Comparison of the clinical characteristics and outcomes of pediatric patients with and without diabetic ketoacidosis at the time of type 1 diabetes diagnosis

Purpose@#We investigated the possible effects of diabetic ketoacidosis (DKA) at the initial diagnosis of type 1 diabetes mellitus (T1DM) on the clinical outcomes of pediatric patients. @*Methods@#Medical records of children and adolescents with newly diagnosed T1DM seen in the Ajou University Hospital from January 2008 to August 2020 were reviewed and analyzed. @*Results@#Among 129 diagnosed T1DM patients, 40.3% presented with DKA. Although demographic and basic characteristics did not differ between DKA and non-DKA patients, DKA patients needed a significantly higher insulin dosage than non-DKA patients for 2 years after diagnosis. However, control of glycated hemoglobin was not different between the DKA and non-DKA groups during the observation period. In the biochemical analysis, C-peptide, insulin-like growth factor-1, and insulin-like growth factor binding protein 3, high-density lipoprotein cholesterol, free T4, and T3 values were lower, but thyroid-stimulating hormone, initial serum glucose, uric acid, total cholesterol, triglyceride, and low-density lipoprotein cholesterol values were higher in DKA patients than non-DKA patients at the diagnosis of T1DM; however, these differences were temporarily present and disappeared with insulin treatment. Other clinical outcomes, such as height, thyroid function, and urine microalbumin level, did not vary significantly between the DKA and non-DKA groups during 5 years of follow-up. @*Conclusion@#DKA at initial presentation reflects the severity of disease progression, and the deleterious effects of DKA seem to impact insulin secretion. Although no difference in long-term prognosis was found, early detection of T1DM should help to reduce DKA-related islet damage and the socioeconomic burden of T1DM.

Hyperosmolar hyperglycemic state as the first manifestation of type 1 diabetes mellitus in an adolescent male: a case report

A hyperosmolar hyperglycemic state (HHS) is a life-threatening complication rarely seen in children and adolescents with type 1 diabetes mellitus (T1DM). However, early diagnosis and proper treatment are vital to reduce the high morbidity and mortality rates associated with HHS. We describe a male patient who presented with polydipsia, polyuria, and a drowsy mental status. His initial biochemistry results demonstrated severe hyperglycemia (1,456 mg/dL), hyperosmolarity of 359 mOsm/kg (effective osmolarity, 323 mOsm/kg), and mild acidosis (venous pH, 7.327). The patient was diagnosed with HHS and T1DM based on the presence of hyperosmolarity, hyperglycemia, and positivity for antiglutamic acid antibodies. Intensive intravenous fluid and regular insulin (0.025 units/kg/hr) were administered. After hydration and insulin treatment, the patient's mental status and serum glucose and sodium levels improved, and no neurological complications were observed. In summary, most cases of HHS are observed in adult patients with type 2 diabetes. However, occurrences in children and adolescents with T1DM have also been reported. Therefore, HHS should be considered in the differential diagnosis of hyperglycemic emergencies.

Factors influencing growth hormone therapy effect during the prepubertal period in small for gestational age children without catch-up growth

Purpose@#Because small for gestational age (SGA) children who fail to experience catch-up growth have an increased risk of short stature in adulthood, growth hormone (GH) treatment is recommended for effective growth. In this study, we evaluated the effect of GH treatment during the prepubertal period and analyzed for correlation between GH treatment response and clinical factors in SGA children. @*Methods@#A retrospective, single-center study was conducted from 2014 to 2020. A total of 34 prepubertal children of short stature up to 4 years of age and born as SGA were enrolled. We recorded clinical data including birth data, age, weight, height, bone age (BA), and insulin-like growth factor 1 (IGF-1) levels. @*Results@#The mean gestational age and birth weight were 37.50±2.51 weeks and 2,200.00±546.79 g. At the start of GH treatment, the mean chronological age and BA were 5.54±1.73 years and 4.52±1.85 years, respectively. The height standard deviation score (SDS) (-2.47±0.45) and IGF-1 SDS (0.16±1.57) were calculated. Height velocity was 9.43±1.40 cm during the first GH treatment year and 7.63±1.16 cm during the second year (P<0.05). The treatment growth response was positively correlated with young age (P=0.047) and lower BA (P=0.049) at the start of treatment. In multiple regression analysis, IGF-1 SDS change had a significantly positive association with GH treatment response (P=0.045). @*Conclusion@#GH treatment is effective for short stature SGA children who do not experience catch-up growth. Early initiation of GH treatment improved growth outcomes. As IGF-1 SDS is positively correlated with height SDS, IGF-1 monitoring is important during GH treatment of SGA prepubertal children.

