Is Toxic Synovitis?
Toxic synovitis is a temporary condition that causes hip pain in
children. It’s also known as transient synovitis. It mainly occurs in children between
3 and 8 years old. It’s two
to four times more common in boys than girls.
Although it’s troubling for parents, this condition usually
clears up on its own within a week or two and causes no lasting damage.
Causes Toxic Synovitis?
Toxic synovitis occurs when there’s inflammation in the hip
joint. The cause is unknown, but it often occurs after a viral infection. It
usually only affects one hip, but it’s possible for swelling and inflammation to
spread to other joints.
Are the Symptoms of Toxic Synovitis?
The most common symptom of toxic synovitis is hip pain. This pain
might occur on and off in one or both hips. It might flare up when your child
gets up after sitting or lying down for a long time.
Other symptoms include:
- limping or walking on tiptoe due to discomfort
- pain in the thigh or knee and no hip pain
- low-grade fever under 101°F
- refusing to walk if the pain is severe
- crying and irritability in younger children
Common signs of toxic synovitis in babies include crying,
especially when moving their hip joints, and unusual crawling movements or
being unwilling or unable to crawl.
Is Toxic Synovitis Diagnosed?
Ruling Out Other Conditions
Toxic synovitis can be difficult to diagnose. Other conditions
that are much more serious can also cause hip pain. Since these conditions
require prompt medical treatment, your child’s doctor must first test for them
before making a toxic synovitis diagnosis. These include the following:
- Septic arthritis is a bacterial or fungal
infection that results in joint inflammation and can lead to permanent joint
damage if it’s left untreated.
- Legg-Calve-Perthes disease is an insufficient
blood flow to the hip joint, leading to the collapse of the joint as the bone
- Lyme disease is bacterial infection caused by tick
bites that can result in long-term joint problems if it’s left untreated.
- Slipped capital femoral epiphysis (SCFE) occurs when
the ball of the hip joint and the thighbone, or femur, separates. This leads to
a joint disorder called osteoarthritis later in life.
Diagnosing Toxic Synovitis
Your child’s doctor will perform a physical exam to find out
which movements are causing pain. This involves moving your child’s hips,
knees, and other joints.
Your doctor might order an ultrasound of your child’s hip to
check for fluid in the joint, which is a sign of inflammation.
Blood tests can show how severe the swelling is. They might also
check for other causes of hip pain, such as Lyme disease.
Your child’s doctor might remove a fluid sample and send it to a
lab for testing. This is usually done when the swelling or fever is serious and
septic arthritis hasn’t been ruled out.
Your child’s doctor might take X-rays to rule out
Legg-Calve-Perthes disease or SCFE.
Are the Treatments for Toxic Synovitis?
Treating toxic synovitis involves controlling or reducing its symptoms.
The inflammation caused by the viral infection generally goes away on its own.
Over-the-counter (OTC) medications such as ibuprofen and naproxen
can help reduce inflammation temporarily. This can provide short-term pain
relief. Your child’s doctor might prescribe a stronger pain reliever if OTC
medications don’t work.
Your child should rest the affected hip to help it heal. Walking
is usually safe, but your child should avoid strenuous activities, such as
contact sports. Your child should also try not to put too much weight on the
Are the Complications Associated with Toxic Synovitis?
Although this condition is rarely serious, you should call your
child’s doctor if:
- the fever or pain becomes worse even after
taking anti-inflammatory medication
- the joint pain lasts longer than three weeks or
comes back after your child stops taking medication
- the anti-inflammatory medication doesn’t start
working within a few days
Your child’s doctor might need to prescribe a different
medication or perform additional tests to check for other causes of hip pain.
Is the Long-Term Outlook?
Toxic synovitis clears up in about one to two weeks in most
cases, but it can last as long as five weeks. It can occur repeatedly in some
children when they have viral infections like colds.