🩺 Unintentional Weight Loss

Unintentional weight loss is a common and often distressing presenting symptom in primary and secondary care. It is defined as an involuntary decline in body weight, typically >5% of baseline over 6–12 months. It serves as a nonspecific marker for underlying physical illness, psychological distress, or socio-economic challenges. In approximately 25% of cases, no cause is found even after extensive investigation. Clinical management focuses on excluding malignancy while simultaneously screening for metabolic and psychiatric causes.

History should focus on the 'Review of Systems' to localise the cause. Enquire about appetite (increased in hyperthyroidism/malabsorption vs. decreased in malignancy/depression), altered bowel habit, night sweats, and persistent cough. Screen for 'The Three Ds': Depression, Diabetes, and Dementia. A detailed medication review is essential, as drugs like digoxin, metformin, or SSRIs can cause anorexia. Assess social factors like poverty, isolation, or difficulty with grocery shopping/cooking.

Perform a 'head-to-toe' assessment looking for signs of occult malignancy and systemic disease. This must include palpation of all lymph node basins (Virchow’s node), thyroid examination, abdominal palpation for organomegaly or masses, and digital rectal examination (DRE) for pelvic pathology or occult blood. Examine the skin for acanthosis nigricans or cachexia, and perform a brief cognitive and mood assessment to screen for depression or dementia.

Malignancy (GI, lung, lymphomas); Endocrine (Hyperthyroidism, Diabetes Mellitus, Addison’s); Gastrointestinal (Malabsorption/Coeliac, IBD); Psychosocial (Depression, Anorexia Nervosa, Poverty/Neglect); Chronic Infection (TB, HIV, Subacute Endocarditis).

Night sweats or persistent pyrexia (lymphoma/TB); Change in bowel habit/rectal bleeding (colorectal cancer); Dysphagia or persistent dyspepsia (upper GI cancer); New palpable mass or significant lymphadenopathy; Persistent cough or haemoptysis (lung cancer).

A 'screening bundle' of investigations is recommended: FBC (anaemia/leukaemia), ESR/CRP (inflammatory markers), U&Es (uraemic anorexia), LFTs (liver mets/alcohol), TFTs (hyperthyroidism), calcium (hypercalcaemia of malignancy), and HbA1c (diabetes). A chest X-ray and urinalysis (blood/protein/glucose) are mandatory first-line tests. If initial screening is negative and weight loss persists, consider CT thorax/abdomen/pelvis or faecal immunochemical testing (FIT) based on age and local 2-week wait (2WW) protocols.

Weight loss is considered clinically significant if ≥5% of body weight is lost involuntarily over 6 months. In the elderly, always look for the 'nine Ds' of weight loss: dentition, dysgeusia, dysphagia, diarrhoea, depression, dementia, disease, drugs, and dysfunction (poverty). Remember that a normal physical exam and baseline bloods have a high negative predictive value for occult malignancy.

Aligns with the MLA's 'General/Nonspecific' and 'Gastrointestinal' domains. Focus on identifying when to refer via 2-week wait pathways (e.g., unexplained weight loss with abdominal pain or change in bowel habit).