Quick facts
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Joint infections can be life-threatening to horses and should be caught and aggressively treated early for the best outcome.
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Treat any signs of infected or contaminated joints as an emergency.
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Check wounds over joints right away to make sure the joint isn’t involved.
Joint infection (septic arthritis) can harm the soundness, athletic career and even life if horses receive poor or delayed treatment.
How do horses get joint infections?
Bacteria from a distant site enter the bloodstream and cause joint infection in foals. Many often blame the navel, but the gut and lungs can be equally responsible. Foals may also have the following:
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Diarrhea
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Pneumonia
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Failure to drink enough high quality colostrum (passive transfer)
In studies of foals with septic joints, 50 to 88 percent had partial or total failure of passive transfer.
Mature horses can get joint infections from the following:
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Wounds over the joint (most common).
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Diagnosis or treatment of joint problems such as joint infections or surgeries.
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Some medications (can change the normal joint defenses).
Infection signs and what to do
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Lameness occurs 8 to 24 hours after infection.
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Swelling in the joint, which you may or may not detect.
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Fever after establishing infection may occur in mature horses.
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Foals usually run a fever before any signs of lameness or joint swelling.
It can be hard to diagnose a joint infection, especially in foals and horses with open wounds. Your veterinarian can take a joint fluid sample to test for joint infection. But if the joint is already open, they may not be able to take a sample. In this case, your veterinarian can use one of the following methods:
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Fluid injection
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Ultrasound
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Radiographs (x-rays)
If you have a foal, your veterinarian will take blood samples and complete a physical exam.
Veterinarians will monitor for signs of deeper infection and arthritis using x-rays. They may use x-rays to get a baseline view and repeat later to check for any changes from infection. Changes can take weeks to months to appear.
When joint fluid drains out through an open laceration, the horse is rarely lame and may not have swollen joints. Foals can have multiple and deep joints infected. Due to the difference in their immune response, the development of clinical signs may be delayed in foals.
The goals of treatment are to:
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Stop the infection.
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Reduce swelling.
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Quickly get the limb back to normal use.
Finding the infection early and treating it aggressively is key. This will clear the infection and prevent problems from overuse of other limbs. Treatment can start on the farm, but often the best approach can occur at an equine hospital. Treatment involves the following:
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Antibiotics given through the veins (IV).
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Flushing the joints.
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Anti-inflammatory agents, which reduces swelling.
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Surgical cleaning.
Outcomes are usually good with early findings and surgical treatment. Researchers evaluated racehorses (Thoroughbreds and Standardbreds) with joint infections. They found that 85 percent of aggressively treated horses survived and 56 percent returned to racing.
The outcome for foals with septic joints is poor. Studies report that 42 to 84 percent of foals with infected joints survive. Early and aggressive treatment is key to success. A study showed that 71 percent of foals treated within two days of clinical signs survived. Only 4 percent survived when treatment started after 2 days.
Reviewed in 2021