General MedicineTier 1Approach to a presentation

Undifferentiated presentations - weight loss

Red flags

Unintentional weight loss >5% body weight over 6-12 months - always investigate
Weight loss + night sweats + lymphadenopathy - lymphoma
Weight loss + change in bowel habit/PR bleeding - colorectal cancer
Weight loss + dysphagia - oesophageal malignancy
Weight loss in the elderly with self-neglect - consider abuse/neglect, depression, dementia

Differential by mechanism

Malignancy (found in a substantial minority of unexplained cases, rises with age)

GI, lung, haematological, pancreatic (classically silent, weight loss + new diabetes + painless jaundice)

Endocrine/metabolic

Hyperthyroidism, diabetes (new/uncontrolled), Addison's disease, phaeochromocytoma

GI

Malabsorption (coeliac disease, pancreatic insufficiency, IBD), peptic ulcer, chronic liver disease

Infective/inflammatory

TB, HIV, chronic infection, connective tissue disease

Psychiatric/social

Depression (commonest cause overall in the elderly), anxiety, dementia, eating disorder, alcohol/substance use, social isolation, poverty/food insecurity, elder abuse/neglect

Cardiorespiratory

Chronic heart failure (cardiac cachexia), COPD

Focused history

Confirm true weight loss (measured, not just clothes looser) and quantify percentage/timeframe
Appetite - increased (hyperthyroid, diabetes, malabsorption) vs decreased (malignancy, depression, chronic disease)
Systemic symptoms - fever, night sweats, bowel habit change, dysphagia
Mood, cognition, social circumstances, living situation, access to food, carer involvement
Full medication and substance use history

Focused examination

BMI/objective weight trend, muscle wasting
Lymphadenopathy, abdominal masses/organomegaly, thyroid exam
Cognitive screen, mood assessment
Signs of neglect/poor hygiene, pressure injuries if elderly/dependent

Investigation strategy

FBE, UEC, LFT, TFT, glucose/HbA1c, CRP/ESR, calcium
Coeliac serology, faecal occult blood/calprotectin
CXR; age/symptom-directed endoscopy or CT chest/abdomen/pelvis
HIV test where relevant

Management

Investigate systematically before attributing to "just old age"
Treat the underlying cause once found
Depression is the most common cause in older adults and is treatable - do not stop the workup at "unremarkable" investigations without a mental health assessment
Nutritional support (dietitian referral) while cause is being established, especially in frail/elderly patients
If elder abuse/neglect suspected - see relevant safeguarding pathway

Traps

Unintentional weight loss is never "normal ageing" - it always warrants at least a basic screen
Depression and malignancy present near-identically with weight loss and low mood/energy - screen for both, don't assume either
Self-reported weight loss without objective confirmation can be inaccurate - use documented weights where possible
Social causes (poverty, isolation, inability to cook/shop) are under-asked-about in a purely biomedical work-up

Talk track

"Any unintentional weight loss over 5% gets a basic malignancy and metabolic screen before I call it benign."
"I ask about mood and living situation as routinely as I order bloods - depression and neglect are common causes."

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