Many kids can relate to the unpleasant experience of growing pains – they come on at night and can cause sharp, shooting, as well as dull and nagging pain. But what people may not know is what causes them, why do they affect some children and not others, and most importantly, when should parents be concerned that they could be something much more serious?

Dr. Suzanne Marie Yandow, chief of Orthopedics and Sports Medicine at Seattle Children’s Hospital, answers these common questions below.

What causes growing pains?

The direct cause of growing pains is unknown, but they typically present in children 3 to 5 years of age and may persist much later in some cases in kids ages 8 to 12. Some studies have shown that more than one out of three children displays symptoms at some point in their lives, and the symptoms most often arise during periods of rapid growth.

What are the common symptoms?

Growing pains often come on in the evening and at night, and the pain is usually in the muscles rather than the joints. This pain usually presents bilaterally, meaning the pain will occur in both legs, rather than just one or the other. Frequently they are present in the front of the legs or shin area.

Children are often more aware of the pain at night, and while it may be a nuisance, the pain is typically not severe enough to wake them from a sound sleep. If this occurs, it could be a sign of a more serious underlying condition.

What other more common serious conditions could be mistaken for growing pains?

Toxic synovitis is a common cause of hip pain in children that can often be mistaken for growing pains or a pulled muscle. Toxic synovitis is a temporary condition that occurs due to inflammation of the inner lining of the hip joint. This inflammation may cause pain or stiffness in some children. Toxic synovitis is much more common in boys and most often affects preschool to early school-aged kids, but younger kids can develop it as well.

Unlike the symptoms of growing pains, children with toxic synovitis will often experience leg or hip pain in just one leg, and this pain is more constant throughout the day rather than just in the evening. Other symptoms include limping and reluctance or refusal to bear weight on the limb. In babies, they may cry in situations where their hip joints are being moved, such as diaper changing, or they will refuse to move the limb.

By itself, toxic synovitis is not a serious condition, but the biggest risk in missing its diagnosis is the potential for missing more serious conditions like certain forms of childhood cancer, or a case of septic arthritis. While septic arthritis is uncommon, it’s a surgical emergency when it does occur.

Septic arthritis, which most commonly affects the hip, presents with many of the same symptoms as toxic synovitis, but it is also frequently accompanied by a fever. If left untreated, septic arthritis can damage and destroy the joint that is infected.

How is the underlying cause of the pain diagnosed?

The first thing a doctor will do is examine your child, checking to see what kind of movement is painful by moving the knee, the hip and other joints to confirm where the pain is coming from.

A blood draw can show abnormalities that help to distinguish toxic synovitis from the more dangerous septic arthritis, and the doctor may order an ultrasound that will determine whether there is fluid in the hip joint. Your doctor may also run additional scans and tests to rule out certain forms of cancer.

With many of the symptoms overlapping, what should the main takeaway be for parents and caregivers?

The most important takeaway for parents who are trying to distinguish growing pains from a more serious condition is to pay attention to your child’s symptoms. Cases of toxic synovitis and septic arthritis are much more common in babies and young children, making it much easier to miss. The primary symptoms parents should watch for that indicate it’s time to call the doctor include:

  • If your child is limping or refusing to use a limb
  • If your child’s pain is restricted to one limb
  • If your child’s pain is so intense that it wakes them from a sound sleep
  • If your child’s pain is accompanied by a fever

Parents who have babies should also remember that infants may refuse to move their limbs or hold either their leg or arm very still, which could be a sign of a deeper infection in the joint, muscles or bones.

Overall, growing pains and toxic synovitis are extremely common ailments for children to have, but septic arthritis is an urgent situation that needs to be excluded first. If you have concerns, don’t wait to call a doctor.

Watch the video below to see Dr. Yandow speak about this topic on New Day Northwest:

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