What is the diagnosis and treatment for Horner syndrome?

From the Guidelines

Horner syndrome should be diagnosed and treated by addressing the underlying cause, with a comprehensive clinical examination including a complete ophthalmic examination, sensorimotor evaluation, and consideration of additional tests such as the three-step test and upright-supine test, as recommended by the most recent guidelines 1. The diagnosis of Horner syndrome involves a thorough clinical examination to identify the characteristic triad of symptoms: miosis (pupil construction), ptosis (drooping eyelid), and anhidrosis (reduced sweating) on the affected side of the face. The syndrome can be caused by various conditions, including stroke, tumors, trauma, or other lesions affecting the sympathetic chain anywhere along its path from the hypothalamus through the brainstem, spinal cord, and up to the face. Key elements of the examination should include:

• A complete ophthalmic examination with emphasis on the sensorimotor evaluation, complete three-step test, and consideration of the additional upright-supine test 1
• A careful check for other neuro-ophthalmic signs and symptoms looking for Horner’s syndrome, cranial nerve palsy, INO, nystagmus, and hearing loss
• Fundus examination to check for papilledema or optic atrophy
• Visual field testing, which may provide additional information on the etiology Treatment focuses on addressing the underlying cause rather than the symptoms themselves. For instance, if a tumor is causing compression of the sympathetic pathway, surgical removal may be necessary. If stroke is the cause, standard stroke management protocols would be followed, as outlined in the adult strabismus preferred practice pattern 1. The primary goal of treatment should be to address the underlying cause, with the prognosis depending on the underlying cause, and some cases resolving completely if the primary condition is successfully treated, while others may result in permanent symptoms 1.

From the Research

Diagnosis of Horner Syndrome

• The diagnosis of Horner syndrome is based on the classic triad of eyelid ptosis, miosis, and facial anhidrosis, which is caused by an interruption of the oculosympathetic nerve pathway 2.
• Pharmacological tests, such as apraclonidine, can be used to confirm the diagnosis of Horner syndrome 2, 3.
• Imaging studies, such as MRI, are recommended to evaluate the underlying cause of Horner syndrome 2, 4, 5.

Classification of Horner Syndrome

• Horner syndrome can be classified as central, pre-, or postganglionic, based on the localization of the nerve pathway interruption 2.
• The central type is associated with other symptoms and signs from the central nervous system 2.
• The preganglionic type is most often caused by a tumor or trauma 2.
• The postganglionic type is often associated with pain/headache and is most frequently seen as a consequence of carotid artery dissection or during cluster headache 2.

Treatment of Horner Syndrome

• The treatment of Horner syndrome depends on the underlying cause 3, 6.
• In some cases, the identification of Horner syndrome can lead to the discovery of important underlying conditions, such as carotid dissection or tumor 3.
• Imaging studies, such as MRI, can help to elucidate the aetiology of Horner syndrome and guide treatment 6, 5.

Causes of Horner Syndrome

• The causes of Horner syndrome can be varied and include tumors, trauma, vascular disease, and iatrogenic causes 2, 3, 6.
• In children, Horner syndrome can be classified as congenital or acquired, and imaging studies are critical in delineating the nature and extent of any underlying pathology 5.
• In adults, procedures in the neck, chest, skull base, and paraspinal region account for most of the identified causes of Horner syndrome 3.