Chapter 193 It has long been believed that glucocorticoid therapy, by suppressing local and systemic immunity, may predispose to UTI. Two studies found positive urine culture results in 39% of dogs (Ihrke et al, 1985) and 18% of dogs (Torres et al, 2005) with chronic skin disorders that received long-term low-dose corticosteroids, compared with no positive urine culture results in dogs with chronic skin disorders that did not receive steroids. In these studies, no dogs had clinical signs of UTI. The type of steroid administered, frequency of administration, duration, and dosage of corticosteroid were not correlated with culture results. Dogs receiving short-term steroid therapy also may be affected because dogs administered dexamethasone in the 48 hours before hospital admission for surgical fixation of intervertebral disk disease were 11.4 times more likely to have a positive urine culture result (>5 CFU/ml) than dogs undergoing such surgery that had not received dexamethasone (Levine et al, 2008). For patients with intervertebral disk disease, this increased risk may be due to the immunosuppressive properties of dexamethasone in combination with altered neurologic function (inability to void completely). Of dogs with naturally occurring hyperadrenocorticism, 46% were found to have a UTI (>1000 CFU/ml), but clinical signs of UTI were rare (Forrester et al, 1999). UTI in these dogs may be caused by systemic immunosuppression, dilute urine causing local alterations in immunity, or concurrent disease. The antiinflammatory properties of glucocorticoids also may influence the development of clinical signs related to UTI and the presence of pyuria on urine sediment examination. Veterinary patients with diabetes mellitus have been considered at increased risk for UTI because of factors such as immunosuppression, inappropriate urine concentration, and glucosuria. In human patients, diabetic individuals with asymptomatic bacteriuria do not have an increased risk of developing symptomatic UTI or other diabetic complications requiring hospitalization; no similar data are available for companion animals. In canine studies, UTI (>1000 CFU/ml) was present in 24% to 37% of dogs with diabetes mellitus, but few patients had clinical signs specific for UTI (Forrester et al, 1999; McGuire et al, 2002). Cats with diabetes mellitus also may be at increased risk of subclinical UTI, with 12% to 13% of diabetic cats found to have bacterial growth in their urine; clinical signs were present in 14% to 44% of those with bacterial growth (Bailiff et al, 2006; Mayer-Roenne et al, 2007). Emphysematous cystitis, most often caused by gas production associated with Escherichia coli invasion of the urinary bladder wall, is a complication of UTI specifically recognized in diabetic veterinary patients as well. Dogs and cats with chronic kidney disease (CKD) may have impaired systemic immunity (neutrophil dysfunction, reduced cell-mediated immunity) and local immune function (altered urine composition) that could lead to increased risk of UTI. In two studies bacterial growth in urine culture was identified in 22% to 30% of cats with CKD, with 23% of these cats showing clinical signs of lower urinary tract disease (Barber et al, 1999; Mayer-Roenne et al, 2007). Although female sex was associated with UTI in both studies, there was no association between UTI and age (>10 years) in either study, which suggests that young and middle-aged cats with CKD also are at risk of UTI. Numerous other systemic illnesses may predispose dogs and cats to clinical or subclinical UTI. In one study, 12% of hyperthyroid cats had positive urine culture results, but no cats had clinical signs of a UTI (Mayer-Roenne et al, 2007). In dogs with parvoviral enteritis, 23% developed subclinical UTI (>1000 CFU/ml), suspected to be caused by fecal contamination of the urogenital tract combined with neutropenia (Koutinas et al, 1998). It is also commonly believed that veterinary patients receiving chemotherapy or nonsteroidal immunosuppressive therapy (e.g., cyclosporine) are at increased risk of UTI due to immunosuppression. Finally, morbidly obese dogs (>45% body fat) have been documented to have 7.5 times greater risk of asymptomatic UTI than dogs with less than 45% body fat (Lusby et al, 2011).
Surveillance for Asymptomatic and Hospital-Acquired Urinary Tract Infection
Risk Factors
Exogenous and Endogenous Steroids
Diabetes Mellitus
Kidney Disease
Miscellaneous Systemic Conditions
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
