Page 568 - The Veterinary Laboratory and Field Manual 3rd Edition

Necropsy guidelines 505

which interfere with iodine absorption from are very prone to effects of post-mortem hypo-
the GI tract or conjugation of colloid. static congestion (see section of post-mortem
• Goitre is of particular significance in small artefacts).
ruminants, pigs and cattle. Maternal iodine • For this reason, colour change can be mis-
insufficiency will result in congenital goitre leading and gentle palpation of lung tissue is
and is a cause of foetal loss, abortion and required to detect changes in texture or the
birth of weak-born neonates. presence of masses.
• Unilateral increase in size may indicate • After this the lungs should be bread loafed
benign or malignant neoplasia. via transverse sections perpendicular to the
• Of most significance in cats and dogs. mainstem bronchi.
• Cats frequently suffer from functional thyroid
neoplasia resulting in thyrotoxicosis. tHInGS to notE
• Dogs uncommonly suffer from non-functional • Excess fluid or material in airways: note char-
malignant neoplasia. Morbidity is associated acter, amount and presence of any material:
with locally invasive growth and pulmonary
metastasis. • clear fluid or foam: suggestive of oedema,
heart failure or acute alveolar damage
Parathyroids • opaque, thick, yellow-green: suggestive of
purulent exudate, acute of chronic inflam-
• Bilateral enlargement can be indicative of mation
hyperplasia resulting in secondary hyperpara- • dark red, thick: suggestive of haemor-
thyroidism: occurring as a result of dietary rhage.
deficiency of calcium or vitamin D (nutri-
tional hyperparathyroidism), or as a result of • Changes in texture: this will usually mani-
chronic renal failure (renal hyperparathyroid- fest as increased firmness of affected tissue.
ism). Note particularly the distribution of lesions
• Identification of bilateral enlarged parathy- as this can particularly useful in identifying
roids should prompt thorough examination the cause of lesions:
of the kidneys and long bones.
• Unilateral enlargement can be indicative of • diffuse: oedema or interstitial pneumo-
neoplasia or less commonly a parathyroid cyst. nia: consider left sided heart failure, viral
• Functional neoplasia can result in primary infection, toxic lung disease (for example,
hyperparathyroidism causing derangements fog fever)
in calcium metabolism and chronic depletion • multifocal: embolic process: consider
of bone mineral. septic emboli (search for primary source,
heart valves, caudal vena cava, mammary
gland) or neoplastic emboli
Lungs
• focal: inflammation (abscess versus granu-
• Lungs should be diffusely soft, air filled, pale loma) rather than primary neoplasia
pink to red. • cranioventral: consistent with broncho-
• Airways should be empty or contain a very pneumonia (see Figure A2.7a).
small amount of clear, tan fluid.
• Lungs are particularly well-vascularized with
abundant, loose interstitial tissue and as such

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