An alcoholic man who was admitted with an acute onset of neck pain and confusion was diagnosed as suffering from a subarachnoid hemorrhage after rupture of an anterior communicating artery aneurysm. Additionally, he showed a bilateral 6th nerve palsy of variable extent. The postoperative course was complicated by pulmonary edema and adult respiratory distress syndrome. He died on Day 28 after admission. At autopsy, surprisingly, the concomitant diagnosis of acute thiamine-deficient encephalopathy was made. Thiamine had been given only in minimal amounts during hospitalization. We describe the striking clinicopathological features of this previously undocumented case and consider the relationship between the two central nervous diseases.