Weight loss

Dr Daniel J Bell et al.

A clinical presentation of weight loss is extremely common and often a source of marked anxiety for the patient. The commonest cause of unintentional weight loss (UWI) is gastrointestinal tract disease, and not malignancy.

The published literature lacks a consistent definition of what constitutes clinically-significant unintended weight loss. A loss of body weight of ≥5% in ≤6 months is often employed for this purpose 2. Although in the context of lymphoma, the presence of weight loss, as one of the B symptoms, is defined as a loss of body weight of ≥10% within six months 3.

  • gastrointestinal
  • malignancy
  • psychosocial
  • endocrine
  • cardiopulmonary
  • alcohol excess
  • rheumatological 
  • miscellaneous
  • dieting
  • physical exercise
  • bariatric surgery
  • medications (purgatives, anxiolytics, diuretics, etc.)
  • self-induced vomiting

On cross-sectional imaging, the most striking feature of a patient who has lost a large amount of weight is usually the distinct lack of subcutaneous and intra-abdominal fat. This often makes studies difficult to read as the solid organs, bowel loops and nodes may be difficult to separate visually, especially on non-contrast CT examinations.

The use of imaging to identify the underlying cause of unintentional weight loss is increasingly common. In a retrospective study of 200 patients with unexplained weight loss, from 2018, whole body CT was able to elucidate the primary cause in a third of patients (33.5%) 4.

Share article

Article information

rID: 72807
Section: Approach, Gamuts
Synonyms or Alternate Spellings:
  • Involuntary weight loss
  • Involuntary loss of weight
  • Unintentional loss of weight
  • Unexplained loss of weight
  • Unintentional loss of body weight
  • Unexplained loss of body weight
  • Loss of body weight
  • Loss of weight
  • Unexplained weight loss (UWI)
  • Unintentional weight loss (UWI)
  • Wt loss

Support Radiopaedia and see fewer ads

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.