Headache occurs in all age groups and accounts for 1-2% of emergency department evaluations and up to 4% of medical office visits; the causes are myriad (Table 6-1). Although most often a benign condition (especially when chronic and recurrent), headache of new onset may be the earliest or the principal manifestation of serious systemic or intracranial disease and therefore requires thorough and systematic evaluation.
Table 6-1.Causes of Headache and Facial Pain. ||Download (.pdf) Table 6-1. Causes of Headache and Facial Pain.
Other cerebrovascular diseases
Meningitis or encephalitis
Ophthalmic disorders (glaucoma, acute iritis)
Less common causes
Spontaneous intracranial hypotension
Giant cell (temporal) arteritis
Intracranial mass (tumor, subdural hematoma, abscess)
Idiopathic intracranial hypertension/pseudotumor cerebri
Trigeminal neuralgia (tic douloureux)
Persistent idiopathic facial pain
Medication overuse headache
Cluster headache and trigeminal autonomic cephalgias
Cervical spine disease
An etiologic diagnosis of headache is based on understanding the pathophysiology of head pain; obtaining a history, with characterization of the pain as acute, subacute, or chronic; performing a careful physical examination; and formulating a differential diagnosis.
Headache is caused by traction, displacement, inflammation, or distention of the pain-sensitive structures in the head or neck. The bony skull, most of the dura, and most regions of brain parenchyma are not pain sensitive.
A. Intracranial Pain-Sensitive Structures
These include the venous sinuses (eg, sagittal sinus); anterior and middle meningeal arteries; dura at the base of the skull; trigeminal (V), glossopharyngeal (IX), and vagus (X) nerves; proximal portions of the internal carotid artery and its branches near the circle of Willis; brainstem periaqueductal gray matter; and sensory nuclei of the thalamus.
B. Extracranial Pain-Sensitive Structures
These include the periosteum of the skull; skin; subcutaneous tissues, muscles, and arteries; neck muscles; second (C2) and third (C3) cervical nerves; eyes, ears, teeth, sinuses, and oropharynx; and mucous membranes of the nasal cavity.
RADIATION OR PROJECTION OF PAIN
The trigeminal (V) nerve carries sensation from intracranial structures in the anterior and middle fossae of the skull (above the cerebellar tentorium). Discrete intracranial lesions in these locations can produce pain that radiates in the trigeminal nerve distribution (Figure 6-1).
The glossopharyngeal (IX) and vagus (X) nerves convey sensation from part of the posterior fossa; pain originating in this area may also be referred to the ear or throat, as in glossopharyngeal neuralgia.
The upper cervical (C2-C3) nerves transmit stimuli from infratentorial and cervical structures; therefore, pain from posterior fossa lesions ...