Amaurosis Fugax due to embolic strokes

 

History:

A pleasant 76-year old lady presented with a 3 months history of blurring of vision in the right eye. This had occurred on two occasions lasting up to 10 minutes. Again, prior to presentation, she had a sudden onset of visual loss in the same eye described as "like a shutter coming down". There were no other symptoms. She had a previous history of atrial fibrillation, hypercholesterolaemia and peripheral vascular disease. Clinical examination was normal. Ophthalmological examination was normal. Doppler ultrasound scan of the carotid confirmed >90% stenosis of the right internal carotid artery (ICA). There was no significant stenosis on the left. MRI of the brain demonstrated an old capsular infarct and no evidence of previous strokes in the occipital lobe. MRA also confirmed the >90% stenosis on the right ICA. She was consented for a right carotid endarterectomy under local anesthesia. The operation was uneventful.

Discussion:

Patients describe visual symptoms due to TIA in various ways. The symptom in this case is highly suggestive of Amaurosis Fugax due to emboli from the internal carotid artery territory (ICA) travelling into the retinal artery.Ophthalmic examination did not demonstrate a retinal detachment nor any sign of blood in the vitreous humour. This is important and ocular examination is a vital part of the care of patients with history of amaurosis fugax. Retinal detachment can cause the symptom and should be managed by the appropriate specialist. Although, no occipital infarcts were seen on the scan, there may be evidence in some cases. The stenosis of the right ICA was confirmed by MRA and the atheromatous plaque was removed surgically. Carotid Endarterectomy has been proven to be of benefit in symptomatic patients with >75% stenosis.

Images

1: MRI brain

No major infarct but evidence of small vessel disease.

2: MRA carotids

Follow the right common carotid to the very tight bifurcation.

Compare with the left side (left, is on your right hand-side!)

Created by B I Ogungbo in September 2002. Modified January 2008. ©