On an annual basis, headache as a presenting symptom to the emergency department (ED) accounts for about 2.2–4.5% of all ED visits. Less than 1% of these patients are found to have a life-threatening condition. The ability to quickly differentiate immediate, life-threatening etiologies from benign headaches relies heavily on a thorough history and physical examination. Understanding the underlying pathophysiology of headaches will also aid in risk stratifying patients who present with the complaint of headache.
Headache is caused by traction, displacement, inflammation, or distention of pain-sensitive structures in the head or neck. Disorders of the scalp, teeth, eyes, ears, and of the mucous membranes of the nose, sinuses, and oropharynx can also produce headache pain. Pain-sensitive structures about the calvarium include the scalp and its blood vessels, the neck muscles, and the upper cervical nerves. The skull, brain, and most of the dura are not pain sensitive. In general, discrete intracranial lesions above the cerebellar tentorium produce pain in trigeminal distribution (anterior to ears), whereas lesions in the posterior fossa project pain to the second and third cervical dermatomes (posterior to ears).
IMMEDIATE EVALUATION AND MANAGEMENT OF HEADACHE CAUSED BY LIFE-THREATENING CONDITIONS
Before performing a thorough history and physical examination, certain questions must be asked to quickly identify potential life-threatening situations.
Management of complaints of headache.
Has Head Trauma Occurred?
If recent head trauma has occurred, evaluation of this problem takes precedence (Chapter 22).
Patients may have headache following one or more grand mal seizures. However, because the seizures may themselves be due to serious underlying disease (eg, subdural hematoma), evaluation of this problem takes precedence (Chapter 19).
Are There Focal Neurologic Abnormalities?
The presence of new focal neurologic abnormalities with headache, especially if papilledema is present as well, is strongly suggestive of a mass lesion (tumor, hematoma, abscess). Computed tomography (CT) scan or magnetic resonance imaging (MRI) should be performed as soon as possible to make the diagnosis. Further evaluation is discussed in Chapter 37.
Is Headache New or of Acute Onset?
The single most important item of information to obtain from a patient with headache is whether the headache is new or acute in onset. A new headache is one occurring in a patient without a history of headaches, or a novel pattern or quality of pain in a patient with a history of headaches. A headache that is acute in onset is far more likely to have underlying pathology that may be life threatening requiring prompt investigation.