Factors influencing growth hormone therapy effect during the prepubertal period in small for gestational age children without catch-up growth

Purpose@#Because small for gestational age (SGA) children who fail to experience catch-up growth have an increased risk of short stature in adulthood, growth hormone (GH) treatment is recommended for effective growth. In this study, we evaluated the effect of GH treatment during the prepubertal period and analyzed for correlation between GH treatment response and clinical factors in SGA children. @*Methods@#A retrospective, single-center study was conducted from 2014 to 2020. A total of 34 prepubertal children of short stature up to 4 years of age and born as SGA were enrolled. We recorded clinical data including birth data, age, weight, height, bone age (BA), and insulin-like growth factor 1 (IGF-1) levels. @*Results@#The mean gestational age and birth weight were 37.50±2.51 weeks and 2,200.00±546.79 g. At the start of GH treatment, the mean chronological age and BA were 5.54±1.73 years and 4.52±1.85 years, respectively. The height standard deviation score (SDS) (-2.47±0.45) and IGF-1 SDS (0.16±1.57) were calculated. Height velocity was 9.43±1.40 cm during the first GH treatment year and 7.63±1.16 cm during the second year (P<0.05). The treatment growth response was positively correlated with young age (P=0.047) and lower BA (P=0.049) at the start of treatment. In multiple regression analysis, IGF-1 SDS change had a significantly positive association with GH treatment response (P=0.045). @*Conclusion@#GH treatment is effective for short stature SGA children who do not experience catch-up growth. Early initiation of GH treatment improved growth outcomes. As IGF-1 SDS is positively correlated with height SDS, IGF-1 monitoring is important during GH treatment of SGA prepubertal children.

Long-term outcomes of Graves’ disease in children and adolescents receiving antithyroid drugs

Purpose@#Antithyroid drugs (ATDs) are primarily used as an initial treatment in pediatric patients with Graves’ disease (GD). We aimed to investigate the long-term outcomes in pediatric GD patients receiving ATDs. @*Methods@#Retrospective data from a single center were collected from April 2003 to July 2020. A total of 98 children and adolescents aged 2–16 years diagnosed with GD and receiving ATDs was enrolled. We investigated the factors correlated with remission by comparing children who achieved remission after 5 years and those with persistent disease. @*Results@#The study included 76 girls (77.6%) and 22 boys (22.4%). During the 5-year follow-up period, 18 children (18.3%) maintained remission, ATDs could not be discontinued in 74 patients (75.5%), and relapse occurred in 6 patients (6.2%). The remission group had significantly lower thyroid-stimulating hormone-binding inhibitory immunoglobulin (TBII) level at diagnosis (P=0.002) and 3 months (P=0.002), 1 year (P=0.002), 2 years (P≤0.001), 3 years (P≤0.001), 4 years (P≤0.001), and 5 years (P≤0.001) after ATD treatment than did the nonremission group. The remission group also had a shorter time for TBII normalization after ATD treatment (P≤0.001). Multiple logistic regression analysis showed that the time to TBII normalization (cutoff time=2.35 years) was related to GD remission (odds ratio, 0.596; 95% confidence interval, 0.374–0.951). @*Conclusion@#TBII level and time to TBII normalization after ATD treatment can be used to predict remission in pediatric GD patients.

