Urethral Obstruction in Cats

A urethral obstruction is usually caused when material exiting the bladder won’t fit through the urethra (the narrow tube leading from the bladder to the outside of the body). The material blocks the passage and urine backs up. Bladder stones, sediment, or other material can cause an obstruction, and male cats are typically affected due to their longer, narrower urethras. A urinary obstruction is not only extremely painful, if left untreated it can turn fatal fast —one to two days or less. Emergency treatment involves relieving the obstruction and correcting metabolic issues associated with condition. A veterinarian may then treat an underlying condition, such as urine crystal accumulation, or recommend surgery to address the problem long term.

Overview

Cats who suffer urethral obstruction are commonly referred to as being “blocked.” This ominous nomenclature happens to be altogether too apt. These cats cannot pass urine at all.

Urine flows from the kidneys down the ureters and into the bladder, where it is stored until it is released through the urethra. A urethral obstruction occurs when the urethra becomes blocked, preventing urination. There are many possible reasons for a blockage, including urinary stones, mucus or sediment plugs, blood clots, tumors, urethral inflammation and scarring. Although any animal is susceptible to a urethral obstruction, male cats are at far greater risk for urethral blockage than female cats because their urethras are narrow and long, making them easier to plug.

A urethral obstruction is usually caused by a buildup of solid material in the bladder that is unable to fit through the urinary opening. Urinary sediment (crystals), mucus, and inflammatory cells can accumulate in the urine and form a urethral plug. In addition, bladder stones (alone or in combination with other material) may get caught in the urethra on their way out of the body.

Urethral obstruction can cause life-threatening complications. If urine is prevented from exiting the bladder, pressure within the urinary tract can damage the kidneys. Urine contains metabolic waste products that the body needs to eliminate; urethral obstruction causes these toxins to build up. Another possible complication of urinary obstruction is scarring of the urethra, which makes it even narrower and prone to future blockages. In addition, the bladder wall may be stretched to the point where muscle function is lost; in the worst cases, it ruptures (which can be fatal). Most cats that die, however, succumb to fatal cardiac arrhythmias (that occur as a result of electrolyte imbalances), or metabolic issues relating to the buildup of toxins in the blood.

A urethral obstruction is an emergency situation, and you should go to your veterinarian immediately if you suspect that your pet is blocked. If not treated quickly, pets with a urinary obstruction can die in 24 to 48 hours or even less.

Symptoms and Identification

If a male cat tries multiple times to urinate and produces just a few drops of urine or none at all, it’s possible that he is completely or partially blocked. As the condition progresses, cats may show evidence of abdominal pain and yowl when touched or when trying to urinate. Within 24 hours, a cat in this condition will become lethargic, hide in unusual locations, and may be reluctant to get up, move, or eat. If left untreated, a urinary obstruction will be fatal.

Physical examination will reveal the presence of a large, firm bladder in a cat’s abdomen. Once an obstruction is confirmed, hospitalization for emergency treatment and stabilization will be recommended. Diagnostic testing, procedures, and treatments will be aimed at identifying the underlying causes for the condition and managing the complications associated with the obstruction.

In so doing, veterinarians may recommend any or all of the following:

  • Bloodwork to assess toxin levels and hydration status
  • Urinalysis to look for an infection and/or crystals
  • Urine culture to determine if there is an infection and, if so, what bacteria may be responsible
  • Radiographs (X-rays) to look for bladder or urethral stones

Affected Breeds

Sadly, all breeds of cats appear equally susceptible.

Treatment

Treating urethral obstruction in cats is — at the outset — all about re-establishing flow or urine through the urethra while helping the body eliminate toxins and restore normal electrolyte levels. With that in mind, procedures include (any or all of these may be required):

  • Intravenous catheter placement, which allows for fluids and medications to be administered
  • Removal of urine directly from the bladder, which allows for easier urinary catheter insertion
  • Urinary catheter placement (under heavy sedation or general
  • anesthesia), which provides a way to flush the bladder and keep it empty for one to three days (or more) while inflammation subsides Intravenous fluids, which helps maintain blood pressure, correct dehydration, and help the body rid itself of toxins
  • Antibiotics, which treat bacterial infections
  • Antispasmodics, which relax the urethra in order to allow material to pass through it
  • Cystotomy (surgery to remove bladder stones)
  • Perineal urethrostomy, which is surgery to make the urethral opening permanently larger, thus reducing the risk of future obstructions Long-term dietary changes and urine monitoring

Prevention

This is a perennial topic of lively debate within veterinary circles.

Unfortunately it is very difficult to prevent feline urethral obstructions, as it is not always known what causes them. Bladder infections may have a role in the formation of urinary sediment and stones, so infections should be treated promptly. Increasing water intake may also be beneficial. Several diets can help reduce the risk of urethral obstruction in cats that are prone to this problem. Ask your veterinarian if your cat should be on a special diet to reduce the risk of urethral obstruction.

This article has been reviewed by a Veterinarian.

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