Page 197 - Problem-Based Feline Medicine

11 – THE CAT STRAINING TO URINATE 189

– Nephrotoxic antimicrobials (aminoglycosides) Prevent the recurrence of infection.
should be avoided and when used, they should ● Bacterial.
not be given for more than 7–10 days without – If urinary tract infection recurs, determine if it
carefully monitoring renal function, especially is due to a relapse or reinfection. Reoccurrence
urinalysis for evidence of casts. of infection with the same organism (relapse)
– Response to therapy should be based on urinal- usually indicates that the original treatment
ysis and bacterial culture, rather than on clini- did not eliminate the infection. Recurrence of
cal response to treatment, as most cats will show infection with a different organism (reinfection)
a marked clinical improvement, despite unsuc- suggests that the original treatment was effec-
cessful eradication of the urinary tract infection. tive but predisposing factors have allowed a new
– Repeat urinalysis without culture should be infection to occur.
done 7 days after commencement of therapy to – Urinary acidifiers can be used for long-term
ensure that bacteriuria is no longer present. therapy to provide a less-favorable environment
– A urine sample for urinalysis should be examined (pH < 6.5) in the urinary tract.
on the last day of antimicrobial therapy for evi- – Encourage the patient to urinate more fre-
dence of pyuria (>5 WBC/hpf). Urinalysis and quently by providing clean litter trays or ready
bacterial culture should be repeated 7 days access to outdoors, thus utilizing mechanical
after antimicrobial therapy has ceased and washout.
again at monthly intervals until two consecutive – If urinary tract infection persists because pre-
urine samples are negative. disposing causes cannot be corrected, ampi-
– Treatment for urinary tract infections associated cillin, amoxicillin, sulfa-trimethoprim and
with indwelling catheters may be delayed, if signs methenamine can be used for long-term ther-
are absent, until the urinary catheter is removed, apy. Give half the daily dose late in the evening.
to avoid developing antimicrobial resistance.
● For viral infections.
Prognosis
– Use lysine (250 mg/cat orally every 12 hours) or
interferon alpha (30 U/cat orally daily). Prognosis depends on the causative agent, the use of
● For fungal infections. appropriate drug therapy and the identification and cor-
– Ketoconazole and itraconazole have been sug- rection of predisposing causes.
gested but their efficacy in the cat with urinary
tract infection has not been determined.
● For parasitic infestations. URETHRAL TRAUMA*
– For Capillaria use fenbendazole (25 mg/kg orally
every 12 hours for 3–10 days). Alternatively, Classical signs
methyridine 200 mg/kg orally once has been
● History of trauma, especially following
used.
motor vehicle accidents, falling from high
– No known effective treatment has been reported
places and after forceful or excessive
for Encephalitozoon in cats, but albendazole and
urethral catheterization.
the antibiotic fumagillin have been shown to
● Dysuria.
have efficacy in humans and mice.
● Perineal swelling.
Correct predisposing cause, if possible.
● Anatomical abnormalities, such as ectopic ureter(s)
Pathogenesis
should be surgically corrected.
● Urethral incompetence and loss of mechanical Urethral trauma may result from motor vehicle acci-
washout should be corrected, if possible. dents or abdominal trauma, especially those that result in
● The continued use of indwelling catheters associ- pelvic fractures, perineal surgery via scalpel blade or
ated with secondary urinary tract infections should excessive handling of the urethra, and catheterization,
be reassessed. especially when associated with urethral obstruction.