Feline lower urinary tract disease (FLUTD) – also called feline urologic syndrome (FUS), feline lower urinary tract inflammation, lower urinary tract signs (LUTS), feline interstitial cystitis or idiopathic cystitis – is not a "disease" per se, but rather refers to a group of clinical signs and symptoms seen in cats that together represent a disease syndrome of the urinary tract. "Idioptathic" means of unknown origin or cause. The lower urinary tract consists of the urinary bladder, bladder sphincters and the urethra. FLUTD is the most common lower urinary tract disorder of domestic cats, and lower urinary tract abnormalities are reportedly the most common health concern of companion cat owners.
Causes of FLUTD
The cause of FLUTD is not known. Some cats seem to have a disorder that affects their neurological response to stress and causes their urinary system to be chronically over-stimulated. "Congenital" means present at birth. Another theory is that the condition may be affected by the water and mineral content of a cat's diet and its corresponding urinary pH (which pertains to the acidic or alkaline quality of urine). Nervous, fearful or aggressive cats, including those that suffer from separation anxiety, seem to be predisposed to developing FLUTD.
There are some factors that seem to contribute to the development of FLUTD. One of these is the present of urethral plugs, which are a pastelike substance made mainly of struvite crystals and mucus. Struvite crystals are made of magnesium, phosphate and ammonium. Blood and white blood cells can also contribute to urethral plugs. Struvite and calcium oxalate can also form stones, or uroliths, which can block the urethra, especially in male cats. Recurrent bacterial urinary tract infections can greatly enhance development of FLUTD, as can the pH of the urine, the composition of the cat's diet and water quality and intake.
Prevention of FLUTD
Environmental enrichment protocols are often enough to resolve the symptoms in cats with lower urinary tract conditions. Some recommendations are to provide at least one food bowl, one water bowl and one litter box for each cat in the household, at a minimum. These should be placed in private, quiet places where the cat(s) using them cannot be disturbed by people or by other pets. Owners should also provide places for their housecats to rest, hide, play and explore safely, including window perches, climbing structures, scratching trees and the like. Quality companion and snuggle time by and between cats and their people should happen regularly. Any inter-household cat conflicts must be managed. Pheromone products are commercially available that may contribute towards a calm, soothing, stress-free environment. Medications are also available that can be used in refractory cases. Moist diets are thought to increase urine volume and help flush urine and toxins out of the body. Proper litter box hygiene is essential, and of course free access to fresh water should always be provided. Obese cats are prone to developing FLUTD, so weight management is important.
The goals of managing FLUTD are to rule out or resolve any physical blockage (more common in male cats), relieve the patient's pain and alleviate or at least reduce sources of environmental stress.
Feline lower urinary tract disease is not a "disease" per se. Rather, it is a characterization given to a collection of clinical signs in cats, but only after all other known causes of those signs are ruled out. The most common patient with FLUTD is a young adult, neutered male indoor cat, although any cat can be affected.
Symptoms of FLUTD
Affected animals tend to develop a number of the following symptoms, typically with a very sudden noticeable onset. The symptoms frequently wax and wane.
Periuria - urination in inappropriate or unusual locations, instead of in the litter box (Periuria usually is the reason that an owner first seeks veterinary counsel for affected cats.)
Hematuria - fresh blood in the urine
Dysuria - painful or difficult urination, often seen with prolonged squatting and vocalization while trying to urinate
Pollakiuria - frequent passage of small amounts of urine
Anuria – inability to pass urine
Stranguria - straining to urinate
Frequent attempts to urinate
Excessive licking of the penis or vulva
Distended, painful abdomen – caused by partial or complete urethral obstruction by uroliths ("stones"), calculi, urethral plugs or crystals.
Loss of appetite – (anorexia; inappetence; associated with obstruction)
Vomiting – associated with obstruction
Protruded penis – associated with obstruction
Cats at Increased Risk
FLUTD can affect cats of any age and either gender. However, the anatomy of the male cat's lower urinary tract predisposes males to develop obstructions. There is no recognized genetic predisposition, although Persians, Himalayans and other longhaired breeds may be at increased risk, while Siamese cats may be at a reduced risk. Other reported predisposing factors are neutering, obesity, inactivity and living in a multi-cat household. The most common presentation is a young to middle-aged adult, spayed or neutered, overweight indoor cat with a tendency to inactivity, nervousness and/or aggression.
