Horner's syndrome

Horner’s Syndrome -Etiology and Localization

Yazeed Alwelaie

PGY1

Introduction

Horner’s Syndrome

• Also called oculo-sympathetic paresis

• Classic triad:

– Ptosis

– Miosis

– Anhidrosis

Horner's syndrome can be produced by alesion anywhere along the sympatheticpathway that supplies the head, eye, andneck.

Neuroanatomy

Neuro-ophthalmology: the requisites in ophthalmology, Krachmer, JH (Ed), Mosby, St. Louis2000. Copyright ©2000 Elsevier.

Three – neuron pathway

Neuro-ophthalmology: the requisites in ophthalmology, Krachmer, JH (Ed), Mosby, St. Louis2000. Copyright ©2000 Elsevier.

First – Order Neuron

Neuro-ophthalmology: the requisites in ophthalmology, Krachmer, JH (Ed), Mosby, St. Louis2000. Copyright ©2000 Elsevier.

Second – Order Neuron

Neuro-ophthalmology: the requisites in ophthalmology, Krachmer, JH (Ed), Mosby, St. Louis2000. Copyright ©2000 Elsevier.

Third – Order Neuron

Neuro-ophthalmology: the requisites in ophthalmology, Krachmer, JH (Ed), Mosby, St. Louis2000. Copyright ©2000 Elsevier.

Third – Order Neuron

Innervates the iris dilator muscles & Müller's muscle

Clinical Features

©2014 UpToDate®

Anisocoria

©2014 UpToDate®

Ptosis

• Ptosis is minor, usually less than 2 mm

• Paralysis of the Müller's muscle, which is

innervated by the sympathetic pathway

• "upside-down ptosis"

Anhidrosis

• Anhidrosis is present in central or preganglionic

(first or second-order) lesions

• This sign is frequently not apparent to patients or

clinicians

Neuro-ophthalmology: the requisites in ophthalmology, Krachmer, JH (Ed), Mosby, St. Louis2000. Copyright ©2000 Elsevier.

Horner’s in Children

• Impaired facial flushing (Harlequin sign) is often

more apparent than anhidrosis

• Acute features of sympathetic disruption can

also include ipsilateral conjunctival injection,

nasal stuffiness, and increased near point of

accommodation

Harlequin signSource: http://picornot.com/keyword/harlequin+sign

Congenital Horner's Syndrome

Localizing/Associated

Symptoms

• Diplopia, vertigo, ataxia, lateralized weakness

suggest a brainstem localization

• Bilateral or ipsilateral weakness, long tract signs,

sensory level, bowel and bladder impairment

suggest involvement of the cervicothoracic cord

• Arm pain and/or hand weakness typical of brachial

plexus lesions suggest a lesion in the lung apex

• Ipsilateral extraocular pareses, particularly a sixth

nerve palsy, in the absence of other brainstem signs

localize the lesion to the cavernous sinus

• An isolated Horner's syndrome accompanied by

neck or head pain suggests an internal carotid

dissection

Etiology

First-order syndrome

Lesions of the sympathetic

tracts in the brainstem or

cervicothoracic spinal cord

can produce a first-order

Horner's syndrome.

Lateral Medullary Infarction

• Strokes, tumors, and demyelinating lesions affecting

the sympathetic tracts in the hypothalamus,

midbrain, pons, medulla, or cervicothoracic spinal

cord are other potential causes of a central Horner's

syndrome.

• Syringomyelia and cervical cord trauma can also

produce a Horner's syndrome.

Second-order syndrome

Second-order or

preganglionic Horner's

syndromes can occur with

trauma or surgery involving

the spinal cord, thoracic

outlet, or lung apex

• Lumbar epidural anesthesia can also produce a

Horner's syndrome. This is most often described in

association with obstetrical procedure.

Third-order syndrome

Third-order Horner's

syndromes often indicate

lesions of the internal

carotid artery such as an

arterial dissection,

thrombosis, or cavernous

sinus aneurysm.

An acute Horner's syndrome with neck or facialpain should be presumed to be caused by carotiddissection until proven otherwise.

Between 40 and 60 percent of patients presentwith an isolated painful third-order Horner'ssyndrome.

Emergent diagnostic tests should be obtained

Carotid Dissection

Diagnosis

Pharmacologic Testing

• Pharmacologic tests can be useful to confirm the

diagnosis and to localize the lesion

• Two agents are used: cocaine

or apraclonidine drops and hydroxyamphetamine

drops

Confirmation of Horner’s

Syndrome

• Pharmacological testing with cocaine

or apraclonidine drops can confirm the diagnosis of

Horner's syndrome in subtle cases

• If the diagnosis of Horner's syndrome is clear

clinically, then use of cocaine or apraclonidine can

be avoided

Cocaine

• Blocks the reuptake of norepinephrine at the

sympathetic nerve synapse

• Intact pathway – dilates pupil. No effect on

impaired sympathetic pathway

Apraclonidine

• Alternative to cocaine

• Direct alpha-adrenergic receptor agonist.

Apraclonidine has weak alpha-1 and strong alpha-2

activity

• Alpha-1 mediates pupillary dilation, while alpha-2

downregulates norepinephrine release at the

neuromuscular junction

Date of download: 6/9/2014Copyright © 2014 American Medical

Association. All rights reserved.

From: Ocular Effects of Apraclonidine in Horner Syndrome

Arch Ophthalmol. 2000;118(7):951-954. doi:10-1001/pubs.Ophthalmol.-ISSN-0003-9950-118-7-ecs90240

Localization of the Lesion

• First-order neuron(brainstem or cervical cord)

• Second-order neuron(chest or neck)

• Third-order orpostganglionic neuron(above the superior cervicalganglion at the carotidbifurcation).

Hydroxyamphetamine

• It releases stored norepinephrine from the

postganglionic adrenergic nerve endings

• A normal pupil and a first or second-order Horner's

pupil will dilate, whereas a third-order Horner's pupil

will not dilate as well as the normal pupil.

©2014 UpToDate®

Postganglionic right

Horner's syndrome

Summary

• Classic signs of a Horner's syndrome include

miosis, ptosis, and anhidrosis.

• The miosis is typically mild, associated with a

dilation lag and most prominent in dim light.

• The ptosis is also mild and also involves the lower

lid.

• Anhidrosis occurs with first or second-order lesions

only

• The common etiologies of Horner's syndrome are

categorized by which of the three neurons is affected.

• The differential diagnosis is also distinct in children

versus adults26

• The presence of a Horner's syndrome can be confirmed

pharmacologically with either cocaine or apraclonidine

eye drops

• Hydroxyamphetamine eye drops can help distinguish a

third-order (postganglionic) Horner's syndrome from

either a first or second-order syndrome.

• In the absence of a clear history of trauma as the

cause of Horner's syndrome, imaging studies will be

required.