0000000000205297
AUTHOR
Herman J. Gelmers
Clinical Syndromes, Pathogenesis, and Differential Diagnosis
The temporal sequence of signs and symptoms in patients with cerebral ischemia provides important information for the analysis of underlying pathophysiologic mechanisms and in the search for a major hemodynamic or embolic cause. The signs reported and symptoms assessed are useful for localization of the ischemic region of the brain and identification of the affected vascular territories. Even in the case of a typical clinical picture the clinical findings alone are often insufficient for unequivocal anatomic and pathologic identification, however important they may be in the choice of diagnostic and therapeutic measures. In the first few hours after cerebral ischemia, determining the progno…
Pathophysiology of Cerebral Ischemia
The weight of the brain amounts to only 2% of total body weight, but it receives 15% of the cardiac output and uses 20% of the oxygen consumed by the body. The energy supply is provided almost exclusively by glucose metabolism. The substrate for this is stored in the brain in the form of glucose or glycogen and is sufficient to cover the energy requirements for only about 1 min. Consequently, there is a delicate equilibrium between oxygen and nutrient supply from the blood and the energy requirements of the brain. Disturbances in neurologic function appear after a few seconds of ischemia, although they are not necessarily persistent at first.
Treatment and Prophylaxis
Following a stroke, the patient’s neurologic deficit may be most impressive, but his treatment and prognosis depend largely upon accompanying systemic disorders. Acute treatment, for instance, must take into consideration such things as cardiovascular disorders (myocardial infarction, valve defects, arrhythmias, hypertension), disorders of renal function, and diabetes mellitus. The early detection and treatment of such systemic problems can help to prevent complications that would be difficult to control later. Thus, in a patient with latent heart disease hypervolemic therapy with low molecular weight dextran may in fact elicit right heart failure and pulmonary edema instead of helping the …
Applied Anatomy of the Cerebral Arteries
Four arteries supply the brain with blood: the two carotid and the two vertebral arteries. Although these four vessels are ultimately interlinked via a basal arterial network, the circle of Willis, and anastomoses at the brain surface, Heubner’s anastomoses, it is useful to distinguish anterior (carotid anterior and middle cerebral) and posterior (vertebrobasilar posterior cerebral) vascular territories (Gillian 1957, 1968; Lazorthes 1961; Kaplan and Ford 1966; Ganshirt 1972; Seeger 1978; Dorndorf 1983; Duus 1983).
Epidemiology and Classification of Strokes
Epidemiology concerns the occurrence and distribution of diseases in the population. By prevalence is meant the number of cases of the disease at a particular moment in a given group of persons, for example, in the entire population of a certain territory or in a clearly demarcated population group. Incidence refers to the number of new cases of the disease occurring in a population in a particular period of time. Figures on prevalence and incidence are meaningful only if the given disease is unequivocally defined. If the definition is too specific, many cases are not included (false-negative cases), whereas too broad a definition leads to many false-positive identifications (Table 3.1). Di…