Horner Syndrome Clinical Presentation

The clinician should determine whether the patient has recently undergone an interventional procedure that has the potential to cause relevant neurologic damage. Iatrogenic Horner syndrome has been reported as a complication of a variety of chest, neck, and otolaryngologic procedures^{[9, 10, 11]} ; for example, ptosis may rarely complicate injection of botulinum toxin for glabellar lines.^[12]

Symptoms depend on the underlying cause.

• Patients may not be able to open the affected eye completely and may not sweat on that side of the face.
• Patients with preganglionic lesions may have facial flushing. This symptom (ie, harlequin effect) occurs with physical exercise in some patients.
• Patients with postganglionic lesions may have ipsilateral orbital pain or a migrainelike headache.
• Raeder, a Norwegian ophthalmologist, described patients with a combination of orbital pain, miosis, and ptosis and termed it paratrigeminal syndrome.^[13]

  • If this set of symptoms is associated with lesions of the cranial nerves (CN) III through VI on the ipsilateral side, suspect a mass lesion in the middle cranial fossa (eg, Raeder paratrigeminal syndrome, type I).
  • A benign form characterized by episodic retrobulbar or orbital pain, with miosis and ptosis but without associated cranial nerve findings, is considered a migraine variant (ie, Raeder paratrigeminal syndrome, type II).
• Patients with carotid artery dissection may present with ipsilateral head, neck, or facial pain.

• Pupillary characteristics

  • The pupil on the affected side may be round and constricted (ie, miosis).
  • Patients may have a loss of the ciliospinal reflex (ie, afferent C2, C3). The pupil fails to dilate when the skin on back of the neck is pinched. Most authors, however, have found this finding unreliable.
  • Patients' anisocoria is greater in darkness. The affected pupil dilates more slowly than the normal pupil does because the affected pupil lacks the pull of the dilator muscle (ie, dilation lag).
• Facial skin characteristics

  • Patients have dry skin (ie, anhidrosis) on the same side of their face as the affected pupil.
  • The pattern of a patient's inability to sweat may be helpful in localizing the lesion.
  • If a patient has a lesion in the common carotid artery area, loss of sweating involves the entire side of the face.
  • With lesions distal to the carotid bifurcation, the lack of sweating is confined to the medial aspect of the forehead and the side of the nose.
• Other findings

  • Patients may have partial ptosis.
  • Patients may have apparent enophthalmos. Contrary to some statements, true enophthalmos does not occur; the ptosis merely gives an illusion created by narrowing of the palpebral fissure, which results from weakness of the muscle of Mueller in both the upper lid (causing partial ptosis) and lower lid (causing slight elevation of lower eyelid).
  • The amplitude of accommodation increases.
  • Heterochromia irides may be present if the lesion is in a child younger than 2 years. The affected iris may remain blue when the other iris changes to brown. Iris pigmentation is under sympathetic control during development, which is completed by age 2 years. Heterochromia is uncommon in patients with Horner syndrome acquired later in life.
  • Patients may have paradoxical contralateral eyelid retraction.
  • Patients may experience a transient decrease in intraocular pressure and changes in tear viscosity.
  • Patients may not have a horizontal eyelid fold or crease in the ptotic eye, especially those patients with congenital Horner syndrome.
  • Patients may have red conjunctiva.

Horner syndrome can be congenital, acquired, or purely hereditary (autosomal dominant). The interruption of the sympathetic fibers may occur centrally (ie, between the hypothalamus and the fibers' point of exit from the spinal cord [C8 to T2]) or peripherally (ie, cervical sympathetic chain, superior cervical ganglion, along the carotid artery).

• Central causes (uncommon)

  • Horner syndrome may be associated with lesions in the hypothalamus, medulla, or upper cervical cord. Wallenberg lateral medullary syndrome (stroke), demyelination, and, rarely, trauma or syringomyelia may result in Horner syndrome.
  • It is rare in coma, but Horner syndrome may occur ipsilateral to a large cerebral hemorrhage that affects the thalamus. Ipsilateral Horner syndrome in a patient with laryngeal palsy suggests an intramedullary lesion.
  • Horner syndrome occurring in association with spinal cord trauma suggests a high cervical cord lesion because it does not occur with lesions below T2 or T3.
• Peripheral causes

  • Horner syndrome may be caused by lesions in the sympathetic chain, in the superior cervical ganglion, or along the carotid artery resulting from a Pancoast tumor (eg, apical bronchial carcinoma), trauma, subclavian and internal jugular vein cannulation, or, rarely, carotid dissection or carotid artery blowout following chest tube insertion for pleural fluid drainage,^[14] sarcoidosis, or tuberculosis in the cervical lymph nodes.
  • Ipsilateral Horner syndrome and cranial neuropathy affecting cranial nerves IX through XII can be associated with an impending carotid artery blowout, a rare but fatal complication of lateral pharyngeal space infection.
• The common lesions that cause Horner syndrome interfere with preganglionic fibers as they course through the upper thorax. Virtually all lesions producing postganglionic sympathetic dysfunction are located intracranially or intraorbitally because the superior cervical ganglion is near the skull.

  • Preganglionic Horner syndrome indicates a serious underlying pathology and is associated with a high incidence of malignancy. Common causes of acquired preganglionic Horner syndrome include trauma, aortic dissection, carotid dissection, Pancoast tumor, metastasis to cervical lymph nodes, and sarcoidosis or tuberculosis of cervical lymph nodes.
  • Painful Horner syndrome suggests the possibility of silent internal carotid artery dissection.
  • Postganglionic involvement has primarily benign causes (ie, usually a vascular headache). Common causes of postganglionic Horner syndrome include trauma, cluster migraine headache, and neck or thyroid surgery.