LESIONS

A Guide to Localisation in Neurology

Case 22 - Asymmetric pupils

Outcome

Horner’s syndrome was noted in the left eye, and in the context of exercise-induced severe neck pain and headache on the ipsilateral side, this was concerning for carotid artery dissection. The transient neurological symptom was also thought to have been a left hemispheric TIA with dysphasia and weakness.

A CT angiogram was performed, showing a dissection of the internal carotid artery within the cavernous sinus. This explained the Horner’s syndrome and had likely cased an embolic TIA.

The patient was given antiplatelet therapy to prevent further embolic events. His pain settled with analgesia in the coming weeks.

He was investigated for possible rheumatological disorders, including hereditary connective tissue diseases, though no evidence was found of an underlying condition to have predisposed to the dissection.

He had a further episode of neck pain several months later, and a repeat CT showed resolution of the dissection. He was able to discontinue antiplatelets. The Horner syndrome largely improved though he had minor residual anisocoria (about 1mm discrepancy) most visible in the dark.

Left intracranial internal carotid artery dissection causing Horner’s syndrome and left hemispheric TIA

1. Acute sudden-onset neck pain, particularly after exertion, raises concern for arterial dissection
2. Carotid dissection can lead to neurological features either due to disruption of adjacent cranial nerves (IX-XII), the sympathetic plexus, or via embolic TIA or stroke
3. Dissection can be associated with underlying connective tissue disorders - it is worth screening for relevant symptoms and considering genetic testing in certain cases
4. Dissection injuries heal over several months, so antiplatelet therapy is only required during a temporary period – there is no long-term risk of serial stroke after the dissection heals