Is there a subpopulation of children with growing pains who really have Restless Legs Syndrome? A review of the literature

Abstract

Symptoms of Restless Legs Syndrome (RLS) can begin in childhood and persist into adulthood. To our knowledge, no one has done a systematic review of the literature to determine if the descriptions of ‘growing pains’ are consistent with the diagnosis of childhood RLS. Our group and that of Ekbom have noted that childhood onset RLS can be misdiagnosed as ‘growing pains’. We therefore reviewed the work of seven groups of authors that addressed ‘growing pains’ as an isolated phenomenon in order to determine whether the descriptions of ‘growing pains’ were consistent with the clinical features of RLS. We found no consistent pattern in the descriptions even when articular pain was excluded. Thus, it is unlikely that all patients with ‘growing pains’ have RLS and it is likely that ‘growing pains’ is a heterogeneous disorder. The aforementioned authors were not looking for features unique to RLS and descriptions of the complete symptom complex of RLS are usually lacking. Further complicating the data are problems with methodology, e.g. in some studies small children and their parents were asked to retrospectively recall remote and infrequent events, and in other studies, articular pain was not adequately ruled out. Inconsistent with the hypothesis that RLS and ‘growing pains’ are the same are the high association of ‘growing pains’ with migraine headaches and abdominal pain. However, from this background emerge subsets of patients with ‘growing pains’ that are described as having one, some, or all of the following features consistent with the diagnosis of RLS: symptoms that are primarily in the legs, the patients rub their legs to get relief of the discomfort, the symptoms are worse at night, sleep disturbance is present and the discomfort is sometimes accompanied by motor restlessness A non-painful form of ‘growing pains’ has even been described. Ekbom and Brenning, a contemporary of Ekom, directly addressed the relationship between ‘growing pains’ and RLS. Ekbom felt that ‘growing pains’ and RLS were probably different since ‘growing pains’ disappear after childhood and one of his patients described her childhood ‘growing pains’ as being different from the sensory discomfort of her adult onset RLS. However, Brenning showed that RLS-like features in adulthood and a previous history of ‘growing pains’ in childhood occurred far more frequently in the parents of children with ‘growing pains’ than in control parents. More work needs to be done on the potential relationship between ‘growing pains’ and RLS.