Makindo Medical Notes

⚠️ Central Retinal Artery Occlusion (CRAO) is an ophthalmic emergency. 👁️ All patients should be urgently assessed by ophthalmology to exclude giant cell arteritis (GCA) and other causes. Most cases are embolic, often from carotid or cardiac sources.

About

• Acute occlusion of the central retinal artery → painless monocular visual loss.
• May be due to arteritis (e.g. temporal arteritis) or more commonly atherosclerosis/embolism.
• Consider CRAO as the “ocular stroke” – same vascular risk factors and prognosis.

Aetiology

• 🫀 Embolism from carotid plaque, aortic arch, or cardiac source (AF, valvular disease).
• 🔥 Vasculitis, particularly giant cell arteritis (GCA).
• Rare causes: trauma, hypercoagulable states.

Risk Factors

• 👴 Older age, ♂ male sex.
• 🚬 Smoking, hypertension, obesity, diabetes.
• 💉 Hyperlipidaemia, cardiovascular disease, arrhythmias (esp. AF).
• 🧬 Thrombophilia.

Clinical Presentation

• ⚡ Sudden, painless monocular visual loss (often profound).
• ⏳ May be transient (amaurosis fugax) or persistent.
• Exam: look for carotid bruit, AF, murmurs, vascular risk factors.
• Ophthalmoscopy: pale ischaemic retina with a cherry red spot at the macula (classic sign).

Pale Ischaemic Retina with Cherry Red Spot

Differential Diagnosis

• 🌋 Temporal arteritis (arteritic CRAO).
• 🩸 Central retinal vein occlusion (CRVO).
• 👁️ Retinal detachment.
• 🌈 Migraine aura with transient visual loss.

Investigations

• 🧪 Bloods: FBC, ESR/CRP (for GCA), U&E, glucose, lipids.
• 🫀 ECG (look for AF), echocardiogram if embolic source suspected.
• 🩻 Carotid Doppler US for stenosis/plaques.
• 🧠 MRI brain/angiography if concern for cerebral embolism or stroke.

Management

• 👁️ Visual prognosis is usually poor; severity correlates with degree of retinal oedema.
• ⚡ Emergency measures (limited evidence): ocular massage, IV acetazolamide, anterior chamber paracentesis, hyperbaric oxygen. Often of questionable efficacy but may be attempted acutely.
• 💉 Consider thrombolysis if onset <4.5h, but this remains controversial and trial-dependent.
• 📉 Vascular risk reduction is key:
  • Aspirin 300 mg stat then 75–300 mg OD, or Clopidogrel 300 mg stat then 75 mg OD.
  • Atorvastatin 20–40 mg OD (or high-intensity statin per lipid profile).
  • Anticoagulation if AF confirmed.
• 🩺 Carotid endarterectomy/stenting if ipsilateral stenosis >50% and peri-op risk is acceptable.
• 🔥 If GCA suspected: start high-dose IV/PO steroids immediately while awaiting biopsy.

References

• JAMA Neurol. 2015;72(10):1148–54 – CRAO Review
• BNF Guidance