What is the pathophysiology and treatment approach for vestibular migraine?

Pathophysiology and Treatment of Vestibular Migraine

Pathophysiology

The precise mechanisms underlying vestibular migraine remain incompletely understood, but the condition is believed to involve peripheral and central activation of the trigeminovascular system, with genetic factors likely playing a role, particularly when unilateral auditory symptoms are present. 1

The pathophysiological substrate involves:

• Trigeminovascular system activation affecting both peripheral and central vestibular pathways, similar to the mechanism in typical migraine 1
• Cortical spreading depression is thought to be the underlying neurophysiological substrate of migraine aura, which may extend to vestibular structures 1
• Genetic predisposition appears to contribute to susceptibility, especially in cases with auditory involvement 1
• Cerebellar and deep white matter lesions are frequently observed on MRI in migraine patients, suggesting structural changes that may contribute to vestibular symptoms 1

The condition affects approximately 3.2% of the population over their lifetime and accounts for up to 14% of vertigo cases, making it the most common neurological cause of spontaneous episodic vertigo in adults 2, 3

Diagnostic Criteria

Diagnosis requires ≥5 episodes of vestibular symptoms lasting 5 minutes to 72 hours, with concurrent or historical features of migraine, after ruling out other vestibular disorders. 2

Key diagnostic features include:

• Episode duration: 5 minutes to 72 hours, though the core episode rarely exceeds 72 hours 1
• Vestibular symptoms: May include spontaneous vertigo, positional vertigo, visually induced vertigo, or head-motion intolerance 1
• Migrainous features: At least 50% of episodes must have headache with migraine characteristics, photophobia, phonophobia, or visual aura 1
• Exclusion of other causes: Central causes (stroke, multiple sclerosis), Ménière's disease, BPPV, and vestibular neuritis must be ruled out 2

Treatment Approach

First-Line: Lifestyle Modifications

Begin immediately with dietary and lifestyle modifications, which serve as the foundation of treatment regardless of attack frequency. 2, 4

Implement the following changes:

• Dietary restrictions: Limit salt/sodium intake, avoid excessive caffeine, alcohol, and nicotine 2, 4
• Nutritional support: Eat well-balanced meals, maintain adequate hydration, consider vitamin B2 and magnesium supplementation 2, 5
• Sleep hygiene: Establish regular sleep patterns and ensure restful sleep 2, 5
• Stress management: Implement stress reduction techniques, relaxation exercises, and biofeedback 2, 6
• Regular exercise: Begin a consistent exercise program, which has been shown to be as effective as pharmacological approaches when combined with other interventions 2

Acute Attack Management

For acute vestibular migraine attacks, use antiemetic medications such as diphenhydramine or meclizine to ameliorate symptoms, and consider triptans for concurrent headache. 2, 6

Acute treatment options:

• Antiemetics: Diphenhydramine, meclizine, or metoclopramide can help reduce vertigo and nausea during attacks 2, 6
• Triptans: May be used for concurrent headache, though evidence for vertigo relief is very limited 2, 7
• Vestibular suppressants: Centrally acting anticholinergics like scopolamine can suppress acute vertigo but have significant side effects and should not be used long-term 2, 8
• Benzodiazepines: May help with acute symptoms but carry risk of drug dependence and should be avoided for prolonged use 2, 8

Critical pitfall: Limit simple analgesics to fewer than 15 days/month and triptans to fewer than 10 days/month to prevent medication overuse headache 2

Preventive Pharmacotherapy

Initiate preventive medication when symptoms occur ≥2 days per month despite optimized lifestyle modifications, starting with first-line agents: beta blockers, topiramate, or candesartan. 2, 4

First-Line Preventive Medications:

• Beta blockers: Propranolol, metoprolol, atenolol, or bisoprolol—particularly useful in patients with comorbid hypertension 2, 4
• Topiramate: 50-100 mg oral daily—especially beneficial in obese patients (common adverse effects include cognitive inefficiency, paresthesia, fatigue, and weight loss) 2, 6
• Candesartan: Angiotensin receptor blocker—first-line option, particularly useful in hypertensive patients 2

Second-Line Preventive Medications (if first-line agents fail):

• Flunarizine: 5-10 mg oral once daily—calcium channel blocker effective for prevention, but should be avoided in patients with Parkinsonism or depression 2, 6
• Amitriptyline or nortriptyline: Tricyclic antidepressants—particularly useful for patients with coexisting anxiety or depression 2, 6
• Valproic acid: 600-1,500 mg oral once daily—option for men only; absolutely contraindicated in women of childbearing potential due to teratogenicity 2

