Explain migraine with aura.

Migraine with Aura: Clinical Overview

Migraine with aura is a recurrent neurological disorder characterized by fully reversible visual, sensory, or other central nervous system symptoms that develop gradually over at least 5 minutes, typically lasting 5-60 minutes, and are usually accompanied or followed within 60 minutes by headache. 1

Core Diagnostic Criteria

To diagnose migraine with aura, the following must be met 1, 2:

• At least 2 attacks fulfilling the aura and characteristic criteria
• One or more fully reversible aura symptoms from the following types:
  • Visual (most common, occurring in 96.3% of cases) 3
  • Sensory (present in 31-33% of cases) 2, 3
  • Speech and/or language (25.6% of cases) 3
  • Motor (rare, 1.8% of cases) 3
  • Brainstem (8.5% of cases) 3
  • Retinal 1

Critical Temporal Characteristics

At least 3 of the following 6 characteristics must be present 1, 2:

• Gradual spread over ≥5 minutes (this "marching" quality is pathognomonic) 1
• Two or more aura symptoms occur in succession 1
• Each individual aura symptom lasts 5-60 minutes (motor symptoms may last up to 72 hours) 1
• At least one aura symptom is unilateral 1
• At least one aura symptom is positive (scintillations for visual, pins and needles for sensory) 1
• The aura is accompanied or followed within 60 minutes by headache 1

Important Clinical Nuances

Timing of Headache Relative to Aura

A critical misconception is that aura always precedes headache—in reality, 73% of attacks have headache present during the aura phase itself. 4 Within the first 15 minutes of aura onset, 54% of patients already report headache meeting migraine criteria. 4

Associated Symptoms During Aura

During the aura phase itself, patients frequently experience 4:

• Photophobia (88% of attacks)
• Phonophobia (73% of attacks)
• Nausea (51% of attacks)

Coexistence with Migraine Without Aura

Many patients with migraine with aura also experience attacks without aura—both diagnoses should be made when this pattern exists. 1 This is not an either/or diagnosis.

Aura Relapses

13% of patients experience aura relapses within 24 hours, which is an underrecognized phenomenon. 3

Key Differential Diagnosis: Distinguishing from TIA

The most critical clinical distinction is between migraine aura and transient ischemic attack (TIA). 2

Migraine aura characteristics 1, 2:

• Symptoms spread gradually over ≥5 minutes
• Symptoms occur in succession with a "marching" quality
• Positive symptoms (scintillations, tingling) are common

TIA characteristics 1, 2:

• Symptoms have sudden, simultaneous onset
• Maximal deficit at onset
• No gradual spread or marching quality

Pathophysiology

Cortical spreading depolarization (SD) is recognized as the mechanism underlying aura symptoms, though the relationship between aura and subsequent headache remains incompletely understood. 5 The trigeminovascular system activation following SD is implicated in headache generation. 6, 5

Common Diagnostic Pitfalls

• Failing to recognize that headache often begins during (not after) the aura phase 4
• Missing atypical aura presentations such as brainstem or motor symptoms 3
• Not diagnosing both migraine with aura AND migraine without aura when both patterns occur 1
• Confusing gradual aura spread with sudden TIA onset 1, 2