Introduction
Background
Horner syndrome (Horner’s syndrome) refers to a constellation of signs produced when sympathetic innervation to the eye is interrupted. Lesions at any point along the sympathetic pathway may result in Horner syndrome.1 Signs found in all patients, regardless of the level of interruption include mild-to-moderate ptosis owing to denervation of the sympathetically controlled Müller muscle, slight elevation of the lower lid (upside-down ptosis) due to denervation of the lower lid muscle analogous to the Müller muscle in the upper lid, and miosis and dilation lag, where pupillary dilation after psychosensory stimuli is slower in the affected pupil than the unaffected pupil.
Depending on the level of the lesion, impaired flushing and sweating may be found ipsilaterally. Anhydrosis affects the ipsilateral side of the body with central, first-order neuron lesions. Lesions affecting second-order neurons may cause anhydrosis of the ipsilateral face. With postganglionic lesions occurring after vasomotor and sudomotor fibers have branched off the sympathetic chain, anhydrosis is either absent or limited to an area above the ipsilateral brow. The pupils react normally to light and accommodation.
Iris heterochromia (with the affected eye being hypopigmented) is seen in congenital Horner syndrome or Horner syndrome that occurs in children younger than 2 years. Iris heterochromia also may occur in long-standing Horner syndrome.
Pathophysiology
First-order central sympathetic fibers arise from the posterolateral hypothalamus, descend uncrossed through the mid brain and pons, and terminate in the intermediolateral cell column of the spinal cord at the level of C8-T2 (ciliospinal center of Budge). Second-order preganglionic pupillomotor fibers exit the spinal cord at the level of T1, and enter the cervical sympathetic chain, where they are in close proximity to the pulmonary apex and the subclavian artery.
The fibers ascend through the sympathetic chain and synapse in the superior cervical ganglion at the level of the bifurcation of the common carotid artery (C3-C4). Postganglionic pupillomotor fibers exit the superior cervical ganglion and ascend along the internal carotid artery. Shortly after the postganglionic fibers leave the superior cervical ganglion vasomotor and the sudomotor fibers branch off, they travel along the external carotid artery to innervate the blood vessels and sweat glands of the face. The pupillomotor fibers ascending along the internal carotid artery enter the cavernous sinus. Then, the fibers leave the carotid plexus briefly to join the abducens nerve (cranial nerve VI) in the cavernous sinus and enter the orbit through the superior orbital fissure along with the ophthalmic branch of the trigeminal nerve (V1) via the long ciliary nerves. Then, the long ciliary nerves innervate the iris dilator and the Müller muscle.
Mortality/Morbidity
Depends on specific etiology
Clinical
History
Obtaining a careful history is very helpful in the localization of lesions causing Horner syndrome.
- First-order neuron lesions may be associated with signs and symptoms such as hemisensory loss, dysarthria, dysphagia, ataxia, vertigo, and nystagmus.
- Second-order neuron lesions may be preceded by trauma and may be accompanied by facial, neck, axillary, shoulder or arm pain, cough, hemoptysis, history of thoracic or neck surgery, history of chest tube or central venous catheter placement, or neck swelling.
- Symptoms associated with third-order neuron lesions include diplopia from sixth nerve palsy, numbness in the distribution of the first or second division of the trigeminal nerve, and pain.
- The presence, absence, and/or location of anhydrosis is an important localizing sign that may be elicited from the history.
- Although Horner syndrome is commonly an incidental finding related to a benign cause, it occasionally may be a manifestation of a serious and life-threatening disorder. Careful direction of the history to rule out such life-threatening disorders is of the utmost importance (see Causes).
