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Horner syndrome is a disorder that affects one side of the body's face and eye. It is caused by a neural route interruption from the brain to the head and neck.
Horner syndrome is characterized by decreased pupil size, drooping eyelids, and decreased perspiration on the affected side of the face.
Horner syndrome can be caused by another medical condition, such as a stroke, tumor, or spinal cord injury. In certain circumstances, there is no underlying cause. Horner syndrome has no specific treatment, but treating the underlying cause may restore nerve function.
Horner syndrome, also known as Bernard-Horner syndrome or oculosympathetic palsy, is a neurological disorder.
WHAT ARE THE SYMPTOMS OF HORNER SYNDROME?
Horner syndrome often only affects one side of the face. The following are some common indications and symptoms:
- A stubbornly tiny pupil (miosis)
- A significant disparity in pupil size between the two eyes (anisocoria)
- In low light, the damaged pupil opens slowly or not at all.
- Upper eyelid drooping (ptosis)
- A slight elevation of the lower lid, often known as upside-down ptosis.
- The damaged eye appears sunken.
- On the affected side of the face, there is little or no sweating (anhidrosis).
- Ptosis and anhidrosis, in particular, can be subtle and difficult to detect.
Children
Additional signs and symptoms of Horner syndrome in children may include:
A child under the age of one has a lighter iris color in the affected eye.
Changes in color on the affected side of the face caused by heat, physical activity, or emotional reactions
WHAT ARE THE CAUSES OF HORNER SYNDROME?
Horner syndrome is caused by injury to a sympathetic nervous system circuit. The sympathetic nervous system controls your heart rate, pupil size, sweat, blood pressure, and other functions that allow you to react swiftly to changes in your surroundings.
Horner syndrome affects three types of nerve cells in the nerve system (neurons).
First-order neurons
This neuron pathway begins in the hypothalamus at the base of the brain and extends into the upper region of the spinal cord. Horner syndrome is associated with the following problems in this region that can affect nerve function:
- Stroke
- Tumor
- Diseases that cause the loss of a neuron's protective sheath (myelin)
- Neck injury
- In the spinal column, there is a cyst (syringomyelia)
Second-order neurons
This neuron path runs from the spinal column through the upper chest and into the side of the neck. The following factors may contribute to nerve injury in this area:
- Cancer of the lungs
- Tumor of the myelin sheath (schwannoma)
- The primary blood vessel leading from the heart has been damaged (aorta)
- Surgical procedure in the chest cavity
- Traumatic injury
Third-order neurons
This neuron path runs along the side of the neck and connects to the facial skin as well as the iris and eyelid muscles. Nerve injury in this area may be linked to the following:
Carotid artery damage on the side of the neck
Jugular vein damage on the side of the neck
Infection or tumor near the base of the skull
Migraines
Cluster headaches, a disease that causes cyclical bouts of severe headaches.
Children
The following are the most common causes of Horner syndrome in children:
- Injury to the neck or shoulders during birth
- Aorta defect apparent at birth
- Hormonal and nervous system tumors (neuroblastoma)
Unknown causes
In certain circumstances, the reason of Horner syndrome is unknown. This is referred to as idiopathic Horner syndrome.
HOW IS HORNER SYNDROME DIAGNOSED?
In addition to a routine medical assessment, your doctor will most likely do tests to evaluate the nature of your symptoms and a probable reason.
Confirmation tests for Horner syndrome
Based on your medical history and symptoms, your doctor may be able to diagnose Horner syndrome.
An ophthalmologist (eye expert) may also confirm a diagnosis by placing a medicated eye drop in both eyes — either a drop that dilates the pupil of a healthy eye or a drop that constricts the pupil of a healthy eye. The doctor can assess whether nerve injury is the cause of problems in the suspect eye by comparing the reactions in the healthy eye to those in the suspect eye.
Tests to pinpoint the location of nerve damage
The nature of your symptoms may aid your doctor in narrowing down the cause of Horner syndrome. Your doctor may also request additional tests or imaging to find the lesion or irregularity interfering with the nerve pathway.
If Horner syndrome is caused by a third-order neuron irregularity — a disruption somewhere in the neck or above — your doctor may prescribe an eye drop that will dramatically dilate the healthy eye and only slightly dilate the damaged eye.
Your doctor may perform one or more of the imaging procedures listed below to pinpoint the location of a possible abnormality causing Horner syndrome:
- Magnetic resonance imaging (MRI) is a technology that produces detailed images by using radio waves and a magnetic field.
- Magnetic resonance angiography (MRA), which is used to assess blood arteries
- Chest X-ray
- Computerized tomography (CT), a specialist X-ray technology
WHAT ARE THE TREATMENTS FOR HORNER SYNDROME?
Horner syndrome has no specific treatment. Horner syndrome frequently resolves when an underlying medical issue is adequately treated.