Growing pains and periodic limb movements of sleep in children

Growing pains in Danish preschool children: a descriptive study

This study provides a detailed description of growing pains in young Danish children as standardized diagnostic criteria are needed to avoid misclassifications of other musculoskeletal diagnoses. The study is nested in a cohort study of Danish preschool children. At baseline, parents completed a questionnaire with sociodemographic information. During the study, the parents received a text message every two weeks inquiring about musculoskeletal pain in the child. If pain was reported, a telephone interview about pain characteristics was conducted. The present study includes data from 2016 to 2019 with 777 children, aged 3-6 years of age at baseline. The prevalence of growing pains was 24-43%, depending on the definition. The pain occurred most frequently 1-3 times per week and most commonly in the lower legs, could be unilateral or bilateral and was usually without consequences. The prevalence increased with age, and there were no consistent associations with socio-economic factors. We suggest using Evan's criteria with the addition of unilateral pain as standard diagnostic criteria in the future. We found no relation to periods of rapid growth and suggest that the term is a misnomer. Etiology and long-term courses of pain need to be explored in future studies.

"Growing pains" in children and adolescents as an early symptom of migraine: A prospective study

BACKGROUND

Children and adolescents may experience pain in the lower limbs, predominantly at the end of the day or during the night, without any relation to organic disease. These pains are often called "growing pains" (GP) by pediatricians and orthopedists. They are commonly attributed to rapid growth.

OBJECTIVE

The aim of this study was to review and characterize GP in children and adolescents as a precursor/comorbidity with migraine.

METHODS

The study was of a cross-sectional, prospective, longitudinal cohort, with group comparison. A sample of 100 children/adolescents born to mothers with migraine seen at a headache clinic was recruited in a random order chosen by lot, maintaining the ratio of 1:1 for the group with GP and the controls. Both groups were followed for a period of 5 years.

RESULTS

After 5 years of follow-up, 78 patients completed the study, of which 42 were from the GP group and 36 were from the control group. Headache fulfilling the International Classification of Headache Disorders, 3rd edition diagnostic criteria for migraine without aura or probable migraine occurred in 32/42 (76%) of patients with GP and in 8/36 (22%) of controls (p < 0.001). In the sample that initially had "growing pains," these pains persisted in 6/42 (14%) and appeared in 14/36 (39%) of those who were previously asymptomatic (p = 0.026).

CONCLUSIONS

Pain in the lower limbs of children and adolescents, commonly referred to as GP by pediatricians and orthopedists, may reflect a precursor or comorbidity with migraine.

Defining Growing Pains: A Scoping Review

BACKGROUND AND OBJECTIVES

Up to one third of children may be diagnosed with growing pains, but considerable uncertainty surrounds how to make this diagnosis. The objective of this study was to detail the definitions of growing pains in the medical literature.

METHODS

Scoping review with 8 electronic databases and 6 diagnostic classification systems searched from their inception to January 2021. The study selection included peer-reviewed articles or theses referring to "growing pain(s)" or "growth pain(s)" in relation to children or adolescents. Data extraction was performed independently by 2 reviewers.

RESULTS

We included 145 studies and 2 diagnostic systems (ICD-10 and SNOMED). Definition characteristics were grouped into 8 categories: pain location, age of onset, pain pattern, pain trajectory, pain types and risk factors, relationship to activity, severity and functional impact, and physical examination and investigations. There was extremely poor consensus between studies as to the basis for a diagnosis of growing pains. The most consistent component was lower limb pain, which was mentioned in 50% of sources. Pain in the evening or night (48%), episodic or recurrent course (42%), normal physical assessment (35%), and bilateral pain (31%) were the only other components to be mentioned in more than 30% of articles. Notably, more than 80% of studies made no reference to age of onset in their definition, and 93% did not refer to growth. Limitations of this study are that the included studies were not specifically designed to define growing pains.

CONCLUSIONS

There is no clarity in the medical research literature regarding what defines growing pain. Clinicians should be wary of relying on the diagnosis to direct treatment decisions.

