HYDRATION VITAL FOR SHIPPING FEVER RECOVERY
Reduced kidney function is an ominous sign in horses battling serious respiratory disease, according to a new study. Horses with bloodwork showing elevated kidney values were five times less likely to survive the illness.
Researchers at Purdue University and Hagyard Equine Medical Institute examined the records of 97 horses admitted to their facilities with pleuropneumonia, an infection of the lungs that causes inflammation and the accumulation of fluid in the chest cavity.
Commonly known as “shipping fever,” pleuropneumonia is mainly associated with transport, but other factors can also make a horse susceptible to the condition. “A significant number of horses in this study were racehorses, in whom viral infections, stress and high-intensity exercise influence in the development of the disease,” says Gabriela Arroyo, DVM. “Prolonged head elevation and general anesthesia can also lead to pleuropneumonia.”
The researchers reviewed each horse’s medical records, documenting the signs, treatment and outcome, and then analyzed the data to see which factors might be associated with survival.
Overall, 67 percent of the horses survived to be discharged from the hospital. Horses whose initial bloodwork (taken upon admission) showed high levels of creatinine were five times less likely to survive. Creatinine is a chemical waste product of metabolism that is normally excreted by the kidneys. When levels build up in the blood, it is an indication of compromised renal function.
Elevated creatinine “is likely associated with dehydration and hypovolemia (a decreased blood volume in the body),” says Arroyo, “These horses have severe respiratory distress and chest wall pain, which makes it difficult to drink or eat, which leads to severe
dehydration. Fluid loss into the chest cavity, as well as severe dehydration, leads to hypovolemia and subsequently decreased perfusion of the kidneys. Therefore, the worse the pleuropneumonia is, the more dehydrated the horse is likely to be, which leads to kidney damage and a worse prognosis.” She adds that the use of certain medications can further stress the kidneys if a horse is dehydrated.
In light of this finding, Arroyo says, measures to protect the kidneys could help increase survival rates in horses with pleuropneumonia, particularly in those so sick that they are not eating and drinking normally. “Intravenous fluids with close monitoring of hydration status, blood creatinine levels and urine parameters is important,” she says. “Another important factor is to be very cautious when using nonsteroidal antiinflammatory drugs, such as phenylbutazone or flunixin meglumine, or gentamicin (antibiotic) in dehydrated horses with pleuropneumonia, since these drugs can be toxic to the kidneys.