Physical
- Important aspects of the physical examination include the following:
- Measurement of pupillary diameter in dim and bright light and their reactivity to light and accommodation
- Examination of the upper lids for ptosis
- Examination of the lower lids for upside-down ptosis (eg, position of the lower lid with respect to the inferior limbus)
- 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
Causes
- First-order neuron lesions
- Arnold-Chiari malformation
- Basal meningitis (eg, syphilis)
- Basal skull tumors
- Cerebral vascular accident (CVA)/Wallenberg syndrome (lateral medullary syndrome)
- Demyelinating disease (eg, multiple sclerosis)
- Intrapontine hemorrhage
- Neck trauma (eg, traumatic dislocation of cervical vertebrae, traumatic dissection of the vertebral artery)
- Pituitary tumor
- Syringomyelia
- Second-order neuron lesions
- Pancoast tumor (tumor in the apex of the lung - most commonly squamous cell carcinoma)
- Birth trauma with injury to lower brachial plexus
- Cervical rib
- Aneurysm/dissection of aorta
- Subclavian or common carotid artery
- Central venous catheterization
- Trauma/surgical injury (eg, radical neck dissection, thyroidectomy, carotid angiography, coronary artery bypass graft)
- Chest tubes
- Lymphadenopathy (eg, Hodgkin disease, leukemia, tuberculosis, mediastinal tumors)
- Mandibular tooth abscess
- Lesions of the middle ear (eg, acute otitis media)
- Neuroblastoma
- Third-order neuron lesions
- Internal carotid artery dissection (associated with sudden ipsilateral face and/or neck pain)
- Raeder syndrome (paratrigeminal syndrome) - Oculosympathetic paresis and ipsilateral facial pain with variable involvement of the trigeminal and oculomotor nerves
- Carotid cavernous fistula
- Cluster/migraine headaches
- Herpes zoster
- Drugs (may cause symptoms similar to Horner syndrome and may affect any region)
- Acetophenazine
- Alseroxylon
- Bupivacaine
- Butaperazine
- Carphenazine
- Chloroprocaine
- Chlorpromazine
- Deserpidine
- Diacetylmorphine
- Diethazine
- Ethopropazine
- Etidocaine
- Fluphenazine
- Guanethidine
- Influenza virus vaccine
- Levodopa
- Lidocaine
- Mepivacaine
- Mesoridazine
- Methdilazine
- Methotrimeprazine
- Oral contraceptives
- Perazine
- Prilocaine
- Procaine
- Prochlorperazine
- Promazine
- Promethazine
- Propoxycaine
- Reserpine
- Thioproperazine
- Thioridazine
- Trifluoperazine
More on Horner Syndrome |
 Overview: Horner Syndrome |
| Differential Diagnoses & Workup: Horner Syndrome |
| Treatment & Medication: Horner Syndrome |
| Follow-up: Horner Syndrome |
| References |
| Next Page » |
References
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Perez-Inigo MA, Gonzalez I, Fernandez FJ, Díaz S, Ferrer C, Alias E, et al. [Usefulness of apraclonidine in the diagnosis of Horner syndrome]. Arch Soc Esp Oftalmol. Feb 2009;84(2):105-8. [Medline].
Freedman KA, Brown SM. Topical apraclonidine in the diagnosis of suspected Horner syndrome. J Neuroophthalmol. Jun 2005;25(2):83-5. [Medline].
Dewan MA, Harrison AR, Lee MS. False-negative apraclonidine testing in acute Horner syndrome. Can J Ophthalmol. Feb 2009;44(1):109-10. [Medline].
Watts P, Satterfield D, Lim MK. Adverse effects of apraclonidine used in the diagnosis of Horner syndrome in infants. J AAPOS. Jun 2007;11(3):282-3. [Medline].
Albert DM, Jakobiec FA. Principles and Practice of Ophthalmology. 1994;4:2473-4.
American Academy of Ophthalmology. Basic and Clinical Science Course: Neuro-ophthalmology. 1999-2000;5:97-99, 109-111.
Fraunfelder, FT. Drug-Induced Ocular Side Effects and Drug Interactions. 1996;4:553.
Gutman I, Levartovski S, Goldhammer Y, et al. Sixth nerve palsy and unilateral Horner's syndrome. Ophthalmology. Jul 1986;93(7):913-6. [Medline].
Loewenfeld I. The Pupil: Anatomy, Physiology and Clinical Applications. 1993;2:1131-1177.
Mokhtari F, Massin P, Paques M, et al. Central retinal artery occlusion associated with head or neck pain revealing spontaneous internal carotid artery dissection. Am J Ophthalmol. Jan 2000;129(1):108-9. [Medline].
Roy FH. Ocular Syndromes and Systemic Diseases. 1989.
Further Reading
Keywords
Horner syndrome, Horner’s syndrome, Bernard-Horner syndrome, oculosympathetic deficiency, oculosympathetic paralysis, Raeder paratrigeminal syndrome, iris heterochromia, Bernard syndrome, Horner’s oculopupillary syndrome, Horner oculopupillary syndrome, Horner’s sign, Horner sign, Horner's symptom complex, Horner symptom complex, Horner's triad, Horner triad, Hutchinson’s syndrome, Hutchinson syndrome, Mitchell’s syndrome III, Mitchell syndrome, Raeder’s paratrigeminal syndrome, heterochromia irides, von Passow’s syndrome, von Passow syndrome, miosis, constricted pupil, partial ptosis, hemifacial sweat, hemifacial anhidrosis, facial sweating, facial flushing, harlequin effect
