Page 801 - Small Animal Clinical Nutrition 5th Edition

Introduction to Canine Urolithiasis 831

VetBooks.ir Surgical candidates include patients: 1) with urolith-induced nitude that indicate rapid recurrence is likely. Surgical incisions

obstruction to urine outflow that cannot be corrected by nonsurgical should be repaired using meticulous technique if protein-restricted
techniques, especially in patients with concomitant UTI, 2) with canine litholytic foods are used.
uroliths that are refractory to current methods of dietary and med-
ical dissolution (e.g., silica, calcium oxalate and calcium phosphate PREVENTION OF UROLITH RECURRENCE
uroliths), 3) with uroliths that are increasing in size or number Uroliths tend to recur. Prevention of recurrent uroliths, which
despite dietary and medical therapy designed to inhibit their growth reduces the need for dietary and medical therapy and surgery, is
or cause their dissolution (especially if they are obstructing urine therefore cost effective. In general, preventive strategies are
outflow or causing progressive deterioration in renal function), 4) designed to eliminate or control the underlying causes of various
with nephroliths and renal dysfunction of such a nature that the time types of uroliths. When causes cannot be identified, preventive
required to induce dietary and medical dissolution is likely to be strategies encompass efforts to minimize risk factors associated
associated with more renal dysfunction than that associated with with lithogenesis. These strategies commonly include dietary modi-
surgical procedures, 5) with anatomic defects of the urogenital tract fication.
that predispose patients to recurrent UTI and urolithiasis and are
amenable to surgical correction at the time uroliths are removed and The Bibliography for Box 38-2 can be found at
6) unable to respond to dietary and medical management because www.markmorris.com
of poor client compliance with therapeutic recommendations.
Complete obstruction to urine outflow caused by uroliths in
patients with concomitant UTI should be regarded as a surgical
emergency. In this situation, rapid spread of infection and associat-
ed damage to the urinary tract, especially the kidneys, are likely to
induce septicemia and peracute renal failure caused by a combina-
tion of obstruction and pyelonephritis.
Unilateral nephroliths and ureteroliths that cause outflow obstruc-
tion and markedly impair function of the associated kidney should be
managed by surgical intervention or (if possible) percutaneous
nephropyelolithotomy. Dietary and medical therapy designed to
induce urolith dissolution over several weeks in patients with poorly
draining kidneys is unlikely to be effective because the urolith(s) will
not be continuously bathed with newly formed urine modified to
induce litholysis. The same concept applies to urethroliths that can-
not be removed by nonsurgical methods.
Surgical removal of uroliths followed by dietary and medical
litholytic protocols may be of value in some patients. Examples
include patients in which uroliths or fragments of uroliths remain
after surgery, and patients with crystalluria of a character and mag-