In the obstructive form, more commonly observed in male cats, the narrow pathway from the urinary bladder to the external world, the urethra, contains proteinaceous or crystalline or mineralized solid or semi-solid material which impedes (i.e. "obstructs") the flow of urine. Urine produced by the kidneys accumulates in the bladder; the bladder becomes distended, inflamed and painful. The ensuing pressure from urine retention negatively affects the kidneys and can result in rupture of the bladder. Toxins, metabolites and electrolytes normally cleared by urine voiding may accumulate in the blood. Animals are sick, painful, noticeably distressed and if able, strain to urinate in or out of the litter box. This condition is potentially life-threatening and requires immediate veterinary intervention!

Infection:.... In some instances, lower urinary tract infection can precipitate subsequent development of FLUTD. However , in cats infection can also develop secondarily to ongoing FLUTD

Stress...may play a role in the development of FLUTD, though exactly how it contributes is not yet clear.

Allergy...is postulated to sometimes affect bladder wall mucosa and result in inflammation. Allergen may include food(s) and environmental sources.

Diet.... A dietary role has been postulated, in part based upon the decrease in the incidence in this syndrome since the introduction of specially formulated ("prescription") diets over the last decade or so^1,2,3. Additionally, retrospective studies several years ago at The Ohio State University Veterinary School suggest that cats eating kibble diets are more likely to develop FLUTD than cats consuming canned (moist) diets

Gender and/or age of neutering.... have also been suggested as contributory factors: The relatively narrow lumen of the male cat urethra (compared to the female counterpart) possibly predisposes to obstruction. However, there is no evidence supporting the view that early (prior to puberty) neutering retards the development of the urethral diameter in any way leading to or exacerbating the liklihood of obstruction.

• If dire, life-threatening status, then correction of hydration, electrolyte and metabolic disturbances if possible is attempted. If the bladder has ruptured, then surgery is required.

• Obstruction must be relieved. Quite often, cats are anesthetized and a urinary catheter is placed (in the urethra) to dislodge the offending occlusion and to empty the bladder. Sometimes, to maintain patency, the catheter is left in place for several days.

• Antibiotics are administered if urinary infection is suspected; fluids are given to "flush" bladder content (diurese), maintain urine flow, hydration and to correct metabolic and electrolyte derangements.

• If crystals or urinary tract calculi ("stones") are suspected, based upon physical exam, urinalysis or x-rays, special diets and medications may be perscribed (depending upon the nature of the crystals/stones). However, some types are not amenable to medical dissolution and surgery may be required.

• Other medications: antiinflammatories, analgesics and antispasmodics are employed if needed

• In animals who experience recurring obstruction or are particularly refractory to the standard protocol, surgical enlargement of the urethra may be a prudent option.