Migraine

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management

Definition

Migraine is a common primary headache disorder characterised by recurrent attacks of moderate to severe headache, often associated with nausea, photophobia, and phonophobia. It may occur with or without aura.

Aetiology

The exact cause of migraine is unclear, but it is believed to be related to neurovascular dysregulation.

Pathophysiology

  • Involves abnormal activation of the trigeminovascular system.
  • Cortical spreading depression may cause aura symptoms.
  • Neurotransmitter changes (e.g., serotonin fluctuations) contribute to pain perception.
  • Inflammatory mediators cause vasodilation and neuronal sensitisation.

Risk factors

  • Family history (strong genetic component).
  • Hormonal changes (menstrual migraines).
  • Stress and anxiety.
  • Dietary triggers (caffeine, alcohol, chocolate, processed foods).
  • Sleep disturbances.
  • Environmental factors (bright lights, loud noises, strong smells).

Signs and symptoms

Migraine presents in different phases:

1. Prodromal Phase (Hours to Days Before Headache):

  • Fatigue.
  • Mood changes (irritability, depression, or euphoria).
  • Food cravings.

2. Aura (Present in Migraine with Aura):

  • Visual symptoms: scintillating scotoma, flashing lights.
  • Sensorimotor symptoms: tingling, numbness, speech difficulties.
  • Reversible: aura symptoms resolve within 5–60 minutes.

3. Headache Phase:

  • Location: unilateral (but can be bilateral).
  • Quality: throbbing or pulsatile.
  • Severity: moderate to severe.
  • Duration: 4–72 hours.
  • Aggravated by: physical activity.
  • Associated symptoms: nausea, vomiting, photophobia, phonophobia.

4. Postdromal Phase ("Migraine Hangover"):

  • Fatigue, difficulty concentrating.
  • Lingering head sensitivity.

Investigations

  • Clinical diagnosis: based on characteristic history.
  • MRI brain: if red flags are present (e.g., new onset headache in older age, neurological deficits).

Management

1. Acute Treatment (Abortive Therapy):

  • First-line: NSAIDs (ibuprofen 400 mg) or paracetamol.
  • Triptans: Sumatriptan 50–100 mg oral or nasal spray.
  • Anti-emetics: Metoclopramide or prochlorperazine for nausea.

2. Preventative Treatment (If Frequent or Severe Migraines):

  • First-line: propranolol or amitriptyline.
  • Alternative: topiramate (avoid in pregnancy).

3. Lifestyle Modifications:

  • Identify and avoid triggers (food, stress, sleep disruption).
  • Regular sleep schedule and hydration.
  • Relaxation techniques (CBT, yoga, mindfulness).

4. Specialist Referral:

  • Neurology referral for complex or refractory migraines.
  • Consider secondary headache causes if atypical symptoms.
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