When a patient presents for evaluation of headache(s), the goal of the history and examination is to answer two questions:
Is there an underlying cause of headache(s) in need of further laboratory/neuroimaging evaluation (i.e., secondary headache)?
If there is no underlying cause of headache(s), which primary headache syndrome best describes the headache (e.g., migraine, tension, cluster)?
When headaches are determined to be primary rather than secondary, although they may be benign with respect to etiology, such headaches can be extremely disabling. Proper recognition of the precise primary headache syndrome is important because different headache syndromes respond to different abortive and prophylactic medications.
Importantly, a headache syndrome that perfectly fits the description of one of the primary headache syndromes does not always signify that there is no underlying cause. Acute stroke or a structural lesion can produce headaches that meet clinical criteria for primary headache syndromes such as migraine (symptomatic migraine), so clinical context is important in determining the need for further evaluation.
SECONDARY CAUSES OF HEADACHE
The causes of secondary headache range from benign (e.g., eye strain due to need for prescription glasses) to life threatening (e.g., aneurysmal rupture, bacterial meningitis). Causes of secondary headache can be broadly classified as related to:
Intracranial structures: meninges, brain, and/or cerebral blood vessels
Head and neck structures: eyes, ears, nose, sinuses, jaw/teeth, neck
Systemic causes: hypertension, systemic infection, medications
In some patients in whom a cause for headache cannot be found, headache may be a symptom of an underlying psychiatric disorder (e.g., somatization disorder).
Red flags in a patient’s history that should raise concern for a serious underlying etiology of headache can be divided into (Table 26-1):
Characteristics of the headache itself:
Onset: concerning if acute and maximal in intensity at or shortly after onset (thunderclap headache)
Evolution: concerning if increasing in frequency and/or severity
Timing: concerning if worse at night
Relation to prior headaches: concerning if different in quality, severity, and/or timing
Provoking factors: concerning if worsens with coughing, straining, sneezing, supine position
Accompanying symptoms/signs: concerning if fever, seizure, focal neurologic signs, and/or papilledema present
Context/patient history: concerning if:
New headache in an older adult with no prior history of headache
History of cancer
History of immunosuppression (e.g., medications or HIV)
Any of these features warrant evaluation with neuroimaging to look for an underlying cause.
TABLE 26–1Headache Red Flags and Their Clinical Significance. |Favorite Table|Download (.pdf) TABLE 26–1 Headache Red Flags and Their Clinical Significance.
| ||Underlying Potentially Concerning Pathophysiology ||Not-to-Miss Diagnoses |
|Thunderclap onset ||Vascular || |
Venous sinus thrombosis
Cervical artery dissection
|Worse at night ||Elevated intracranial pressure || |
Idiopathic intracranial hypertension
|Worse with coughing/sneezing/straining...|