Feline lower urinary tract disease (FLUTD), sometimes called feline urologic syndrome (FUS), encompasses a number of disorders with similar symptoms. Those with FLUTD urinate small amounts frequently, have pain when they do, and scratch themselves extensively whenever they have to use their litter boxes. Often they don't even bother to seek out the litter box, but urinate wherever they may happen to be, often in front of their owner. As if to counteract burning or itching, cats suffering from this disorder lick themselves repeatedly. Cats with FLUTD may suffer from or several of the following:
Urolithiasis - stones in the bladder; it occurs when substances that are usually excreted in the urine precipitate out of solution and form crystals within the bladder. This happens when urine is saturated with various salts and low in fluids. Most bladder stones are composed of struvite, a combination of magnesium, ammonium and phosphate. Urilithiasis occurs with equal frequency in male and female cats.
Urinary tract infections (UTIs) are most often caused by bacteria, but may also be activated by fungi and viruses. However, bacterial urinary tract infections are the most common by far and can occur alone, or in combination with urolithiasis.
Obstructed urinary flow can usually be traced to a urethral obstruction, a condition seen in male cats. The urethra is the canal which discharges urine from the bladder. Obstruction can be caused by mucus, a blood clot, or sloughed fragments of tissue, but most commonly by struvite bladder stones. Blockage can also occur without the presence of the material at the obstruction site. Swelling of the urethra, cancer, scar tissue and prostate disease can interfere with urinary flow. Untreated urinary obstruction can cause acute kidney failure, rupture of the bladder and death. A urinary obstruction requires emergency care. Most veterinarians will catheterize the urethra to remove the blockage and establish the flow of urine. Then they administer intravenous fluids to promote kidney function. If an infection is present, antibiotics will be prescribed.
Reoccurrences of feline lower urinary tract disease can be controlled with dietary changes. Although foods themselves do not cause this condition, some contribute to stone formation. Veterinarians have found that by limiting dietary magnesium and feeding cats diets that produce acidic urine the incidence of FLUTD episodes can be reduced. Since magnesium is a component of struvite stone production, limiting the cat's intake and thus reducing magnesium in the urine, also decreases struvite crystallization. Struvite crystals form most rapidly in a nonacidic environment. The problem can be minimized by a diet that promotes an acidic urine. Large bladder stones can be treated by a diet that dissolves them, or they can be removed surgically.