Feline lower urinary tract disease (FLUTD is a collection of clinical signs that typically include urination in inappropriate places, blood in the urine, painful or difficult urination, abnormally frequent passage of small amounts of urine and partial or complete urethral obstruction by urinary stones, calculi or crystals.
How FLUTD is Diagnosed
Since FLUTD is not actually a disease, it is technically inaccurate to say that it can be "diagnosed," any more than vomiting or diarrhea can be "diagnosed." Idiopathic feline lower urinary tract disease is a characterization or a conclusion applied to a given cat once all other causes of its symptoms have been ruled out. "Idiopathic" simply means of unknown cause or origin. FLUTD is called a diagnosis of or by exclusion. The normal work-up of cats suspected of being affected includes a complete blood count and serum chemistry profile, a urinalysis, a complete history and a thorough physical examination. The physical examination should include digital rectal palpation of the bladder and urethra to assess whether masses or stones are present. The veterinarian will also palpate the cat's bladder abdominally, to determine whether the cat is able to void urine. A physical examination, history and assessment of the cat's symptoms may be enough for the attending veterinarian to reach a presumptive diagnosis of FLUTD. However, if any part of the cat's urinary tract is obstructed, or if it has a urinary tract infection, further diagnostics are essential.
Analysis of a urine sample can disclose urinary tract infection, crystals or blood in the urine or other abnormal conditions. The sample can be submitted to a referral laboratory for culture, as well. Radiographs (X-rays) of the entire urinary tract, from kidneys to the termination of the urethra, can reveal urinary stones (also called uroliths) and may also disclose anatomical abnormalities in urinary tract structures. Ultrasonography is also available and, when used, should likewise assess the entire urinary tract, from start to finish. Another advanced diagnostic evaluation can be performed with contrast-enhanced cystography-urethrography, which the attending veterinarian can discuss with the owner. This may require referral to a veterinary teaching hospital or specialized clinic. Cats with urinary obstruction may require emergency surgery.
The outcome for cats with feline lower urinary tract disease depends upon the liver and kidney function affects from the disease, as well as genetic predispositions, duration of the disease and frequency of observable problems.
Cats with FLUTD may present with mild signs or with extremely serious signs that qualify as a true medical emergency. The attending veterinarian will assess the degree of discomfort and the seriousness of the situation when deciding which diagnostic and treatment protocols to follow. The goals of treatment are to relieve or rule out any physical obstruction of the urinary tract, relieve pain, restore urine flow, restore fluid and electrolyte balance and alleviate stress.
If the cat is obstructed, the obstruction must be cleared as quickly as possible. This is a medical emergency that can quickly become life-threatening. The veterinarian will draw a blood sample and decompress the cat's urinary bladder through a technique called cystocentesis. This involves inserting a fine needle through the abdomen and directly into the bladder, and then draining the urine out through an attached syringe. A urinalysis will be done on a sample of that urine, and probably a culture as well to determine whether a bacterial infection is present. The results of these routine tests need not be reviewed before further treatments are initiated.
If the animal is in obvious distress, a catheter normally will be placed and intravenous fluid therapy will begin. Fluid and electrolyte imbalances are common with urinary track blockages. The cat will be sedated or placed under general anesthesia if it is necessary to place a urinary catheter. Often, the stone or other source of an obstruction can be dislodged and flushed out through a soft, flexible urinary catheter. Sometimes, an indwelling urinary catheter is necessary. If an obstruction cannot be removed through these procedures, surgery may be required. Male cats with recurrent obstructions may need a perineal urethrostomy, which involves making a permanent surgical opening for the urethra, between the anus and the scrotum.
Once any blockage has been relieved, the cat should be managed medically for as long as necessary. Pain medications (called analgesics), and additional fluid therapy, can be used to facilitate restoration of kidney function and urine production. Urine output should be carefully monitored until it returns to normal levels. Antibiotics are appropriate if a bacterial infection is identified through urine analysis and culture. The contribution of steroids and non-steroidal anti-inflammatory drugs (NSAIDs) is controversial and not well-documented. An electrocardiogram may be recommended to assess the cat's heart, which can be adversely affected from severe electrolyte abnormalities.
Affected cats may be placed on a restricted diet, depending on the particular composition of any plugs, crystals or stones that are retrieved. The veterinarian can prescribe the appropriate food.
The prognosis for cats with FLUTD is highly variable and depends on a combination of factors, including:
The underlying cause of the condition
The frequency and severity of symptoms, especially obstructions
The owner's emotional and financial commitment to treatment and environmental enrichment
The number of and relationships between cats in the household
The owner's degree of tolerance to urine soiling in the house