What is septic arthritis?
Septic arthritis (also known as infectious arthritis) happens when an infection spreads to one or more of your joints and causes inflammation. The inflammation is in the surface of the cartilage (a type of connective tissue) that lines your joints and the synovial fluid that lubricates your joints. Bacteria, a virus or fungus may cause the infection, which usually comes from another part of your body and spreads to your joint through your blood. Large joints such as your hip and knee are more commonly affected, but you could get septic arthritis in other joints such as your shoulder and ankle.
In the world of medicine, arthritis covers any type of joint inflammation. There are several different kinds of arthritis, including:
- Rheumatoid arthritis.
- Psoriatic arthritis.
You might think that only older people get arthritis, but anyone at any age can get a type of arthritis. In fact, children more commonly experience septic arthritis than adults.
Which joints are more likely to have septic arthritis?
The joint that is most likely to be affected by septic arthritis depends on different factors. In general, larger joints in the lower half of your body, such as your hips, knees and ankles, are more commonly affected.
- Children are most likely to get septic arthritis in their hip.
- Adults are most likely to get septic arthritis in their knee.
- Injection drug users are more likely to get septic arthritis in the joints that connect your pelvis and lower spine (sacroiliac joints) and in the joint that connects your clavicle, or collarbone, to your sternum, or breastbone (sternoclavicular joint).
Can septic arthritis spread to other places in my body?
If the infection that caused your septic arthritis is not treated, the infection can spread to other parts of your body. This is called sepsis and is life-threatening.
Most cases of septic arthritis only involve one joint. In rare cases, multiple joints can have septic arthritis. Staphylococcal infections are the most common cause of septic arthritis, and most cases only involve one joint. Septic arthritis caused by Neisseria bacteria usually involves multiple joints.
Who does septic arthritis affect?
Septic arthritis more commonly affects children, but adults can get it as well. People born male at birth between 2 and 3 years of age are most likely to get septic arthritis.
How common is septic arthritis?
Septic arthritis is not very common. There are approximately 2 to 6 cases of septic arthritis per 100,000 people per year.
How serious is septic arthritis?
Although it’s rare, septic arthritis is a serious condition. It can cause permanent damage to your affected joint and other complications. It can also cause death if it’s not treated. Be sure to see your healthcare provider or go to the nearest hospital immediately if you experience symptoms.
Symptoms and Causes
What are the symptoms of septic arthritis?
Symptoms of septic arthritis can include:
- Experiencing pain and tenderness in your affected joint.
- Having swelling and warmth at your affected joint.
- Having limited range of motion in your affected joint.
- Not wanting to use or move your affected joint.
- Having a fever.
What causes septic arthritis?
Septic arthritis is caused by an infection. It can be from bacteria, fungus, mycobacteria, a virus or other pathogens. In most cases, the infection begins somewhere else on or in your body and then spreads through your blood to your joint. More specifically, the following organisms can cause septic arthritis:
- Staphylococcus aureus: This bacteria (also known as staph) is the most common cause of septic arthritis in both children and adults.
- Methicillin-resistant Staphylococcus aureus (MRSA): MRSA is a type of staph infection that is resistant to some antibiotics. People who have a higher risk of getting septic arthritis from MRSA include those who use IV drugs, HIV (human immunodeficiency virus infection) or diabetes.
- Groups A and B streptococci: Streptococci are a kind of bacteria. Elderly people and people with chronic diseases such as diabetes and cirrhosis are at higher risk of getting septic arthritis from streptococci.
- Neisseria gonorrhoeae: This bacterium causes gonorrhea, a sexually transmitted infection (STI). People who have gonorrhea can get gonococcal arthritis, which is a form of septic arthritis.
- Neisseria meningitides (meningococcus): This bacterium causes meningitis, which is a condition that involves inflammation (swelling) of the protective membranes covering your brain and spinal cord. While it can happen, getting septic arthritis from Neisseria meningitides is rare.
What is the most common bacteria that causes septic arthritis?
Staphylococcus aureus, a type of bacteria, is the most common cause of septic arthritis in both children and adults. Approximately 37% to 56% of septic arthritis cases are caused by Staphylococcus aureus.
Is septic arthritis contagious?
Septic arthritis is not contagious. However, the bacteria that cause septic arthritis, such as Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA) and Neisseria gonorrhoeae, can spread from person-to-person contact.
