Aneurysms, ischaemic limb and occlusions
Aneurysm is a localised, permanent dilatation of an artery due to weakening of the vessel wall.
Peripheral aneurysms (e.g., femoral, popliteal) often present as pulsatile masses and carry risks of thrombosis, embolisation, or rupture.
Arterial occlusion can be acute (embolus, thrombosis, trauma) or chronic (atherosclerosis, peripheral arterial disease – PAD).
👉 Early recognition and referral are key to preventing limb loss and mortality.
⚠️ Complications of Peripheral Aneurysms
- 💥 Rupture: Life-threatening haemorrhage → hypovolaemic shock. Femoral aneurysm rupture carries high morbidity.
- 🩸 Thrombosis: Intraluminal clot → acute limb ischaemia (ALI).
- 🚨 Embolisation: Distal thrombus → “blue toe syndrome”, gangrene risk.
- 🧩 Compression: Adjacent nerves/veins → neuropathy, DVT, oedema.
🧑⚕️ Clinical Features
- 🔍 Pulsatile mass in femoral triangle or popliteal fossa.
- Groin/leg discomfort, swelling, or neuropathic symptoms from compression.
- Signs of acute limb ischaemia (“6 Ps”): Pain, Pallor, Pulselessness, Paraesthesia, Paralysis, Perishingly cold.
- Claudication and trophic changes in chronic occlusion.
- Blue/purple toes in embolisation (“blue toe syndrome”).
🔎 Investigations (NICE & Vascular Society guidance)
- 🩺 Bedside assessment: Palpate pulses, compare bilaterally; ABPI to quantify perfusion.
- 🖥️ Duplex Doppler US: First-line imaging for aneurysm size, patency, and flow.
- 🧲 CT Angiography / MR Angiography: Pre-operative planning or complex anatomy.
- 🧪 Blood tests: FBC, U&E, coagulation profile, cross-match if surgery likely.
- ⚖️ Cardiovascular assessment: ECG, echocardiogram if embolic source suspected (AF, mural thrombus).
🛠️ Management of Aneurysms
- 🆘 Emergency: Ruptured or acutely thrombosed → urgent vascular surgery referral, haemodynamic support.
- 🔪 Surgical repair: Open resection & grafting for symptomatic or large aneurysms (femoral >2.5 cm, popliteal >2 cm), or if rupture risk high.
- 🩻 Endovascular repair: Stent-graft in selected cases (high-risk comorbidities or anatomical suitability).
- 💊 Medical: Antiplatelets, statins, BP optimisation for underlying atherosclerosis; smoking cessation essential.
- 📅 Surveillance: Small, asymptomatic aneurysms can be monitored with regular ultrasound per local vascular protocols.
🚨 Acute Limb Ischaemia (ALI)
ALI = sudden decrease in limb perfusion (<14 days), threatening limb viability.
Causes: embolus (AF, mural thrombus), thrombosis in situ (PAD), dissection, trauma.
- 🔑 6 Ps: Pain, Pallor, Pulselessness, Paraesthesia, Paralysis, Perishingly cold.
- ❗ Paralysis and absent Doppler signals indicate late presentation with poor prognosis.
- 💉 Immediate: ABCs, IV heparin bolus, urgent vascular surgery consultation.
- 🔪 Definitive: Embolectomy, thrombectomy, bypass, or catheter-directed thrombolysis depending on cause and anatomy.
🌙 Chronic Limb Ischaemia / PAD
- 🚶 Intermittent claudication: Pain on exertion, relieved by rest.
- 🛌 Rest pain: Severe PAD; pain at night relieved by dependent position.
- 🩻 Critical limb ischaemia (CLI): Rest pain + ulceration or gangrene.
- 🛠️ Management:
- Risk factor modification: smoking cessation, lipid-lowering, BP control, glycaemic optimisation.
- Supervised exercise therapy to improve walking distance (NICE 2018).
- Endovascular intervention: angioplasty/stenting for suitable lesions.
- Surgical bypass for extensive or symptomatic disease.
- Foot care and infection prevention crucial in CLI.
📌 Key Exam Pearls
- Always check bilateral femoral & popliteal pulses in suspected aneurysms.
- Acute limb ischaemia is a surgical emergency – give heparin, call vascular urgently.
- Femoral aneurysms can mimic inguinal hernia or lymphadenopathy.
- Peripheral aneurysms are often multiple → consider screening for popliteal/aortic aneurysm.
- Blue toe syndrome = distal embolisation from aneurysm or atherosclerotic plaque.
📚 References
