Canis ISSN: 2398-2942

Dyssynergia

Synonym(s): Detrusor urethral dyssynergia, reflex dyssynergia, urethrospasm, functional urinary obstruction, functional urethral obstruction

Contributor(s): Kyle Braund, Kathy Lunn

Introduction

  • Cause: many underlying etiologies resulting in lack of co-ordination between detrusor contraction and urethral relaxation.
  • Signs: dysuria, abnormal urine stream.
  • Diagnosis: history, signs and rule out other causes.
  • Treatment: urinary tract motility modifying agents.
  • Prognosis: guarded.

Pathogenesis

Etiology

  • Usually idiopathic.
  • Rule out anatomical or neurogenic causes of failure of bladder contraction or urethral relaxation.
  • Supra-sacral spinal cord lesion.

Predisposing factors

General
  • Sexual excitement may exacerbate problem in male dogs.
  • Overfull bladder.
  • Prostatic disease.

Pathophysiology

  • Functional abnormality of urinary tract.
  • Normal urine voiding requires co-ordination of detrusor muscle contraction and relaxation of internal and external sphincters.
  • In dyssynergia, the bladder contracts against tight sphincters.
  • The most common form is sympathetic dyssynergia where internal sphincter cannot relax.
  • Somatic dyssynergia (failure of the external sphincter to relax) is rare.
  • Original insult to urinary tract results in urine retention.
  • The bladder becomes over-distended and stretching of tight junctions results in poor contractility.
  • Bladder contraction is not associated with urethral relaxation so bladder contracts against obstructed outflow.
  • Urination may start but then ceases abruptly.
  • Once bladder reaches critical size intravesicular pressure exceeds urethral resistance and urine leaks when animal is relaxed - often when resting or sleeping.

Timecourse

  • Weeks to months.

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.
  • Díaz Espiñeira M M, Viehoff F W & Nickel R F (1998) Idiopathic detrusor-urethral dyssynergia in dogs - a retrospective analysis of 22 cases. JSAP 39 (6), 264-270 PubMed.
  • Gookin J L& Bunch S E (1996) Detrusor-striated sphincter dyssynergia in a dog. JVIM 10 (5), 339-344 PubMed.
  • Blackwell N J (1993) Reflex dyssynergia in the dog. Vet Rec 132 (20), 516 PubMed.


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