Canis ISSN: 2398-2942

Urethra: obstruction

Contributor(s): Phil Nicholls, Lori Ludwig, Aidan B McAlinden

Introduction

  • Cause: urolithiasis, trauma, neoplasia (intra-luminal or extra-luminal), iatrogenic intervention, stricture, granulomatous urethritis.
  • Signs: stranguria, dysuria, hematuria or variable flow.
  • Diagnosis: clinical signs, radiography, cystoscopy, biopsy.
  • Treatment: priority is to correct metabolic anomalies, divert urine and stabilize animal prior to definitive management.
  • Prognosis: depends on cause and extent of renal damage.

Pathogenesis

Etiology

  • Urolithiasis.
  • Trauma, eg os penis fracture.
  • Neoplasia.
  • Iatrogenic intervention.
  • Strangulation of penis or penile foreign body.
  • Bladder herniation Bladder: herniation.

Predisposing factors

General
  • Urethral stricture following trauma or surgery.
  • Urinary tract infection associated with struvite urolithiasis.
  • Bladder neoplasia most common in bitches.
  • Hypercalcemia Hypercalcemia: overview → calcium oxalate uroliths.

Pathophysiology

  • Obstruction of normal flow of urine leads to:
    • Dilation of kidney calyces and collecting ducts: reduced renal blood flow and glomerular filtration rate.
    • Hydronephrosis and hydroureter Hydronephrosis / hydroureter.
    • Impaired secretion and resorption: azotemia Azotemia , hyperkalemia, metabolic acidosis Acid base imbalance.
    • Increased pressure: ischemia with or without superimposed infection; permanent kidney damage. (Severity depends on degree, duration and level of obstruction with or without presence of infection.)

Timecourse

  • Complete obstruction usually results in death in 3-5 days if untreated.
  • Signs of uremia Uremia develop if complete obstruction present for 48 hours.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers


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