Diagnosis and Tests
How is septic arthritis diagnosed?
After a physical exam of your joint, if your healthcare provider suspects you have septic arthritis, they will most likely withdraw synovial fluid (the fluid that lubricates your joint) from your affected joint with a needle. This is called aspiration. They will then do a laboratory test to look at the synovial fluid. Having bacteria in the synovial fluid of your joint confirms the diagnosis of septic arthritis.
What tests are used to diagnose septic arthritis?
Tests that are used to diagnose septic arthritis include:
- Synovial fluid aspiration: Your healthcare provider may withdraw fluid from your affected joint with a fine needle to check it for bacteria. This is known as aspiration.
- Blood tests: Your provider may have you undergo blood tests to see if your body’s immune system is responding to an infection and/or to rule out other possible issues.
- X-rays: X-rays use radiation to take images of your bones. X-rays can show widened joint spaces and bulging of the soft tissues, which can be signs of septic arthritis.
- Ultrasound: Ultrasound uses sound waves to take pictures inside your body. An ultrasound can help your provider see how swollen your joint is and help them see your joint fluid when aspirating it.
- MRI: An MRI (magnetic resonance imaging) uses a large magnet, radio waves and a computer to make detailed images of your organs and bones. An MRI can help detect early cases of septic arthritis.
Management and Treatment
How is septic arthritis treated?
The following treatments are used for septic arthritis:
- Surgery: Removal of the inflamed tissue (surgical debridement) and IV (intravenous) antibiotics are necessary in most cases.
- Antibiotics: All cases of septic arthritis need to be treated with antibiotics. Your healthcare provider may give you antibiotics through an IV and/or in pill form.
- Joint fluid drainage: Your provider may drain (aspirate) fluid from your joint using a fine needle. They may have to do this more than once as you recover.
- Physical therapy: You will likely need physical therapy to restore function in your joint and prevent the muscles around your joint from weakening.
- Removal of an artificial joint: If you get septic arthritis in an artificial (prosthetic) joint, you will likely have to have your artificial joint removed and replaced with a joint spacer, a device made of antibiotic cement. After several months, your healthcare provider will replace your artificial joint.
How long does it take septic arthritis to heal?
The length of time it takes for septic arthritis to fully heal depends on what caused your infection and your overall health. You may have to take antibiotics for a few weeks. It could take longer for your joint to fully heal if the infection caused damage to your joint and the surrounding soft tissues.
Does septic arthritis go away on its own?
Septic arthritis cannot go away on its own since it’s an infection. Bacterial infections need to be treated with antibiotics. If you’re experiencing signs and symptoms of septic arthritis, contact your healthcare provider right away or go to the nearest hospital. Septic arthritis can lead to serious complications and can be life-threatening if it’s not treated.
What are the risk factors for developing septic arthritis?
The risk factors for developing septic arthritis are different for children and adults. Risk factors for children include:
- Age: Newborn children are at a higher risk of getting septic arthritis because their immune systems aren’t as strong.
- Having hemophilia: Children who have hemophilia, an inherited bleeding disorder in which their blood does not clot properly, are at a higher risk of developing septic arthritis.
- Having a weakened immune system: Children who are immunocompromised (have a weak immune system) from conditions like sickle cell anemia and HIV have a higher risk of getting septic arthritis.
- Being on chemotherapy: Chemotherapy weakens your immune system, which makes it more likely that people undergoing it will develop septic arthritis.
Risk factors for adults include:
- Age: Adults over the age of 80 are at a higher risk of getting septic arthritis.
- Having rheumatoid arthritis (RA) or osteoarthritis: People who have damaged joints from rheumatoid arthritis or osteoarthritis are more susceptible to septic arthritis. Cases of septic arthritis in people who have rheumatoid arthritis are up to 70 per 100,000 people per year.
- Having HIV (human immunodeficiency virus): HIV weakens your immune system, which makes it more likely that you’ll get an infection, which could lead to septic arthritis.
- Having diabetes: Having high blood sugar can weaken your immune system. People who have diabetes and have persistent high blood sugar are at a greater risk of getting an infection and septic arthritis.
- Having skin infections: Since septic arthritis is usually caused by an infection elsewhere on or in your body, having a skin infection could lead to septic arthritis.
- Having a recent joint surgery: Having a recent joint surgery puts you at a higher risk of getting septic arthritis because the wound from the surgery could become infected.
