We report on a 70 year-old-man with mycotic aneurysm. The patient had perianal abscess and splenic abscess before rupture of the aneurysm, but he did not have any other causal disease of mycotic aneurysm.
At first, the patient complained of left abdominal pain followed by general convulsion and lost consciousness. He recovered within a short time and then he came to our hospital. On arrival, he was alert and able to walk. He did not have headache. After about half an hour, his blood pressure fell under 90 mmHg suddenly. The duty doctor therefore administered dopamine as intravenously and his blood pressure rose to 140 mmHg, at which point the duty doctor stopped administering dopamine. But about half an later dopamine, the patient complained of severe headache, then developed general convulsion and lost consciousness again. Furthermore, he manifested right hemiparesis. Computed tomography showed a high density area in the sylvian fissure on the left side, and cerebral angiography revealed an aneurysm located along the left middle cerebral arteries and lack of opacification of the left prefrontal artery with delayed retrograde filling. A blood test revealed systemic inflammation. We therefore diagnosed occlusion of the prefrontal artery and subarachnoid hemorrhage caused by rupture of the mycotic aneurysm. During the operation, we found an embolus in the lumen of prefrontal artery located just distal of the aneurysm. A specimen of the aneurysmal wall showed marked infiltration of inflammatory cells.
The above, suggested that the first general convulsion was caused by arterial embolism and the second one was caused by the rupture of mycotic aneurysm. In this case, the rupture of mycotic aneurysm was caused by the elevation of systemic blood pressure after arterial occlusion of distal part of the aneurysm