Fetal autopsy

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The fetal autopsy is done to determine the cause of death in a fetus. An introduction to the autopsy is in the autopsy article.

External exam

Post-mortem changes

Sequences of changes with intrauterine death:[1]

  • Normal ~0-12 hours.
  • Skin blistering - usu. prominent on head ~12-48 hours.
  • Moderate skin separation (sloughing) - usu. hands & feet ~48-72 hours
  • Massive skin separation and loosing of symphysis menti (midline mandible), symphysis pubis ~72+ hours.

Common measures[2]

  • Body mass (weight).
  • Crown-to-heel length.
  • Crown-to-rump length.
  • Occipito-frontal circumference.
  • Chest circumference - at nipples.
  • Abdominal circumference - at umbilicus.

Routinue sections

  1. Rib.
  2. Thymus, skin, diaphragm, psoas muscle.
  3. Rectum, duodenum, ileocecal region, mesentery.
  4. Adrenal gland.
  5. Kidney.
  6. Bladder.
  7. Internal genitalia.
  8. Spleen.
  9. Stomach, GE junction, GD junction, pancreas.
  10. Liver.
  11. Right lung.
  12. Left lung.
  13. Heart.
  14. Upper airway with thyroid.
  15. Pituitary.

Microscopic

Adrenal gland

  • Centre regresses.

Adrenal fetal fat pattern

  • Can be access with oil red O staining.

The pattern of adrenal fat is informative about duration of stress prior to (intrauterine) demise:[3]

  • Pattern I: scant fat/fat only close to medullary zone; acute death/no stress reaction.
  • Pattern II: widespread fat; subacute death/moderate stress reaction.
  • Pattern III: massive fat - fetal zone and cortex; chronic death/marked stress reaction.

Additional ref.: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1545415/pdf/archdisch00800-0007.pdf.

Kidney

  • Cortex regresses.
  • Nephrogenic rests.[4]

Lung

Thymus

  • Hassall's corpuscles (thymic corpuscle).

Image:

Amniotic rupture sequence

  • AKA amnion rupture sequence.

General

The term encompasses:[5]

  • Amniotic band syndrome.[6]
  • Amniotic adhesion sequence.
  • Limb-body wall complex - characterized by ventral body wall defects.[7]

Etiology:

  • Congenital.
    • Thought to arise due to an amniotic tear in the first trimester.[8]
    • Karyotypes are usually normal.

Gross

Features:

  • Autoamputation of appendages and body wall defects +/- anomalies of internal organs.
  • +/-Fibrous bands (seen cases labelled amniotic band syndrome).

Images:

Developmental stuff

Neural tube defects

  • Anencephaly - top of head missing.
  • Spina bifida.
    • Spina bifida cystica.
      • Meningocele - less severe, herniation of only the membrane.
      • Myelomeningocele - more sever, herniation of membranes and cord.
    • Spina bifida occulta.

Chiari malformations

Numbered from least severe to most severe:

  • Chiari type I - tonsils herniated[9] (radiologic definition: 4-6 mm below the plane of the foramen magnum).
    • Associated with: sudden death, sleep apnea, cerebellar ataxia.
  • Chiari type II - often assoc. with hydrocephaly at birth.
  • Chiari type III - cerebellum + brain stem herniate through foramen magnum +/- encephalocele.[10]
  • Chiari type IV - cerebellar hypoplasia or no cerebellum.

Dandy-Walker syndrome

  • AKA Dandy-Walker malformation (DWM).
  • Prevalence: ~ 1/5000 live borns.
  • Diagnosis: ultrasound.

Features:[11]

  • Complete or partial agenesis of the vermis.
  • Cystic dilatation of the fourth ventricle.
  • Large posterior fossa.
  • +/-Hydrocephalus.
  • +/-Elevation of cerebellar tentorium.

DDx:

  • Arachnoid cyst.
  • Blake's pouch cyst - on a contiunuum with DWM.[12]

Growth parameters

Main article: Growth charts

See also

References

  1. ↑ Burton, Julian L.; Rutty, Guy N. (2010). The Hospital Autopsy A Manual of Fundamental Autopsy Practice (3rd ed.). Oxford University Press. pp. 191. ISBN 978-0340965146.
  2. ↑ Burton, Julian L.; Rutty, Guy N. (2010). The Hospital Autopsy A Manual of Fundamental Autopsy Practice (3rd ed.). Oxford University Press. pp. 196, 198. ISBN 978-0340965146.
  3. ↑ Becker MJ, Becker AE (September 1976). "Fat distribution in the adrenal cortex as an indication of the mode of intrauterine death". Hum. Pathol. 7 (5): 495–504. PMID 964978.
  4. ↑ URL: http://www.wilmstumour.com/rests.asp. Accessed on: 28 March 2011.
  5. ↑ URL: http://moon.ouhsc.edu/kfung/jty1/neurotest/Q11-Ans.htm. Accessed on: 26 October 2010.
  6. ↑ Lin, HH.; Wu, CC.; Hsieh, FJ.; Hsieh, CY.; Lee, TY. (Dec 1989). "Amniotic rupture sequence: report of five cases.". Asia Oceania J Obstet Gynaecol 15 (4): 343-50. PMID 2624577.
  7. ↑ Prasun, P.; Behera, BK.; Pradhan, M.. "Limb body wall complex.". Indian J Pathol Microbiol 51 (2): 255-6. PMID 18603699.
  8. ↑ Jamsheer, A.; Materna-Kiryluk, A.; Badura-Stronka, M.; Wiśniewska, K.; Wieckowska, B.; Mejnartowicz, J.; Balcar-Boroń, A.; Borszewska-Kornacka, M. et al. (Mar 2009). "Comparative study of clinical characteristics of amniotic rupture sequence with and without body wall defect: further evidence for separation.". Birth Defects Res A Clin Mol Teratol 85 (3): 211-5. doi:10.1002/bdra.20555. PMID 19180633.
  9. ↑ URL: http://rarediseases.info.nih.gov/GARD/Disease.aspx?diseaseID=9230. Accessed on: 6 May 2011.
  10. ↑ URL: http://www.ninds.nih.gov/disorders/chiari/detail_chiari.htm. Accessed on: 6 May 2011.
  11. ↑ URL: http://moon.ouhsc.edu/kfung/jty1/neurotest/Q12-Ans.htm. Accessed on: 26 October 2010.
  12. ↑ Calabrò, F.; Arcuri, T.; Jinkins, JR. (Apr 2000). "Blake's pouch cyst: an entity within the Dandy-Walker continuum.". Neuroradiology 42 (4): 290-5. PMID 10872175.
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