Frederick R. Jelovsek MD
Involuntary weight loss is defined as a decrease of at least
5% of body weight in a 6 month period that isn't due to
dieting, diuretic use or medical diseases known to affect
weight. If you are overweight, you may wish for this, but if
you or a friend are losing weight unintentionally, it needs
to be diagnosed so there is not an increased risk of disease
or dying. Many times, involuntary weight loss is associated
with elderly adults but it is possible to happen to anyone.
Up to 8% of patients presenting to primary care physicians
complain of weight loss. In 25% of those, no cause for the
weight loss is ever found.
A recent review paper, Bianchi A, Toy EC, Baker B III:
The evaluation of involuntary weight loss. Prim Care
Update Ob/Gyns 1998;5:263-267, categorized
three basic causes of weight loss:
- decreased intake - the most common cause, most often in
teenagers and elderly adults
- increased fluid-nutrient loss - associated with
malabsorption and diabetes
- excess metabolic demand - malignancies often associated
with gastrointestinal tract, genitourinary system and breast
It is important to document the fact that weight loss is
taking place. Believe it or not, many who complain of
involuntary weight loss have no weight change by objective
documentation. There are some factors, however, that are
diagnostic predictors of underlying illness:
-
recent change in cough
- nausea or vomitting
- a 20 pack-year history of smoking
- a recent change in appetite
- a decrease in activity due to fatigue
- an abnormality on physician's physical examination
If the cause of weight loss is not obvious, the physician
should check initial laboratory tests including CBC, HIV,
blood chemistry, urinalysis, thyroid function, chest xray
and routine recommended cancer screening. The following
specific diseases may be present.
Diseases Causing Involuntary Weight Loss
| Category | examples |
Decreased intake | |
| gastrointestinal disease | peptic ulcer,
cholelithiasis
|
| malignancy | G.I., ovarian |
| eating disorders | anorexia, bulemia nervosa
|
| hyperemesis gravidarum | |
| poor dentition | |
| social isolation or poverty | |
| depression or dementia | |
| substance abuse | alcohol, cocaine,
amphetamines
|
| medications | digitalis, theophylline,
procainamide |
| age-related changes | |
| infection | HIV |
| systemic diseases | |
Increased fluid-
nutrient loss | |
| malabsorption | |
| persistent diarrhea | |
| recurrent vomitting | |
| fistulous drainage | |
| medications | cholestyramine, laxatives |
| pancreatic insufficiency | |
| infection | giardiasis |
| inflammatory bowel disease | Crohn's disease,
diverticultits |
| uncontrolled diabetes mellitus | |
Excess metabolic demand | |
| hyperthyroidism | |
| tumor of adrenal gland | pheochromocytoma |
| malignancy | disseminated, metastatic |
| fever and/or infection | malaria, TB, HIV |
| manic or anxiety states | |
| trauma and burns | |
| excess exercise | |
| systemic disease | |
In one fourth of patients with this problem, no diagnosis
will be found. Another one fourth will have malignancies. Of
the remaining 50%, half will have depression or some
psychiatric disease and half will have a medical cause.
Although sometimes malignancies are found as a cause of
involuntary weight loss, most of the time
there are specific treatments that are successful for the
remaining people without malignancies.
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