Spontaneous thrombosis of internal carotid artery: a natural history of giant carotid cavernous aneurysms.

OBJECTIVE To describe five cases of giant carotid cavernous aneurysms which evolved with spontaneous thrombosis of internal carotid artery (STICA), with emphasis at epidemiology, clinical presentation, natural history, related factors and neurological outcome. METHOD There were 711 consecutives patients with 802 aneurysms with and without surgical treatment during a period of 19 years. We selected 35 patients with 40 carotid cavernous aneurysms (5%) of which 20 (50%) were giant aneurysms. Among those cases, 5 patients evolved with STICA (25%). Symptoms and findings at presentation were recorded and compared with those at outcome. RESULTS Clinical presentation was commonly related to atherosclerotic factors such as elevated blood pressure (80%), diabetes mellitus (40%) and dislipidemy (40%). All patients presented with hemicranial headache, ophthalmparesy and retro bulbar pain, and after STICA all presented improvement of symptoms. After STICA, 4 patients had regression of deficit, 2 partial and 2 complete. Four patients had sensorial trigeminal neuropathy in V1 and V2 territories, also showing improvement of symptoms after STICA. CONCLUSION STICA is a common outcome in giant carotid cavernous aneurysms, and is related with significant improvement of symptoms; however, it may be catastrophic for those patients without efficient collateral circulation.