[Does alcohol consumption promote the manifestation of strokes? Considerations on pathophysiology].

Arterial hypertension is the most important risk factor in all types of stroke. The significance of alcohol in the pathogenesis of stroke is less well defined. Chronic alcoholism leads to an elevation of blood pressure. Thus, the association between alcohol and stroke might be the blood pressure effect of alcohol. However, some studies have shown a significant influence of alcohol on the incidence of stroke--especially of intracerebral haemorrhage and subarachnoid haemorrhage--even after adjustment for blood pressure. Many possible pathomechanisms are discussed. Alcohol inhibits aggregation of thrombocytes, and chronic alcohol abuse may induce thrombocytopenia, which could lead to a haemorrhagic stroke. Alcohol withdrawal leads to rebound thrombocytosis. Acute alcohol ingestion induces a decrease in fibrinolytic activity and an increase in factor VIII activity, which enhances the thrombotic potential. Additionally, alcohol increases plasma osmolarity, erythrocyte aggregability, haematocrit and blood viscosity, and decreases deformability of erythrocytes. The effects of alcohol on cerebral blood flow are still under debate; there is a deterioration in autoregulation of cerebral blood flow anyway. In animal studies alcohol induced dose-dependent vasospasm of the cerebral blood vessels, which could be a possible pathomechanism in ischaemic, as well as in haemorrhagic stroke. Chronic alcoholism is the most common cause of secondary non-ischaemic cardiomyopathy, which can lead to cerebral embolism via rhythm disorders or intracardiac thrombus formation.(ABSTRACT TRUNCATED AT 250 WORDS)