbiology. Most prosectors would also dissect the heart in situ before block removal. This dissection in situ allows easier identification of anomalies as continuity between the lungs, heart, and great vessels is maintained.
It is first necessary to dissect the thymus free, to allow inspection of the heart, taking care not to damage the brachiocephalic veins. The size of the thymus may help assess the length of time of an illness. It is normally bilobed and overlies most of the heart and the roots of the great vessels but may often also extend up the neck. The presence of petechial haemorrhages and surgi- cal emphysema should also be noted. The pericardium should then be opened anteriorly. The size and shape of the heart can then be assessed, together with the major incoming and outgoing vessels, that is, superior and inferior vena cava, azygous vein, aortic root, brachiocephalic artery, left carotid artery, left subclavian artery, pulmonary trunk, and ductus venosus.
In Situ Dissection of the Heart (See Fig. 14.4)
Careful inspection of the chambers, the free walls, and the septum should be made during these cardiac incisions.
Step 1.
The superior and inferior venae cavae are connected by an incision that starts as a nick in the lateral aspect of the superior vena cava and runs down the lateral aspect of both venae cavae and the right side of the right atrium.
Step 2.
The right atrium is opened between the origins of the superior and inferior
venae cavae, from the midpoint of the first incision. This cut can then be
continued through the tricuspid valve and along the posterior wall of the
right ventricle to end at the apex. This exposes the inflow tract of the right
side of the heart. At this point it is convenient to assess the state of the
foramen ovale by pressing on the left atrium, thus causing blood trapped
within it to press against the septum primum and occlude the opening. A
probe can then be used to touch the right side of the flap, near the normal
opening. This will cause a small amount of blood to leak into the right
ventricle and proves that the valve flap is both anatomically patent and functionally closed.
Step 3.
The incision is continued along the anterior wall of the right ventricle and through the pulmonary outflow tract. The patency of the ductus arteriosus can then be assessed by extending the incision into the ductus or by using a probe. The pulmonary arteries can also be probed at this point.
Step 4.
The pulmonary veins are connected by a transverse incision. Before this can be accomplished in situ, the inferior vena cava must be transected so that the heart can be turned over superiorly to expose the left inflow tract.
Figure 14.4. Opening the heart in situ. (a) First cut (right atrium exposed). (b) Second cut (right inflow tract exposed). (c) Third cut (right outflow tract exposed).
(d) Fourth cut (left atrium exposed). (e) Fifth cut (left inflow tract exposed). (f) Sixth cut (left outflow tract exposed). A, Aorta; IVC, inferior vena cava; LA, left atrium; LV, left ventricle; PA, pulmonary artery; RA, right atrium; RV, right ventri- cle; SVC, superior vena cava. (Reprinted with permission from MacPherson TA, Valdes-Dapena M. Textbook of fetal and perinatal pathology, 2ndedit. Wigglesworth JS and Singer DB, eds. Blackwell Scientific Publications, 1998;96.)
