High dose barbiturates in non-traumatic brain swelling.

which occurs in only 6% of the general population 9 ).Small, asymp tomatic atrial septal defects may similarly allow paradoxical embolism, although usually they are detected by high-quality echocardiography.10 However, one of our patients presented with stroke, a "functional murmur,'' and a normal ECG, chest x-ray and M-mode echocardiogram and was found to have a small atrial septal defect by cardiac catheteriza tion.A final source of emboli to the brain that may require cardiac catheter ization for diagnosis is pulmonary arterovenous fistulas; they were identified twice in our 100 patients.Chest x-rays sometimes suggest the diagnosis, but many patients require chest tomography or right heart catheterization.11 -12 Unexplained stroke after a thorough evaluation (including cerebral arteriography, CSF examination, echocardiography and serological studies) in young adults is rare; searching for the unusual in order to prevent recurrent stroke is justified.We believe that occult embolism is the most common etiology of stroke in this subset of young patients and that right and left heart catheterization, which carry minimal morbidity in young adults, should be strongly considered.