P. 616

An Urban Experience
R. Dorsch1
1Medizinische Kleintierklinik, Department für klinische Tiermedizin, München, Germany
Causes, Investigation and Diagnosis of lower urinary tract disease In cats
Roswitha Dorsch, Dipl. ECVIM-CA, Dr. med. vet., Dr. habil.
Center for Clinical Veterinary Medicine, Ludwig Maximilian University Munich
Feline lower urinary tract disease (FLUTD) is a common reason for cat owners to seek veterinary care. Cats with any disease of the lower urinary tract present with similar clinical signs, such as hematuria, pollakiuria, stranguria, voiding outside the litter box, and/or urethral obstruction. In the literature, there is a consensus that feline idiopathic cystitis (FIC) is the most common diagnosis in cats with FLUTD and is responsible for the symptoms in 55 to 69% of cats (1-3). The proportion of cats with cystouroliths is reported to be 15 to 30%. The proportion of cats with urinary tract infections (UTI), however, differs across the literature. Studies from the United States show that less than 3% of young and middle-aged cats with signs of FLUTD suffer from UTI (3), while studies performed in Europe (Switzerland, Norway, Germany) reveal a higher proportion of 8 to 20% (2, 4, 5). One possible reason
is that the European studies included a higher number of  rst opinion cases whereas the U.S. studies were performed in referral hospitals.
There are signi cant age-related differences in the incidence of the various causes of FLUTD (5, 6). It has been shown that in cats younger than 10 years, FIC is diagnosed in 65% of patients with FLUTD but only in 35% of cats older than 10 years. UTI and neoplasia were signi cantly more common in cats over 10 years than in younger cats (UTI 42% vs. 13.4%; neoplasia 12.9% vs. 1%). Another study in geriatric cats also revealed a high proportion of cats with UTI of 46%. Seventeen per cent of these old cats suffered from urolithiasis and UTI, 10% from uroliths, 7% had urethral plugs, 5% FIC, and 3% neoplasia.
A diagnostic work-up must be performed to identify the cause of FLUTD. This includes a urinalysis (dipstick, urine sediment, aerobic urine culture), abdominal radiographs to identify radio-dense cystoliths or urethroliths, and ultrasound of the urinary tract to exclude radiolucent cystoliths and focal bladder abnormalities such as polyps
or neoplasms. If no speci c cause can be identi ed,
the disease is classi ed as idiopathic cystitis. Double contrast cystoscopy and transurethral cystoscopy are also helpful to exclude radiolucent cystoliths and con rm the presence of FIC.
Urethral obstruction is a common complication associated with FLUTD in male cats and has been reported in 55 - 57% of cats with idiopathic cystitis and 67 - 76% of cats with urolithiasis (1, 5). The treatment
of cats with obstructive FLUTD includes circulatory support, treatment of metabolic complications such as hyperkalemia and metabolic acidosis, analgesia, and reestablishment of urine  ow by urinary catheterization with or without previous decompressive cystocentesis. Due to the low percentage of UTIs causing urethral obstruction, treatment with antibiotics is rarely necessary.
Opinions on the use of decompressive cystocentesis are divided. Possible risks associated with decompressive cystocentesis include: bladder rupture caused by puncture of an already compromised, ischemic bladder wall, additional damage to the already in amed urinary bladder, and iatrogenic damage to the aorta or another abdominal organ. On the other hand, bene ts of decompressive cystocentesis include immediate relief
of patient discomfort due to bladder overdistension
and relief of back pressure of urine to the kidney. There
is more time for patient stabilization for sedation and catheterization of the urinary bladder. In addition, by lowering intraluminal pressure, it facilitates passage
of a transurethral catheter and  ushing of intraluminal plugs or debris back into the urinary bladder. Two
studies have shown that the risk of bladder rupture following decompressive cystocentesis is low (7, 8).
One study included 47 cats that had been treated
with decompressive cystocentesis once before urinary catheterization. In this study, no cat was diagnosed with bladder rupture. The current recommendation by Hall et al. (2015) is to perform a single cystocentesis with a small needle (22 G) attached to an extension set with a three- way stopcock to avoid repeated punctures. The needle should be placed in the region of the bladder neck at a 45° angle. With the needle in this position, it will not slide out of the bladder while emptying it. After cystocentesis, a small (3.5 Fr) transurethral catheter should be placed to keep the bladder small and minimize the risk of possible urine leakage from the cystocentesis site.

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