Page 571 - The Veterinary Laboratory and Field Manual 3rd Edition

508 Samuel Sharpe

Things to note by change within the lobules, the functional
liver unit. Dark red points indicative of con-
• Weigh the liver. Values for normal liver
weights by species are published, but a good gestion of central veins and centrilobular
rule of thumb is that the liver should be about sinusoids with hepatocellular loss are sur-
4% of body weight. rounded by areas of tan pallor which come
• Lay the liver out with the cranial (surface from intact but degenerate hepatocytes swol-
facing the diaphragm) uppermost and exam- len by abundant intracellular lipid.
ine the gross anatomy ensuring that all liver • Diffusely enlarged, swollen, dark red, exu-
lobes are present. dative cut surface: this may indicate acute
• Note any marked discrepancy in size of liver venous congestion.
lobes. Note any diffuse changes in colour or • Swollen, pallid, rounded caudal borders, soft
texture: is the tissue softer or firmer than texture: accumulations of fat or glycogen
expected? Note if the caudal border of the within hepatocytes as a result of hepatocellular
liver is bulging or rounded. dysfunction or extra-hepatic disease can give
• Capsular surface: the capsular surface should the liver a swollen appearance. The tissue will
be homogenous and smooth. Look for areas be soft, friable and may have a greasy texture.
of red or tan discolouration, material adher-
ent to the capsular surface, depressions,
nodules, or mass lesions. 14 Examining the Spleen:
• Cut surface: bread loaf the organ into 1 cm
slices and carefully examine the cut sec- • The spleen is a strap-like parenchymatous
tion of each piece. The cut section should organ with a fibromuscular outer capsule. The
be homogenously dark red/orange, exude a spleen is comprised of the blood filled, sinu-
small amount of red tinged fluid, and contain soidal spaces which make up the red pulp and
cross sections of blood vessels and bile ducts. lymphoid tissue of the periarteriolar lymphatic
These will have a larger diameter closer to sheaths which is termed the white pulp.
the hilus. Note any areas of discolouration, • The ability of the splenic capsule to stretch
masses, nodules and if any of the lesions seen and red pulp sinuses to dilate and fill with
on the capsular surface extend onto the cut blood means the spleen can vary dramatically
section. in size.
• Note any thickening of vessel or bile duct • Lymphoid hyperplasia can be grossly apparent
walls. as myriad tan nodules (2–3 mm in diameter)
visible grossly on cut surface.
coMMon cHanGES tHat May bE notEd
aFFEctInG aLL or Part oF tHE LIvEr Things to note
• Small, firm, pallid: This may indicate atrophy
and fibrosis and is suggestive of a chronic If the spleen is enlarged it can be useful to char-
change following inflammation or ischaemia. acterize gross changes in the spleen into four
• Nutmeg liver: chronic passive venous conges- categories.
tion resulting from impaired venous return
to the heart is common. The name is derived 1 Diffusely soft and bloody: congestion:
from the appearance of the cut surface which
takes on a finely mottled appearance reminis- • artefact of barbiturate anaesthesia
cent of a nutmeg. The appearance is imparted • acute septicaemia: anthrax, salmonella

Vet Lab.indb 508 26/03/2019 10:26