Thyrotoxic periodic paralysis (TPP) is a rare complication of hyperthyroidism, with recurrent muscle paralysis and hypokalemia that are caused by an intracellular shift of potassium. TPP is relatively common in Asian males, but is extremely rare in children and adolescents, even for those of Asian descent. We describe a 16-year-old Korean adolescent presenting with a two-week history of episodic leg weakness in the morning. He showed sinus tachycardia, lower leg weakness, and hypokalemia. Thyroid function test showed hyperthyroidism, and thyroid ultrasonography revealed a diffuse enlarged thyroid with increased vascularity, consistent with Graves' disease. He was treated with β-adrenergic blocker and antithyroid drugs. He has been symptom free for one year, as his hyperthyroidism has been controlled well with antithyroid drugs. TPP should be considered in children and adolescents with acute paralysis of the lower extremities and hypokalemia.
Thyrotoxic periodic paralysis; Graves' disease; Adolescent; Korean
HbA1c variability; microalbuminuria; type 1 diabetes
Short stature is a very common reason for visits to pediatric endocrine clinics. It could be the first sign of an underlying disease. The purpose of this study is to investigate the etiologies and general characteristics of subjects who visited an outpatient clinic due to short stature.
We retrospectively reviewed the medical records of 3,371 patients who visited Severance Children's Hospital with the chief complaint of short stature from 2010 to 2012. Medical history, auxological data, and laboratory tests including bone age were collected and analyzed. Chromosome studies or combined pituitary function tests were performed if needed.
Approximately 89.4% of the subjects with the chief complaint of short stature who visited the outpatient clinic were of normal height, and only 10.6% of subjects were identified as having short stature. Of the subject of short stature, 44.7% were classified as having normal variant short stature; that is, familial short stature (23.0%), constitutional delay in growth (17.7%), and mixed form (3.9%). Pathological short stature was found in 193 subjects (54.2%). Among pathological short stature, most common etiology was growth hormone deficiency (GHD) (38.9%).
A majority of children had a normal height. Among children with short stature, pathological short stature and normal variants occupied a similar percentage. GHD was the most common cause of pathological short stature and found in about 20% of the children with short stature. In pathological short stature, the height, height velocity, and IGF-1 level were lower than in normal variants.
Short stature; Etiology; Growth
Previous studies have revealed many inconsistent results regarding the relationship between vitamin D and metabolic syndrome. The purpose of our study was to investigate the association between serum 25-hydroxyvitamin D (25(OH)D) concentration and factors that characterize metabolic syndrome in Korean children and adolescents.
We analyzed data from 2,880 children and adolescents aged 10-18 years collected from the 2008-2010 Korean National Health and Nutrition Examination Survey. We investigated the data according to quartiles of 25(OH)D concentrations.
Systolic blood pressure and diastolic blood pressure with adjustment for sex and age differed significantly between the serum 25(OH)D groups and exhibited negative trend as 25(OH)D concentrations increased. The number of subjects with metabolic syndrome was greater in the low 25(OH)D groups (I, II, and III quartile) than in the high 25(OH)D group (IV quartile) (P=0.029). BMI and waist circumference were lower in the high 25(OH)D group. Serum 25(OH)D concentration correlated negatively with homeostasis model assessment estimate of insulin resistance (ρ=-0.073, P<0.001) and correlated positively with quantitative insulin sensitivity check index (ρ=0.095, P<0.001).
Low serum 25(OH)D level is associated with an increase of insulin resistance and metabolic syndrome in children and adolescents.
25-hydroxyvitamin D; Metabolic syndrome; Child; Obesity; Insulin resistance
There is controversy surrounding the growth outcomes of treatment with gonadotropin-releasing hormone agonist (GnRHa) in central precocious puberty (CPP). We analyzed height preservation after treatment with GnRHa with and without growth hormone (GH) in girls with CPP.
We reviewed the medical records of 82 girls with idiopathic CPP who had been treated with GnRHa at Severance Children's Hospital from 2004 to 2014. We assessed the changes in height standard deviation score (SDS) for bone age (BA), and compared adult height (AH) with midparental height (MPH) and predicted adult height (PAH) during treatment in groups received GnRHa alone (n=59) or GnRHa plus GH (n=23).
