What is Bone Infection?
Bone infections occur when a bacterial or fungal infection occurs in the bone or bone marrow, referred to as osteomyelitis. This can happen directly in the bone after a fracture or surgical event, or it can be spread to the bone by the bloodstream from an infection in another part of the body. The infection causes inflammation of the bone and surrounding tissues. Your pet might not show any sign of bone infection for some time before symptoms occur, making it likely for the infection to be severe by the time it is diagnosed. If you believe your cat may have a bone infection, seek veterinary assistance immediately. Medical treatment will be required to get rid of the infection, and the sooner treatment begins the better the result for your pet. In some cases, bone infections will require surgery or amputation to treat. Treatments may require several weeks of hospitalization.
Symptoms of Bone Infection in Cats
A bone infection can cause a variety of symptoms in your cat, the most common being lameness or favoring of a limb, apathetic behavior or listlessness, and fever. In cases which the infection has spread to the bone or bone marrow from another part of the body, your pet may exhibit other localized symptoms related to the infection. It is also possible for your cat to have general symptoms of infection like breathing difficulty, runny nose or eyes, fever, or vomiting and diarrhea.
- Apathy or depression
- Ulcers or lesions
- Limb pain
- Stiffness or arthritis
- Reluctance to use the limb
- Wasting or pulling back of muscles
- Limb swelling
- Joint swelling
- Lack of appetite and anorexia
- Pus or oozing from wound site or soft tissues
Bone infection can be caused by an acute or sudden, short-term infection or by a chronic, long-term condition. Types of bone infection include:
- Bacterial infections
- Fungal infections
Causes of Bone Infection in Cats
A bone or bone marrow infection is most commonly caused by bacteria or fungus that has entered the body through normal means of transmission like ingestion, exposure to other sick animals, or through a wound. Once the germs are in your cat’s system, they can be transported through the blood to infect other parts of the body, including the bones. The infection gets into the bone and marrow, causing inflammation and pain, resulting in your cat’s symptoms.
Some common causes that lead to bone infection include:
- Injuries – from fracture, trauma, or bites and claw wounds
- Post-surgery or implant
- Soft tissue infection
- Dental infection
- Other infections
Diagnosis of Bone Infection in Cats
Your veterinarian will use a combination of techniques to verify that bone infection is causing your cat’s issues. Be prepared to discuss your pet’s medical history and any symptoms you’ve observed in detail. This will help identify risk factors, like recent wounds, other infections, or chronic conditions, which point to a bone infection. A physical examination will be completed, and your veterinarian may require X-ray or other imaging to pinpoint the location and severity of the infection. A variety of diagnostic tests will also be required to identify the source of the infection so an appropriate treatment plan can be created. Blood and urine analysis will occur, and veterinary staff may also take samples of any pus or drainage. Bone marrow aspiration or a bone biopsy may be required to identify the infection source if other methods are not successful.
Treatment of Bone Infection in Cats
Treatment methods will vary depending on several factors, including if the infection is acute or chronic, its location, its severity, and the type of organism causing it. If your cat’s bone infection is secondary to another infection or a wound then additional treatments will be required to manage that condition. Your veterinarian may begin some treatments, like antibiotics, even before the exact organism causing the infection has been identified. Common treatments for bone infection include:
Antibiotics: In bacterial infections, antibiotics will be administered to destroy the bacteria and allow the immune system to focus on healing. Antibiotic treatments may continue for several weeks to resolve the issue. Bone infections are often slow to heal, and resistant bacteria make it even more difficult. Your pet may be given more than one type of antibiotic during the course of their treatment.
Debridement: Draining, flushing, and removing dead tissue will be required to help rid your cat’s body of infection and speed the healing process. This may require surgical intervention if there is no other way to open the affected area. This is a routine process with a low risk to your pet.
Analgesics: Used to reduce and control pain and inflammation, these drugs will be used to make your cat comfortable while undergoing other treatment. Your veterinarian will choose the appropriate dose for your pet to reduce risk.
Surgery or Amputation: If damage is severe, surgical methods might be required to control the issue and repair damage. In cases where there is a large amount of bone loss and tissue damage, amputation of the affected limb may be the safest and surest course of action.
Intravenous (IV) Fluids: Symptoms like lack of appetite and lethargy can lead to additional health concerns. IV fluids are a routine way to help maintain hydration and can also be used to provide medication and nutrients to your pet during treatment.
Recovery of Bone Infection in Cats
Your pet’s prognosis will be dependent on numerous factors. If treatment is successful, your pet will need additional support after they return home. Immobilization of the affected limb may be required for a short period, and restricted movement will be necessary for several weeks. Make sure your cat has a safe, comfortable place to rest and recuperate. Place food, water, and their litter box in close proximity so they don’t have to go far to get what they need. In some cases, your pet may need caged to reduce movement. Follow all your veterinarian’s instructions, being sure to finish the full course of antibiotics and return for any required follow-up visits. Nutrition also plays an important role in healing so ensure your pet has access to healthy food.
If your cat required an amputation to treat their bone infection, you will need to provide extra support until they have adjusted to their new limitations. Avoid lifestyle changes while your pet adapts. Most animals are able to learn to function with a missing limb fairly quickly. Ensure that the amputation site and any surgical incisions are properly cleaned and cared for. Return your pet to the veterinarian immediately if you see any signs of infection such as spreading redness, pus or oozing, or a foul smell.
Bone Infection Questions and Advice from Veterinary Professionals
My cat probably has osteomyelitis of the jaw. What is the prognosis? How common is a fungal cause compared to a bacterial cause? Local vet seems unsure about whether it could be cancer or Osteomyelitis.
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My 16 year old cat had dental work 2 months ago and had a couple of teeth removed, including one which fractured during extraction. He took a couple of weeks for him to recover, but now has is experiencing such severe jaw pain that he swats his mouth when trying to eat even watered down canned food. We have tried many remedies, with no success. My vet has offered a "last suggestion" of putting him on Clindamycin to treat a possible deep bone infection. She was reluctant however, as he also has Kidney and Liver disease. My question is...should I take a chance putting him on a heavy duty antibiotic to cure a possible infection, or am would I just be making him sicker and more uncomfortable with the added side effects of this antibiotic? He currently receives sub-q fluids 2X a week, Azodyl, and buprophrine for the pain.
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Boo has a fractured tooth and swelling in the upper jaw, so we went to the vet and he has been on antibiotics for 2 weeks now. The swelling feels hard to the touch and is showing no signs of improvement. We thought it was a bone infection from the fractured tooth, but I am worried it is something worse.
If there is exposure of the internal dentine then it would be extremely painful. If you are not seeing any improvement, visit your Veterinarian again as in a cat Boo’s age certain conditions can take longer to heal and may cause other complications. Without examining Boo I cannot suggest a change in treatment. Regards Dr Callum Turner DVM
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My cat has been sitting with his right hind leg sticking out to the front. The knee is swollen but not sure what happen because he doesn't show signs of pain or limping. Why is it swollen?
Swelling of the knee would prevent Earl from bending the knee normally leaving it sticking out straight. The swelling may be due to infection (from a bite for example), trauma (sprain, ligament rupture) or dislocated patella. You should visit your Veterinarian to determine the actual cause and prescribe treatment as treatment is different for each problem. Regards Dr Callum Turner DVM
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