[Case of hemodynamic brain infarction diagnosed by transcranial Doppler]

A 64 year-old man was admitted to our hospital because of left leg weakness after a lot of alcohol drink. On admission, his blood pressure was 96/43 mmHg, and heart rate was 97 beats/min and regular. His laboratory data showed severe anemia, and Hb was 5.0 g/dl due to bleeding from gastric cancer. His clinical condition indicated pre-shock and we began to give him a blood transfusion immediately after admission. His neurological findings on admission were mild consciousness disturbance without aphasia, left unilateral spatial neglect, and mild monoparesis on left leg. Brain diffusion-weighted magnetic resonance images demonstrated the small hyper-intense lesions in the borderzone area between the anterior cerebral artery and the middle cerebral artery (MCA). MR angiography showed the occlusion of the right internal carotid artery (ICA) and the right MCA was fully supplied through anterior communicating artery from the left ICA. Transcranial Doppler (TCD) revealed the blunted waveform with low-resistance in the right MCA, but normal flow wave in the left MCA. We diagnosed him as having a hemodynamic brain infarction based on MRI and TCD findings. On day 5, severe anemia and pre-shock improved to Hb 8.2 g/dl and 148/78 mmHg, respectively. According to elevation of blood pressure, his neurological findings normalized. Follow-up TCD revealed that the abnormal waveform in the right MCA changed to normal. Finally we considered the stroke mechanism of this case as hemodynamic stroke based on TCD findings. Serial TCD examinations are useful to identify the hemodynamic mechanism of stroke in such case.