TRANSIENT ISCHEMIC ATTACKS - DIAGNOSIS AND PROGNOSIS

The diagnosis of transient ischemic attacks (TIAs) is subject to consi derable interobserver variation. One of the reasons may be that the di agnostic guidelines are phrased in abstract diagnostic terms such as a maurosis fugax, which require an interpretation of symptoms. The relia bility of the diagnosis of TIA can be improved if the nature and time course of the symptoms are recorded in plain language. Another reason may be the arbitrary upper time limit of 24 h, while most clinical evi dence suggests that TIAs and ischemic strokes should be regarded as a continuum rather than as separated subgroups. The overall risk of stro ke or death in untreated TIA patients is approximately 10% per year. R ecent studies have identified the following specific risk factors: inc reased age; male gender; multiple attacks; dysarthria; other vascular diseases, including diabetes, claudication, and angina, and the presen ce of various abnormalities on CT scan or electrocardiography. Patient s with monocular visual symptoms only or vertigo as a main symptom hav e half the risk of patients with hemispheric attacks. The risk of stro ke is specifically associated with an elevated hematocrit, and gradual ly increases with the duration of symptoms, independent of the classic al 'boundaries' at 24 h and 6 weeks which separate TIAs, reversible is chemic neurological deficits and strokes. Patients with symptoms atypi cal for a TIA may have a low risk of stroke but a high risk of major c ardiac events. These findings underscore the need to (1) stratify pati ents with cerebral ischemia according to the risk of subsequent vascul ar events, especially in therapeutic trials, and (2) focus on the natu re rather than the duration of symptoms.