Ask The Vet: Urinary Tract Problems in Cats

One of the most common and truly life threatening emergencies that cats experience is urinary tract blockage.  It is also one of the few times cats are demonstrably distressed.  There are other, less dangerous but also painful problems of the urinary tract in both male and female cats.  Because some cats are less vocal and because advanced life threatening problems do not necessarily look worse than less life threatening problems, any cats exhibiting urinary tract signs should be evaluated immediately.

Signs of significance include frequent trips to the litter box, a sudden development of urinating outside the box, unproductive straining in or outside of the box, yowling, licking at genital region and/or blood in the urine.

In male cats, because the urinary tract is long and narrow, obstruction is common.  This can be due to physical debris (blood clots, grit, stones), tissue swelling or tissue spasm.  Male cats will commonly respond to this by licking at their genitals, which can cause much damage.  They act like all urinary tract cats initially (frequent trips, small amounts) but are not always observed demonstrating this behavior.  Once they have been obstructed for any length of time, they become increasingly depressed, may vomit and often become very lethargic.  In many cases, they collapse in or near their litter boxes.

Male cats that are obstructed may need a little or a great deal of help.  Removing the obstruction is the first step.  IV fluids, pain relief, antispasmodics and glycosaminoglycans are commonly administered.  Radiographic imaging can detect stones or grit that would mandate a dietary change.  Depending on the state of the urinary tract and the patient, the urinary catheter may need to stay in place for several or more days.  A very sick kitty may require IV fluids for a day or more. 

Female cats only rarely obstruct and are more apt to have a bacterial infection, both due to the fact that they have wider, shorter urinary tracts.  They can have sudden onset of pain and straining due to inflammation, though this abrupt onset of signs does not mean the problem has just started.  In some cases, there is a smoldering chronic inflammation that then has acute onset of symptoms.  In any event, they squat frequently, pass small amounts or no urine, may pass blood, and are often restless and vocal as they go in and out of the litter box and/or void in inappropriate places.

Collecting and analyzing their urine is an important first diagnostic step.  Initial therapy includes medications for comfort, medications to promote healing of the urinary tract, medications to relive tissue spasm and fluids to promote flushing of the urinary tract.  Additional diagnostics that may be appropriate include imaging (x-rays or ultrasound) to look for stones, urine culture and bloodwork.  In older cats, an opportunistic bladder infection may be due to inadequate kidney function and, conversely, bacterial infections that start in the lower urinary tract (bladder and urethra) can ascend into the upper urinary tract (kidneys).  If infection is believed or proven to be a significant part of the problem, antibiotics become part of the therapy.  Some cats have true ‘kidney stones’ as a contributing factor (stones located in the kidneys, not the bladder).

A bladder stone in bladder

Surgery may become necessary in any of these cats.  In males with severe or recurrent obstruction, removal of the narrowest portion of the urinary tract (procedure called perineal urethrostomy) often gets them feeling well and happy quickly.  Surgery to remove bladder stones is often advised;  analyzing these stones helps guide recommendations for diet and medications.  Sometimes structural changes to the bladder, such as polyps or an out pouching diverticulum, will need to be corrected surgically.  In some cases, biopsy and culture of the bladder wall will be needed to direct therapy.  With new technologies now available, some of these surgeries can be done with minimally invasive laparoscopic procedures, especially useful for removal of bladder stones.

A laparoscopic procedure

Cats, male or female, with intermittent and/or recurrent urinary problems may have interstitial cystitis. (This is also common in human women.)  Over time, the mucosal inner barrier of the bladder, comprised of glycosaminoglycans erodes away and urine can seep into the bladder wall causing chronic inflammation.  The bladder walls of such kitties is much thicker and harder than regular healthy bladders.  Restoration of the bladder lining is part and parcel of healing, though it is not entirely clear how to do this.  Providing oral supplemental glycosaminoglycans is a safe, cheap and reasonable approach.   (In women, the bladder is sometimes treated with direct infusions of these substances.)

Long term management may require serial re-analysis of urine samples to adjust medical and dietary recommendations.  The goal is to minimize inflammation and maintain a urine pH that does not promote formation of irritating crystals or stones.  Maintaining the proper urine pH (acidity) is most easily accomplished with a special diet.

There are myriad behavioral problems that rarely manifest acutely but which may have started with a painful litter box experience.  Offering these kitties a choice of litter, choice of litter boxes, and choice of litter box locations may help lure them back to normal litter box habits.  If these simple approaches fail to work, a number of anti-anxiety, anti-inflammatory and other behavioral modification medications might be recommended.