Clinical Appearance, Pathology and Diagnostics of Subarachnoid Hemorrhage (SAH)

Abstract

Spontaneous subarachnoid hemorrhage is a hemorrhage into the subarachnoid space between the arachnoid layer and the cortical surface of the brain. The subarachnoid space comprises essentially the basal cisterns, the interhemispherical fissure and the Sylvian fissure (Yasargil, 1984). The incidence of SAH lies between 0.06 and 0.08/1000 persons/year (Linn et al., 1996). There are considerable regional differences with a particularly high incidence in Finland of 0.21/1000 persons/year (Linn et al., 1996). Women are affected approximately 1.6 times more often than men (Linn et al, 1996). Smoking, arterial hypertension and alcohol ingestion of more than 150 g per week increase the risk to sustain an SAH (Teunissen et al., 1996; Taylor et al., 1995). According to an epidemiological study on the incidence of cerebrovascular disease in the community of Oxford and surroundings, the most common primary manifestation in a time span of four years was cerebrovascular occlusive disease with 81%, followed by intracerebral hemorrhage (10%) and subarachnoid hemorrhage with an incidence of 5%, as well as 5% unclear cases (Bamford et al., 1990). In so far, SAH represents a much more infrequent illness in comparison to cerebrovascular occlusive disease or traumatic brain injury. In Germany alone a total of approximately 150,000 persons per year are affected by traumatic brain injury with a fatal outcome in 30,000 cases (Gilsbach, Mayfrank and Lennartz, 1996). According to reliable evidence from the USA, the incidence rate of traumatic brain injury is approximated to 200/100,000 persons per year (Kraus, 1987).