🩺 Ankle Swelling

Ankle swelling (peripheral oedema) is a common clinical sign caused by the accumulation of fluid in the interstitial space. It results from an imbalance in Starling forces—either increased capillary hydrostatic pressure, decreased plasma oncotic pressure, or increased capillary permeability. The clinician’s primary goal is to differentiate between local causes (transudate/exudate) and systemic diseases (organ failure). Acute unilateral swelling requires urgent exclusion of venous thromboembolism.

Establish the onset (acute vs. chronic) and whether it is unilateral or bilateral. Ask about associated symptoms like shortness of breath, orthopnoea, or paroxysmal nocturnal dyspnoea (suggesting heart failure). Inquire about risk factors for DVT (recent surgery, immobility, malignancy). Review medications, especially Amlodipine, NSAIDs, or steroids. Consider systemic symptoms like frothy urine (nephrotic syndrome) or jaundice (liver disease). Evaluate the impact on mobility and skin integrity.

Assess whether the swelling is unilateral or bilateral and the extent (pitting vs. non-pitting). Examine the cardiovascular system for signs of heart failure (elevated JVP, displaced apex beat, heart murmurs, or lung crackles). Check for signs of chronic venous insufficiency like varicose veins, haemosiderin staining, or venous ulcers. Palpate for tenderness/warmth in the calf and look for 'Stemmer’s sign' (inability to pinch the skin on the dorsal surface of the second toe) for lymphoedema. If abdominal causes are suspected, check for hepatomegaly or ascites.

Congestive Heart Failure, Chronic Venous Insufficiency, Deep Vein Thrombosis (DVT), Medication-induced (CCBs/NSAIDs), Lympoedema, Nephrotic Syndrome, Liver Cirrhosis, and Cellulitis.

Sudden onset unilateral swelling with calf pain/tenderness, chest pain/haemoptysis (Pulmonary Embolism), gross proteinuria, and new-onset breathlessness.

Initial tests should include FBC, U&Es, LFTs (for albumin and liver function), and TFTs. If heart failure is suspected, order a B-type Natriuretic Peptide (BNP) and an ECG. A urinalysis is essential to screen for proteinuria (nephrotic syndrome). For suspected DVT, use the Wells Score to determine if a D-dimer or a proximal leg vein ultrasound is indicated. If there is diagnostic uncertainty regarding chronic swelling, a pelvic ultrasound may be required to exclude extrinsic venous compression.

Unilateral swelling is a DVT until proven otherwise; use the Wells Score. Bilateral swelling is often multifactorial (e.g., HF plus venous insufficiency). Always check the medication list for Calcium Channel Blockers (CCBs) like Amlodipine, which are a very common cause. If the swelling extends to the thigh, consider pelvic pathology or iliac vein compression. Pitting oedema is characteristic of systemic causes, whereas non-pitting oedema (lymphoedema) often involves the toes (Stemmer’s sign).

Prioritise the exclusion of DVT and Heart Failure. Understand the mechanism of CCB-induced oedema and the importance of checking BNP before requesting Echocardiography. Be aware of the 'Two-Week Wait' criteria for suspected pelvic or abdominal masses causing venous obstruction.