Blocked urinary tracts can kill male cats, and quickly


The neutered male cat had arrived that morning, 28 years ago, suffering from Feline Lower Urinary Tract Disease ( FLUTD) — a catchall term for several inflammatory conditions of the urinary tract that look clinically similar with symptoms including straining to urinate or going more frequently than normal. Mister 28-Years-Ago had a serious complication of FLUTD — urethral obstruction.

What’s that? Let’s start with Mister’s anatomy. Urine is made in the kidneys, then travels down two tiny tubes called ureters into the bladder. When empty, the bladder is a thin, collapsed sac, like a balloon that is not inflated. As the bladder fills, it expands. A sphincter at the base acts like fingers pinching the end of the balloon, keeping the urine inside. When the bladder is full, the inner sphincter relaxes and urine travels down another little tube called the urethra from the bladder, through the cat’s penis, to the outside. The last half inch of Mister’s urethra narrows and makes a funny little S-shaped curve. Herein lies the trouble.

In FLUTD, the urinary tract becomes inflamed. Urine may contain red and white blood cells, crystals, and other particulate matter not normally present in large quantities. This stuff can gum together, forming a kind of “sand.” Female cats have shorter urethras without the narrowing or S-shape at the end, thus the sand simply flows out with the urine. Missus may be uncomfortable, hopping in and out of the litter box. She may have bloody urine or try to show you something is wrong by urinating in the bathtub, or right in front of you on the kitchen counter. But the urine comes out.

This is not always so with male cats. The sand can get stuck anywhere along that long urethra, and most especially in that last S-shaped portion. Technically called urethral obstruction, veterinarians just call it a “blocked cat.”

Most common in male cats between two and ten years old, classic symptoms are straining to urinate, often accompanied by vocalization. Other signs can include lethargy, loss of appetite, abdominal discomfort, vomiting, and eventually collapse. Left untreated, a blocked cat will die. Although difficult for owners to assess, a veterinarian can usually diagnose a blockage by simply palpating Mister’s tummy. Carefully squeezing the bladder helps assess if a blockage is complete or partial. Once we know what we are dealing with, each veterinarian has their own preferred protocol. I start by examining Mister’s private parts closely. Sometimes that urethral plug is at the very tip and can be broken up with gentle manipulation, thus relieving the blockage. Partial obstructions can occasionally be treated medically with pain medication and drugs to relax the urinary tract. But those are best-case scenarios.

Complete urethral obstruction is a life-threatening emergency. Obstructed cats can rapidly have cardiac arrest as a result of electrolyte imbalances. Kidney failure and rupture of the bladder are other possible consequences. A blocked cat needs help and he needs it fast.

Sedation or even general anesthesia is often necessary to proceed. Once Mister is under, we can try again to “express” the bladder by squeezing gently. Occasionally the relaxation caused by the anesthesia is enough to allow the obstruction to move. More often, we need to alleviate the blockage by urinary catheterization. Easier said than done. Mister’s private parts are pretty small and hidden, so having an assistant to help arrange and hold the feline family jewels steady is often essential. The catheter is lubricated, then advanced slowly up the urethra. If we’re lucky, it passes fairly easily, relieving the obstruction. Usually not.

In that case, we try “urohydropulsion” — literally “moving urine with water.” A syringe of sterile saline is attached to the catheter. While advancing the catheter, at any point where it sticks, we flush in saline, hoping to unblock that spot. You have to go gently or risk tearing the urethra.

Mister Twenty-Eight-Years-Ago was a tough case. Once anaesthetized, the catheter still wouldn’t pass. I flushed it repeatedly. After each flush, I would gently squeeze his bladder again, but only a drop of urine would ooze slowly out the end of his urethra. Try again.

Catheter, flush, express. Catheter, flush, express. I knew the next step would be to drain the bladder with a needle through the belly wall, drawing the urine out by syringe. This lessens the back pressure from the bladder, after which catheterization is usually successful. But I decided to give my current technique one more try. Catheter, flush — I put my hands on Mister’s belly, isolated his bladder, and squeezed gently — express.

Suddenly I felt his bladder relax. A lot. Too much. Stretched thin by excessive urine, and weakened by inflammation, Mister’s bladder had popped. I had ruptured it. Since he was under anesthesia, he felt nothing. I, on the other hand, was engulfed by a wave of nausea and panic as I realized what had happened, but after a minute sitting with my head between my knees, I pulled myself together.

With the bladder no longer tensely distended and the back pressure relieved, I was now able to pass the catheter. But he would need emergency surgery to repair the damage. Asking an assistant to prep Mister for surgery, I went to call the owners with a lump in my throat. Complications such as a ruptured bladder or torn urethra do occur with urethral obstruction treatment, but they are exceedingly rare.

The most common “complication” is an owner not recognizing the problem or not seeking veterinary care quickly enough. Usually your veterinarian can unblock your cat without such problems, after which, depending on underlying cause, severity of blockage, your cat’s general condition, and your budget, your veterinarian may send Mister home on medication or may advise further observation and treatment. Mister Twenty-Eight-Years-Ago’s surgery went smoothly. The small tear in his bladder was easily repaired, and his owners were understanding. Mister recovered uneventfully. So did I. More or less.

Twenty-eight years later I still fleetingly relive that moment every time I express a cat’s bladder. Very…very…gently.