- Having an artificial (prosthetic) joint: Infections are more common in prosthetic (artificial) joints than in natural joints. Having a prosthetic joint increases your risk of getting septic arthritis.
- Injection drug use: Injection drug use puts you at a higher risk of getting septic arthritis because the needle can introduce harmful bacteria and other organisms into your body when it breaks the skin.
- Sexual activity: Sexual activity, especially unprotected sex, can put you at a higher risk of developing septic arthritis from the bacteria that causes gonorrhea, a sexually transmitted infection (STI). The bacterium is called Neisseria gonorrhoeae.
How can I prevent septic arthritis?
While not all cases of septic arthritis are preventable, there are a few things you can do to try to prevent getting it, including:
- Make sure cuts and wounds don’t get infected: If you have a cut or wound on your skin, keep it clean to prevent infection. If you are experiencing signs of an infection — such as redness, warmth and/or pus in or around your wound — contact your healthcare provider immediately.
- Try to manage your chronic health condition(s) well: If you have a chronic health condition such as diabetes or AIDS (acquired immunodeficiency syndrome), try to manage your condition as well as you can in order to stay healthy.
- Practice safe sex: Always follow safe sex practices, such as always using a condom or dental dam and talking with your sexual partner about past partners and STI (sexually transmitted infection) history.
- Don’t abuse drugs: Injection drug use can cause infections. Only take medications as prescribed by your healthcare provider.
Outlook / Prognosis
What is the prognosis (outlook) for septic arthritis?
The prognosis (outlook) for septic arthritis depends on a few factors, including:
- The type of bacteria or organism that caused your infection.
- How long your infection lasts.
- Your age and overall health.
Some types of bacteria, such as MRSA, are more challenging to treat than others. The longer septic arthritis lasts, the more likely the affected joint will become damaged. People who have weakened immune systems are also more likely to have damage to their affected joint.
Can septic arthritis be fatal?
Despite the use of antibiotics for treatment, there’s a 7% to 15% mortality (death) rate for septic arthritis. If you’re experiencing signs or symptoms of septic arthritis, be sure the contact your healthcare provider or go to the nearest hospital as soon as possible.
Are there complications associated with septic arthritis?
Septic arthritis is a serious condition. Complications of septic arthritis can include:
When should I see my healthcare provider?
If you’re experiencing symptoms of septic arthritis, such as pain, fever, extreme warmth, redness or tenderness in your joint and having limited mobility in your joint, contact your healthcare provider or go to the nearest hospital immediately. Septic arthritis is a serious condition that needs to be treated with antibiotics. If left untreated, it can be life-threatening.
Frequently Asked Questions
What is the difference between septic arthritis and osteomyelitis?
Osteomyelitis and septic arthritis are both rare and serious conditions. Osteomyelitis is an infection of the bone. Septic arthritis is inflammation in the surface of the cartilage that lines the joint and the synovial fluid that lubricates the joint that is caused by an infection. Both conditions are usually caused by the bacterium Staphylococcus aureus.
Osteomyelitis and septic arthritis can be tricky to tell apart because they have similar symptoms, including pain, tenderness and swelling in the affected area. Septic arthritis can lead to osteomyelitis, and you can have both at the same time. If you have symptoms of osteomyelitis and/or septic arthritis, go to the nearest hospital immediately. Both conditions need medical treatment. Your healthcare provider will perform certain tests to determine which condition is causing your symptoms.
What is the difference between septic arthritis and gout?
Gout is a common form of inflammatory arthritis that’s caused by a crystal called uric acid. Septic arthritis is inflammation in a joint that’s caused by an infection.
Septic arthritis is a rare, but serious, complication of gout. Since both conditions may have similar symptoms, such as inflammation of the affected joint with redness and swelling, it can be difficult to tell them apart. If you are experiencing symptoms of gout and/or septic arthritis, contact your healthcare provider as soon as possible. Your healthcare provider will ask you questions about your symptoms and may have you come to the hospital to perform certain tests to determine which condition is causing your symptoms.
A note from Cleveland Clinic
Septic arthritis is a rare but serious condition. The good news is that it’s treatable. If you’re experiencing symptoms of septic arthritis, such as intense pain, swelling and lack of mobility in your joint, go to the nearest hospital as soon as possible. The sooner your healthcare provider can diagnose and treat your septic arthritis, the sooner you will feel better.
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