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Headache is a common complaint for patients presenting to an emergency department (ED). The majority of headaches have benign causes (96%), although evaluating patients for potential high-risk features may be useful when screening for headaches associated with significant morbidity or mortality (see Table 140-1).

Table 140-1

High-Risk Features for Headache: Clinical “Red Flags”


Identify patients with high-risk features, such as patients older than 50 years with a new or worsening headache. Sudden onset of a maximum intensity headache, often described as a “thunderclap headache,” is associated 10% to 14% of the time with a high-risk etiology (see Table 140-2).

Table 140-2

Causes of Thunderclap Headache

Assess headache quality, pattern, frequency, intensity, location, and any associated symptoms such as fever or visual changes. Additional information such as medication history, potential toxic exposures, prior headache history, substance abuse, comorbid conditions, or family history of headaches may be useful.

Tailor the physical examination based on patient history to identify potential causes of headache. Specific physical examination findings may help to focus potential diagnoses, such as the presence of fever, hypertension, sinus or temporal artery tenderness, papilledema or elevated intraocular pressure, neck stiffness, or neurologic abnormalities.

While laboratory testing is often of limited value in the workup of an acute headache, erythrocyte sedimentation rate (ESR) and/or C-reactive protein (CRP) are useful when temporal arteritis is suspected. When indicated, a noncontrast head CT scan can be useful to evaluate for intracranial hemorrhage, subdural hematoma, space-occupying lesion, signs of potentially elevated intracranial pressure, or subarachnoid hemorrhage. Additional diagnostic studies may be indicated when the head CT is negative, for example, if clinical suspicion remains for a subarachnoid hemorrhage. Depending on clinical suspicion, other imaging modalities may be useful, such as MRI to assess for cerebral venous thrombosis, and MR or CT angiography to evaluate for arterial dissection or small subarachnoid hemorrhage. Lumbar puncture can be utilized when meningitis or encephalitis is suspected (see Chapter 148, “Central Nervous System ...

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