MIGRAINE 

1. Definition

Migraine is a primary headache disorder characterized by recurrent attacks of moderate–severe headache, usually unilateral, pulsatile, associated with nausea and/or photophobia–phonophobia, with or without transient focal neurological symptoms (aura).

2.  Epidemiology

• Prevalence: ~12–15% worldwide
• Female:Male = 3:1
• Peak: 20–50 years
• Strong genetic component (esp. migraine with aura)

3.  Pathophysiology 

A. Trigeminovascular System Activation

• Activation of trigeminal nerve → release of:
• CGRP (Calcitonin Gene-Related Peptide)
• Substance P
• Neurokinin A
• Leads to:
• Vasodilation
• Neurogenic inflammation
• Pain transmission

B. Cortical Spreading Depression (CSD)

• Key mechanism for aura
• Wave of neuronal depolarization → suppression
• Starts in occipital cortex → spreads anteriorly
  → explains visual aura progression

C. Brainstem Dysfunction

• Dysfunction in:
• Periaqueductal gray
• Dorsal raphe nucleus

D. Central Sensitization

• Leads to:
• Allodynia
• Chronic migraine progression

4.  Classification (ICHD-3)

1. Migraine WITHOUT aura (most common)

2. Migraine WITH aura

3. Chronic migraine

(≥15 headache days/month, ≥8 migraine days)

4. Complications:

• Status migrainosus
• Persistent aura without infarction
• Migrainous infarction

5. Migraine WITHOUT Aura — Diagnostic Criteria (ICHD-3)

≥5 attacks fulfilling:

• Duration: 4–72 hours
• ≥2 of:
• Unilateral
• Pulsating
• Moderate–severe
• Aggravated by routine activity
• During headache ≥1:
• Nausea/vomiting
• Photophobia + phonophobia

6. Migraine WITH Aura — Diagnostic Criteria

≥2 attacks with:

Aura features:

• Fully reversible
• Develop gradually over ≥5 min
• Each symptom lasts 5–60 min

Types of aura:

• Visual (MOST common)
• Sensory
• Speech/language
• Motor (hemiplegic migraine)
• Brainstem

Common Visual Aura

• Scintillating scotoma
• Fortification spectra (zig-zag lines)
• Expanding visual field defect

7. Phases of Migraine

1. Prodrome (hours–days)

• Yawning
• Mood change
• Food craving

2. Aura (if present)

• Visual/sensory disturbances

3. Headache phase

• Throbbing, unilateral
• Nausea, vomiting

4. Postdrome

• Fatigue
• Cognitive slowing

8. Red Flags (Rule out secondary headache) — SNOOP

• S: Systemic symptoms (fever, cancer)
• N: Neurological deficit
• O: Onset sudden (thunderclap)
• O: Older age (>50)
• P: Pattern change

9.  Investigations

 Clinical diagnosis (NO routine imaging)

Imaging indicated if:

• Atypical aura
• First/worst headache
• Focal deficits
• Seizures

10. Management (GUIDELINE-BASED)

A. Acute (Abortive) Treatment

Stepwise approach

1. Simple analgesics

• Paracetamol
• NSAIDs (Ibuprofen, Naproxen)

2. Triptans (First-line moderate–severe)

• Example: Sumatriptan
• Others:
• Rizatriptan
• Zolmitriptan

 Mechanism:

• 5-HT1B/1D agonist → ↓CGRP + vasoconstriction

3. Antiemetics

• Metoclopramide
• Prochlorperazine

4. Newer drugs 

• CGRP antagonists:
• Ubrogepant
• Rimegepant
• Ditans:
• Lasmiditan

## Avoid

• Opioids (guideline: strongly discouraged)

B. Preventive (Prophylaxis)

Indications:

• ≥4 attacks/month
• Significant disability
• Poor response to acute therapy

First-line

• Beta-blockers:
• Propranolol
• Antiepileptics:
• Topiramate
• Sodium valproate
• TCA:
• Amitriptyline

CGRP monoclonal antibodies

• Erenumab
• Fremanezumab

Others:

• Candesartan
• Botulinum toxin (chronic migraine)

C. Non-Pharmacological

• Trigger avoidance:
• Stress
• Sleep deprivation
• Certain foods (cheese, chocolate)
• Lifestyle:
• Regular sleep
• Hydration
• Exercise

11. Special Types 

Hemiplegic migraine

• Motor weakness
• Can mimic stroke

Basilar (Brainstem) migraine

• Vertigo
• Diplopia
• Ataxia
• No motor weakness

Retinal migraine

• Monocular vision loss

Menstrual migraine

• Estrogen withdrawal trigger

12. Complications

• Status migrainosus (>72 hrs)
• Medication overuse headache
• Stroke risk ↑ (especially with aura + OCP + smoking)

13.  Migraine vs Tension vs Cluster 

14.PEARLS

• Aura → gradual onset, NOT sudden
• Visual aura → zig-zag lines = fortification spectra
• First-line acute = triptan + NSAID
• Chronic migraine → botox + CGRP inhibitors
• Avoid triptans in:
• IHD
• Stroke
• Uncontrolled HTN

15.  Exam Traps

• Sudden visual loss → think TIA, not migraine
• First aura after age 50 → investigate
• Persistent aura → consider stroke