Contributors: Andrew Gardiner, Melissa Wallace, Aidan B McAlinden
Species: Feline | Classification: Diseases
- Causes: urolithiasis, urethral plugs, trauma, neoplasia, extra-urethral mass, idiopathic inflammation, iatrogenic intervention.
- Signs: straining (stranguria) and difficulty associated with urination/variable flow.
- Diagnosis: clinical signs and physical examination.
- Treatment: priority is to correct metabolic abnormalities and stabilize animal prior to definitive management.
- Prognosis: depends on cause and extent of renal damage.
- Hematuria Hematuria.
- Signs may be interpreted as straining to defecate by some owners.
Chronic untreated case
- Extreme discomfort - distended bladder.
- Prolonged obstruction → hyperkalemia → cardiac arrythmias .
- Urolithiasis Urolithiasis, urethral matrix-crystalline plugs.
- Neoplasia Urethra: neoplasia.
- Extra-urethral mass.
- Iatrogenic intervention.
- Urolithiasis: structure of male urethra.
- Feline urethral obstruction is (unlike canine) often complete and is an urgent situation.
- Most obstructions occur at the distal penile urethra or the membranous urethra.
- Obstruction of normal flow of urine leads to:
- Dilation of kidney calyces and collecting ducts: reduced renal blood flow and glomerular filtration rate.
- Impaired excretion: azotemia Azotemia, hyperkalemia Hyperkalemia, metabolic acidosis Acid base imbalance.
- Increased pressure: renal ischemia with or without superimposed infection; permanent kidney damage (severity depends on degree, duration and level of obstruction with or without presence of infection.).
- Hyperkalemia may → cardiac arrythmias → death.
- Bladder distention will reach critical proportions within hours of a complete blockage.
- Difficulty and straining (stranguria, dysuria) associated with urination.
- Variable urine flow: may cease midstream, continuous slow dribble, non-productive.
- Bleeding from urethra.
- Increased frequency of micturition/attempts to urinate.
- Frequent licking of genital area.
- Urination in abnormal places.
- Distended bladder palpable; cannot express urine with gentle pressure.
- Urethral catheterization Urethra: catheterization reveals level of obstruction and often allows relief of obstruction by retrohydropulsion.
- See abdominal radiography Radiography: abdomen.
- Presence of radiopaque calculi .
- Extra-urethral mass.
- Retrograde urethrography Radiography: urethrography:
- Demonstration of radiolucent uroliths or soft tissue lesions.
- See ultrasonography of the bladder and urinary tract Ultrasonography: bladder and urinary tract.
- Demonstration of radiolucent or soft tissue lesions .
Initial Symptomatic Treatment
- Place intravenous catheter and start IV fluid therapy (eg 0.9% saline).
- Correct acid/base, electrolytes Fluid therapy: for acid-base imbalance Fluid therapy: for electrolyte abnormality.
- Tranquilize or anesthetize (as high risk patient). Anesthesia preferred as it provides better urethral relaxation.
- Attempt to pass a urethral catheter:
- An end-opening, non traumatic catheter should be used.
- Ideally 3.5 F.
- Extrude penis and place catheter in penile tip.
- Gently extend penis in caudal and dorsal direction - this will straighten the urethra and ease passage of the catheter.
- Flush catheter with sterile saline and attempt to advance it.
- Gentle urethral massage per rectum can sometimes assist in displacing a urolith/urethral plug.
- If the catheter cannot be advanced retrograde urohydropulsion can be attempted.
- Gently occlude the urethra proximal to the obstruction per rectum.
- Infuse saline until the urethra distends under pressure.
- Release the occlusion to help flush urolith/plug into the bladder.
- If urethral catheterization fails, drain urinary bladder by cystocentesis Cystocentesis and attempt to relieve urethral obstruction again.
- If urethral catheterization fails, consider temporary tube cystostomy to drain bladder Cystostomy: tube.
- Body temperature.
- Fluid balance.
- Electrolytes, acid/base.
- Urinary bladder size.
- Fluid balance, electrolytes, acid/base.
- Urine output.
- Good prognosis for early treatment.
- Urolithiasis has a high incidence of recurrence, without dietary changes.
Expected Response to Treatment
- Ability to pass urine normally.
- Resolution of uremia and electrolyte abnormalities if present.
Reasons for Treatment Failure
- Delayed treatment allowing renal failure to develop lin Kidney: acute renal failure.
- Inability to remove blockage.
- Stenosis recurring at site of trauma, urolith, or urethral tear.
- Recent references from PubMed and VetMedResource.
- Gerber B, Eichenberger S & Reusch C E (2008) Guarded long-term prognosis in male cats with urethral obstruction. J Fel Med Surg 10 (1), 16-23 PubMed.
- Lee J A & Drobatz K J (2003) Characterization of the clinical characteristics, electrolytes, acid-base, and renal parameters in male cats with urethral obstruction. J Vet Emerg Crit Care 13 (4), 227-33 VetMedResource.
- Foster S F, Hunt G B & Malik R (1999) Congenital urethral anomaly in a kitten. J Feline Med Surg 1 (1), 61-64 PubMed.