Effectiveness of growth hormone therapy in children with Noonan syndrome

Purpose@#Recombinant human growth hormone (rhGH) has been used to improve growth in children with Noonan syndrome (NS). This study aimed to investigate the efficacy of rhGH therapy in Korean children with NS. @*Methods@#Seventeen prepubertal children (10 boys, 7 girls) with NS who received rhGH therapy for at least 3 years between 2008 and 2017 were included. To compare the response, age- and sex-matched children with GH deficiency (GHD; n=31) were included. Height and growth velocity before and during treatment were analyzed. @*Results@#The mean age of NS patients was 6.34±2.32 years. After treatment, the height standard deviation score (SDS) increased from -2.93±0.81 to -1.51±1.00 in patients with NS and from -2.45±0.42 to -1.09±0.47 in patients with GHD. There were no significant differences in growth velocity or change in height SDS between patients with NS and GHD. Growth velocity in the first year of treatment was higher in patients with PTPN11 mutations than those without PTPN11 mutations, but the change in height SDS was not significantly different between those 2 groups. @*Conclusion@#rhGH therapy can increase linear growth in prepubertal children with NS. The growth response between patients with NS and patients with GHD was not significantly different. Furthermore, we observed that lower doses of growth hormone have a similar effect on height compared to previous studies in patients with NS. Our study indicates that rhGH treatment is useful for growth promotion.

Changes in body mass index in boys with central precocious puberty over 2 years of gonadotropin-releasing hormone agonist therapy

Purpose@#Gonadotropin-releasing hormone agonist (GnRHa) is a safe and effective therapy used to treat central precocious puberty (CPP). Although most studies have reported no significant difference in body mass index (BMI) in girls during and after GnRHa therapy, few studies have investigated changes in BMI in boys with CPP. This study evaluated the effects of GnRHa therapy on BMI in boys with CPP. @*Methods@#This study included 75 boys with CPP at Ajou University Hospital between January 1, 2007 and December 31, 2016, who treated with leuprorelin acetate or triptorelin acetate every 4 weeks for at least 2 years. The subjects were divided into 3 groups according to BMI: normal weight, overweight, and obese. We analyzed the BMI standard deviation score (SDS) in each group before therapy and after 1 year and 2 years of therapy. @*Results@#Of the 75 boys, 37 were in the normal weight group, 21 were in the overweight group, and 17 were in the obese group. Magnetic resonance imaging that was performed before treatment showed abnormal findings in 9 boys. The mean BMI SDS for all participants at initiation was 1.0±0.8, and that in the normal weight, overweight, and obese groups was 0.3±0.4, 1.3±0.1, and 1.9±0.3, respectively. There were no significant differences in BMI SDS in any group after 1 or 2 years of treatment. @*Conclusion@#The BMI SDS in boys with CPP did not significantly change over 2 years of GnRHa therapy.

Genetic aspects of type 1 diabetes

Type 1 diabetes mellitus (T1DM) is characterized by autoimmune destruction of pancreatic beta-cells in genetically predisposed individuals, eventually resulting in severe insulin deficiency. It is the most common form of diabetes in children and adolescents. Genetic susceptibility plays a crucial role in development of T1DM. The human leukocyte antigen complex plays a key role in the pathogenesis of T1DM. Furthermore, genome-wide association studies and linkage analysis have recently made a significant contribution to current knowledge relative to the impact of genetics on T1DM development and progression. This review focuses on current knowledge of genetics as a pathogenesis for T1DM. It also discusses mechanisms by which genes influence the risk of developing T1DM as well as the clinical and research applications of genetic risk scores in T1DM.

