Pseudo-occlusion of the internal carotid artery

In a ten-year period, 31 cases of pseudo-occlusion of the internal carotid artery were seen; 42 carotid angiograms were available for analysis. On the first film of the series the contrast came to a tapered end in the cervical portion of the internal carotid artery in 16; extended to the carotid canal in 11; to the siphon in eight and to proximal intracranial vessels in seven. In 17 patients later films showed advance of the contrast. In four it did not get beyond the foramen lacerum; in eight it reached the siphon and in five the proximal intracranial vessels. Eight angiograms of patients with intracranial occlusion were examined and showed identical appearances. Contrast opacified the middle menigeal artery in 29 of the 31 pseudo-occlusion cases. The circulation time was slow in 28. The circulation times through the middle menigeal artery were more or less identical with those in the superficial temporal arteries and unaffected by systolic blood pressure. Twenty-three of the pseudo-occlusion cases were being ventilated and 25 had fixed dilated pupils. The commonest aetiological factors were trauma, haematoma due to ruptured aneurysm and primary tumour. In the occlusion group no case was being ventilated and only one had fixed dilated pupils. Course of action on finding the appearances of pseudo-occlusion is suggested.