Stroke chameleons: Uncommon presentations of a common disease

Abstract

Stroke is one of the major causes of death and morbidity worldwide and carries an important economic impact. The diagnosis is still a clinical one, supported by brain imaging. However, up to 30% of suspected stroke presentations have a different diagnosis. In these cases, two scenarios must be considered: a false positive diagnosis, or “stroke mimic”, and a false negative or “stroke chameleon”. The diagnosis of acute ischemic stroke is often straightforward. The sudden onset of a focal neurologic deficit in a recognizable vascular distribution with a common presentation - such as hemiparesis, facial weakness and aphasia - identifies a common syndrome of acute stroke. But differential diagnostic problems remain because there are several subtypes of stroke and also because some non-vascular disorders may have clinical pictures that appear identical to strokes. Acute ischemic stroke (AIS) with neurological deficit is a very debilitating condition, especially in younger patients and the rate of false positive diagnosis of ischemic stroke labeled ''stroke mimics'' ranges from 1.3% to 25%.