Factors Associated With Septic Pleuropneumonia Survival

Factors Associated With Septic Pleuropneumonia Survival

A thoracotomy—opening the chest wall by making incisions between two ribs to remove thick fluid (such as pus), fibrin (a protein involved in blood clotting), and/or necrotic (dead) lung tissue)—improved affected horses' survival rates.

Photo: Anne M. Eberhardt/The Horse

Septic pleuropneumonia—pneumonia complicated by pleurisy (inflammation of the thin, transparent membrane covering the lungs and lining the chest cavity) and sepsis (bacteria in the bloodstream), is a common cause or mortality in horses, but there is limited data available about factors associated with survival.

In a recent study evaluating factors associated with septic pneumonia survival, Sandra Taylor, DVM, PhD, Dipl. ACVIM, an assistant professor at the Purdue University College of Veterinary Medicine, in West Lafayette, Indiana, and colleagues found that performing a thoracotomy improved the survival rates of horses with septic pleuropneumonia.

A thoracotomy involves a veterinarian opening the chest wall by making incisions between two ribs to remove thick fluid (such as pus), fibrin (a protein involved in blood clotting), and/or necrotic (dead) lung tissue that cannot drain from a large chest tube.

“We tend to think of thoracotomy as an aggressive treatment reserved for the sickest of horses and therefore, horses with a worse prognosis,” said Taylor. “Perhaps we should consider thoracotomy as more of a standard treatment.”

Conversely, Taylor and colleagues found that dehydration increased the odds of death in affected horses. “Dehydration leading to kidney dysfunction lowered the odds of survival, making it imperative that a horse is diagnosed and treated early,” she said.

Additionally, Taylor emphasized the importance of testing fluid samples to determine the type of bacteria present. “Given that identification of bacterial isolates is necessary to guide appropriate antibiotic treatment, it is recommended that both tracheal aspirate (fluid from the trachea) and pleural fluid (fluid from the chest cavity) be submitted for microbial culture and antibiotic sensitivity testing,” she said.

Being aware of the risk factors for pleuropneumonia development is key to helping prevent disease.

“A horse’s age (young horses are susceptible), crowding, stress, and travel (especially if the head is tied in the trailer, preventing inhaled microorganisms from draining out the nose) can all contribute to the development of septic pleuropneumonia,” Taylor said.

Once you’re aware of the risk factors, you can take preventive measures such as implementing basic biosecurity measures in barns or at racetracks; allowing horses to lower their heads in the trailer during travel; decreasing travel duration, when possible; and vaccinating against equine herpesvirus and equine influenza virus to promote herd immunity and lower the risk of secondary bacterial pleuropneumonia.

The study, “Factors associated with survival in 97 horses with Septic Pleuropneumonia,” was published in the Journal of Veterinary Internal Medicine

About the Author

Katie Navarra

Katie Navarra has worked as a freelance writer since 2001. A lifelong horse lover, she owns and enjoys competing a dun Quarter Horse mare.

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