Page 589 - The Veterinary Laboratory and Field Manual 3rd Edition

526 Samuel Sharpe

Figure A2.14 Abdomen, dog. Bile imbibition: The liver Figure A2.15 Liver, sheep. Pseudomelanosis. The
is on the left side of the picture (*) and the left liver liver is viewed from the caudal surface with the ven-
lobe has been retracted to reveal the orange green tral aspect at the bottom of the picture. The right and
gallbladder (†). There has been extensive imbibition of quadrate lobes are noticeably darker in colour than
bile pigment into the serosa of the adjacent stomach the rest of the liver consistent with build up of iron
(‡). Note the bland appearance of the affected tissue sulphide in the tissues as a result of post-mortem
with no signs of an inflammatory response which bacterial overgrowth. Note also post-mortem emphy-
would have been present had bile leakage occurred sema in the wall of the gallbladder. See also Plate 53.
pre-mortem. See also Plate 52. Photo: courtesy of Mr Photo courtesy of Mr R. Irvine, University of Glasgow,
R. Irvine, University of Glasgow, UK. UK.

green discolouration of surrounding tissues. barbiturate salt precipitate
This must be differentiated from pre-mortem
bile leakage which is a serious clinical issue. In If euthanasia is performed by the intravenous
post-mortem bile imbibition, the affected tis- administration of barbiturates characteristic
sues appear bland and homogenously stained lesions are associated. Pentobarbital is solubi-
(Figure A2.14). Bile is very irritant and so when lized in glycerol and ethanol which can impart
leakage occurs pre-mortem it is associated with a strong alcoholic smell to tissues of euthanized
significant inflammation producing a localized animals. In addition, the solution has a low
or diffuse peritonitis. pH and will coagulate blood into a gritty, pale
brown paste particularly in the right ventricle.
Barbiturates will also come out of solution and
Pseudomelanosis crystallize on the endocardial surface or on the
pleura or other parts of the lungs if direct intra-
Activity of bacteria involved in autolysis can pro- cardiac injection is attempted (Figures A2.16
duce iron sulphide which will impart a very dark and A2.17).
grey-black colour to tissues and should not be
confused with increased pigmentation (Figure
A2.15). Melanosis is sometimes seen as sharply
demarcated areas of black discolouration in oth-
erwise unremarkable organ particularly in lungs
and meninges.

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