Also known as oculosympathetic palsy, is a neurological condition characterised by a set of symptoms resulting from disruption of the sympathetic nerve pathway that controls certain involuntary functions of the eye and face.
Tldr
Horner syndrome involves a triad of:
- Ptosis: Drooping of the upper eyelid on the affected side.
- Miosis: Constricted pupil in the affected eye.
- Anhidrosis: Decreased sweating on the affected side of the face.
Causes/Factors
The causes can be remembered as the 4 Ss, 4 Ts and 4 Cs mnemonic. S for Sentral, T for Torso (pre-ganglionic) and C for Cervical (post-ganglionic).
Central lesions:
- S – Stroke
- S – Multiple Sclerosis
- S – Swelling (tumours)
- S – Syringomyelia (cyst in the spinal cord)
Pre-ganglionic lesions:
- T – Tumour (Pancoast tumour)
- T – Trauma
- T – Thyroidectomy
- T – Top rib (a cervical rib growing above the first rib and clavicle)
Post-ganglionic lesions:
- C – Carotid Aneurysm
- C – Carotid artery dissection
- C – Cavernous sinus thrombosis
- C – Cluster headache
Symptoms
Horner Syndrome primarily affects one side of the face and eye, resulting in the following set of characteristic symptoms:
-
Ptosis: Drooping of the upper eyelid on the affected side.
-
Miosis: Constricted pupil in the affected eye.
-
Anhidrosis: Decreased sweating on the affected side of the face.
-
There may also be enopthalmos
Signs
- Congenital Horner syndrome is associated with heterochromia
Diagnostic Tests
- Imaging: MRI or CT scans to identify lesions or abnormalities in the central or sympathetic nervous system.
- Underlying Cause Investigation: Determining the root cause of Horner Syndrome through medical history, physical examination, and additional tests.
- Cocaine eye drops can be used to test for Horners by trying to stimulate the dilator muscles of the iris. In Horner syndrome the nerves are not releasing noradrenaline so blocking reuptake makes no difference
- Adrenaline eye drops - will dilate the pupil in Horner syndrome but not a normal pupil
Management
- Identify underlying cause