Septic Arthritis (Infectious Arthritis) in Children
What is septic arthritis in children?
Septic arthritis is an infection in the joint fluid (synovial fluid) and joint tissues. It occurs more often in children than in adults. The infection usually reaches the joints through the bloodstream. In some cases, joints may become infected due to an injection, surgery, or injury.
What causes septic arthritis in a child?
Different types of bacteria, viruses, and fungi can infect a joint. The types that can cause septic arthritis include:
Staphylococci. These are common bacteria that often cause skin infections.
Haemophilus influenzae. These are bacteria that can infect the larynx, trachea, and bronchi.
Gram-negative bacilli. This is a group of bacteria that includes Escherichia coli, or E. coli.
Streptococci. This is a group of bacteria that can lead to many different diseases.
The most common type of bacteria that causes septic arthritis is called Staphylococcus aureus. It is also known as S. aureus. This bacteria can enter the body in many ways, such as:
An infection that spreads from another place on the body, such as the skin or genitals
An infected wound
A broken bone that goes through the skin (open fracture)
Foreign object that goes through the skin
Injury that breaks the skin
Which children are at risk for septic arthritis?
Septic arthritis may occur without any known risk factors. But children who have an open skin wound and an impaired immune systems due to diabetes, kidney disease, HIV infection, or cancer may be at greater risk of septic arthritis.
What are the symptoms of septic arthritis in a child?
The most common joints affected by septic arthritis are the knee, hip, shoulder, elbow, and wrist. Most often, only one joint is affected. Symptoms may vary in each child. Common symptoms include:
Joint pain, often severe
Redness in the affected area
Warmth around the infected area
Limited use of the affected limb, such as not wanting to walk
Guarding or protecting the affected area to keep it from being touched or seen
Other symptoms of illness, such as vomiting, sore throat, or headache
Being grouchy (irritable)
These symptoms can seem like other health conditions. Make sure your child sees his or her healthcare provider for a diagnosis.
How is septic arthritis diagnosed in a child?
Early diagnosis of septic arthritis is important. This is to prevent long-term (permanent) damage to the joint. Your child’s healthcare provider will take your child’s medical history and give him or her a physical exam. Tests may also be done, such as:
Removal of joint fluid. This is done to check for white blood cells and bacteria.
Blood tests. These are done to look for bacteria.
Phlegm, spinal fluid, and urine tests. These are done to look for bacteria and find the source of infection.
X-ray. This test uses a small amount of radiation to make images of internal tissues, bones, and organs.
Bone scan. This imaging test uses a tiny amount of a radioactive substance to look for arthritis changes in the joints.
MRI. This test uses large magnets and a computer to make detailed images of organs and other tissues.
Radionuclide scans. These scans use a tiny amount of a radioactive substance to look at organs and the blood flow to them.
How is septic arthritis treated in a child?
Your child's healthcare provider will figure out the best treatment plan for your child based on:
How old your child is
Your child’s overall health and medical history
How sick your child is
How well your child handles certain medicines, treatments, or therapies
If your child’s condition is expected to get worse
The opinion of the healthcare providers involved in your child's care
Your opinion and preference
Septic arthritis often needs treatment right away with antibiotics. This can improve symptoms within 48 hours. Some infections caused by fungi need treatment with antifungal medicine. Viral infections are not treated with medicine.
A fluid called pus may be drained from the joint. Pus buildup can damage the joint. The pus is drained with a needle, tube, or surgery. Other treatment may include:
Medicines for pain and fever
Physical therapy to keep muscle strength
A splint on the joint to ease pain
What are the possible complications of septic arthritis in a child?
Septic arthritis can cause joint damage. If your child’s growth plate was affected, this may cause an arm or leg to not grow to the full adult length. The growth plate is the part of the bone where new bone is created. This area of the bone helps determine its final adult length. Make sure to follow up with your child's healthcare provider to prevent long-term problems.
When should I call my child’s healthcare provider?
Tell the healthcare provider if your child’s symptoms get worse or there are new symptoms.
Key points about septic arthritis in a child
Septic arthritis is an infection in the joint fluid (synovial fluid) and joint tissues. It occurs more often in children than adults.
Different types of bacteria, viruses, and fungi can infect a joint.
Symptoms include fever, joint pain, swelling, redness, and warmth.
Quick treatment with antibiotics is needed to stop the risk of joint damage.
Other treatments include medicines for pain and fever, draining the joint, physical therapy, and splints.