In the GnRHa alone group, the height SDS for BA was increased during treatment. AH (160.4±4.23 cm) was significantly higher than the initial PAH (156.6±3.96 cm) (P<0.001), and it was similar to the MPH (159.9±3.52 cm). In the GnRHa plus GH group, the height SDS for BA was also increased during treatment. AH (159.3±5.33 cm) was also higher than the initial PAH (154.6±2.55 cm) (P<0.001), which was similar to the MPH (158.1±3.31 cm). Height gain was slightly higher than that in the GnRHa alone group, however it statistically showed no significant correlation with GH treatment.
In CPP girls treated with GnRHa, the height SDS for BA was increased, and the AH was higher than the initial PAH. Combined GH treatment showed a limited increase in height gain.
Central precocious puberty; Gonadotropin-releasing hormone; Growth hormone; Treatment outcome
The rapid increase in the incidence of precocious puberty in Korea has clinical and social significance. Gonadotropin-releasing hormone (GnRH) stimulation test is required to diagnose central precocious puberty (CPP), however this test is expensive and time-consuming. This study aimed to identify factors that can predict a positive response to the GnRH stimulation test.
Clinical and laboratory parameters, including basal serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol (E2), were measured in 540 girls with clinical signs of CPP.
Two hundred twenty-nine of 540 girls with suspected CPP had a peak serum LH level higher than 5 IU/L (the CPP group). The CPP group had advanced bone age (P<0.001), accelerated yearly growth rate (P<0.001), increased basal levels of LH (P=0.02), FSH (P<0.001), E2 (P=0.001), and insulin-like growth factor-I levels (P<0.001) compared to the non-CPP group. In contrast, body weight (P<0.001) and body mass index (P<0.001) were lower in the CPP group. Although basal LH was significantly elevated in the CPP group compared to the non-CPP group, there was considerable overlap between the 2 groups. Cutoff values of basal LH (0.22 IU/L) detected CPP with 87.8% sensitivity and 20.9% specificity.
No single parameter can predict a positive response on the GnRH stimulation test with both high sensitivity and specificity. Therefore, multiple factors should be considered in evaluation of sexual precocity when deciding the timing of the GnRH stimulation test.
Precocious puberty; Diagnosis; Gonadotropin-releasing hormone; Forecasting; Female
Longitudinal standards for height and height velocity are essential to monitor for appropriate linear growth. We aimed to construct standards in Korean children and adolescents through the population-based longitudinal Kangwha study. Our study was a part of a community-based prospective cohort study from 1986 to 1999 with 800 school children. Height and height velocity were recorded annually from age 6 until final height. Results were compared with cross-sectional data from the 2007 Korean National Growth Charts. Final height was 173.5 cm in boys and 160.5 cm in girls. Although final height was similar between longitudinal and cross-sectional standards, the mean height for age was higher in the longitudinal standard by 1-4 cm from age 6 until the completion of puberty. Using the longitudinal standard, age at peak height velocity (PHV) was 12 in boys and 10 in girls; height velocity at PHV was 8.62 cm/yr in boys and 7.07 cm/yr in girls. The mean height velocity was less than 1 cm/yr at age 17 in boys and 15 in girls. Thus, we have presented the first report of longitudinal standards for height and height velocity in Korean children and adolescents by analyzing longitudinal data from the Kangwha cohort.
Growth; Height Velocity; Longitudinal Studies; Reference Standards; Child
This study was done to characterize the natural course of C-peptide levels in patients with type 1 diabetes and identify distinguishing characters among patients with lower rates of C-peptide decline. A sample of 95 children with type 1 diabetes was analyzed to retrospectively track serum levels of C-peptide, HbA1c, weight, BMI, and diabetic complications for the 15 yr after diagnosis. The clinical characteristics were compared between the patients with low and high C-peptide levels, respectively. The average C-peptide level among all patients was significantly reduced five years after diagnosis (P < 0.001). The incidence of diabetic ketoacidosis was significantly lower among the patients with high levels of C-peptide (P = 0.038). The body weight and BMI standard deviation scores (SDS) 15 yr after diagnosis were significantly higher among the patients with low C-peptide levels (weight SDS, P = 0.012; BMI SDS, P = 0.044). In conclusion, C-peptide level was significantly decreased after 5 yr from diagnosis. Type 1 diabetes patients whose beta-cell functions were preserved might have low incidence of diabetic ketoacidosis. The declines of C-peptide level after diagnosis in type 1 diabetes may be associated with changes of body weight and BMI.
