Horner's syndrome

Question 1

What is the epidemiology of Horner’s syndrome?

Answer 1

Very rare:

1.42 per 100 000 patients younger than 19 years

Birth prevalence of 1 in 6250 for those with a congenital onset

Question 2

What is the pathophysiology of Horner’s?

Answer 2

Injury to sympathetic fibres entering the head from the sympathetic trunk - at any point along this pathway

Question 3

What are the different aetiologies of Horner’s?

Answer 3

Can be divided according to presence and location of anhidrosis

Central – face, arm and trunk

i) MS
ii) Encephalitis
iii) Brain tumours

Preganglionic – face

i) Cervical rib traction on stellate ganglion
ii) Thyroid carcinoma
iii) Thyroidectomy
iv) Goitre
v) Pancoast tumour (apical lung cancer)
vi) Trauma/surgery to the base of neck

Post ganglionic – no anhidrosis

i) Cluster headache or migraine
ii) Carotid artery dissection or aneurysm
iii) Cavernous sinus thrombosis
iv) Middle ear infection
v) Nerve blocks – cervical or stellate ganglion

In paediatrics:
Birth trauma
Neuroblastoma

Also idiopathic and possible genetic variants

Question 4

How does Horner’s present?

Answer 4

Partial ptosis – failure of superior tarsal muscle

Miosis (small pupil) – inactivation of dilator muscle; maintaining of light reflex (as is parasympathetic)

Anhidrosis – no sweating

Also pseudoenophthalmus - apparent appearance of inset eyeball due to partial ptosis

Question 5

How do you investigate Horner’s?

Answer 5

Clinical observation

To look for underlying cause:

Eye drops:
i) Apracloidine – alpha adrenergic agonist and will cause dilation of a pupil with intact sympathetic innervation and mild constriction of the non-affected pupil

CT/MRI: head/neck/spine

Bloods – tumour markers

Question 6

What is it important to differentiate Horner’s from and how is it done?

Answer 6

Differentiate from the ptosis caused by CN3 lesion:

Will occur with a constricted pupil due to loss of sympathetic in Horner’s

Will occur with a dilated pupil in CN3 lesion; this ptosis is also more severe – often occluding the whole eye

Acute CN3 lesion may have serious underlying pathology e.g. space occupying lesion, raising ICP and putting pressure on the 3rd nerve as it passes over the petrous portion of the temporal bone

Question 7

How do you manage Horner’s?

Answer 7

Treat any underlying cause e.g. resect/radio/chemo tumours