Improved definition of growing pains: A common familial primary pain disorder of early childhood

Background

Commonly applied diagnostic criteria for growing pains (GP) have evolved without determination by an authoritative representative body. GP and restless legs syndrome (RLS) share anatomical, distributional, temporal, and other clinical features and are associated in individuals over time, in families, and in population samples. In this study, we tested the hypothesis that GP, diagnosed by widely used criteria, is confounded by cases of painful restless legs syndrome (RLS-Painful).

Methods

A twin family study of genetic influence and associations of GP using questionnaires was administered by Twins Research Australia. Twins (3-18 years; monozygous 503, dizygous 513), their oldest siblings, mothers, and fathers were randomly selected from the twin registry. Family members completed the questionnaires assessing lifetime prevalence of GP by commonly applied criteria and covariates including the history of iron deficiency and pediatric pain disorders. A GP-Specific phenotype was defined as GP without urge to move the legs. We determined similarities in twin pairs for the GP and GP-Specific phenotypes, family associations, and estimated familial and individual-specific associations for each phenotype.

Results

Lifetime prevalence was one-third lower for GP-Specific than for GP among the twin and family members. Monozygous twin pairs were more similar than dizygous twin pairs for GP and for the derived GP-Specific phenotype by three methods, consistent with genetic influence. There were familial associations, but the essential evidence for genetic influence was the twin-cotwin data. GP was associated, in multivariable analyses, with migraine, headaches, recurrent abdominal pain, and iron deficiency, while GP-Specific associations were limited to migraine and headaches.

Conclusions

GP is hybrid, one-third of cases having symptoms and associations of RLS, necessarily RLS-Painful. GP-Specific (without symptoms and associations of RLS) could have a genetic etiology. We propose new criteria to facilitate etiological and therapeutic research.

Periodic limb movements during sleep: a narrative review

Objective

Using narrative review techniques, this paper evaluates the evidence for separable underlying patho-mechanisms of periodic limb movements (PLMs) to separable PLM motor patterns and phenotypes, in order to elucidate potential new treatment modalities.

Background

Periodic limb movement disorder (PLMD) is estimated to occur in 5–8% of the paediatric population and 4–11% of the general adult population. Due to significant sleep fragmentation, PLMD can lead to functional impairment, including hyperactivity and delayed language development in children, and poor concentration and work performance in adults. Longitudinal data demonstrate that those with PLMD are at greater risk of depression and anxiety, and a 4-fold greater risk of developing dementia. PLMD has been extensively studied over the past two decades, and several key insights into the genetic, pathophysiological, and neural correlates have been proposed. Amongst these proposals is the concept of separable PLM phenotypes, proposed on the basis of nocturnal features such as the ratio of limb movements and distribution throughout the night. PLM phenotype and presentation, however, varies significantly depending on the scoring utilized and the nocturnal features examined, across age, and co-morbid clinical conditions. Furthermore, associations between these phenotypes with major neurologic and psychiatric disorders remain controversial.

Methods

In order to elucidate potential divergent biological pathways that may help clarify important new treatment modalities, this paper utilizes narrative review and evaluates the evidence linking PLM motor patterns and phenotypes with hypothesised underlying patho-mechanisms. Distinctive, underlying patho-mechanisms include: a pure motor mechanism originating in the spinal cord, iron deficiency, dopamine system dysfunction, thalamic glutamatergic hyperactivity, and a more cortical-subcortical interplay. In support of the latter hypothesis, PLM rhythmicity appears tightly linked to the microarchitecture of sleep, not dissimilarly to the apnoeic/hypopneic events seen in obstructive sleep apnea (OSA).

Conclusions

This review closes with a proposal for greater investigation into the identification of potential, divergent biological pathways. To do so would require prospective, multimodal imaging clinical studies which may delineate differential responses to treatment in restless legs syndrome (RLS) without PLMS and PLMS without RLS. This could pave the way toward important new treatment modalities.

Clinical characteristics of Korean pediatric patients with restless legs syndrome

OBJECTIVES

Restless legs syndrome (RLS) is a common neurological disorder but it is not sufficiently recognized in children and adolescents. It often overlaps with growing pains in children, and as a result the clinical characteristics of pediatric RLS are not well studied, especially in Asia. The purpose of this study is to investigate the clinical characteristics of pediatric RLS patients in Korea and compare it to those of adult RLS patients.

