From the Guidelines
Investigation is typically not necessary for patients presenting with a classic migraine headache pattern in general practice, unless certain red flags are present, as outlined in the guidelines by the U.S. Headache Consortium 1. When evaluating a patient with a headache consistent with migraine, it is essential to consider the patient's overall clinical presentation and history to determine the need for investigation.
- The U.S. Headache Consortium guidelines suggest that testing should be avoided if it will not lead to a change in management, and testing is not recommended if the patient is not significantly more likely than a person in the general population to have a significant abnormality 1.
- Red flags that may indicate the need for investigation include sudden-onset severe headache, new headache in patients over 50 years, headaches that worsen with Valsalva maneuvers or positional changes, headaches accompanied by fever or neck stiffness, neurological deficits that don't resolve, headaches in immunocompromised patients, or a significant change in previously stable headache patterns.
- For patients with concerning features, appropriate investigations may include neuroimaging (CT or MRI), lumbar puncture, or blood tests depending on the suspected underlying cause, as suggested by the American Academy of Neurology and the U.S. Headache Consortium 1. The goal of selective investigation is to identify potentially serious secondary causes of headache, such as subarachnoid hemorrhage, meningitis, tumor, or arterial dissection, that require specific management, while avoiding over-investigation of typical migraine presentations.
- A detailed history and thorough physical and neurologic examination are crucial in determining the need for investigation, and physicians should be aware of the patient's sources of medical information, such as the National Headache Foundation website 1.
- Electroencephalography is not useful in the routine evaluation of patients with headache but may be appropriate in those who have associated symptoms suggestive of a seizure disorder, atypical migrainous aura, or episodic loss of consciousness 1.
From the Research
Investigation for Migraine in General Practice
When a patient presents with a headache consistent with migraine in general practice, the decision to investigate further depends on several factors.
- The presence of red flags is a crucial determinant for the need for investigation. Red flags include symptoms such as seizures, cognitive changes, sudden onset, or associated symptoms that suggest a secondary cause for the headache 2, 3, 4.
- Atypical features of the headache, such as unusual, prolonged, or persistent aura, increasing frequency, severity, or change in clinical features, also warrant further investigation 5.
- Patients with a normal neurologic examination and no atypical features or red flags are unlikely to require neuroimaging, as clinically significant abnormalities are relatively rare in this population 5.
- The usefulness of the ICHD 3 criteria in differentiating primary from non-primary headaches has been suggested, with fulfilling these criteria being associated with primary headaches 4.
Indications for Investigation
Investigation may be considered in the following situations:
- Unusual, prolonged, or persistent aura
- Increasing frequency, severity, or change in clinical features
- First or worst migraine
- Migraine with brainstem aura
- Migraine with confusion
- Migraine with motor manifestations (hemiplegic migraine)
- Late-life migraine accompaniments
- Aura without headache
- Side-locked headache
- Posttraumatic headache 5
Non-Indications for Investigation
- Patients with headaches consistent with migraine who have a normal neurologic examination and no atypical features or red flags do not require neuroimaging, as the yield is likely to be low 5.