Post Mortem Examination: Why & How?

M.12, W.1, L.1

list several different scenarios when a PME might be valuable

• Diagnostic Investigation

  • identify cause of death in individual or group

• Legal Investigation

  • collect evidence for forensic/legal case

• Herd Health Investigations

• Research Purposes

• Ancillary Testing

list and describe the two basic dissection approaches to a PME:

1. Dorsal Approach

• animal positioned on back (dorsal recumbency)

• often used in small animals

2. Lateral Approach

• animal positioned on side (lateral recumbency)

• common in large animals

what do both dissection approaches involve?

• external exam

• internal exam

• In situ organ observation

• removal of organs for further inspection

List the basic steps in a PME

1. External Examination

2. Internal Examination (Dissection)

3. Lesion Identification and Description

4. Recording & Interpretation

describe what to do during external examination for a PME

• confirm ID

• record species, age, breed, and sex

• assess BCS and weight

• examine skin, orifices, limbs & joints, axillae, hips, elbows and shoulders

• look for trauma, discharges, and abnormalities

describe what to do during internal examination for a PME

• open body cavities

• observe organs in situ

• remove organs systematically

• inspect: color, size, shape, consistency, and distribution of lesions

• incise organs where appropriate

describe what to do during ‘Lesion identification & description’ for a PME (what to distinguish and how to describe lesions)

• Distinguish:

  • Normal for species or breed

  • PM changes?

  • Artefact?

• when describing lesions, include:

  • location

  • distribution

  • size

  • shape

  • color

  • consistency

describe what to do during ‘recording & interpretation’ for a PME

• document findings clearly

• interpret significance

• produce a report

why is it important to remove renal and urinary tract together?

in case of ascending infection (pyelonephritis)

• removing both systems together preserves them

Describe a sample submission for histopathology (size of tissue, what to submit it in)

• Tissue:

  • less than 1 cm in at least ONE dimension

• Submit in

  • formalin

    • 10 parts formalin: 1 part tissue

  • wide-mouth, leak-proof jar

Why does a sample for histopathology have to be less than 1 cm in at least one dimension?

so formalin can penetrate tissue

Describe a sample submission for Bacteriology/Virology (size of tissue, what to submit it in/on)

• at least 1 cm cube of FRESH tissue

• on ICE

What size sample should be submitted for toxicology test?

50g of appropriate tissue

what size and kind of sample should be submitted for parasitology testing?

100g of feces