Thyrotoxic hypokalemic periodic paralysis due to Graves' disease in 2 adolescents

Thyrotoxic periodic paralysis (TPP) is a notable and potentially lethal complication of thyrotoxicosis, and Graves' disease is the most common cause of TPP. TPP is commonly reported in Asian males between 20–40 years of age, but it is rare in children and adolescents. We report 2 Korean adolescents (a 16-year-old male and a 14-year-old female) with episodes of TPP who were previously diagnosed with Graves' disease. These 2 patients presented with lower leg weakness in the morning after waking up. They were diagnosed with TPP-associated with thyrotoxicosis due to Graves' disease. After they were initially treated with potassium chloride and antithyroid drugs, muscle paralysis improved and an euthyroid state without muscle paralytic events was maintained during follow-up. Therefore, clinicians should consider TPP when patients have sudden paralysis and thyrotoxic symptoms such as goiter, tachycardia, and hypertension.

Prevalence of Pathological Brain Lesions in Girls with Central Precocious Puberty: Possible Overestimation?

BACKGROUND: Brain magnetic resonance imaging (MRI) is routinely performed to identify brain lesions in girls with central precocious puberty (CPP). We aimed to investigate the prevalence and type of brain lesions among Korean girls with CPP and evaluate the need for routine brain MRI examinations. METHODS: This retrospective cross-sectional study evaluated data on 3,528 girls diagnosed with CPP from April 2003 to December 2016, and identified 317 girls who underwent sellar MRI. Exclusion criteria were patients with a known brain tumor or who did not undergo brain MRI due to refusal or the decision of the pediatric endocrinologist. RESULTS: Normal sellar MRI findings were observed in 291 of the 317 girls (91.8%). Incidental findings were observed in 26 girls (8.2%). None of the patients had pathological brain lesions. CONCLUSION: The prevalence of intracranial lesions among girls who were generally healthy and without neurological symptoms but diagnosed with CPP was lower than that previously reported. Furthermore, none of the identified lesions required treatment. It may be prudent to reconsider the routine use of brain MRI to screen all patients with CPP, especially if they are healthy and neurologically asymptomatic, and are girls aged 6–8 years.

Evaluation of bone mineral status in prepuberal children with newly diagnosed type 1 diabetes

PURPOSE: Many studies have reported that patients with type 1 diabetes have reduced bone mineral density (BMD). We assessed bone status in prepubertal children with type 1 diabetes mellitus (type 1 DM) at initial diagnosis and investigated factors associated with BMD. METHODS: Prepubertal children (n=29) with newly diagnosed type 1 diabetes from 2006 to 2014 were included. Dual-energy X-ray absorptiometry measured regional and whole-body composition at initial diagnosis. BMD was compared with healthy controls matched for age, sex, and body mass index (BMI). RESULTS: The mean age of all subjects (16 boys and 13 girls) was 7.58±1.36 years (range, 4.8–11.3 years). Initial mean glycosylated hemoglobin (HbA1c) level was 12.2%±1.9%. The mean BMD z-scores of lumbar spine, femur neck, and total body were not significantly different between patients and controls. Three patients (10.3%) had low bone density (total body BMD standard deviation score [SDS] < -2.0). To identify determinants of lumbar spine BMD z-score, multivariate regression analysis was performed with stepwise variable selection of age, pubertal status, BMI SDS, insulin like growth factor-1, and HbA1c. Only BMI SDS was significantly correlated with lumbar spine BMD z-score (β=0.395, P=0.023). CONCLUSIONS: Prepubertal children with newly diagnosed type 1 DM had similar bone mass compared to healthy peers. However, patients with low BMI should be carefully monitored for bone density in type 1 DM.

