⚖️ Unintentional weight loss in adults is a red flag symptom that warrants careful evaluation. 📉 Defined as >5% body weight loss over 6–12 months, it may indicate underlying malignancy, endocrine disease, infection, psychiatric illness, or social causes. 🧠 Clinicians must approach systematically: history → examination → investigations → management.

🩺 Clinical History

⏱️ Onset & Duration: When did weight loss begin? Gradual vs rapid?
📊 Quantify: How much weight lost? (% body weight over time).
🍽️ Appetite & Dietary Changes: Loss of appetite, early satiety, dietary restriction?
🧾 Associated Symptoms: - Fatigue, weakness - GI: nausea, vomiting, diarrhoea, abdominal pain, steatorrhoea - Psychological: depression, anxiety, stress - Infection: fevers, night sweats, cough
📜 Past Medical History: Diabetes, hyperthyroidism, IBD, malignancy.
💊 Medications: Metformin, SSRIs, chemotherapy agents, appetite suppressants.
🏠 Social History: Alcohol, drugs, smoking, food insecurity, bereavement, recent stressors.

👩‍⚕️ Physical Examination

👀 General Inspection: Cachexia, muscle wasting, pallor, jaundice, lymphadenopathy.
📈 Vital Signs: BP, HR, temperature (sepsis, thyrotoxicosis, adrenal crisis).
📏 BMI: Quantify severity of weight loss.
🔍 Systematic Examination: - GI: abdominal masses, hepatomegaly, stigmata of chronic liver disease - Endocrine: goitre, tremor, tachycardia, pigmentation - Respiratory: cachexia, clubbing, chest signs - Neurological: cognitive decline, weakness

🔬 Investigations

🧪 Blood Tests: - FBC (anaemia, malignancy, infection) - LFTs, U&Es, calcium - TFTs (hyperthyroidism) - HbA1c/glucose (diabetes) - ESR/CRP (chronic infection/inflammation) - HIV, TB tests if risk factors
🖥️ Imaging: - CXR (malignancy, TB, CHF, COPD) - Abdominal ultrasound (masses, liver disease) - CT/MRI for unexplained weight loss
🧫 Other Tests: - Stool tests (fat, parasites, occult blood) - Endoscopy/colonoscopy if GI symptoms - Psychiatric/psychological assessment if mood/eating disorder suspected

📚 Causes of Weight Loss

🎗️ Malignancy: Lung, pancreatic, GI, lymphoma.
🦠 Chronic Infections: TB, HIV, parasitic diseases.
🔁 Endocrine: Hyperthyroidism, diabetes, adrenal insufficiency.
🍽️ GI/Malabsorption: Coeliac, Crohn’s, chronic liver disease.
🧠 Psychiatric: Depression, anxiety, anorexia nervosa.
💊 Medications: Metformin, SSRIs, chemotherapy.
❤️ Chronic disease: COPD, CHF, CKD.
🍺 Substance misuse: Alcohol, drugs.

⚕️ Management Principles

🎯 Treat the underlying cause (thyroid therapy, ART for HIV, chemotherapy for malignancy).
🥗 Nutritional support: Dietitian referral, supplements, enteral feeding if severe.
🧠 Psychiatric support: CBT, SSRIs, eating disorder services where indicated.
🔄 Regular follow-up: Monitor weight, nutrition, functional status.
🤝 Multidisciplinary care: GP, dietitian, psychiatry, oncology, gastroenterology as required.

📊 Summary Table

Cause	Investigations	Management
Malignancy	CT/MRI, biopsy, tumour markers	Surgery, chemotherapy, radiotherapy, palliative care
Endocrine (Thyroid, Diabetes, Adrenal)	TFTs, HbA1c, cortisol/ACTH	Antithyroid drugs, insulin/oral hypoglycaemics, steroid replacement
GI/Malabsorption	Stool tests, endoscopy/colonoscopy, biopsies	Gluten-free diet, biologics for IBD, supplements
Infections (TB, HIV)	HIV test, TB screen, CXR, cultures	ART, antitubercular therapy, nutrition
Psychiatric	Psychological evaluation, screening questionnaires	CBT, SSRIs, eating disorder services
Chronic Disease (CHF, COPD)	Echocardiogram, spirometry, BNP, CXR	Optimise medical therapy, oxygen, rehab, nutrition
Substance Misuse	Drug screen, LFTs, history	Detox, rehab, support groups, nutrition

Additional related clinical topics

OSCE Unintentional Weight Loss

Candidate Instructions:You are a final-year medical student in the GP clinic. A 68-year-old patient presents with unexplained weight loss. Take a focused history, screen for red flags, and outline possible differentials and initial management. You do not need to perform an examination. You have 8 minutes.

