Clinical course of isolated brain stem strokes

Introduction: While supratentorial strokes can be classified etiologically into lacunar, territorial, hemodynamic or embolic lesions, brain stem ischemia is often understood as a nosological entity without etiological differentiation. This imposes difficulties in predicting the clinical prognosis of these patients. There is only scarce data on the clinical course of isolated brain stem strokes. Aim: To study the clinical course and prognosis of solitary ischemic brain stem lesions. Methods: Patients with MRI proven acute brain stem ischemia, signs and symptoms were assessed at three time points: 1. acute state (standardized interview and neurologic examination 1–3 days after symptoms onset); 2. early state (standardized interview and neurologic examination 9–11 days after symptoms onset); 3. 5-year follow-up (standardized interview, modified rankin scale). Results: 230 patients admitted for clinically suspected acute brain stem stroke were included in the study. In 103 patients of these (45%) an acute and solitary brain stem ischemic lesion could be verified by MRI. The most frequent complaints leading to hospital admission were lurching gait (78%) and vertigo (58%); in 66% ataxia was demonstrable in the neurological examination. These findings were independent of lesion localization. 10 days later most of the signs and symptoms had improved, with the exception of disturbances of sensation of the face/limbs, which remained unchanged in 30%/20% after 10 days. Also ataxia recovered poorly over the first 10 days. In contrast, paralysis showed improvement in 96%, while only in a few cases motor performance deteriorated. After 5 years 50 patients were amenable for follow-up. 40% of these were free of symptoms. 80% had regained functional autonomy (Rankin 0–2). The localization of the ischemic lesion did not influence prognosis. 16% of the patients suffered a further ischemic stroke and 10% had a myocardial infarction. Three patients had succumbed due to consequences of the brain stem stroke – one of these in the acute phase. Conclusion: Our study demonstrates the good clinical prognosis of solitary ischemic brain stem lesion. More data is needed to clarify the clinical course of etiological subgroups of subtentorial stroke.