Successful switching from insulin to sulfonylurea in a 3-month-old infant with diabetes due to p.G53D mutation in KCNJ11

Permanent neonatal diabetes mellitus is most commonly caused by mutations in the ATP-sensitive potassium channel (KATP) subunits. Prompt initiation of sulfonylurea treatment can improve glycemic control in children with KCNJ11 mutation. In this report, we present a case of permanent neonatal diabetes caused by a mutation in the KCNJ11 gene that was successfully treated via early switching of insulin to sulfonylurea treatment. A 53-day-old female infant presented with diabetic ketoacidosis. Insulin was administered for the ketoacidosis and blood glucose regulation. At 3 months of age, using genomic DNA extracted from peripheral lymphocytes, direct sequencing of KCNJ11 identified a heterozygous mutation of c.158G>A (p.G53D) and confirmed the diagnosis of permanent neonatal diabetes mellitus. Subsequently, treatment with sulfonylurea was initiated, and the insulin dose was gradually tapered. At 4 months of age, insulin therapy was discontinued, and sulfonylurea (glimepiride, 0.75 mg/kg) was administered alone. At 6 months after initiation of administration of sulfonylurea monotherapy, blood glucose control was stable, and no hypoglycemic events or developmental delays were reported. C-peptide levels increased during treatment with sulfonylurea. Early switching to sulfonylurea in infants with permanent diabetes mellitus owing to a KCNJ11 mutation could successfully help regulate glycemic control, which suggests the need for early genetic testing in patients presenting with diabetes before 6 months of age.

Prevalence of autoimmune thyroiditis in patients with type 1 diabetes: a long-term follow-up study

PURPOSE: Type 1 diabetes mellitus (DM) is associated with autoimmune diseases such as thyroiditis. Therefore, we aimed to investigate the prevalence of autoimmune thyroiditis in patients with type 1 DM. METHODS: A total of 102 patients who were diagnosed and followed up (mean age, 8.1±4.0 years) in Ajou University Hospital were enrolled in this study. All the patients were evaluated for beta cell autoimmunity, including insulin autoantibody, glutamic acid decarboxylase antibodies (GADA), and islet cell antibody. Moreover, autoantibodies to thyroid peroxidase and thyroglobulin were assessed at initial diagnosis and annually thereafter. RESULTS: The mean patient age (49 men and 53 women) was 19.2±4.8 years. The prevalence of at least one thyroid antibody was 30.4%. Patients with thyroid anti­bodies had a significantly higher frequency of GADA at the time of the diagnosis. Autoimmune thyroiditis was more prevalent in the older age group. GADA was a significant risk factor for development of thyroid autoantibodies after diagnosis of type 1 DM (odds ratio, 4.45; 95% confidence interval, 1.399–14.153). CONCLUSIONS: In patients with type 1 DM, the prevalence of autoimmune thyroiditis was higher than in the general population. Moreover, GADA positivity at diagnosis was associated with thyroid autoimmunity.

Association Kikuchi disease with Hashimoto thyroiditis: a case report and literature review

Kikuchi-Fujimoto disease (KFD) is a benign and self-limited disease characterized by fever and lymphadenopathy. The etiology of KFD is unknown, but an autoimmune cause has been suggested. Hashimoto thyroiditis is the most common autoimmune thyroid disorder in children and is known to be associated with other autoimmune diseases. Only a few cases of Hashimoto thyroiditis associated with KFD have been documented. We report a case of a 16-year-old girl who was first diagnosed with KFD and developed Hashimoto thyroiditis 2 years and 6 months later during her follow-up period. Physicians of patients with KFD should consider the possibility of autoimmune diseases like Hashimoto’s thyroiditis.

