Canis ISSN: 2398-2942

Episodic falling (Cavalier King Charles Spaniel)

Synonym(s): Muscle hypertonicity, muscle cramping

Contributor(s): Kyle Braund, Laurent Garosi

Introduction

  • Cause: genetic disease.
  • Episodic attacks first observed at 3-4 months old, precipitated by stress, exercise, apprehension or excitement.
  • Animal normal between attacks.
  • Signs: abnormal posture of the limbs characterized by hypertonicity, collapse without loss of consciousness.
  • Diagnosis: signs, breed, DNA testing.
  • Treatment: oral acetazolamide and/or clonazepam.
  • Prognosis: lifelong condition.

Pathogenesis

Etiology

  • Genetic.
  • Microdeletion affecting the brevican gene (BCAN) which encodes the brain-specific extracellular matrix proteoglycan brevican.

Predisposing factors

General
  • Excitement, stress, exercise.

Pathophysiology

  • Episodic falling is a condition of transient intermittent collapse in Cavalier King Charles Spaniels.
  • Microdeletion affecting the brevican gene (BCAN) which encodes the brain-specific extracellular matrix proteoglycan brevican.
  • Brevican belongs to the lectican family of aggregating extracellular matrix (ECM) proteoglycans, which comprises aggrecan, brevican, neurocan and versican.
  • The ECM complex at node of Ranvier is thought to play a pivotal role in maintaining a local microenvironment, acting as a diffusion barrier for K+ and Na+ around the perinodal extracellular space.
  • The disruption of ECM complexes governing synapse stability and nerve conduction velocity is likely to underlie the episodic falling phenotype.

Timecourse

  • Variable but episodes often develop shortly after a period of stress, apprehension, excitement or exercise.

Diagnosis

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Prevention

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Outcomes

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Gill J L et al (2012) A canine BCAN microdeletion associated with episodic falling syndrome. Neurobiology of Disease 45 (1), 130-136 PubMed.
  • Garosi L S et al (2002) Hypertonicity in Cavalier King Charles spaniels. JVIM 16, 330 ResearchGate.
  • Ǻblad B (1990) Episodic falling in a Cavalier King Charles Spaniel. Svensk Vet 42 (8-9), 385 VetMedResource.
  • Wright J A et al (1986) Muscle hypertonicity in the Cavalier King Charles Spaniel - myopathic features. Vet Rec 118 (18), 511-512 PubMed.
  • Herrtage M E et al (1983) Episodic falling in the Cavalier King Charles Spaniel. Vet Rec 112 (19), 458-459 PubMed.


ADDED