Most liver function
tests usually remain normal in geriatric patients and this probably reflects the
huge reserve capacity of this organ, however, in humans bromsulphalein (BSP) retention
does increase with age.
Hepatic lipidosis is common in cats, and may or may not
be associated with obesity. Up to 50% of liver biopsies taken from cats in the USA
are reported to demonstrate lipidosis on histological examination (Davenport 1991
personal cornmunication). This condition can be secondary to diamellitus, hyperadrenocorticism,
hypothyroidism or protein-energy malnutrition and affected animals may show gross
hepatomegaly, elevated liver enzyme concentrations (serum alanine aminotransferase (ALT)
and alkaline phosphatase (AP) and disturbances of liver function.
Cirrhosis is a chronic progressive disease usually affecting
older animals resulting in loss of parenchymal mass and therefore reduced function.
Primary and secondary hepatic neoplasia may also occur, eventually causing reduced
In the presence of impaired hepatic function the plasma
clearance rate for drugs may be decreased resulting in increased duration of action.
At the same time drugs and nutrients that need to be converted to an active form
by the liver may exhibit reduced activity.