Horner Syndrome

Basics

Description

A unilateral lesion along the sympathetic pathway that supplies the head, eye, and neck produces Horner syndrome:

  • Ptosis (drooping of the eyelid):
    • Relaxation of retracting muscles in upper and lower lids
  • Miosis (unopposed pupillary constriction):
    • Loss of pupillary dilator innervation
  • Anhidrosis (unilateral lack of sweating):
    • Loss of sympathetic stimulation of sweat glands (may be absent)

Etiology

  • Can be categorized based upon location of the sympathetic fiber lesion.
  • Central (13%):
    • Stroke/infarction (Wallenberg syndrome)
    • Tumor/compression
    • Trauma
    • Demyelinating lesions
  • Preganglionic (44%):
    • Tension pneumothorax
    • Pulmonary apical lesions:
      • Apical lung/mediastinal tumor (primary or metastasis)
      • Subclavian artery aneurysm
      • Cervical rib
      • Iatrogenic
    • Infection of cervical nodes
    • Thyroid malignancies
  • Postganglionic (43%):
    • Superior cervical ganglion lesion (trauma, jugular venous ectasia, iatrogenic)
    • Internal carotid artery lesion (dissection, aneurysm, trauma, arteritis, thrombosis)
    • Skull base lesion (nasopharyngeal carcinoma, lymphoma)
    • Cavernous sinus lesion (tumor, thrombosis, aneurysm)
    • Miscellaneous (cluster headache)
  • Unknown (40%)

Pediatric Considerations

  • Congenital causes:
    • Birth trauma (may cause damage to sympathetic chain)
    • Hereditary (irregular coloration on affected side may also be present)
  • Acquired causes:
    • Tumor (new onset in a child should prompt work up for tumor/mass such as neuroblastoma)
    • Demyelination
    • Thrombosis
    • Idiopathic

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