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Unexplained weight loss

What weight loss is clinically significant?

  • The well-accepted definition of clinically important wt loss is 5% over a period of 6-12m.
  • Up to 8% of all adult outpatients and 27% of people >65 years. Normal aging is ass with only very small decrements in wt (0.1-0.2 kg/year).
  • It is associated with increased mortality, which can range from 9% to as high as 38% within 1 to 2.5 years after weight loss has occurred.


What are the possible causes of unexplained weight loss?

  • Neoplasm- Cancer of the lung, colon, pancreas, breast, and prostate were the most common malignancies.
  • Benign GI disease- peptic ulcer disease, motility disorders, cholelithiasis, IBD
  • Psychiatric disorders
  • Endocrine causes- Thyroid, diabetes mellitus, adrenal insufficiency (all pts have anorexia, nausea & wt loss)
  • No cause (in upto 25%)

Chronic use of alcohol, nicotine, lead, opiates & CNS stimulants can cause decreased appetite and wt loss. Depression and malignancy are the commonest causes of isolated weight loss.

How do you approach pts with unexplained weight loss?

  • It is imp to establish up front the presence of wt loss as up to half of people who claim to have lost weight have no documented evidence of wt loss.
  • Careful history to elicit;
    • Appetite- key question
    • Think in terms of the fractional change in wt.
    • For how long has the patient been losing weight?
    • To what extent has the patient’s weight changed during adult life?
    • Localising symptoms
    • All elderly patients should be screened for dementia (MMSE) & depression.
    • Young pts consider eating disorder

What is the practical approach to investigations in the absence of diagnostic clues?

  • FBC, LFT, U&E, Ca, TSH, ESR, iron profile, glucose, coeliac antibody, HIV tests (in pts at risk)
  • There are no guidelines for how to proceed in the assessment of a patient with weight loss and negative initial findings. The diagnostic yield of a whole body CT examination to assess for occult or metastatic malignant disease has not been determined. We use whole body CT if the initial findings are negative.
  • OGD is indicated for patients with early satiety. Colonoscopy is not indicated in the evaluation of weight loss, as colon cancer does not induce weight loss unless there is obstruction or extensive metastases.


How do you manage patients with unexplained weight loss?

  • Treat any underlying illness
  • Nutritional supplements lead to improvements in biochemical, anthropometric and QoL parameters in a number of trials. A systematic review showed a reduction in mortality among elderly patients who received protein-energy supplements, irrespective of whether they had weight loss.

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