Third-Line Preventive Medications (for refractory cases):

• CGRP monoclonal antibodies: Erenumab (70 or 140 mg subcutaneous once monthly), fremanezumab (225 mg subcutaneous once monthly or 675 mg quarterly), galcanezumab, or eptinezumab (100 or 300 mg intravenous quarterly)—assess efficacy after 3-6 months 2, 8
• OnabotulinumtoxinA: 155-195 units to 31-39 sites every 12 weeks—the only FDA-approved therapy for prophylaxis of headache in adults with chronic migraine with vestibular symptoms; assess efficacy after 6-9 months 2, 8

Treatment Assessment Timeline

Assess efficacy of oral preventive medications after 2-3 months at therapeutic dose; do not abandon treatment prematurely, as efficacy takes weeks to months to establish. 2, 8

• Oral preventives: Evaluate after 2-3 months at therapeutic dose 2
• CGRP monoclonal antibodies: Assess after 3-6 months 2
• OnabotulinumtoxinA: Assess after 6-9 months 2
• Treatment duration: Consider pausing treatment after 6-12 months of successful control to determine if preventive therapy can be stopped 2
• Monitoring tools: Encourage patients to maintain a headache diary and use validated disability tools such as the Migraine Disability Assessment Score and HIT-6 to track treatment response 2

Non-Pharmacological Approaches

Implement vestibular rehabilitation therapy (VRT) regardless of etiology, as it promotes central compensation and is as effective as pharmacological approaches. 2, 8

VRT components:

• Exercise focus: Progressive exercises targeting habituation, adaptation, and compensation for vestibular deficits 8, 4
• Cawthorne-Cooksey exercises: Performed until symptoms fatigue 8
• Delivery method: Home-based therapy is equally effective as clinician-supervised therapy, though initial instruction is important 8
• Biobehavioral therapy: Relaxation techniques, stress management, and biofeedback can be as effective as pharmacological approaches and should be combined with medication 2, 6
• Neuromodulatory devices: Can be considered as adjuncts or stand-alone treatment when medication is contraindicated 2

Management of Comorbidities

Screen for and treat comorbid anxiety, depression, and sleep disturbances, as these worsen vertigo and require concurrent treatment. 8, 4

• Psychiatric comorbidities: Anxiety and depression are frequently found in vestibular migraine and should be addressed concurrently 9
• Modifiable risk factors: Identify and manage obesity, medication overuse, caffeine use, obstructive sleep apnea, and stress 2
• Coexisting vestibular conditions: Screen for vestibular migraine in patients with other vestibular disorders, as 35% of Ménière's disease patients also meet criteria for vestibular migraine 1

Critical Pitfalls to Avoid

Never use oral ergot alkaloids, opioids, or barbiturates due to questionable efficacy with considerable adverse effects and dependency risk. 2, 8, 4

Additional pitfalls:

• Premature treatment abandonment: Failure of one preventive treatment does not predict failure of other drug classes 2, 8
• Overuse of acute medications: Risks medication overuse headache—limit use as specified above 2, 8
• Prolonged vestibular suppressant use: Impairs central compensation and should be avoided 8, 4
• Inadequate follow-up: Reassess within 1 month to confirm symptom resolution or identify treatment failure 4
• Ignoring comorbidities: Failure to recognize and manage anxiety, depression, and sleep disturbances worsens outcomes 2, 4

Treatment Algorithm Summary

1. Immediate implementation: Lifestyle and dietary modifications for all patients 2, 4
2. Acute attacks: Antiemetics ± triptans for concurrent headache 2, 6
3. Preventive therapy indication: Symptoms ≥2 days/month despite lifestyle modifications 2, 4
4. First-line preventive: Beta blockers, topiramate, or candesartan 2, 4
5. Assessment: Evaluate efficacy after 2-3 months at therapeutic dose 2
6. Second-line preventive: Flunarizine, amitriptyline/nortriptyline, or valproic acid (men only) if first-line fails 2
7. Third-line preventive: CGRP monoclonal antibodies or onabotulinumtoxinA for refractory cases 2, 8
8. Concurrent VRT: Implement regardless of pharmacotherapy 2, 8, 4
9. Comorbidity management: Screen and treat anxiety, depression, and sleep disorders throughout 2, 4