About This Page
This is a clinician-written, evidence-based guide aligned to the MCC Examination Objectives. It is structured by clinical presentation — the way the MCCQE tests and the way patients actually present. Management reflects current Canadian guidelines (CMA, CFPC, CPS). Always cross-reference with institutional protocols and clinical judgment.
Key points
- First question: unilateral or bilateral? Unilateral = think DVT, cellulitis, lymphoedema, venous insufficiency. Bilateral = think systemic cause (HF, renal, hepatic, meds)
- Acute unilateral leg swelling: rule out DVT (Wells score + D-dimer or compression US) before attributing to other causes
- Generalized oedema with low albumin: nephrotic syndrome (proteinuria), cirrhosis (ascites, jaundice, stigmata), or malnutrition/malabsorption
- Generalized oedema with normal albumin: heart failure (elevated JVP, S3, BNP), medication-related (CCBs, NSAIDs, corticosteroids, TZDs), or idiopathic
- Common medication causes: amlodipine/nifedipine (most common drug cause), NSAIDs, corticosteroids, gabapentin/pregabalin, pioglitazone
Approach to the Presentation
Oedema is a common presentation in both primary care and hospital settings. The approach hinges on two key branch points: (1) Is it localized (unilateral) or generalized (bilateral/diffuse)? and (2) If generalized, is the serum albumin low or normal? Localized oedema is most often due to venous or lymphatic obstruction, inflammation, or dependent pooling. Generalized oedema reflects sodium and water retention from cardiac, renal, or hepatic dysfunction, or from increased capillary permeability. The urgency depends on the underlying cause — DVT and acute decompensated HF require immediate management, while chronic venous insufficiency and medication-related oedema are managed in the outpatient setting.
Differential Diagnosis
| diagnosis | likelihood | key features | distinguishing test |
|---|---|---|---|
| Deep Vein Thrombosis | must-not-miss | Acute unilateral swelling, calf tenderness, warmth, risk factors (immobility, surgery, malignancy, OCP, prior VTE). >3 cm circumference difference | Wells score + D-dimer (low risk) or compression ultrasound (moderate-high risk) |
| Heart Failure | must-not-miss | Bilateral dependent oedema (legs when upright, sacral when supine), dyspnoea, orthopnoea, PND, elevated JVP, S3 gallop, pulmonary crackles | BNP/NT-proBNP + echocardiogram (LVEF, diastolic parameters) |
| Nephrotic Syndrome | must-not-miss | Generalized oedema (often periorbital in morning, peripheral later), frothy urine, albumin <30 g/L, proteinuria >3.5 g/day, hyperlipidaemia | Urinalysis (proteinuria), spot urine protein:creatinine ratio, serum albumin |
| Cirrhosis / Hepatic | must-not-miss | Bilateral oedema + ascites, jaundice, spider naevi, palmar erythema, caput medusae, history of alcohol or hepatitis. Low albumin | LFTs, serum albumin, INR, abdominal ultrasound (ascites, nodular liver, portal HTN) |
| Pre-eclampsia | must-not-miss | Sudden oedema (especially facial/hands) in pregnancy >20 weeks + hypertension + proteinuria. Headache, visual changes, epigastric pain are red flags for severe disease | BP >=140/90 + urine protein:creatinine ratio. Urgent obstetric assessment |
| Chronic Venous Insufficiency | common | Bilateral (often asymmetric), worse at end of day, improved with elevation. Varicose veins, haemosiderin staining (brown discolouration), lipodermatosclerosis, venous ulcers (medial malleolus) | Clinical diagnosis. Venous duplex US if uncertain. Elevated ABI (>0.9) rules out arterial disease |
| Medication-Induced | common | Bilateral, temporal correlation with drug initiation or dose change. Common culprits: CCBs (amlodipine), NSAIDs, corticosteroids, gabapentin/pregabalin, pioglitazone, estrogens | Clinical: temporal correlation + resolution on discontinuation |
| Cellulitis | common | Unilateral erythema, warmth, tenderness, fever. May have portal of entry (skin break, tinea pedis). Spreading erythema | Clinical diagnosis. Blood cultures if systemic sepsis. US to rule out abscess if fluctuant |
| Lymphoedema | less common | Non-pitting (in established disease), progressive, may be unilateral or bilateral. Stemmer sign positive (unable to pinch skin fold on dorsum of 2nd toe). Causes: post-surgical (axillary/inguinal dissection), radiation, filariasis, congenital | Clinical diagnosis. Lymphoscintigraphy if uncertain |
| Hypothyroidism (Myxoedema) | less common | Non-pitting oedema (periorbital, hands, feet), fatigue, cold intolerance, constipation, weight gain, dry skin, bradycardia | TSH (elevated) + free T4 (low) |
Red Flags & Key History
Symptoms
Acute unilateral leg swelling (DVT until proven otherwise)
Sudden facial/hand oedema in pregnancy (pre-eclampsia)
Oedema + dyspnoea + orthopnoea (decompensated heart failure)
Oedema + frothy urine + periorbital swelling (nephrotic syndrome)
Oedema + ascites + jaundice (hepatic decompensation)
Bilateral, worse end of day, improved with elevation, varicose veins (chronic venous insufficiency — less urgent)
