Equis ISSN 2398-2977

Neurology: shivering

Synonym(s): Shivers

Contributor(s): Steve Adair, Frank Andrews, Graham Munroe, Nicola Menzies-Gow

Introduction

  • A progressive disorder frequently seen in draft horses and warmbloods, including their crosses, characterized by a progressive inability to back up.
  • Cause: unknown.
  • Signs: on forced backing, horse shows an unusual shivering or quivering of the pelvic limbs and the tail; the forelimbs may also be affected.
  • Diagnosis: history and clinical signs; lack of other neurological signs.
  • Treatment: none.
  • Prognosis: poor - the condition is progressive and euthanasia Euthanasia may be elected due to unfitness for work.

Pathogenesis

Etiology

Predisposing factors

General

  • Signalment.

Pathophysiology

  • In one study, when compared to controls, calretinin-negative, calbindin-positive, and glutamic acid decarboxylase-positive spheroids were increased 80-fold in Purkinje cell axons within the deep cerebellar nuclei of horses with shivers.
  • Unusual lamellar or membranous structures resembling marked myelin decompaction were present between myelin sheaths of presumed Purkinje cell axons in the deep cerebellar nuclei of shivers but not control horses.
  • The immunohistochemical and ultrastructural characteristics of the lesions combined with their functional neuroanatomic distribution indicate that shivers is characterized by end-terminal neuroaxonal degeneration in the deep cerebellar nuclei, which results in context-specific hypermetria and myoclonus.

Timecourse

  • Clinical signs first apparent before 7 years of age.
  • Progressive in majority of cases.

Epidemiology

  • Young, male, 17hh high, warmblood/Thoroughbred/draught breed most predisposed.

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.
  • Draper A C et al (2015) Epidemiology of shivering (shivers) in horses. Equine Vet J 47 (2), 182-187 PubMed.
  • Valberg S J et al (2015) The equine movement disorder 'Shivers' is associated with selective cerebellar Purkinje cell axonal degeneration. Vet Pathol  52 (6), 1087-1098 PubMed.
  • Reed S M et al (1981) Ataxia and paresis in horses - differential diagnosis. Comp Cont Ed 3 (3), 88-99.


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