 Serious, involuntary weight loss indicates serious illness
underneath it
 -Loss of >10% of body weight in the last 6 months
 -Weight loss should not be considered idiopathic even if
no illness is found underneath in first evaluation
 -The patient should be followed- up with intervals until
the occult disease becomes appearent
The Mechanisms of Weight Loss
 -Increase in energy consumption
 -Increase in energy loss
 -Decrease in food intake
One or more than one of these three mechanisms may be
found in the same patient
The Occasional Causes of Weight Loss
A. Increase in energy consumption
 Hyperthyroidism
 Feochromocytoma
 Extreme exercise
B. Increase in energy loss
 Diabetes Mellitus
 Malabsorption syndromes
C. Decrease in Food Intake(I)
 Congestive heart failure
 Chronic obstructive pulmonary disease
 Chronic hepatic disease
 Neurologic diseases
 Inflammatory/autoimmune diseases
Decrease in Food Intake (II)
 Cancer
 Infections (HIV,Tuberculosis, Endocarditis)
 Hypercalcemia (Malignant diseases, Hyperparathyroidia,
Sarcoidosis)
 Uremia
 Gastrointestinal system obstruction
 Anorexia Nervosa
Decrease in Food Intake(III)
 Adrenal Insufficiency (Primary, Secondary)
 Pernicious Anemia
 Alzheimer’s Disease
 Depression
 The most frequent cause for weight loss is generally
decrease in food intake
 Decrease in food intake is generally due to loss in apetite
 Still, it may be due to obstruction of eosephagus or
stomach with a stricture or an infiltrative or obstructive
mass
Increase in Energy Loss
 may be due to:
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Diabetes Mellitus with glucosuria
Malabsorption with steatorhea
The most frequent cause for steatorhea;
Chronic pancreatitis in alcoholics
Intestinal lymphoma
Celiac Disease, inflammatory bowel disease
Islet cell tm
Obstruction of biliary tract
 If weight loss occurs inspite of increased food intake


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Diabetes Mellitus
Hyperthyroidism
Malabsorption
Rarely leukemias and lymphomas cause weight loss without
anorexia
In Adolescents
 Diabetes Mellitus
 Hyperthyroidism
 Anorexia Nervosa
 Infections (HIV etc.)
In Older People;
 Most frequent cause: Cancer
 Psychiatric disease: Alzheimer’s disease, depression
 In asymptomatic patients weight loss only may be a sign for a
occult disease
 Cancer (Gastrointestinal, pancreatic, hepatic malignancies
cause weight loss in the early period)
 Infectious diseases (sometimes only with weight loss):
Tuberculosis, HIV infection, fungal diseases, bacterial
endocarditis, hepatitis
 Alzheimer’s disease, depression, eating disorders in the early
period
 Pernicious anemia: May cause anorexia before
haematologic changes appear
 Adrenal insufficiency: In the early period; before
electrolyte imbalance, hyperemesis, vomiting and
hypotension appears, it may present with weight loss
 Parasite infections: People coming from foreign countries
Evaluating Involuntary Weight Loss
 Anamnesis
 Physical examination
Laboratory Tests
Preliminary laboratory tests:
 Full blood count, sedimentation, urine analysis, blood
biochemistry, TSH, HIV test in patients with risk, chest
radiography, stool analysis for occult blood
Secondary screening
 Abdominal CT
 In the presence of hypercalcemia: Mammography, serum
protein electrophoresis, PTH-related peptide, ACE (angiotensin
converting enzyme), 1,25 dihidroxy-vitamin D
 If there is iron deficiency anemia or melena or doubt for
inflammatory bowel disease; colonoscopy
 Upper gastrointestinal tract bleeding or dysphagia: upper
gastrointestinal tract endoscopy
 Weakness,pigmentation,hyponatremia/hyperkalemia:
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short ACTH test
Unknown fever with weight loss: blood culture
Blood culture (-): bone marrow biopsy
Chronic diarrehea: fat in 72 hours stool
Headache, neurologic symptoms, endocrine insufficiency:
Cranial CT or MRI
B12 vitamine
 For each patient presenting with weight loss, first stage
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laboratory tests should be performed
Blood chemistry establishes electrolyte abnormalities
which indicates diabetes mellitus, hypercalcemia, renal
insufficiency, hepatic disease, adrenal insufficiency and
gastrointestinal system disease
TSH is used to omit hyperthyroidism
Chest radiography should always be performed
Stool test for occult blood and
HIV test in patients with high risk are mandatory
 If the reason for weight loss can not be diagnosed after
these examinations, secondary screening is undertaken.
 Abdominal CT is generally performed first
 Other procedures change according to the presence of
hypercalcemia, Fe deficiency anemia, fever and
electrolyte imbalance,
 If diarrhea exists, fat analysis in 72 hours stool test and
measurement of hormones like gastrine, somatostatine
and glucaghone are performed
 In unexplained weight loss, B12 vitamine level should be
analyzed even in the absence of anemia and macrositosis
 In the presence of serious, uncommon headache, cranial
CT is indicated regardless of the neurologic symptoms
 Back pain accompanied by fever and neurologic deficits
may indicate paraspinal and epidural abscess (due to tbc
or stafilococcus in IV drug users)
SUMMARY
 Weight loss generally indicates a serious illness
underneath it
 The patient should be followed up closely and tests
should be carried on when the cause is not found
 Patient should be followed up monthly with physical
examinations and laboratory tests if the cause is still not
found
 The follow-up interval can be longer if the cause is not
found in 6 months