Intellectual development in preschool children with early treated congenital hypothyroidism

PURPOSE: Delayed treatment of congenital hypothyroidism (CH) is a common cause of mental retardation. The aim of the present study was to evaluate intellectual outcomes in preschool children with treated CH. METHODS: We retrospectively reviewed the clinical records of 43 children (age range: 13 to 60 days of life; 22 girls and 21 boys) diagnosed with CH. Children aged 5 to 7 years were examined using the Korean Wechsler Intelligence Scale for Children or the Korean Wechsler Preschool and Primary Scale of Intelligence. RESULTS: The patients started treatment between 13 and 60 days of age. The mean intelligence quotient (IQ) of patients tested at age 5 to 7 years was 103.14±11.68 (IQ range: 76–126). None had intellectual disability (defined as an IQ <70). Twenty-one subjects were treated with a low dose (6.0–9.9 µg/kg/day) and 22 with a high dose of levothyroxine (10.0–16.0 µg/kg/day). There was no significant difference in the mean full-scale IQ (FSIQ), verbal IQ (VIQ), and performance IQ (PIQ) scores between the 2 groups. FSIQ, PIQ, and VIQ scores were not significantly correlated with initial dose of L-T4, initial fT4, age at treatment in multivariate analysis. CONCLUSION: IQ scores of subjects with early treated CH diagnosed through a neonatal screening test were within normal range, regardless of etiology, thyroid function, initial dose of levothyroxine, and age at start of treatment.

Predictors of transient congenital hypothyroidism in children with eutopic thyroid gland

PURPOSE: Congenital hypothyroidism (CH) is the most common cause of preventable mental retardation. Recently, the detection of CH cases with eutopic thyroid gland has increased due to neonatal screening programs. In this study, we aimed to identify and evaluate predictive factors that could distinguish between permanent and transient CH in patients with eutopic thyroid gland. METHODS: We retrospectively reviewed 100 children diagnosed with CH and with eutopic thyroid gland. All subjects were treated with levothyroxine and underwent re-evaluation after 3 years of age. RESULTS: Of the 100 CH patients, 35 (35.0%) were diagnosed with permanent CH (PCH) and 65 (65.0%) were diagnosed with transient CH (TCH). The initial thyroid stimulating hormone levels were significantly lower in the TCH subjects than in PCH subjects. In addition, the mean doses of levothyroxine (µg/kg/day) at the 1st, 2nd, and 3rd year of treatment were significantly lower in subjects with TCH than in PCH subjects with eutopic thyroid gland. Based on the receiver operating characteristic (ROC) curve, the optimal cutoff dose of levothyroxine at 3 years of 2.76 µg/kg/day could predict TCH, and was associated with 87.3% sensitivity and 67.6% specificity, with an area under the ROC curve of 0.769. CONCLUSION: The levothyroxine dose requirement during treatment period has a predictive role in differentiating TCH from PCH in CH patients with eutopic thyroid gland.

Multiple Endocrine Neoplasia Type 1 Presenting as Hypoglycemia due to Insulinoma

Multiple endocrine neoplasia (MEN) mutation is an autosomal dominant disorder characterized by the occurrence of parathyroid, pancreatic islet, and anterior pituitary tumors. The incidence of insulinoma in MEN is relatively uncommon, and there have been a few cases of MEN manifested with insulinoma as the first symptom in children. We experienced a 9-year-old girl having a familial MEN1 mutation. She complained of dizziness, occasional palpitation, weakness, hunger, sweating, and generalized tonic-clonic seizure that lasted for 5 minutes early in the morning. At first, she was only diagnosed with insulinoma by abdominal magnetic resonance images of a 1.3 × 1.5 cm mass in the pancreas and high insulin levels in blood of the hepatic vein, but after her father was diagnosed with MEN1. We found she had familial MEN1 mutation, and she recovered hyperinsulinemic hypoglycemia after enucleation of the mass. Therefore, the early genetic identification of MEN1 mutation is considerable for children with at least one manifestation.

