Makindo Medical Notes

Related Subjects: |Neurological History taking |Causes of Stroke |Ischaemic Stroke |Subarachnoid Haemorrhage |Cerebral Arterial Perfusion and Clinical Correlates |Anterior circulation Brain |Posterior circulation Brain |Acute Stroke Assessment (ROSIER&NIHSS) |Carotid Artery dissection |Vertebral artery dissection

🧠 Introduction

• Carotid dissection (CD) accounts for only 1–2% of all ischaemic strokes, but in young and middle-aged adults it causes up to 10–25% of strokes.
• Posterior circulation dissections (vertebral) are also important but less common than carotid.
• Key teaching: Carotid/vertebral dissection without suspicion of SAH is not a contraindication to thrombolysis.
• Always ask about unusual neck trauma (e.g. chiropractor, sports injury, yoga, sneezing) in a young patient with stroke.

⚙️ Aetiology & Pathophysiology

• Dissection = tear in the intimal layer → blood enters vessel wall → intramural haematoma.
• Source of blood: through intimal tear (luminal blood) or rupture of vasa vasorum (or both).
• Consequences:
  • 🩸 Luminal narrowing or occlusion.
  • 🧩 Endothelial damage → thrombosis → artery-to-artery embolisation.
  • ⚠️ Rarely, extension intracranially → subarachnoid haemorrhage (SAH).
• Rationale for therapy = prevent thrombus/embolisation and maintain flow.

📊 Epidemiology

• Always suspect in young adults (<50) with anterior circulation stroke.
• Prognosis is generally good with low recurrence risk.
• Carotid dissections ≈3× more common than vertebral dissections.
• Typical site: internal carotid artery, 2–3 cm distal to bifurcation.
• Genetic/structural predispositions: Marfan’s, Ehlers–Danlos IV, fibromuscular dysplasia (only ~2%).
• Males = females in prevalence; peak incidence = mid-40s.

🩺 Clinical Features

• 🧠 TIA/stroke (most common).
• 🪖 Neck, face, or retro-orbital pain.
• 👁️ Ipsilateral Horner’s syndrome (ptosis, miosis, enophthalmos – but usually no anhidrosis).
• 🧩 Migrainous-type headache.
• 👅 Hypoglossal nerve palsy (due to compression).
• 🫀 PACI/TACI-type stroke due to carotid occlusion or MCA emboli.
• ⚡ Rare: SAH if dissection extends intracranially → thunderclap headache.

💡 Classic triad: unilateral neck pain + Horner’s syndrome + ischaemic stroke = think carotid dissection.

⚡ Common Triggers & Associations

• Violent sneeze, cough, or vomiting.
• Sports: cricket, rugby, rowing, football.
• Neck extension/rotation: yoga, painting ceilings, hairdresser basin.
• Minor trauma: road traffic accidents, blow to head.
• Chiropractic manipulation (may be causal or just association).
• Recent respiratory infection, migraine, or resuscitation procedures.

🔍 Imaging

• 📸 CTA or MRA: Best non-invasive tests; ultrasound often misses dissections above jaw angle or vertebral arteries.
• 🧲 MRI T1 fat-suppression: shows crescentic wall haematoma = classic crescent sign.
• 📉 Angiography (DSA/CTA/MRA): tapered stenosis, “string sign”, or occlusion.
• 🧠 MRI DWI: detects embolic infarcts in affected territory.

⚖️ Management

• 🩹 ABC + acute stroke therapies: IV thrombolysis or thrombectomy are appropriate. Dissection alone is not a contraindication.
• 💊 Antithrombotic therapy:
  • Antiplatelets (aspirin, clopidogrel) often preferred in practice.
  • Anticoagulation (warfarin/DOAC) reasonable alternative; CADISS trial showed no difference between strategies.
• 📅 Duration: typically 3–6 months, then reassess with repeat imaging.
• ⚠️ Intracranial dissections: higher SAH risk → anticoagulation less favoured.
• 📉 Recurrence risk is low; avoiding provoking mechanism is key.

💡 Exam Pearl: Young adult with stroke + neck trauma + Horner’s → think carotid dissection. Antithrombotics reduce early risk; no proven benefit of anticoagulation over antiplatelets.

📚 Further Reading

• Dissection of the Internal Carotid Artery – JRCPE 2009
• Carotid and Vertebral Artery Dissections – Pract Neurol 2005
• CADISS Trial – Stroke risk after Cervical Artery Dissection