Vestibular Migraine

Recurrent vestibular symptoms caused by migraine, and the commonest cause of spontaneous recurrent vertigo. It affects around 1 percent of the general population and up to 10 percent of patients attending dizziness clinics, and is substantially underdiagnosed because vertigo and headache frequently do not occur together.

Mechanism

Not fully established. Proposed mechanisms include cortical spreading depression affecting vestibular cortex, trigeminovascular activation with release of calcitonin gene related peptide affecting inner ear vasculature and vestibular nuclei, ion channel dysfunction shared between the brain and the inner ear, and central sensitisation producing abnormal multisensory integration. The dysfunction is predominantly central rather than labyrinthine, which explains why vestibular tests are frequently normal between attacks.

Diagnostic criteria

Definite vestibular migraine requires:

• At least five episodes of moderate or severe vestibular symptoms lasting 5 minutes to 72 hours.
• Current or previous history of migraine with or without aura.
• One or more migraine features in at least half of episodes: headache with two of unilateral location, pulsating quality, moderate or severe intensity, or aggravation by routine physical activity; photophobia and phonophobia; or visual aura.
• Not better accounted for by another diagnosis.

Probable vestibular migraine is diagnosed when only one of the migraine history or the migraine features accompanying episodes is present.

Overlap with Ménière disease is substantial, and migraine occurs in a high proportion of Ménière patients. Where the two cannot be separated, treating the migraine first is the pragmatic approach.

• Episodic vertigo, which may be spontaneous, positional, visually induced or head motion induced. This variability is characteristic and distinguishes it from the stereotyped attacks of other conditions.
• Duration ranges from minutes to days, with about a third lasting minutes, a third hours and a third several days.
• Headache accompanies the vertigo in fewer than half of attacks, which is the main reason the diagnosis is missed. Vertigo may precede, accompany or follow headache, or occur entirely without it.
• Photophobia, phonophobia and osmophobia during attacks, which are useful diagnostic pointers when headache is absent.
• Visual aura in a minority.
• Marked visual motion sensitivity, with discomfort in supermarkets, on escalators, in traffic and with scrolling screens.
• Motion sickness history, often lifelong and often in childhood, and a family history of migraine.
• Head motion intolerance and persistent low grade unsteadiness between attacks.
• Aural symptoms occur in up to 40 percent, including fullness, tinnitus and mild fluctuating hearing loss, which further blurs the distinction from Ménière disease. Progressive significant hearing loss is not a feature.

Triggers: sleep deprivation, missed meals, stress and the letdown after stress, menstruation, dehydration, specific foods including aged cheese, red wine, chocolate, monosodium glutamate and caffeine withdrawal, and weather change.

Examination

• Usually normal between attacks.
• During an attack, a variety of nystagmus patterns may be seen, including central patterns such as positional downbeat nystagmus, and this variability itself supports the diagnosis.
• Mild central oculomotor abnormalities are found in around 10 to 20 percent between attacks, including saccadic pursuit and gaze evoked nystagmus.

There is no confirmatory test. The diagnosis rests on the history and on exclusion of alternatives.

• Detailed episode history: duration, triggers, associated migraine features, and the temporal relationship to headache.
• A headache and vertigo diary kept over several weeks, which frequently reveals the association the patient has not recognised.
• Pure tone audiometry, which should be normal or show only minor non progressive changes. Progressive low frequency loss points to Ménière disease.
• Vestibular testing, which is normal in the majority between attacks and which serves mainly to exclude peripheral disease.
• Magnetic resonance imaging of the brain and internal auditory meati with gadolinium to exclude vestibular schwannoma, demyelination, posterior fossa lesions and vascular abnormality. Imaging is warranted in most patients presenting with recurrent vertigo where the diagnosis is not already established.
• Investigation for other causes as clinically indicated.

Differential diagnosis and the discriminating features

• Ménière disease: attacks reliably 20 minutes to 12 hours, with progressive documented low frequency sensorineural hearing loss and aural fullness. Vestibular migraine has variable attack duration and no progressive hearing loss.
• Benign paroxysmal positional vertigo: seconds only, with a classical positional nystagmus pattern and response to repositioning. Note that positional vertigo occurring within vestibular migraine will not respond to an Epley manoeuvre.
• Vestibular neuritis: single prolonged episode, not recurrent.
• Transient ischaemic attack and vertebrobasilar insufficiency: older patient, vascular risk factors, associated neurological symptoms.
• Episodic ataxia type 2: episodes lasting hours with interictal downbeat nystagmus and ataxia, responsive to acetazolamide.
• Persistent postural perceptual dizziness, which frequently coexists.
• Panic disorder with vestibular symptoms, which also frequently coexists.

