Urethral Obstruction in Cats

Urethral obstruction is a potentially life-threatening emergency and occurs almost exclusively in male cats due to their urethra being longer and narrower than that of a female cat. When the urethra becomes partially or completely blocked, urine cannot drain from the bladder and the cat is unable to urinate despite repeated efforts. This condition can be extremely painful and can cause acute kidney failure. If not managed properly, death can occur within 2-3 days. 

Signs of Urethral Obstruction

If your cat displays any of the below signs, it could indicate your cat has an obstructed urethra. In this instance, you should call our clinic immediately as this is an emergency situation.

  • Straining to urinate – repeated attempts to urinate that are unproductive
  • Vocalization – may cry or yowl, particularly when attempting to urinate
  • Pain/Discomfort – may be painful when touched or picked up
  • Blood observed in urine
  • Inappropriate urination (outside litter box) or frequent trips to litter tray
  • Change in behaviour – may appear lethargic and have a loss of appetite.

Causes of Urethral Obstruction

  • A 'plug' in the urethra - accumulation of proteins, debris and urinary sediment
  • Small bladder stones or an accumulation of very small stones
  • Swelling and spasm of the urethra - inflammation may cause swelling of the urethral wall

Management of Urethral Blockages

A veterinarian will perform a physical exam and determine if your cat's bladder is enlarged and if an obstruction is likely. If an obstruction is confirmed, the veterinarian will recommend hospitalisation for emergency treatment and stabilization.

The veterinarian may recommend any or all of the following:


  • Blood Test - urethral obstruction can cause acute kidney failure and may develop very high blood potassium concentrations so bloodwork is required to determine hydration status and assess toxin levels
  • Urinalysis - this test will assist the veterinarian in looking for an infection and/or crystals.
  • X-rays or ultrasound may be needed to help determine the underlying cause of the obstruction and to help determine the best treatment method e.g. bladder stones


  • Placing an intravenous catheter which allows for administration of fluids and medications.
  • Removal of urine directly from the bladder (either via cystocentesis or manual expression), allowing easier urinary catheter insertion.
  • Under heavy sedation or a general anaesthetic, a urinary catheter is placed which provides a way to flush the bladder and keep it empty for 1-3 days while inflammation subsides. Once obstruction is relieved, the veterinarian will infuse sterile saline into the bladder via the catheter so that all the blood and debris can be flushed out. This is usually repeated several times to remove as much debris as possible to reduce the chance of re-obstruction. Following this, the veterinarian will then determine if the catheter can be removed or if it needs to remain in place for a few days.
  • Treatments
    • Intravenous fluids which maintains blood pressure, corrects dehydration, and helps eliminate any toxins in the body.
    • Anti-inflammatory medication to relieve swelling in the urethra and other analgesic medication (pain relief) to keep your cat comfortable.
    • Antibiotics that will help treat bacterial infections.
    • Medication to help relieve spasm of the urethra. Usually a combination of two different muscle-relaxing drugs are used which help the bladder contract as well as relax the urethral muscles that allows material to pass through it.
    • Long-term dietary changes and urine monitoring.
  • Surgical Treatments
    • Cystotomy - surgical procedure to remove bladder stones.
    • Perineal Ureterostomy, which is surgery to make the urethral opening permanently larger, thus reducing the risk of future obstructions. Your pet will be referred to a specialist for this procedure. Click here for more information regarding this procedure at QVS. 

Long-Term Management of the Cat with Urethral Obstruction

Preventing future episodes of urethral obstructions is the main long-term goal. In the short-term, the veterinarian may prescribe anti-inflammatory drugs, spasmolytics and analgesics while the initial swelling in the urethra is settling down.

Long-term management is aimed at the underlying cause of the urethral obstruction. Cases associated with uroliths (stones in the bladder and urethra) and/or urethral plugs will need to be managed with special prescription diets to reduce the risk of their recurrence. This may include changing to a wet (tinned or sachet) diet rather than a dry diet along with other measures to increase water intake. The veterinarian will recommend the best prescription diet based on the individual cat and the underlying cause of the urethral obstruction.

If repeated episodes of obstruction occur despite appropriate management, in some cases a surgical operation can be performed. This procedure is known as Perineal Urethrostomy that creates a permanent, enlarged urethral opening along the perineum. This procedure helps in significantly minimising the risk urethral obstructions. If this surgery is recommended, the veterinarian will refer your cat to a specialist.

For detailed information on the Perineal Urethrostomy procedure, visit Queensland Veterinary Specialists.