['Stroke chameleons'].

The diagnosis of acute stroke should be correct and early that allows physician planning the most effective treatment strategies (reperfusion therapy, undifferentiated (basic) treatment, early secondary prevention). However, stroke symptoms can be atypical and similar to some other (non-vascular) event. It can significantly complicate the clinical diagnosis of stroke and decrease the patient's chances for effective treatment. A stroke should be suspected in every patient with acute onset of neurological symptoms, especially when the patient has the 'vascular' risk factors. Furthermore it is important to remember that negative CT-scan data and/or MRI data do not exclude the presence of not only ischemic stroke but also hemorrhagic stroke. The article describes the main variants of strokes with atypical symptoms (strokes-chameleons), emphasizes the importance of careful clinical examination, provides supportive differential diagnostic criteria and discusses limitations of neuroimaging methods.