Management follows migraine principles: trigger avoidance and lifestyle regulation, acute treatment, and prophylaxis, with vestibular rehabilitation for the interictal imbalance.

Lifestyle and trigger management, which delivers a large share of the benefit

• Regular sleep, with a consistent schedule including weekends.
• Regular meals without skipping, and adequate hydration.
• Consistent caffeine intake, avoiding both excess and abrupt withdrawal.
• Identify and reduce dietary triggers using a diary rather than blanket elimination diets.
• Regular aerobic exercise.
• Stress management, since both stress and the post stress letdown are common triggers.
• Limit analgesic use, since medication overuse headache develops with simple analgesics on 15 or more days per month, or triptans, opioids and combination analgesics on 10 or more days per month, and it perpetuates the condition.

Acute treatment

• Effectiveness of acute treatment for the vestibular symptoms specifically is less well established than for headache.
• Triptans: sumatriptan 50 to 100 mg orally, or 20 mg intranasally, or 6 mg subcutaneously for severe attacks; rizatriptan 10 mg orally. Contraindicated in ischaemic heart disease, uncontrolled hypertension, cerebrovascular disease, hemiplegic and basilar migraine, and pregnancy.
• Nonsteroidal anti inflammatory drugs: naproxen 500 mg or ibuprofen 400 to 600 mg early in the attack.
• Antiemetics: metoclopramide 10 mg or domperidone 10 mg, which also improve gastric stasis and absorption of oral analgesics. Metoclopramide carries extrapyramidal risk, particularly in young women, and should be limited to 5 days.
• Vestibular sedatives such as prochlorperazine may be used for a severe prolonged attack, but should be limited to a few days, since chronic use perpetuates dizziness and prevents compensation.

Prophylaxis

Indicated for attacks occurring more than 2 to 3 times per month, for severe or disabling attacks, or where acute treatment is failing or overused. Trial each agent for at least 8 to 12 weeks at an adequate dose before declaring failure, which is the commonest reason for apparent treatment resistance.

• Propranolol 40 mg twice daily titrated to 80 to 160 mg daily, or a modified release preparation. Contraindicated in asthma, significant bradycardia and heart block; caution in diabetes where it masks hypoglycaemia, and in depression.
• Amitriptyline 10 mg at night titrated by 10 mg every 1 to 2 weeks to 25 to 75 mg. Useful where there is comorbid insomnia, anxiety or chronic pain. Anticholinergic effects, weight gain, and caution in cardiac conduction disease, glaucoma and prostatic obstruction.
• Nortriptyline as an alternative with fewer anticholinergic effects.
• Topiramate 25 mg at night titrated by 25 mg weekly to 50 to 100 mg daily in divided doses. Useful where weight gain is a concern. Adverse effects include paraesthesia, cognitive slowing and word finding difficulty, renal stones, angle closure glaucoma, and metabolic acidosis. It is teratogenic and reduces the efficacy of combined oral contraceptives at higher doses, so effective contraception must be discussed in women of childbearing potential.
• Venlafaxine 37.5 to 150 mg daily, particularly effective where anxiety or depression coexists, which is common.
• Flunarizine 5 to 10 mg at night where available, effective but causing weight gain, sedation, depression and parkinsonism with long term use.
• Verapamil 120 to 240 mg daily as an alternative calcium channel option.
• Candesartan 8 to 16 mg daily, which has evidence in migraine prophylaxis and is useful in hypertensive patients.
• Calcitonin gene related peptide monoclonal antibodies such as erenumab, fremanezumab and galcanezumab are effective for migraine and show promise in vestibular migraine, and are options in refractory cases where funding permits.
• Magnesium, riboflavin 400 mg daily and coenzyme Q10 have modest evidence and are reasonable adjuncts.

Vestibular rehabilitation

• Effective for interictal imbalance, visual motion sensitivity and head motion intolerance.
• Programmes must be introduced gradually, since aggressive exercise provocation can trigger attacks in this group, unlike in vestibular neuritis where provocation is therapeutic.
• Optokinetic desensitisation for visual motion sensitivity.

Managing comorbidity

• Anxiety and depression are highly prevalent and worsen outcome. Treat them directly, choosing a prophylactic agent that addresses both where possible.
• Persistent postural perceptual dizziness commonly develops on the background of vestibular migraine and requires its own management.
• Screen for and treat sleep disorders including obstructive sleep apnoea.

Follow up

Review at 8 to 12 weeks with a symptom diary to assess response objectively. Titrate to an effective dose before switching agents. Once control is achieved for 6 to 12 months, consider gradual withdrawal of prophylaxis.