Isolated Third Nerve Palsy as a Rare and Solo Presentation of Internal Carotid Artery Dissection in a Young Female - a Surprising Finding in the Angiogram

Abstract

Internal carotid artery dissection (ICAD) is a known but uncommon cause of ischemic stroke among young and middle-aged patients. A common presentation includes ipsilateral headache, unilateral oculosympathetic palsy (partial Horner syndrome), or ischemic stroke but some reported cases present with less common manifestations, such as lower cranial nerve syndrome (IX, X, XI, XII). However, third cranial nerve palsy is an extremely rare presentation of ICAD. We present a case of ICAD with pseudoaneurysm presenting with third nerve palsy, with ptosis, outward deviation, and binocular diplopia, emphasizing the importance of considering ICAD as a differential diagnosis in patients with third nerve palsy due to the anatomical proximity of ICA to third nerve within the cavernous sinus.

Keywords: angiogram; internal carotid artery aneurysm; internuclear ophthalmoplegia; third nerve palsy.

Figure 1. Eye examination: arrow pointing at left partial ptosis and outward deviation of the left eye

Figure 2. CT brain without contrast: arrow showing a mixed-density mass measuring 2.7 x 2.6 cm, which is seen in the medial aspect of the left middle cranial fossa adjacent to the left temporal lobe suggesting an intracranial neoplasm

Figure 3. MRI brain with and without contrast: arrow showing an extra-axial tumor, measuring 3.3 x 2.4 x 3.0 cm, at the level of the left cavernous sinus with evidence of concavity involving the pituitary gland

Figure 4. Diagnostic cerebral angiogram: arrow demonstrating a partially thrombosed left cavernous internal carotid artery pseudoaneurysm