[A case of paradoxical brain embolism in a 17-year-old boy].

A 17-year-old healthy high school boy suddenly suffered from consciousness disturbance immediately after a karate match. His neurological findings on admission were consciousness disturbance, motor aphasia, right hemiparesis, and right Babinski reflex. Cerebral angiography showed occlusion of the precentral branch of the left middle cerebral artery, and X-ray CT scan on the second day revealed low density area in its territory. No abnormality was found on transthoracic echocardiography or Holter ECG. Contrast transesophageal echocardiography with Valsalva maneuver was performed twice (the 2nd and the 14th day), and patent foramen ovale (PFO) was found only on the second trial. It was supposed that paradoxical embolism had occurred. Transesophageal echocardiography is necessary for the embolic patients of unknown origin, especially young adults. To find PFO, it is important to repeat contrast transesophageal echocardiography carefully. if it is negative on the first trial.