Temporal relationship with new medication (drug-induced — review med list)
Signs
Pitting vs non-pitting: pitting = most causes; non-pitting = lymphoedema, myxoedema
Elevated JVP (heart failure, fluid overload, tamponade)
Hepatojugular reflux (heart failure)
Ascites (cirrhosis, nephrotic, HF, malignancy)
Stemmer sign positive (lymphoedema)
Unilateral calf tenderness + Homan sign (DVT — but Homan sign is unreliable)
Approach to Investigation
First-line
Urinalysis (dipstick)Proteinuria suggests nephrotic syndrome or renal disease. First and most important screening test in bilateral oedema
Serum albuminLow albumin (<30 g/L): nephrotic, cirrhosis, malnutrition, protein-losing enteropathy. Normal albumin: HF, venous insufficiency, meds, hypothyroidism
BNP / NT-proBNPElevated in HF. Normal BNP effectively rules out cardiac cause of oedema
Basic labsCBC, electrolytes, creatinine (renal function), LFTs (hepatic), TSH (hypothyroidism), glucose
Second-line
Compression ultrasonographyIf DVT suspected (acute unilateral swelling). Non-compressible vein = positive
EchocardiogramIf HF suspected: LVEF, diastolic function, valvular disease, estimated PASP
Spot urine protein:creatinine ratio or 24h urine proteinQuantify proteinuria if dipstick positive. >3.5 g/day = nephrotic range
Abdominal ultrasoundAscites, liver morphology (cirrhosis), renal size and echogenicity
Specialist
Renal biopsyIf nephrotic syndrome confirmed and cause unclear from non-invasive workup
LymphoscintigraphyGold standard for lymphoedema if clinical diagnosis uncertain
Management Principles
CCS Heart Failure Guidelines + CSN Nephrotic Guidelines1
DVT
- Anticoagulation: DOAC (rivaroxaban or apixaban) first-line for most patients
- See Venous Thromboembolism presentation for full management
2
Heart Failure
- Loop diuretics (furosemide) for decongestion. Daily weights to monitor fluid status
- GDMT for HFrEF: ARNi/ACEi + beta-blocker + MRA + SGLT2i
- Sodium restriction (<2 g/day), fluid restriction if hyponatraemic
3
Nephrotic Syndrome
- Sodium restriction + loop diuretic (carefully — intravascular depletion risk)
- ACEi/ARB for proteinuria reduction
- Treat underlying cause (minimal change → corticosteroids, membranous → immunosuppression)
- Anticoagulation if albumin <20-25 g/L (high VTE risk)
- Statin for hyperlipidaemia
4
Cirrhosis with oedema/ascites
- Sodium restriction (<2 g/day) + spironolactone (100 mg) + furosemide (40 mg) — 100:40 ratio, titrate together
- Large-volume paracentesis for tense ascites (with albumin replacement if >5 L removed)
- Refer hepatology: TIPS if diuretic-refractory
5
Medication-induced
- Discontinue or reduce offending drug if possible
- If CCB-related and BP control essential: switch to non-DHP CCB or alternative class
- Diuretics are a temporising measure, not definitive — address the cause
6
Chronic venous insufficiency
- Compression stockings (20-30 mmHg graduated) — ONLY after ruling out arterial disease (ABI >0.9)
- Leg elevation above heart level when resting
- Exercise (calf muscle pump activation)
- Wound care for venous ulcers
Complications & Pitfalls
- Missing DVT in unilateral oedema: Always consider and rule out DVT before attributing to cellulitis, venous insufficiency, or Baker cyst rupture
- Over-diuresing nephrotic patients: They may be intravascularly depleted despite peripheral oedema — risk of AKI and thrombosis
- Compression stockings on arterial disease: Never apply compression without confirming ABI >0.9 — compression on ischaemic limbs can cause tissue necrosis
- Ignoring medication causes: CCBs (especially amlodipine) are the most common drug cause of bilateral ankle oedema — always review the medication list
- Anchoring on HF without checking albumin/urine: Low albumin oedema (nephrotic, cirrhotic) requires fundamentally different management than cardiac oedema
MCCQE1 Exam Tips
- 1The first branch point in the oedema approach: unilateral vs bilateral. Unilateral = structural (DVT, cellulitis, lymphoedema). Bilateral = systemic (cardiac, renal, hepatic, meds)
- 2Second branch point for bilateral oedema: check serum albumin. Low albumin = nephrotic, cirrhotic, malnutrition. Normal albumin = HF, meds, venous insufficiency, hypothyroidism
- 3Urinalysis is the single most important initial test in unexplained bilateral oedema — it screens for nephrotic syndrome in seconds
- 4Pre-eclampsia: sudden oedema (face/hands) + HTN + proteinuria after 20 weeks. This is a must-not-miss in any pregnant patient with new oedema
- 5Stemmer sign (inability to pinch dorsal skin fold of 2nd toe) = lymphoedema, not venous oedema. Lymphoedema is non-pitting once established
- 6Amlodipine oedema is bilateral, dependent, and dose-related. It is NOT a sign of heart failure — do not start diuretics reflexively
- 7Nephrotic syndrome carries high VTE risk — anticoagulation should be considered if albumin <20-25 g/L
practicetest your knowledge on EdemaApply what you've learnt with MCCQE1-style questions from the iatroX Q-Bank — Cardiovascular and beyond.
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