Migraine with Brainstem Aura

Migraine with brainstem aura (formerly basilar migraine) is migraine with aura symptoms from the brainstem or both hemispheres, without motor weakness. At least two of dysarthria, vertigo, tinnitus, hypacusis, diplopia, ataxia and decreased consciousness are required.

It is rare and affects about 1 to 3% of people with migraine, with a peak in adolescents and young women. Many have also typical visual aura.

Features of aura. Gradual spread over 5 minutes or more, with each symptom lasting 5 to 60 minutes, followed by headache within 60 minutes, often occipital.

Prognosis. Most patients have a good outlook, and the attacks respond to usual migraine prevention. The risk of stroke is low but not zero, so new features need review.

Pathophysiology.

Spreading cortical depolarisation involving brainstem or posterior cortical regions causes the aura, with trigeminovascular activation causing the headache.

Genetic contributions overlap with those of familial hemiplegic migraine in some families.

• Vertigo, dysarthria, tinnitus, diplopia, ataxia, reduced hearing and bilateral paraesthesia.
• Decreased level of consciousness or confusion in some episodes, rarely syncope like.
• Headache after the aura, with nausea, vomiting, photophobia and phonophobia.
• No weakness, and a normal examination between attacks.

Red flags.

• First attack, or aura lasting over 60 minutes.
• Persistent deficit, new focal signs, or onset after age 50.
• Neck pain or trauma (vertebral dissection) and thunderclap onset.

• Clinical diagnosis by ICHD-3, with at least 2 brainstem aura symptoms and at least 2 aura features, after excluding other causes.
• MRI with MR angiography of the head and neck on the first episode or when atypical, to exclude posterior circulation stroke, vertebral dissection and structural lesions.
• EEG if consciousness is reduced; audiometry and vestibular testing for persistent symptoms.
• Cardiac assessment (ECG) when syncope is a feature.

Differential diagnosis. Posterior circulation TIA or stroke, vertebral artery dissection, vestibular migraine, seizure, Ménière disease, hemiplegic migraine, reversible cerebral vasoconstriction syndrome and arrhythmia.

• Acute attacks: rest in a quiet room, hydration and early symptomatic treatment; avoid triptans and ergots as a precaution, since evidence of safety is limited.
• Paracetamol 1 g orally every 6 hours as needed, maximum 4 g in 24 hours (3 g if under 50 kg, chronic alcohol excess or liver disease), for the shortest period that controls pain. Monitor liver function with prolonged use. Reduce dose in hepatic impairment; extend dosing interval when eGFR is under 30.
• Metoclopramide 10 mg orally or intravenously every 8 hours as needed for nausea. Maximum 30 mg daily and 5 days of use. Monitor for extrapyramidal effects, drowsiness and QT interval. Halve the dose when creatinine clearance is under 60 mL/min or in severe hepatic impairment; avoid in phaeochromocytoma, gastrointestinal obstruction and Parkinson disease; acceptable in pregnancy when needed.
• Prevention for frequent or disabling attacks: topiramate 25 mg orally at night for 1 week, increased by 25 mg weekly in 2 divided doses to 100 mg daily. Maximum 200 mg daily. Review at 3 months and stop if there is no benefit. Monitor bicarbonate, mood, weight, kidney stones and visual symptoms. Halve the dose when creatinine clearance is under 70 mL/min; contraindicated in pregnancy and effective contraception is needed.
• Alternative prevention: amitriptyline 10 mg orally at night, increased by 10 mg every 1 to 2 weeks as tolerated to 30 to 50 mg at night. Maximum 75 mg at night. Review at 6 to 8 weeks. Monitor sedation, anticholinergic effects and postural hypotension; baseline ECG over age 40 or with cardiac risk. Avoid after recent myocardial infarction, with arrhythmia, in angle closure glaucoma or urinary retention; cap at 50 mg in older adults; reduce dose in hepatic impairment.
• Avoid oestrogen containing contraception, and stop smoking.
• Identify and avoid triggers (sleep loss, hunger, alcohol, stress).

Monitoring. Review at 3 months, then every 6 to 12 months with a diary.

Referral and escalation. Neurology for diagnosis; urgent assessment when features are atypical or deficits persist.

Special groups. Women: avoid combined hormonal contraception; plan pregnancy and review preventive drugs. Adolescents: lifestyle, school and sleep support.