Q: My 8-year-old son regularly complains of experiencing pain in his legs. He is very physically active. The severity of the pain has started to concern me, and he is also up at night. I was told that when a symptom continues to wake a child up at night, it might be a sign of something dangerous. Should I be concerned?
A: It is not uncommon for some children to stumble into their parent's bedroom in the middle of the night - usually going to the mom's side of the bed - complaining with tear-filled eyes of excruciating, lower limb pain. I cannot explain with 100% confidence why the majority of children choose to "consult" with their mothers at these odd times of the day, as opposed to the sleeping father who is oblivious to these nocturnal disturbances.
Lower limb pain, otherwise known as “growing pains”, is one of the most common medical complaints in children. It most often occurs between the ages of 4 and 10 years, and affects approximately 42% of school children. Be assured that these episodes are usually innocent, with the majority resolving themselves within three to four years.
Growing pains can usually be described as:
- Typically coming and going.
- Involving the legs.
- Located at nonarticular areas (i.e., no joint involvement).
- Not associated with abnormal physical signs.
- Usually occurring late in the day.
- Usually being resolved with massaging of the legs.
The exact mechanism by which the pain occurs remains speculative. However, recent information on risk factors for chronic, lower limb pain recently appeared in Pediatrics (September 2005). A population-based, prospective study was conducted in Finland with 1,756 preadolescents. This study is the first of its kind, given most other studies on children with growing pains never followed them for as long as four years.
Results showed that of all the children who experienced growing pains, 32% still experienced pain at the one-year follow-up, and 30% reported pain that recurred at the four-year follow-up. The research also revealed two risk factors, which can predict pain that may either persist for one year or recur at four years.
The first factor involves level of physical activity. Children in the study group, who engaged in vigorous physical activity, were more likely to experience persistent growing pains for up to one year after being included in the study. The reverse is also true: Children who were less active were also less likely to have a continuation of their growing pains for as long as one year. In short, children's involvement in vigorous exercise predicts the short-term outcome of growing pains.
The authors of the Finnish study concluded that limitation of vigorous exercise for children with lower limb pain might be protective. However, this should not be used as an excuse for being inactive. For the record, the authors' definition of vigorous exercise involved children who exercised to breathlessness, for at least half an hour as often as 2-7 times per week. And although children's bones and muscles are more elastic than adults, they also tend to heal faster.
Also worth noting is that even though the incidence of childhood obesity continues to climb (due in part to a sedentary lifestyle), there is also data to show that the number of preadolescents involved in organized athletic activity has increased over the past few years. For more information on the actual data, see the publication by S. Rowley, "The Effect of Intense Training on Young Athletes" (London UK, Sports Council, 1989; pp. 6-7).
The second factor to predict chronic leg pain is having lax joints. Children in the study who had hypermobility (i.e., joints that are extra lax and flexible) were more likely to experience a recurrence of their growing pains when followed for as long as four years. This group of children also had a three-fold risk for growing pains to recur, as compared to the “nonhypermobile” group.
This new research enables clinicians to have a better understanding of the natural course of growing pains. It also helps pediatricians to identify the subgroup of children, who are most likely to experience either persistence or recurrence of this common and often frustrating preadolescent diagnosis.
One word of caution though: Parents should seek medical attention when a child limps, refuses to bear weight, has swelling and redness of a joint, or experiences an associated fever. When these symptoms appear, it is very unlikely to be growing pains.
Meanwhile, for parents who have survived many nights of interrupted sleep, there should be a monument in the nation's capital city. Though, perhaps only for the mothers who seem to be the first ones to deal with the tears caused by growing pains!
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