Prevention
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Prognosis
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Definition|
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Septic arthritis is inflammation of a joint
caused by a bacterial infection. It's also known as infectious or bacterial
arthritis.
Septic, or infectious, arthritis is
infection of one or more joints by microorganisms. Normally, the joint is
lubricated with a small amount of fluid that is referred to as synovial fluid
or joint fluid. The normal joint fluid is sterile and, if removed and cultured
in the laboratory, no microbes will be detected. With this form of arthritis,
microbes are identifiable in an affected joint's fluid. Infants and older
adults are most likely to develop septic arthritis.
Most commonly,
septic arthritis affects a single joint, but occasionally more joints are
involved. The joints affected vary somewhat depending on the microbe causing
the infection and the predisposing risk factors of the patient affected. Septic
arthritis is also called infectious arthritis.
Symptoms|
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Septic arthritis typically causes severe
pain, swelling, redness and heat in affected joints. These symptoms tend to
develop quickly over a few hours or days.
Joints most
commonly involved are large joints, such as the knees, ankles, hips, and
elbows. In patients with risk factors for joint infection, unusual joints can
be infected, including the joint where the collarbone (clavicle) meets the
breastbone (sternum). With uncommon microbes, such as Brucella spp., atypical
joints can be infected, such as the sacroiliac joints.
Causes|
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Septic arthritis can be caused by
bacterial, viral or fungal infections. Bacterial infection with Staphylococcus
aureus (staph) is the most common cause. Staph commonly lives on even healthy
skin.
The most common causes of septic arthritis
are bacterial, including Staphylococcus aureus and Haemophilus influenzae. In
certain "high-risk" individuals, other bacteria may cause septic
arthritis, such as E. coli and Pseudomonas spp. in intravenous drug abusers and
the elderly, Neisseria gonorrhoeae in sexually active young adults, and
Salmonella spp. in young children or in people with sickle cell disease. Other
bacteria that can cause septic arthritis include Mycobacterium tuberculosis and
the spirochete bacterium that causes Lyme disease.
Viruses that can cause septic arthritis
include hepatitis A, B, and C, parvovirus B19, herpes viruses, HIV (AIDS
virus), HTLV-1, adenovirus, Coxsackieviruses, mumps, and Ebola. Fungi that can
cause septic arthritis include Histoplasma, Coccidioides, and Blastomyces.
Septic
arthritis is not contagious. However, many of the microbes that cause septic
arthritis can be transmitted from an infected patient to another, including
Neisseria gonorrhoeae, Mycobacterium tuberculosis, and HIV
Risk Factors|
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While joint infection occasionally affects
people with no known predisposing risk factors, it more commonly occurs when
certain risk situations are present.
Risk factors for septic arthritis include:
Existing joint problems. Chronic diseases
and conditions that affect your joints — such as osteoarthritis, gout,
rheumatoid arthritis or lupus — can increase your risk of septic arthritis, as
can an artificial joint, previous joint surgery and joint injury.
Taking medications for rheumatoid arthritis.
People with rheumatoid arthritis have a further increase in risk because of
medications they take that can suppress the immune system, making infections
more likely to occur. Diagnosing septic arthritis in people with rheumatoid
arthritis is difficult because many of the signs and symptoms are similar.
Skin fragility. Skin that breaks easily and
heals poorly can give bacteria access to your body. Skin conditions such as
psoriasis and eczema increase your risk of septic arthritis, as do infected
skin wounds. People who regularly inject drugs also have a higher risk of
infection at the site of injection.
Weak immune system. People with a weak
immune system are at greater risk of septic arthritis. This includes people
with diabetes, kidney and liver problems, and those taking drugs that suppress
their immune systems.
Joint trauma. Animal bites, puncture woods
or cuts over a joint can put you at risk of septic arthritis.
Having a
combination of risk factors puts you at greater risk than having just one risk
factor does.