Key OSCE Learning Points 🔑

Weight loss = unintended loss of ≥5% body weight over 6–12 months.
Broad differential: malignancy, endocrine, gastrointestinal, infection, psychiatric, social.
Always ask about systemic “B” symptoms (fever, night sweats, lymphadenopathy).
Screen for red flags → NICE 2-week wait cancer referral. ⚠️

History to Cover 📝

Onset & Duration: When did the weight loss begin? How much? Over what period?
Associated Symptoms:
- GI: dyspepsia, dysphagia, diarrhoea, blood in stool, change in bowel habit.
- Respiratory: cough, haemoptysis, dyspnoea.
- Systemic: fevers, night sweats, fatigue, pruritus.
- Endocrine: polyuria, polydipsia, heat/cold intolerance, tremor.
Psychiatric: low mood, anhedonia, poor appetite, stress.
Social: diet, access to food, alcohol, smoking, recent bereavement, social isolation.
Past Medical History: TB, HIV, diabetes, thyroid disease, IBD, malignancy.
Medication History: Metformin, SSRIs, chemotherapy, appetite suppressants.
Family History: Malignancy, thyroid disease, diabetes.

Examiner Prompts 👩‍⚕️

Patient has lost 1 stone (~6 kg) over 3 months without trying.
No fevers, sweats, or haemoptysis.
Reports early satiety and occasional upper abdominal discomfort.
No change in bowel habit.
Past history: hypertension only. Non-smoker, moderate alcohol use.

Differential Diagnosis ⚖️

Malignancy: gastric, pancreatic, bowel, lung, lymphoma.
Endocrine: diabetes mellitus, hyperthyroidism, Addison’s disease.
GI: malabsorption (coeliac disease, IBD, chronic pancreatitis).
Infective: TB, HIV, chronic hepatitis.
Psychiatric: depression, anorexia nervosa, dementia.
Social: poverty, neglect, alcoholism.

Investigations 🔬

Bloods: FBC (anaemia), U&E, LFTs, calcium, CRP/ESR, TFTs, HbA1c, coeliac screen.
Infective screen: HIV, hepatitis serology, TB if risk factors.
Cancer screening: FIT test (bowel), PSA (men if appropriate). Tumour markers (CEA, CA19-9) not first-line but may aid follow-up.
Imaging: Chest X-ray (lung malignancy, TB), abdominal ultrasound/CT if red flags or persistent unexplained weight loss.
Endoscopy: OGD/colonoscopy if GI red flag symptoms (dysphagia, melaena, PR bleeding, iron-deficiency anaemia).

🧑‍⚕️ Case Examples - Adult Unintentional Weight Loss

Case 1 (Malignancy - Pancreatic cancer): 🎗️ A 64-year-old man reports 3-month history of weight loss, anorexia, and pale greasy stools. He has painless jaundice and a palpable, non-tender gallbladder (Courvoisier’s sign). CT abdomen shows a pancreatic head mass. Diagnosis: Pancreatic carcinoma with malabsorption. Teaching point: Always consider GI malignancy in older patients with unexplained weight loss.
Case 2 (Endocrine - Hyperthyroidism): 🦋 A 35-year-old woman presents with anxiety, palpitations, heat intolerance, and 6 kg weight loss despite increased appetite. Exam shows goitre and fine tremor. TFTs: suppressed TSH, raised free T4. Diagnosis: Graves’ disease. Teaching point: Weight loss with hyperphagia suggests thyrotoxicosis; look for systemic features (tachycardia, eye signs).
Case 3 (Infective - Tuberculosis): 🦠 A 40-year-old migrant presents with cough, night sweats, and 8 kg weight loss over 2 months. CXR shows apical cavitating lesions; sputum is Ziehl–Neelsen positive. Diagnosis: Pulmonary tuberculosis. Teaching point: Chronic infection with systemic features (fever, sweats, weight loss) is a red flag for TB.
Case 4 (Psychiatric - Depression): 🧠 A 52-year-old man reports poor appetite, insomnia, and 10 kg weight loss over 4 months. He describes low mood, anhedonia, and hopelessness. Diagnosis: Major depressive disorder. Teaching point: Mood disorders are a common but often overlooked cause of weight loss in adults; always screen for depression.
Case 5 (Gastrointestinal - Coeliac disease): 🌾 A 28-year-old woman presents with chronic diarrhoea, bloating, and 7 kg weight loss. Labs show iron-deficiency anaemia. Coeliac serology is positive, and duodenal biopsy confirms villous atrophy. Diagnosis: Coeliac disease. Teaching point: In young adults, malabsorption (especially coeliac) should be considered in unexplained weight loss with anaemia.

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Unintentional weight loss (Adults)