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CANINE DISEASES
Horners syndrome
Horner’s Syndrome is a condition caused by some form of damage to the sympathetic nerve supply to the eye. The sympathetic nerve supply is only one of many different nerves that control the eyes, but it is unique because of its rather tortuous path through the body. The nerve supply travels from the brain, down the side of the spinal cord to the chest and then travels all the way back up the neck to the eye. This is quite extraordinary for a nerve, as most nerves travel in the shortest possible distance to the area they control. The length results in an increase risk of damage anywhere along its path.
There are 3 signs that characterize Horner’s syndrome, enophthalmos (sunken eye and third eyelid protrusion), ptosis (droopy upper eyelid) and miosis (constricted pupil).
Additional signs such as paralysis of front or hind limbs, head tilt, swelling near the eye, and breathing problems may help to indicate the location of the nerve damage.
Forms of damage may include:
- Traumatic injuries to the neck
- Middle ear infections
- Surgical injury
- Idiopathic neuropathies (undiagnosed damage/degeneration of the nerve)
- Tumours-growing and putting pressure on the nerve
- Cats will generally have a specific problem, with a reported incidence of 45% having the idiopathic form of the disease. In contrast as many as 93% of dogs develop the idiopathic neuropathy, for which a cause is not apparent. For this reason many dogs can spontaneously recover over 3-4 months.
Diagnosis of the cause can include radiology (xrays of the head, neck and chest), ultrasound examination of the area around the eye and Cat-Scans of the head. These tests are only usually employed in specific cases where other signs provide a clue to an underlying cause.
Treatments will always be directed at any underlying cause.
Eye drops containing phenylephrine are capable of temporarily alleviating the signs.
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