Age older than 40 years.
Rapid onset and severe intensity (ie, “thunderclap” headache), trauma, onset during exertion.
Fever, vision changes, neck stiffness.
Current or past history of hypertension.
Neurologic findings (mental status changes, motor or sensory deficits, loss of consciousness).
Headache is a common reason that adults seek medical care, accounting for approximately 13 million visits each year in the United States to physicians’ offices, urgent care clinics, and emergency departments. It is the fifth most common reason for emergency department visits, and second most common reason for neurologic consultation in the emergency department. A broad range of disorders can cause headache (see Chapter 24-01). This section deals only with acute nontraumatic headache in adults and adolescents. The challenge in the initial evaluation of acute headache is to identify which patients are presenting with an uncommon but life-threatening condition; approximately 1% of patients seeking care in emergency department settings and considerably less in office practice settings fall into this category.
Diminution of headache in response to typical migraine therapies (such as serotonin receptor antagonists or ketorolac) does not rule out critical conditions such as subarachnoid hemorrhage or meningitis as the underlying cause.
A careful history and physical examination should aim to identify causes of acute headache that require immediate treatment. These causes can be broadly classified as imminent or completed vascular events (intracranial hemorrhage, thrombosis, cavernous sinus thrombosis, vasculitis, malignant hypertension, arterial dissection, cerebral venous thrombosis, transient ischemic attack, or aneurysm), infections (abscess, encephalitis, or meningitis), intracranial masses causing intracranial hypertension, preeclampsia, and carbon monoxide poisoning. Having the patient carefully describe the onset of headache can be helpful in diagnosing a serious cause. Report of a sudden-onset headache that reaches maximal and severe intensity within seconds or a few minutes is the classic description of a “thunderclap” headache; it should precipitate workup for subarachnoid hemorrhage, since the estimated prevalence of subarachnoid hemorrhage in patients with thunderclap headache is 43%. Thunderclap headache during the postpartum period precipitated by the Valsalva maneuver or recumbent positioning may indicate reversible cerebral vasoconstriction syndrome. Other historical features that raise the need for diagnostic testing include headache brought on by the Valsalva maneuver, cough, exertion, or sexual activity.
The medical history can also guide the need for additional workup. Under most circumstances (including a normal neurologic examination), new headache in a patient older than 50 years or with HIV infection warrants immediate neuroimaging (Table 2–8). When the patient has a history of hypertension—particularly uncontrolled hypertension—a complete search for other features of “malignant hypertension” is appropriate to determine the urgency of control of hypertension (see Chapter 11-05). Headache and hypertension associated with pregnancy may be due to preeclampsia. Episodic headache associated with the triad of hypertension, palpitations, and sweats is suggestive of pheochromocytoma. ...