Pathology of the urinary system

NORMAL AND ABNORMAL COLORS (PIGMENTARY CHANGES) IN KIDNEYS

 

 

1) Postmortem Changes (Artifacts)

 

 

 1. 

Autolysis

  

        -  common finding at necropsy, particularly in sheep and fat animals due to retention of body 

heat; 

        -  kidneys are soft and friable (the cortex, in particular, does not have much connective tissue 

support; if cells break down, the whole parenchyma collapses). 

 

 

 2. 

Pseudomelanosis

 (livor mortis) 

        -  a common and often misinterpreted postmortem change; 

        -  dark discoloration of kidneys due to gravitational settling of blood and formation of iron 

pigments; 

        -  dark discoloration ("pseudomelanosis") occurs in autolyzed tissues when hydrogen sulfide 

(H

2

S) produced by saprophytic bacteria reacts with the iron of erythrocytes, forming black 

FeS pigment.