ISSN 2398-2950      

Horner syndrome

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Synonym(s): Horner's syndrome


Introduction

 
  • Usually unilateral.
  • Cause: spinal cord, intrathoracic, intracranial or cervical lesions.
  • Signs: anisocoria, ipsilateral miosis, ptosis upper eyelid, narrowing of palpebral fissure, apparent enophthalmos, protrusion of third eyelid.
  • Diagnosis: can identify location of injury pharmacologically, and sometimes by other associated clinical signs.
  • Treatment: no specific treatment modality aside for treatment of underlying cause if one is identified.
  • Prognosis: usually recover over protracted period, but depends on etiology.
    Follow the diagnostic tree for Horner syndrome Horner syndrome.

Pathogenesis

Etiology

Pathophysiology

  • Loss of sympathetic innervation to the globe and adnexal structures.
  • Pathological change at one of several sites   →   reduction of sympathetic nerve supply to smooth muscle of orbit   →   third eyelid protrusion (inability to retract third eyelid, ptosis, miosis)   →   clinical signs:
    • First order: brain stem to T1-T3 spinal cord lesions.
    • Second order: (pre-ganglionic fibers) arising in spinal cord segments T1-T3 and joining the vago-sympathetic trunk via the rami communicators.
    • Third order: (post-ganglionic fibers) arising at cranial cervical ganglion rostrally joining the trigeminal nerve at the trigeminal ganglion.
  • Post-ganglionic sympathetic fibers to the eye are conveyed by the ophthalmic branch of the trigeminal nerve.
  • Interruption of post-ganglionic fibers distributed with carotid artery   →   blushing skin and increased dermal temperature on ipsilateral side of face.

Timecourse

  • Slow recovery over many months depending on etiology and treatment.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • De Risio L, Fraser McConnell J (2009) Second order Horner's syndrome in a cat. J Feline Med Surg 11 (8), 714-716 PubMed.
  • Lu D, Lamb C R, Wesselingh K et al (2002) Acute intervertebral disc extrusion in a cat: clinical and MRI findings. J Feline Med Surg (1), 65-68 PubMed.
  • Baines S J, Langley-Hobbs S (2001) Horner's syndrome associated with a mandibular symphyseal fracture and bilateral temporomandibular luxation. JSAP 42 (12), 607-610 PubMed.
  • Holland C T (1996) Horner's syndrome and ipsilateral laryngeal hemiplegia in three cats. JSAP 37 (9), 422-6 PubMed.
  • Raw M E (1994) Horner's syndrome in the dog and cat. Vet Ann 34, 181-188 VetMedResource.
  • van den Broek A H M (1987) Horner's syndrome in dogs and cats - a review. JSAP 28 (10), 929-940 VetMedResource.

Other sources of information

  • Garosi L & Lowrie M (2014) Neuro-ophthalmology. In: BSAVA Manual of Ophthalmology. 3rd edn. Gould D & McLellan G (eds). BSAVA edition.
  • Petersen-Jones S & Crispin S (2002) BSAVA Manual of Small Animal Ophthalmology. 2nd edn. British Small Animal Veterinary Association. ISBN 0 905214 54 4

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