⚖️ 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

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Unintentional weight loss (Adults)