The changes of subtypes in pediatric diabetes and their clinical and laboratory characteristics over the last 20 years

PURPOSE: We studied the changes in subtypes of diabetes mellitus (DM) in children and evaluated the characteristics of each group over the past 20 years. In addition, we also examined the correlation between the glycated hemoglobin (HbA1c) values at the time of diagnosis and lipid profiles. METHODS: The patients were divided into 2 groups: there were a total of 190 patients under 20 years of age firstly diagnosed with DM in Ajou University Hospital. The patients in groups I and II were diagnosed from September 1995 to December 2004 and from January 2005 to April 2014, respectively. RESULTS: The characteristics were compared between the 2 groups of patients. The result showed an increase in percentage of type 2 diabetes and maturity onset diabetes of the young (MODY) patients between the 2 groups. HbA1c and total cholesterol level had statistical significances to explain increasing the low-density lipoprotein cholesterol level among age, HbA1c, total cholesterol level, and z-scores of weight and body mass index (BMI) in type 2 diabetes. R-square was 0.074. However, z-score of BMI and total cholesterol level, not HbA1c, had statistical significances in type 1 diabetic patients. R-square was 0.323. CONCLUSION: The increase in the proportions of both type 2 diabetes and MODY in the last 10 years needed to be reminded when diagnosing the subtypes of DM, and the dyslipidemia should be attended more as a common problem of pediatric diabetic patients.

The changes of subtypes in pediatric diabetes and their clinical and laboratory characteristics over the last 20 years

PURPOSE: We studied the changes in subtypes of diabetes mellitus (DM) in children and evaluated the characteristics of each group over the past 20 years. In addition, we also examined the correlation between the glycated hemoglobin (HbA1c) values at the time of diagnosis and lipid profiles. METHODS: The patients were divided into 2 groups: there were a total of 190 patients under 20 years of age firstly diagnosed with DM in Ajou University Hospital. The patients in groups I and II were diagnosed from September 1995 to December 2004 and from January 2005 to April 2014, respectively. RESULTS: The characteristics were compared between the 2 groups of patients. The result showed an increase in percentage of type 2 diabetes and maturity onset diabetes of the young (MODY) patients between the 2 groups. HbA1c and total cholesterol level had statistical significances to explain increasing the low-density lipoprotein cholesterol level among age, HbA1c, total cholesterol level, and z-scores of weight and body mass index (BMI) in type 2 diabetes. R-square was 0.074. However, z-score of BMI and total cholesterol level, not HbA1c, had statistical significances in type 1 diabetic patients. R-square was 0.323. CONCLUSION: The increase in the proportions of both type 2 diabetes and MODY in the last 10 years needed to be reminded when diagnosing the subtypes of DM, and the dyslipidemia should be attended more as a common problem of pediatric diabetic patients.

Effects of short-term potassium iodide treatment for thyrotoxicosis due to Graves disease in children and adolescents

PURPOSE: Graves disease is the most common cause of hyperthyroidism in children. Inorganic iodide has been used in combination with antithyroid drugs for more effective normalization of thyroid hormones in some cases of severe thyrotoxicosis. This study aimed to investigate clinical characteristics of childhood thyrotoxicosis and effectiveness of inorganic iodide in the early phase of treatment. METHODS: Sixty-seven pediatric patients (53 girls/14 boys, 11.1+/-3.4 years of age), with newly diagnosed thyrotoxicosis due to Graves disease were recruited. Forty-nine patients were treated with antithyroid drugs alone, while 18 patients were treated with combination of antithyroid drugs and potassium iodide. Initial thyroid function tests and levels of thyroid antibodies were recorded for all patients. Thyroid function tests were repeated 2 and 8 weeks after the initiation of treatment. Measurement thyroid antibodies were done 8 weeks after the initiation of treatment. RESULTS: Mean triiodothyronine and free thyroxine levels were significantly lower (P<0.05) in the group receiving combined therapy of antithyroid drugs and potassium iodide after 2 weeks of treatment compared to the patients receiving antithyroid drugs alone. Eight weeks after the initiation of treatment, thyroid function tests in the two groups did not show significant differences. CONCLUSION: The use of potassium iodide in combination with antithyroid drug is effective for more rapid normalization of thyroid hormones in the early phase treatment of childhood thyrotoxicosis, but larger studies with adequate power are needed in future.