Page 872 - Small Animal Clinical Nutrition 5th Edition

Canine Struvite Urolithiasis 903

Table 43-7. Mean times for struvite urolith dissolution.
VetBooks.ir Urolith location and infective status Mean time for dissolution Comments and precautions

Approximately 2.5 months
Infection-induced urocystoliths
Use appropriate caution in dogs at increased risk for
(range two weeks to seven
hypoalbuminemic edema
months) pancreatitis, dogs with renal failure and dogs with
Sterile urocystoliths Three to four weeks If idiopathic, appropriately monitor for recurrence
Infection-induced struvite urocystoliths Less than two weeks If circumstances warrant feeding for a longer period,
in immature dogs serial monitor body weight, body condition, serum albumin
concentration and packed cell volume for evidence of
protein-calorie malnutrition
Infection-induced nephroliths Approximately 184 days Contraindicated in dogs with concomitant obstruction to
(range 67 to 300 days) urine outflow

Table 43-8. Managing magnesium ammonium phosphate uroliths refractory to complete dissolution.
Causes Identification Therapeutic goal
Client and patient factors
Inadequate dietary compliance Question owner Emphasize need to feed dissolution food exclusively
Persistent struvite crystalluria
Urea nitrogen >8-12 mg/dl
Urine specific gravity >1.010-1.015
Urinary pH is alkaline during
treatment with the litholytic food*
Inadequate antibiotic administration Question owner Emphasize need to administer the full dose of
Count remaining antibiotic pills antibiotics
Determine if owner is capable and willing to administer
medication
Demonstrate a variety of methods to administer
medication
Clinician factors
Incorrect prediction of mineral type Analysis of retrieved urolith Alter therapy based on identification of mineral type

Inappropriate antibiotic choice Positive urine culture with poor Choose antibiotics based on susceptibility testing
susceptibility for chosen antibiotic
Inappropriate antibiotic dose for Positive quantitative urine culture Administer antibiotic at the higher recommended
degree of diuresis with same bacterial species and dose or consider a higher dose than recommended
same susceptibility; number of
bacteria may be lower (See text.)

Premature discontinuation of antibiotic Discontinuing antibiotic before Prescribe full antibiotic dose for the entire period of
complete urolith dissolution urolith dissolution
Positive urine culture with same
bacterial species and the same
susceptibility (See text.)
Disease factors
Change in bacterial susceptibility Positive urine culture with Choose antibiotic based on susceptibility testing
susceptibility results different from
those of previous culture
New bacterial infection Positive urine culture identifying Choose antibiotic effective against both bacteria
new bacterial species Avoid procedures requiring urinary tract catheterization

Compound urolith Radiographic density of nucleus and Alter therapy based on identification of new
outer layer(s) of urolith is different mineral type
Analysis of retrieved urolith Uroliths not causing clinical signs should be monitored
for potentially adverse consequences (obstruction,
urinary tract infection, etc.)
Clinically active uroliths may require removal
Remove small uroliths by voiding urohydropropulsion
or lithotripsy
*See Table 43-5.