Migraine Headache

Definition

Migraine is a primary headache disorder characterized by recurrent, moderate-to-severe headache attacks often associated with nausea, vomiting, photophobia, and phonophobia, sometimes preceded by aura.

Epidemiology

• Affects approximately 12–15% of the global population.
• More common in women than men (3:1 ratio).
• Onset typically occurs in adolescence or early adulthood.
• Peak prevalence between ages 25–55.
• Family history of migraine is a significant risk factor.

Etiology

• Genetic predisposition: polygenic inheritance pattern.
• Triggers include stress, hormonal changes (menstruation), certain foods (e.g., chocolate, cheese), alcohol, sleep disturbances, and sensory stimuli.
• Neurovascular dysfunction involving trigeminovascular system and cortical spreading depression.
• Neurotransmitter imbalances, particularly serotonin, play a role.

Pathophysiology

• Cortical spreading depression causes transient neuronal hyperactivity followed by suppression.
• Activation of trigeminovascular pathways leads to release of vasoactive neuropeptides (CGRP, substance P) causing inflammation and vasodilation.
• Central sensitization results in hyperalgesia and allodynia.
• Serotonin dysregulation contributes to pain modulation and migraine triggers.
• Autonomic dysfunction can cause associated symptoms like nausea, vomiting, and photophobia.