Equine Urinary Disease

Primary renal disease remains uncommon in equids; however, development of acute kidney injury (AKI) with other disease processes is a serious complication that can increase morbidity and mortality.

 

Of the approximately 2,000 horses presented to Michigan State University’s Veterinary Medical Center each year, approximately 4% have increased amounts of waste products in their blood due to kidney insufficiency (azotemia [excess nitrogen-type wastes in the bloodstream] with a serum creatinine concentration [Cr] greater than 2.5 mg/dL [220 μmol/L]), and 1% have more severe azotemia with Cr levels exceeding 5.0 mg/dL (440 μmol/L).

 

Researchers have found that horses that presented with colic or colitis and had persistent azotemia (failure of azotemia to resolve after three days of treatment) were three times more likely to die or be euthanized as compared to patients in which azotemia resolved. Thus, prompt recognition of compromised renal function, minimizing the use of kidney damaging (nephrotoxic) medications, and institution of appropriate supportive care are critical to improve patient outcome.

 

Non-steroidal anti-inflammatory drugs (NSAIDs) that have a greater inhibitory action against cyclooxygenase-2 (COX-2) have been developed in attempt to limit the unintended side effects of NSAIDs. A misconception has developed that these medications exert less adverse effects on renal function than non-selective COX inhibitors (phenylbutazone and flunixin meglumine). However, COX-2 plays an essential role in maintenance of renal blood flow, thus use of COX-2 selective NSAIDs should not be considered renoprotective therapy.