We report the case of a 27 year old man who presented to the emergency room of a hospital with headache, vomiting and an episode of loss of conciousness. A cranial CT scan was normal and the patient discharged. Ten hours later he came to the emergency room of our hospital with the same complaints. A technically difficult cisternal puncture in an anxious patient who moved during the needle introduction was done. The CSF sample showed 1600 intact red blood cells without other alterations. His headache worsened and after 6 hours he became drowsy, numb and exhibited decerebration signs. A new CT scan showed diffuse subarachnoid and intraventricular blood. An emergency angiogram demonstrated laceration of a left posterior-inferior cerebellar artery in its retrobulbar loop with a pseudoaneurysm. He was succesfully treated by surgical clipping without injury. Sixteen days later he was discharged with a normal neurological exam.
CSF; suboccipital puncture; angiogram; posterior inferior cerebellar artery; pseudoaneurysm; laceration
