Page 311 - Problem-Based Feline Medicine

17 – THE CAT WITH WEIGHT LOSS AND A GOOD APPETITE 303

INTRODUCTION WHAT?
The most common cause of weight loss with a good
MECHANISM? appetite is hyperthyroidism. Other common causes
include various malassimilation syndromes including
While weight loss is a common presenting problem in
combinations of inflammatory bowel disease, pancre-
feline medicine, weight loss in association with a
atitis and/or lymphocytic cholangiohepatitis (in combi-
good appetite is seen less frequently. This occurs
nation termed “triaditis”). Intestinal parasitism,
when the cat is unable to gain sufficient nutrition
diabetes and alimentary lymphosarcoma are seen
from its diet.
reasonably commonly, while hyperadrenocorticism,
This can result from inadequate nutrition (feeding acromegaly, protein-losing nephropathy and lymphang-
insufficient food or a diet of inadequate nutritional con- iectasia are seen very rarely.
tent), or an inability to derive nutrient from the diet.
Disorders which may occasionally present with weight
The latter can result from:
loss with a good appetite, but more typically present
● Inability to digest or absorb nutrients (malassim-
with a poor appetite are discussed elsewhere, e.g. con-
ilation syndromes), e.g. parasitism, inflammatory
gestive heart failure, congenital portosystemic shunts.
bowel disease, pancreatitis/exocrine pancreatic
insufficiency, lymphocytic cholangiohepatitis, ali-
mentary lymphosarcoma or lymphangectasia. DIAGNOSIS
● Inability to utilize absorbed nutrients – as seen
Initial diagnostic evaluation should include history,
with diabetes mellitus, or endocrinopathies which
physical examination, hematology, serum biochem-
result in diabetes, e.g. acromegaly or hyperadreno-
istry, serum thyroxin if > 8 years of age, urinalysis, and
corticism.
fecal examination for parasites.
● Increased utilization of absorbed nutrients
(hypermetabolic states), e.g. hyperthyroidism, Age of cat is an important consideration. Younger
pregnancy, lactation, congestive heart failure, cats are more likely to develop parasitism, inappropriate
excessive physical activity or neoplasia. nutrition, or protein-losing nephropathy. Middle-aged
● Excessive nutrient loss, e.g. diabetes mellitus, cats have a greater risk of hyperadrenocorticism, while
protein-losing nephropathy or lymphangectasia. older cats develop hyperthyroidism, diabetes mellitus,
alimentary lymphosarcoma or acromegaly. Inflammatory
bowel disease can affect cats of any age, but most typi-
cally affects middle-aged or older individuals.
WHERE?
The history is essential. Determine the cat’s environ-
Weight loss with a good appetite may be seen when the ment (inside or outside, competition over food sup-
intestinal tract is unable to digest and/or absorb plies), what and how much is fed, whether nutritional
food (malassimilation syndromes, hyperthyroidism), requirements have changed (pregnancy, going outside
the body tissues are unable to utilize nutrition that in cold weather), or whether diabetogenic drugs have
has been absorbed (diabetes mellitus), the body loses been given.
essential nutrients through the intestines or kidneys
Other clinical signs are important to consider. These
(diabetes, protein-losing nephropathy, lymphangecta-
signs may result from underlying or concurrent disease
sia), or the demands of the body have been raised
processes. Polyuria and/or polydipsia are suggestive
beyond the level that the diet can supply (hyperthy-
of an endocrinopathy or protein-losing nephropathy.
roidism, pregnancy, lactation).
Vomiting and/or diarrhea are suggestive of enteric
Weight loss with a good appetite indicates a gastroin- disease, hyperthyroidism, lymphocytic cholangiohep-
testinal problem, renal problem or a problem- atitis or protein-losing nephropathy. Feces becoming
involving tissue metabolism (either metabolic bulky or fatty suggest malassimilation syndromes or
demands have increased, or the tissues are unable to hyperthyroidism, and increased aggression or restless-
utilize nutrients). ness are suggestive of hyperthyroidism.