Introduction
Unintentional weight loss is a red flag symptom requiring systematic assessment. In a patient who has lost more than 5% of body weight over 6 months without trying, malignancy must be excluded. The OSCE tests your ability to work through a structured screen without missing a sinister cause.
💎 Clinical Pearl
Quantify the weight loss precisely: "How much weight have you lost? Over what time period? Has your appetite changed, or are you eating normally but losing weight?" This distinction is diagnostically critical.
Quantifying Weight Loss
- How much weight lost? (kg or clothes size change if unsure)
- Over what time frame? (6 months = clinical significance threshold)
- Intentional or unintentional?
- Is appetite preserved or reduced?
- Can the patient explain it?
5% of body weight over 6 months = clinically significant unintentional weight loss requiring investigation.
Appetite Assessment — Key Distinction
| Finding | Suggests |
|---|---|
| Decreased appetite (anorexia) + weight loss | Malignancy, depression, chronic disease, thyrotoxicosis early stage |
| Preserved or increased appetite + weight loss | Hyperthyroidism, uncontrolled diabetes, malabsorption, increased metabolic demand |
Systematic Differentials — MEND CAMP
🧠 Mnemonic
MEND CAMP:
Malignancy — always exclude first
Endocrine — hyperthyroidism, Addison's, uncontrolled diabetes
Nutrition — poor intake, malabsorption (coeliac, Crohn's, pancreatic insufficiency)
Depression and psychiatric — depression, anorexia nervosa, dementia
Cardiorespiratory — heart failure, COPD (increased metabolic demand)
Autoimmune — RA, SLE, IBD, vasculitis
Medications — stimulants, SSRI-related nausea, metformin GI effects, opioids
Parasites/Infection — TB, HIV, intestinal parasites
Malignancy Screen
Ask about site-specific symptoms for the most common cancers:
| Cancer | Symptoms to ask about |
|---|---|
| Lung | Cough, haemoptysis, dyspnoea, chest pain, smoking history |
| Colorectal | Change in bowel habit, rectal bleeding, melaena, tenesmus |
| Stomach | Dysphagia, early satiety, vomiting, dyspepsia, epigastric pain |
| Pancreas | Jaundice, back pain, steatorrhoea, new-onset diabetes |
| Lymphoma | Night sweats, lymphadenopathy, itch, alcohol-induced pain |
| Haematological | Bruising, fatigue, recurrent infections, bone pain |
| Renal | Haematuria, loin pain, flank mass |
⚠️ Red Flag
B symptoms — drenching night sweats, fever, and weight loss over 10% in 6 months — suggest lymphoma until proven otherwise. Do not miss lymphadenopathy examination.
Endocrine Screen
Hyperthyroidism
- Heat intolerance, sweating, palpitations, tremor, anxiety, diarrhoea
- Goitre, eye changes (exophthalmos in Graves')
Addison's Disease (Adrenal Insufficiency)
- Fatigue, postural dizziness, nausea, vomiting, salt craving
- Skin hyperpigmentation (buccal mucosa, palmar creases, pressure areas)
- Triggers: infection, surgery, stress
Uncontrolled Diabetes Mellitus
- Polydipsia, polyuria, blurred vision
- Weight loss despite normal or increased appetite = type 1 or severe type 2
Psychiatric and Social Assessment
- Low mood, anhedonia, poor sleep, hopelessness (depression)
- Body image disturbance, fear of weight gain, restriction of intake (eating disorder)
- Social isolation, inability to cook or shop (frailty, dementia)
- Bereavement, financial hardship
Drug History
- SSRIs/SNRIs: nausea in first weeks
- Metformin: GI side effects reducing appetite
- Opioids: nausea and constipation reducing intake
- Stimulants: amphetamines, cocaine, ADHD medications
- Digoxin: nausea at toxic levels
- Chemotherapy: mucositis, nausea
How to Present
"This is a 68-year-old male ex-smoker who has lost 8 kg over 3 months unintentionally with associated reduced appetite. He describes a new cough with occasional haemoptysis and right-sided chest pain. There is no change in bowel habit, no jaundice, and no lymphadenopathy on examination. Unintentional weight loss in a man of this age with a smoking history and haemoptysis is highly suspicious for bronchogenic carcinoma. I would arrange an urgent CXR and CT chest with 2-week wait respiratory referral."
"What is the clinical significance of 5% weight loss over 6 months?"
Unintentional weight loss of 5% or more of body weight over 6 months is clinically significant and requires systematic investigation to exclude malignancy, endocrine disease, and other serious pathology. Greater than 10% weight loss suggests significant malnutrition or advanced disease and is a B symptom in lymphoma staging.
"How does the presence of preserved appetite versus anorexia help narrow the differential?"
Weight loss with reduced appetite (anorexia) suggests malignancy, depression, or chronic inflammatory disease. Weight loss despite preserved or increased appetite suggests hyperthyroidism (increased metabolic rate), uncontrolled type 1 diabetes (glucosuria and catabolism), or malabsorption (food eaten but not absorbed). This distinction is a key discriminating question in the history.
"What are the B symptoms of lymphoma and why do they matter?"
B symptoms in Hodgkin's lymphoma are: drenching night sweats, unexplained fever above 38 degrees C, and unintentional weight loss of more than 10% over 6 months. Their presence upgrades the stage to B and indicates systemic disease, worsening prognosis and often requiring more intensive treatment. Any patient with unexplained weight loss, lymphadenopathy, and night sweats should have an urgent lymphoma workup.
"What investigations would you request for unexplained weight loss?"
First-line investigations: FBC (anaemia, leucocytosis, lymphocytosis), ESR and CRP, LFTs, renal function, glucose, TFTs (thyrotoxicosis), PSA in men, CA125 in women, CXR (lung cancer, lymphoma), and urine dipstick. If these are normal, CT chest, abdomen, and pelvis is warranted. Endoscopy (upper and lower GI) is indicated if GI symptoms are present.
Related guides: Jaundice History OSCE | Thyroid History OSCE | Lymph Node Examination OSCE