Diabetes Mellitus, Type 1; C-Peptide; Body Weight; Body Mass Index; Diabetic Ketoacidosis
Sex hormone-binding globulin (SHBG) modulates the availability of biologically active free sex hormones. The regulatory role of SHBG might be important in the relationship between hormone levels and the modification of lipid profiles in girls with precocious puberty. However, few studies have evaluated the relationship of SHBG, free estradiol index (FEI), and lipid levels in these girls.
One hundred and nine girls less than 8 years of age with pubertal development were enrolled. FEI was calculated with SHBG and estradiol (E2). We analyzed SHBG between peak luteinizing hormone (LH)≥5 (IU/L) (group 1) and LH<5 (IU/L) (group 2) through a gonadotropin releasing hormone stimulation test.
Body mass index (BMI) standard deviation score (SDS) was higher in group 2 than in group 1 (P=0.004). Serum SHBG levels did not differ and FEI was not higher in group 1 (P=0.122). Serum cholesterol, HDL, and LDL did not differ; however, triglyceride levels were higher in group 2 (P=0.023). SHBG was negatively correlated with bone age advancement, BMI, BMI SDS, and FEI, and was positively correlated with HDL. However, SHBG was not correlated with E2 or peak LH.
Serum SHBG itself might not be associated with precocious puberty in girls, but it might be related to BMI and lipid profiles. Further studies are needed to reveal the relationship between sex hormone and obesity in girls with precocious puberty.
Sex hormone-binding globulin; Estradiol; Lipid; Precocious puberty
Spot urinary albumin to creatinine ratio (ACR) measurement has been suggested as a surrogate to 24-hr urine collection for the assessment of microalbuminuria, and cystatin C (cysC) is known as an advantageous marker for renal function. The aim of this study was to evaluate the clinical values of spot urinary ACR and serum cysC for the assessment of diabetic nephropathy instead of 24-hr urine microalbumin in children and adolescents with diabetes. A total of 113 children and adolescents (age 12-19 yr, M:F = 47:66) with type 1 or 2 diabetes were enrolled. We evaluated the validity of spot urine ACR and serum cysC, and then compared them to 24-hr urine microalbumin and creatinine clearance. Spot urine ACR was correlated with 24-hr urine albumin excretion (R2 = 0.828, P = 0.001) and creatinine clearance (R2 = 0.249, P = 0.017). The ROC curve analysis of serum cysC demonstrated higher diagnostic accuracy than that of serum creatinine (AUC 0.732 vs 0.615). Both the measurements of spot urine ACR and serum cysC might better predict the presence of diabetic nephropathy than 24-hr urine microalbumin in childhood diabetic patients.
Diabetic Nephropathies; Albumin to Creatinine Ratio; Cystatin C; Childhood Diabetes
Central precocious puberty (CPP) is caused by premature activation of hypothalamic gonadotropin-releasing hormone (GnRH) secretion. Kisspeptin and G-protein coupled receptor-54 system is the essential gatekeeper of the reproductive system, playing a key role in the activation of the gonadotropic axis at puberty. We aimed to determine whether serum kisspeptin may function as a marker for CPP by investigating serum kisspeptin levels in Korean girls with CPP and their prepubertal controls. Serum kisspeptin levels of Korean girls with CPP (n = 30) and age-matched healthy prepubertal controls (n = 30) were measured with a competitive enzyme immunoassay. Serum kisspeptin levels were significantly higher in CPP group than in control group (4.61 ± 1.78 vs 2.15 ± 1.52 pM/L, P < 0.001). Serum kisspeptin was positively correlated with peak luteinizing hormone (LH), peak/basal LH ratio and peak LH/follicular-stimulating hormone (FSH) ratio during GnRH stimulation test. CPP is supposed to be triggered by premature increase of kisspeptin. Serum kisspeptin may be used as a marker of CPP. Further studies on KISS1 gene polymorphisms leading to higher risk of premature increase of kisspeptin and upstream regulator of kisspeptin are also needed.
Kisspeptin; KISS1 Gene; G-protein Coupled Receptor-54; Central Precocious Puberty; Gonadotropin-Releasing Hormone