Thrombosis of the Internal Carotid Artery

Abstract

In 1936, Egas Moniz, Almeida Lima, and de Lacerda (17) reported a group of four cases of cervical occlusion of the internal carotid artery in which the diagnosis was established by carotid arteriography. Prior to this, the diagnosis had rarely been made antemortem. Following Moniz's demonstration, reports by other workers soon appeared in he literature. Löhr (14), Shimidzu (21), Chao et al. (4), Riechert (19), Siegert (22), Sorgo (23, 24), Andrell (1, 2), and many others (5, 8, 12, 15, 25, 26, 29) published similar cases. The increasing number of such reports indicates that internal carotid thrombosis is not infrequent as a cause of neurological disturbances. As a matter of fact, cervical thrombosis of the internal carotid artery accounted for 0.8 per cent of all cases of suspected brain lesions in Moniz's arteriographic material (16) Etiology and Pathology The following conditions have been responsible for occlusion of the internal carotid artery: 1. Embolism 2. Thrombosis a. Arteriosclerosis b. Thromboangiitis obliterans (10) c. Syphilis d. Inflammatory changes in the intima due to rheumatic fever e. Direct trauma f. Compression from without (e.g., sphenoidal ridge meningioma, subdural hematoma, etc.) In the majority of cases, arteriosclerosis is the principal etiologic factor. In a comprehensive study of 3,500 autopsies, Hultqvist (11) found arteriosclerotic changes in the internal and common carotid arteries in 91 cases (2.6 per cent). In 69 cases the arteriosclerosis was gross, while in 22 cases the findings were noted only microscopically. In a comparable series, Keele (13) found the most marked sclerosis in the carotid vessels to be just below the point of bifurcation. Saphir (20) reported similar changes in the internal carotid artery in its course through the carotid canal and cavernous sinus. These changes were not limited to the older age group but were found also in young individuals. Sorgo (23) suggested that trauma was a relatively frequent factor in the past history of his case material. In most of the cases reported in the literature, however, recognizable trauma was notably absent, exclusive of a small group of patients with an acute violent neck injury (3). Wolfe (29) makes the interesting speculation that carotid thrombosis may be similar to that found in the femoral and popliteal arteries in young men. The latter type of thrombosis was frequently seen during the recent war and was thought to be due to repeated minute intimai injuries from muscular exertion. There are two sites of predilection for carotid thrombosis: (a) just beyond the division of the common carotid artery into its internal and external branches and (b) the region of the carotid siphon (18). At operation, the diameter of the involved internal carotid artery is frequently found to be reduced in caliber and the lumen obliterated by a thrombus of varying color and firmness, depending on the duration of the process.