Makindo Medical Notes

👁️ Transient Monocular Blindness (Amaurosis Fugax) refers to a temporary loss of vision in one eye, usually lasting seconds to minutes. ⚠️ It often reflects reduced flow in the ophthalmic artery and is an important warning sign of embolic stroke.

About

• Transient Monocular Blindness (TMB) = Amaurosis Fugax.
• Represents retinal ischaemia, most often due to carotid or cardiac emboli.
• Identifies patients at high risk of TIA / embolic stroke.

Aetiology

• 🩸 Embolic occlusion or low flow in the ophthalmic artery.
• 💔 Ipsilateral carotid disease (plaque, stenosis) is the commonest cause.
• ❤️ Cardioembolism – atrial fibrillation, valvular disease, endocarditis.

Clinical Features

• Classic description: “Curtain descending over vision”, lasting seconds–minutes.
• Can be complete visual loss or blurred/reduced acuity.
• Resolves spontaneously, but recurrence common.

Differentials

• 🧓 Temporal arteritis (GCA) – especially in patients >50 yrs with headache, scalp tenderness, jaw claudication, ↑ESR/CRP.
• 🌩️ Migraine aura – tends to have positive symptoms (zig-zag lines, flashing lights) and gradual onset.
• Retinal detachment (less transient, progressive loss).
• Optic neuritis (painful visual loss, often younger patients).

Investigations

• 🧪 Bloods: FBC, U&E, LFTs, ESR/CRP (rule out vasculitis/GCA).
• 🫀 ECG (AF detection), Echocardiogram (cardiac embolic source).
• 🧠 Carotid Doppler ultrasound (assess stenosis, plaque).
• Consider MRI/MRA brain + neck vessels if stroke risk suspected.

Management – Vascular Risk Reduction

• 💊 Antiplatelet: Aspirin 300 mg OD stat → then 75–300 mg OD, or Clopidogrel 300 mg stat → then 75 mg OD.
• 🧴 Statin: Atorvastatin 20–40 mg OD (or equivalent) to stabilise atherosclerosis.
• 🔪 Carotid Endarterectomy: Indicated if ipsilateral carotid stenosis >50% and peri-operative risk is low.
• ⚡ Anticoagulation: If due to atrial fibrillation or cardioembolic source.
• 🌍 Lifestyle: smoking cessation, BP control, diabetes optimisation, diet & exercise.

References

• UK Stroke Guidelines
• BNF: Antiplatelets & Anticoagulants