What is Toxic Synovitis?

Toxic synovitis sounds like a very dangerous disease, since most people are used to thinking of the term “toxic” as poisonous. It might help to consider this illness by one of its synonyms, transient synovitis. This condition is usually short lasting and goes away without much treatment. It most often occurs in kids, especially boys, and is an inflammation of the hip at the synovium, or part of the hip’s lining.

Symptoms of toxic synovitis are usually a one-sided limp. There may or may not be discomfort associated with the disease. Usually there is some pain, and one symptom when this condition occurs in infants is crying that appears to have no cause. Sometimes pain isn’t only occurring in the hip joint and might also occur in the knee, the groin and the thigh.

The limp is usually clearly not the result of any injury to the hip and tests for diagnosis might show some extra fluid present at the hip. Also about half of the children who get this condition have previously had a virus. It’s thought that potentially the virus may cause an accelerated immune response in the joint, which results in swelling. Some viruses that have been indicated in causing toxic synovitis include mumps, chickenpox, cytomegalovirus, herpes, mononucleosis, coxsackievirus, and rubella.

The one thing that doctors will want to do if they suspect toxic synovitis is to rule a disease that can present with the same symptoms, called septic arthritis. In septic arthritis, bacteria infect a joint, and if this is not treated appropriately with antibiotics it can result in permanent damage to the hip joint. In many cases fever is present with septic arthritis but not with toxic synovitis, so this can be one method for ruling out the more serious condition.

When doctors are reasonably certain that toxic synovitis is causing the limp, the treatment is very simple. Children should rest the joint and not continue to walk on it. Sometimes pain medication is given, and preference may be toward administering non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, since this may reduce swelling and end the discomfort and limping sooner.

Standard length of the condition is usually about a week to a week and a half, but some kids may have an extended course that lasts longer than this. Most are able to fully resume activities in about a week or so. The hardest part for many kids with this condition may be having to remain inactive and put no weight on the hip for a while.

There isn’t any prevention of toxic synovitis except to prevent those diseases, which may cause it. Many of them are preventable via vaccine. Yet this will not guarantee a child never develops the condition.