Total visual field loss and migraine
A This is seen in retinal migraine, one of the recognised migraine variants and presents with transient visual loss. It is commonly seen in children and young adults.
Retinal migraine is probably due to vasospasm of the choroidal or retinal arteries. Symptoms associated with retinal artery ischemia are similar to those of amaurosis fugax. Choroidal ischemia produces a 'mosaic' or 'jigsaw' pattern of scotomata that enlarge and merge together, producing total visual loss.
The choroidal artery pattern of visual loss is more common and may be due to the fact the choroidal artery receives more sympathetic innervation than the retinal.
A family or personal history of migraine is common. Patients report recurrent (every six-eight weeks) monocular visual loss lasting three to 30 minutes. Episodes are limited to the same eye in more than 90 per cent of patients. Postural changes, exercise (hyperventilation may result in alkalosis precipitating vascular spasm), and oral contraceptive agents may lead to symptoms.
A range of investigations to rule out other causes may be indicated if there are other associated signs and symptoms. These could include carotid duplex ultrasound, fluorescein angiography, MRA or CT angiography including the neck, hypercoagulability work-up and ESR.
As for treatment, anecdotal data support the use of typical antimigraine prophylactic agents.
Dr Sunny Philip is consultant paediatric neurologist and
honorary senior lecturer,
Birmingham Children's Hospital