Severe weight loss over weeks or months

The degree and speed of weight loss is relevant; the more severe, the more likely is it to be due to a demonstrable cause.

Some differential diagnoses and typical outline evidence

Any advancedmalignancy	Suggested by: progressive onset over weeks or months of specific symptoms e.g. neurological deficit, haemoptysis, rectal bleeding, change of bowel habit, etc.
	Confirmed by: metastases on CXR, metastases on ultrasound scan of liver or leukaemic changes on FBC or tumour on bronchoscopy, or GI endoscopy, etc.
Depression	Suggested by: sleep disorders, poor concentration, social withdrawal, lack of interest in usual activities etc.
	Confirmed by: response to antidepressants. Psychotherapy.
	Management: OHCS pp336–41.
Thyrotoxicosis	Suggested by: heat intolerance, tremor, nervousness, palpitation, frequency of bowel movements, goitre, fine tremor, warm and moist palm.
	Confirmed by: TSH↓, ↑FT4, ↑FT3.
	Management: OHCM p304.
Uncontrolled diabetes mellitus	Suggested by: thirst, polydipsia, polyuria.
	Confirmed by: Fasting blood glucose ≥7.0 mmol/L (on two occasions) OR fasting, random or GTT glucose ≥ 11.1mmol/L once only in the presence of symptoms.
	Management: OHCM pp292–6.
Infection e.g. tuberculosis	Suggested by: night sweats, fever, malaise, cough.
	Confirmed by: CXR showing opacification of pneumonia and presence of AFB in sputum on microscopy and culture.
	Management: OHCM pp564–6.
Addison's disease	Suggested by: lethargy, weakness, dizziness, pigmentation (buccal, scar), hypotension.
	Confirmed by: 9 a.m. plasma cortisol ↓ and impaired response to short ACTH stimulation test (short Synacthen test).
	Management: OHCM p312.