Toxic Synovitis

Toxic synovitis is a non-traumatic hip pain, which means that it is not caused by an injury. Instead, pain is caused by swelling and inflammation in the hip. Toxic synovitis often follows an upper respiratory infection such as a cold or flu.

The person with the illness often refuses to walk or walks with a limp. Children 2 years old are most often affected, although it also strikes children between the ages of 3 and 10. It appears to be more common in boys than girls.

Symptoms of toxic synovitis can include:

• pain in one hip
• a limp or inability to bear weight because of the hip pain
• low grade fever at the beginning of the illness
• knee and thigh pain on the affected side

Often, the person with this illness does not appear to be ill.

The cause of toxic synovitis is not known. It often follows an upper respiratory infection.

Since the cause of toxic synovitis is not known, there is no way to prevent it.

To diagnose toxic synovitis, a healthcare professional will take a detailed history and perform a complete physical exam. Tests may include:

• an ultrasound of the hip
• joint x-rays of the hip
• blood tests

A sample of joint fluid from the hip also may be sent to the lab to be analyzed to rule out infection.

It is critically important for a physician to make sure that the symptoms are not due to an infection in the hip joint (septic arthritis). Infections in a joint is a medical emergency, because the infection can destroy a joint in a very short period of time.

Two other conditions that can cause similar symptoms in children, Legg-Calve-Perthes disease, and slipped capital femoral epiphysis, need to be ruled out as well. Toxic synovitis is what is known as a "diagnosis of exclusion".

Usually there are no long-term effects from toxic synovitis.

This condition is not known to be contagious.

Toxic synovitis usually heals without any treatment in 7 to 10 days. Sometimes healthcare professionals suggest bed rest. Crutches may be recommended while the inflammation and pain is resolving.

In rare cases, the use of traction with slight flexion of the hip may be needed. Non-steroidal anti-inflammatory medicines (NSAIDs) such as ibuprofen (i.e. Advil, Motrin) or naproxen (Naprosyn, Aleve, Anaprox, Naprelan) may help decrease the pain and inflammation.

NSAIDS may cause stomach upset.

Toxic synovitis usually resolves without specific treatment within 7 to 10 days. If hip pain or a limp persists after this time, it is important to see a healthcare professional. A repeat exam will be needed to rule out other causes of the pain.

Repeat joint x-rays may be needed. Usually complete recovery is achieved without the need for long-term monitoring.