Page 934 - Small Animal Clinical Nutrition 5th Edition

966 Small Animal Clinical Nutrition

study concluded that feeding the therapeutic food decreased had a second recurrence and two (0.1%) had a third recurrence
VetBooks.ir the risk of urolith recurrence. (Albasan et al, 2006). Mean recurrence times were 23, 38 and
48 months, respectively. Urolith recurrence rate was not differ-
Tables 46-19 and 46-26 list selected veterinary therapeutic
foods marketed for prevention of calcium oxalate urolithiasis
ent between males and females. It is likely that uroliths from
and compare their key nutritional factor content to the recom- some cats with recurrences were not submitted for subsequent
mended levels.The foods listed in Table 46-19 are also intend- evaluation; therefore, the actual recurrence rate was probably
ed to co-manage FIC- and struvite-based FLUTD. These higher. Further study is needed to better define recurrence rates
foods are compared to composite key nutritional factors for all for calcium oxalate uroliths in cats.
three of these types of lower urinary tract disease. For foods All cats should be monitored for recurrence, including uri-
under consideration that are not listed, contact the manufactur- nalysis every three months to detect calcium oxalate crystalluria
er or review published information to determine levels of key and diagnostic imaging every six months to detect uroliths.
nutritional factors. Foods that are most similar to the key nutri- Serum calcium concentration should be monitored in cats with
tional factor target ranges and/or have published evidence of hypercalcemia. If uroliths recur, less-invasive procedures (e.g.,
efficacy for managing calcium oxalate urolithiasis should be voiding urohydropropulsion) are more likely to be effective
selected. Owners of cats that form calcium oxalate crystals and when uroliths are smaller.Table 46-27 summarizes the steps for
uroliths should be cautioned about grocery brand foods with managing cats with calcium oxalate urolithiasis. Box 46-9
urinary tract health claims because these foods are formulated reviews other treatments for calcium oxalate urolithiasis
for healthy cats to avoid struvite crystals and uroliths. Feeding
such foods may actually increase the risk of developing calcium CONCLUSION
oxalate uroliths.The standard of care for decreasing risk of cal-
cium oxalate urolith recurrence is to feed moist food and The most common forms of FLUTD include FIC, struvite dis-
encourage water intake (Table 46-23). In addition, owners ease (uroliths and urethral plugs) and calcium oxalate uroliths.
should be advised to avoid giving treats with increased amounts Trends in occurrence of urolith types have changed in the past
of calcium or oxalate (Tables 46-15 and 46-18). These 25 years. Many risk factors have been identified for FLUTD, in
foods/products may increase urinary excretion of calcium and general; however, additional study is needed to determine
oxalate, which increases the risk for development of uroliths. pathogenesis and show a cause-and-effect relationship.
Therefore,veterinary health care team members need to edu- Although many treatments have been recommended for FIC,
cate owners about the importance of nutritional management only a few have been evaluated by controlled, randomized clin-
in the treatment of cats with calcium oxalate disease, especially ical trials in cats with naturally occurring disease. When evalu-
cats at risk of urethral obstruction.Increasing owners’awareness ating treatment, consider those options that have the highest
may lead to better compliance. level of evidence for effectiveness (Tables 46-20 and 46-21)
(Roudebush et al, 2004; Forrester and Roudebush, 2007).
Assess and Determine the Feeding Method Feeding moist food and recommending other methods to
Based on information currently available, meal feeding moist increase water intake are appropriate for the most common
food is appropriate to manage cats with calcium oxalate forms of FLUTD including FIC,urolithiasis and urethral plugs.
uroliths. Moist foods increase water intake and reduce concen- In addition, implementing environmental enrichment and stress
trations of crystal-forming elements. The method of feeding reduction is indicated for patients with FIC. Feeding a thera-
influences urinary pH throughout the day and therefore may peutic food for one to two months is a very effective method for
affect success of managing cats with calcium oxalate urolithia- dissolving struvite uroliths in cats. Foods formulated to prevent
sis. Although calcium oxalate crystalluria is not as pH depend- recurrence of struvite uroliths or urethral plugs are indicated
ent as is struvite crystalluria formation, management of urinary after urolith dissolution or removal of urethral plugs. Treatment
pH is still important. As discussed above, ingestion of food for calcium oxalate uroliths involves urolith removal,followed by
stimulates a postprandial alkaline tide, unless offset by acidify- feeding moist food formulated to decrease risk of urolith recur-
ing ingredients in the food. When offered food free choice, rence. Cats with lower urinary tract disorders should be moni-
most cats will eat small amounts every few hours, resulting in a tored periodically by performing urinalyses and diagnostic
smaller but more prolonged alkaline tide than with meal feed- imaging to detect recurrence of their original disease, develop-
ing (Figure 46-18) (Taton et al, 1984). Thus, it has been sug- ment of a different lower urinary tract disorder or occurrence of
gested meal feeding, rather than feeding multiple small meals adverse events associated with therapeutic interventions. The
per day (as in free-choice feeding), might lower the risk of cal- therapeutic regimen can then be modified as needed.
cium oxalate urolith formation because of the production of a
more alkaline urinary pH (Bartges and Kirk, 2006). ENDNOTES

Reassessment a. Osborne CA, Lulich JP. Minnesota Urolith Center, University
Of cats with calcium oxalate uroliths submitted to the of Minnesota, St Paul, USA. Unpublished data. 2007.
Minnesota Urolith Center in 1998 (n = 2,393), 169 (7.1%) had b. Oakton pHTestr 1, Model 35624-00. Oakton Instruments,
a recurrence (i.e., subsequent urolith submission), 15 (0.6%) Vernon Hills, IL, USA.