[Differential diagnosis of acute consciousness disorders].

The most important causes of syncope and coma are discussed. Syncope may be due to cardiac, vascular or cerebral disease. A cause of syncope is not established in up to 50% of cases. Where a diagnosis is possible the patient's history, physical examination, ECG and prolonged ECG monitoring serve to establish the underlying disease in most cases. Additional diagnostic tests should only be performed in patients with possible cardiac syncope, since these cases show a higher mortality rate than patients with non-cardiac syncope. Coma may be caused by metabolic disorders, intoxication or cerebral diseases, which are easily identified by history, physical examination and simple laboratory tests in most cases. Further evaluation of patients with unknown cause of coma depends on whether focal neurologic signs, meningeal irritation and fever are present.