METHODS

We retrospectively reviewed the medical records of all pediatric RLS patients (≤18 years) from January 2015 to December 2018 in a regional tertiary hospital sleep center. We randomly selected adult primary RLS patients without comorbid medical disorders from our sleep center's dataset as controls. The number of controls was determined to be twice the number of pediatric RLS patients according to sample size calculation. The clinical and polysomnographic (PSG) characteristics of both groups were compared. The independent t-test, chi-squared test, and Fisher's exact test were used for analyzing quantitative data between the two groups and p < 0.05 was considered statistically significant.

RESULTS

Twenty-nine primary pediatric RLS patients and 57 adult RLS patients were enrolled. Pediatric RLS patients showed equal prevalence between sexes, as opposed to adults where there is female predominance. Ferritin level was significantly lower in pediatric patients, although it remained within the normal range. Also, pediatric RLS patients showed less severe RLS symptoms and had better sleep quality than adults did in both objective and subjective measures. In addition, PLMS was shown to be less common in pediatric RLS patients compared to adults.

CONCLUSIONS

Pediatric RLS patients showed relatively mild to moderate RLS symptoms and a smaller likelihood of experiencing PLMS than adult patients, which is comparable to similar western studies. Long-term evaluation of a patient's clinical course through multicenter clinical studies is strongly suggested for the future.

Limb movements during sleep in children: effects of age, sex, and iron status in more than 1,000 patients referred to a pediatric sleep center

STUDY OBJECTIVES

Limb movements during sleep (LMS) and periodic limb movements during sleep (PLMS) have been shown to vary by age in children. In the current study, we examined this relationship in more detail in a large clinically referred sample adjusting for iron status and sex.

METHODS

Retrospective data analysis was done on a large pediatric population who underwent an overnight sleep study and had ferritin levels measured within 30 days of sleep study between May 2013 and October 2017 at pediatric sleep center. Patients with obstructive or central sleep apneas were excluded.

RESULTS

A total of 1,070 patients were included in the study, with 60% males. Younger age and male sex were associated with increased PLMS and LMS. In addition, there was an increase in PLMS and LMS during adolescence that subsided at a later age, independent of sex. These associations remained significant in models controlling for ferritin level. Ferritin level, in contrast, was not a significant predictor of PLMS or LMS when controlling for sex and age.

CONCLUSIONS

Age and sex may need to be considered when interpreting limb movement indices in pediatric sleep patients regardless of ferritin level.

Correlates and predictors of paediatric leg pain: a case-control study

Paediatric leg pains, long described as 'growing pains', frequently present to clinicians, are prevalent in early childhood, disrupt sleep, and distress affected children and parents. There are many cited associations, but no defined leg pain sub-types, nor revealed predictive factors. We explored the implicated factors (viz. foot arches, foot strength, joint mobility, vitamin D, iron) in children with leg pain versus a control group. Leg pain sub-groups-growing pains (GP), restless legs (RLS), both (mixed)-are defined for the first time. A case controlled study design, in a primary care setting, Mumbai, India. A total of 77 children with leg pains (n = 64) and controls (n = 13), aged 3-12 years, identified by paediatricians, completed data collection. Blood assays for iron and vitamin D, pain, Beighton score, foot arch, foot strength and anthropometrical data were collected. All outcome measures were validated, with standardised protocols. Leg pain (all groups) was predicted by increased joint mobility and increased ankle dorsiflexion strength (β = 0.56, P < 0.05). GP sub-group was predicted by increased ankle dorsiflexion strength (β = - 0.06, P < 0.05). Mixed (GP/RLS) and RLS sub-groups were predicted by increased ankle dorsiflexion strength (β = 0.66, P < 0.05) and pain questionnaire (β = 0.11, P < 0.05). Hypovitaminosis D was detected in 87% of the sample, and anaemia in 13%. Increased strength of ankle dorsiflexors and joint flexibility were each found predictive for leg pain. Increased body weight, waist girth, and BMI were all associated with leg pain.