C. Carotid artery dissection – Explanation
This patient has Horner’s syndrome caused by a carotid artery dissection. This may be caused by
relatively benign trauma to the neck such as hyperextension whilst doing DIY. Cluster headache
would be a differential diagnosis
Horner’s syndrome
Features
- miosis (small pupil)
- ptosis
- enophthalmos* (sunken eye)
- anhydrosis (loss of sweating one side)
Distinguishing between causes
- heterochromia (difference in iris colour) is seen in congenital Horner’s
- anhydrosis: see below
| Central lesions | Pre-ganglionic lesions | Post-ganglionic lesions |
| Anhydrosis of the face, arm and trunk | Anhydrosis of the face | No anhydrosis |
| Stroke Syringomyelia Multiple sclerosis Tumour Encephalitis |
Pancoast’s tumour Thyroidectomy Trauma Cervical rib |
Carotid artery dissection Carotid aneurysm Cavernous sinus thrombosis Cluster headache |
*in reality the appearance is due to a narrow palpebral aperture rather than true enophthalmos
