Which physical findings suggest Horner syndrome?

Updated: May 01, 2019
  • Author: Christopher M Bardorf, MD, MS; Chief Editor: Edsel Ing, MD, MPH, FRCSC  more...
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Important aspects of the physical examination include the following:

  • Measurement of pupillary diameter in dim and bright light and the reactivity of the pupils to light and accommodation
  • Examination for dilation lag of the pupil immediately after the room lights are dimmed
  • Examination of the upper lids for ptosis
  • Examination of the lower lids for upside-down ptosis (eg, the position of the lower lid with respect to the inferior limbus)
  • Observation of extraocular movements
  • Biomicroscopic examination of the pupillary margin and iris structure and color
  • Confrontational visual field testing and testing of facial sensation
  • Observation for the presence of nystagmus, facial swelling, lymphadenopathy, or vesicular eruptions

The pupil on the affected side may be round and constricted (ie, miosis). In individuals with Horner syndrome, the anisocoria is greater in darkness than in light. 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). Patients may have a loss of the ciliospinal reflex (ie, afferent C2, C3), in which the pupil fails to dilate when the skin on back of the neck is pinched. (Most authors, however, consider this finding unreliable.)

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 area of the common carotid artery, 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 that may be noted include the following:

  • Partial ptosis
  • Apparent enophthalmos – Assertions to the contrary notwithstanding, 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 Müller in both the upper lid (causing partial ptosis) and the lower lid (causing slight elevation of lower eyelid)
  • Increased amplitude of accommodation
  • Iris heterochromia (heterochromia iridis) – The affected iris may remain blue when the other iris changes to brown; this may be present if the lesion is in a child younger than 2 years but is uncommon in older patients; iris pigmentation is under sympathetic control during development, which is completed by the age of 2 years
  • Unilateral straight hair ipsilateral to the side affected by congenital Horner syndrome
  • Paradoxical contralateral eyelid retraction
  • Transient decrease in intraocular pressure and changes in tear viscosity
  • Absence of a horizontal eyelid fold or crease in the ptotic eye, especially in patients with congenital Horner syndrome
  • Red conjunctivae

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