Horner’s Syndrome

What is Horner’s Syndrome?

Horner’s syndrome is a mainly eye related disorder, comparatively rare development. This disorder developed due to disrupted interruption of sympathetic nerve fibers on one side of the facial zone and mainly affects ocular nerves.

The Horner syndrome may be congenital disorder or it can be accrued at the latter stage of life.  The exact cause of Horner syndrome is not yet discovered. No age, sex or racial bar is noticed, any cause which interrupts the basic sympathetic neuro-anatomy which initiate from the hypothalamus and extends through the spinal cord and reached to internal carotid artery, which supplies to circulatory vessels and sweat glands of the facial zone and ultimately reached in the eye through the superior orbital fissure. (1,2)

Horner syndrome pathophysiology

Signs & Symptoms

The following symptoms often patient complains for Horner syndrome:

  • Unable to open eye completely due to drooping of the upper eyelid
  • Decreased perspiration on the affected side
  • Flushing occur due to the facial region due to preganglionic lesion
  • Miosis or constriction of the eye associated with smaller sized pupil is common.
  • In case of postganglionic lesion, headache and orbital pain is developed

In addition of these depending upon the underlying cause, symptoms vary, such as in congenital abnormality the color of the iris remnants blue-gray.


The following sign is observed by the doctor during a physical examination of the eye and associated parts.

  • In a dark room, the constricted pupil size of the affected side of the face is prominent in the following conditions:
  • Flash a direct light on the eye make the pupil size constricted, but removing the direct light source cause dilation of the pupil, whereas same response is not obtained in the other side of the eye.

Decrease facial sweating cause Ipsilateral dry skin:

  • The dryness can feel by placing the index and middle finger on the forehead and pass over the forehead or in the precise upper portion of the eyebrows and feeling of friction is more in the affected side assists to detect the dryness of the affected side.
  • The involvement of the carotid artery cause decreased sweating to the entire face and usual site of sweating on the sides of the nose become decreased. (1,2,3)


The different ailments which need to dissect the carotid artery can provide Horner syndrome as a outcome. The following are the included ailments:

  • Tumor formation in the neck or chest cavity,
  • Tumor formation or neuroblastoma development in the upper part of the lung, clinically termed as pancoast tumor;
  • A growth of lesion in brain stem, midbrain, neck, upper spinal cord, or eye orbit;
  • Swelling of the neck due to inflamed lymph nodes development
  • Surgical or other intervensive trauma affects the neck or upper spinal cord region.

The common reason behind the development of the Horner syndrome is an interrupted sympathetic nerve supply to the eye orbit due to a traumatic injury or unwanted tissue growth. The traumatic injury can occur in any part of the sympathetic nervous system pathway which runs from the eye to the hypothalamus (part of the brain controls the sympathetic nervous system). The function of the sympathetic nervous system is to control different involuntary functions like glands secretion, motility of internal muscular organ and many more.

The idiopathic incidence is common in Horner syndrome, but medical researchers also found that some of the Horner syndrome incidence has an inherited autosomal dominant genetic trait. Genetic ailments have definite disarrangement of genes for an exact trait, which depends upon the parental genetic arrangement from where chromosomes transferred to the fetus. (4)


The physical examination of the eye is the first important diagnosis and for this eye drop test is conducted and suspected findings need to conduct MRI or CT scan for confirmation.

Eye drop test

Eye drops like apraclonidine is applied to both eyes and alteration of the pupil of the eye is noticed. After 48 hours, ophthalmologist again administer hydroxyamphetamine eye drop on both the eyes and again changes of the pupil is noticed and determine whether the test result is similar as expected in Horner syndrome.

MRI or CT scan

MRI (Magnetic resonance imaging) or CT (computed tomography) scan of the brain, neck, chest,  or  spinal cord to check any tumor growth or other severe ailments that may be interrupting nerve fibers, which connect the brain and the eye. (1,2)


Underlying cause and expert’s decision are the main features of the treatment of Horner syndrome. Experts decide treatment plan depending upon the location and reason of the traumatic injury or tumor. The available treatment options are surgical intervention, radiotherapy and chemotherapy.

Genetic counseling may be of suggested for the benefit of patients and supporting the family member in case of defective genetic involvement.  Even depending upon the symptomatic relief and provide supportive care different treatment options may apply to improve the quality of the life of the patient. (4)


  1. Phillip Low; Horner Syndrome; Merck Manual; Retrieve from: http://www.merckmanuals.com/home/brain,-spinal-cord,-and-nerve-disorders/autonomic-nervous-system-disorders/horner-syndrome
  2. Christopher M Bardorf (2016); Horner Syndrome; Medscape; http://emedicine.medscape.com/article/1220091-overview
  3. Horner’s Syndrome; Patient Info; Retrieve from: http://patient.info/in/doctor/horners-syndrome
  4. Horner’s Syndrome (2003); National Organization for Rare disorders; Retrieve from: http://rarediseases.org/rare-diseases/horners-syndrome/

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