6.3: Subarachnoid hemorrhage

The headache following subarachnoid hemorrhage is acute, severe, continuous, and generalized. It is virtually always associated with nausea, vomiting, meningismus, focal neurologic symptoms, and loss of consciousness (Weir, 1994). In a series of 192 patients with SAH, 10 percent described no headache at the onset and 8 percent described a mild, gradually increasing headache (Walton, 1956). The various sites of the headache at onset were occipital 32 percent; frontal 17 percent; back of neck 11 percent; generalized 10 percent; temporal 6 percent; and other 21 percent. In patients with mild or no headache at the onset, complaints of neck and back pain attributable to meningeal irritation may lead to misdiagnosis (Evans, 1996). A supple neck does not exclude SAH; on examination, a stiff neck is absent in 36 percent of patients (Kassell et al, 1990).

    Sentinel headache

A sentinel headache occurs before a major subarachnoid hemorrhage. It is a retrospective diagnosis and is believed to be caused by a small subarachnoid hemorrhage or warning leak (Ball, 1975; Gillingham, 1958,1967) occurring in 15 to 60 percent of patients before a major rupture of an intracranial aneurysm (Bassi et al, 1991;Hauerberg, 1991). A number of patients do not receive rapid medical attention because the headaches may be minor or they are sometimes given incorrect diagnoses such as migraine or sinusitis (Kassell, 1985). The importance of making a proper diagnosis is emphasized by Evans and others because it can be lifesaving. When a patient has few neurologic symptoms prior to a major rupture, they are the best candidates for surgery. Mortality following a major subarachnoid hemorrhage is 50 to 70 percent and occurs in 30 to 50 percent in the days or weeks after the sentinel headache (Bassi et al, 1991; LeBlanc, 1987; and Wilterdink, 1994). The sentinel headache may be transient, but usually persists for several hours or days (Ostergaard,1990; Wilterdink, 1994). The time interval between the warning leak and the major aneurysmal rupture in one major study was less than one week in 18.1 percent and less than 1 month in 61.4 percent (Hauerberg, 1991).

In a retrospective Canadian report of 34 patients with headaches caused by a "premonitory minor leak," the onset of the headache was sudden, usually unremitting, and persisted until a major aneurysmal rupture or up to 2 weeks has passed (LeBlanc, 1987; Evans, 1996). In 17 patients with a posterior communicating artery or internal carotid artery aneurysm, 53 percent described an ipsilateral periorbital, hemicranial, or hemifacial headache and 18 percent described a diffuse headache. In anterior communicating aneurysms in 10 patients there was an ipsilateral headache in 33 percent, frontal and bifrontal in 40 percent, bioccipital in 40 percent, and bitemporal in 10 percent, and diffuse in 10 percent. As emphasized by many others including Evans (1996), when patients present with a sudden onset of the worst headache in their life it is not possible to distinguish between subarachnoid hemorrhage and benign types of headache without appropriate diagnostic testing (Harling et al, 1989).

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