Horner Syndrome Flashcards
Definition of Horner syndrome
Triad of symptoms caused by a disruption of the sympathetic nerve supply to the eye and face:
Partial or complete ptosis (drooping of the upper eyelid),
Miosis (constriction of the pupil)
Anhidrosis (lack of sweating) on the affected side of the face.
Causes of Horner syndrome
Central causes:Strokes, tumors, or multiple sclerosis, can disrupt the sympathetic pathway.
Pre-ganglionic causes: Conditions affecting the sympathetic pathway between the hypothalamus and the superior cervical ganglion, such as spinal cord injuries, brachial plexus injuries, or tumors.
Post-ganglionic causes: Lesions affecting the sympathetic pathway beyond the superior cervical ganglion, such as lung tumors, carotid artery dissection, or cluster headaches.
Symptoms of Horner syndrome
Ptosis: Partial or complete drooping of the upper eyelid on the affected side. It may cause asymmetry of the eyes.
Miosis: Constriction of the pupil on the affected side, resulting in a smaller pupil compared to the unaffected eye.
Anhidrosis: Decreased or absent sweating on the affected side of the face, typically involving the forehead and cheek.
Diagnosis of Horner syndrome
Pupillary testing: Measuring the size and response of the pupils using a pupillometer or light stimulation to confirm miosis on the affected side.
Pharmacological testing: The instillation of specific eye drops, such as apraclonidine, to assess the pupillary response. In Horner syndrome, the affected pupil will dilate more than the unaffected pupil due to the lack of sympathetic innervation.
Imaging studies: Depending on the suspected cause, imaging tests like MRI, CT scan, or ultrasound may be performed to identify lesions or abnormalities along the sympathetic pathway.
Treatment of Horner syndrome
If a tumor is causing Horner syndrome, treatment may involve surgical removal, radiation, or chemotherapy.
Rehabilitation: If the syndrome is caused by nerve injury or trauma, physical therapy or occupational therapy may be recommended to aid in recovery and improve muscle function.
Supportive care: Managing symptoms and optimizing function may involve the use of lubricating eye drops, sunglasses to alleviate photophobia, and moisturizing creams for dry skin on the affected side.
