Luis Eduardo P. Calliari

Evaluation of the hypothalamic-pituitary-thyroid axis in children with Down syndrome

OBJECTIVE To determine the thyroid stimulating hormone (TSH) secretion in children with Down syndrome (DS), who do not present clinical and laboratory evidence of classical hypothyroidism and concomitant undetectable antibodies. METHODS Fourteen children with DS with a mean age of 3.4 (+/- 1.8) years were studied. Patients with classical hypothyroidism or hyperthyroidism or those with positive antithyroid antibodies were excluded. The DS group was compared to a control group of 16 children with a mean age of 11.8 (+/- 3.8) years, diagnosed as having familial short stature or constitutional growth delay. Both groups underwent hormonal measurements at basal condition to determine serum TSH, T3, T4, free T4 and prolactin concentrations and after stimulation with thyrotropin releasing hormone (TRH). Thyroid hormones concentrations were also compared when children with DS were subdivided into two groups according to their basal TSH levels. RESULTS Basal TSH and prolactin levels were significantly higher in DS group. After stimulation with TRH, TSH peak was higher in the DS group. The number of patients presenting basal TSH levels higher than 5 microU/mL and TSH peaks higher than 30 microU/mL were significantly higher in the DS group. CONCLUSIONS Children with Down syndrome present frequent increase in basal TSH concentrations, despite the presence of normal basal thyroid hormones levels and negative antithyroid antibodies. Most of them (65%) show early intense response after TRH stimulation. Our data demonstrate that in spite of the absence of classic hypothyroidism and/or antithyroid antibodies, an abnormal pattern of TSH secretion occurred in patients with Down syndrome, possibly related to hypothalamic dysfunction.

Partial Glucocorticoid Resistance in Obese Children Detected by Very Low Dose Dexamethasone Suppression Test

The effects of glucocorticoids (GC) are mediated by the activation of specific receptors that can be quantified in vitro by several laboratory tests. In vivo, other tests to determine GC sensitivity have been described, but only employing pharmacological doses. In this study, we used a very low dose of dexamethasone, an in vivo model to assess individual GC sensitivity. Fifty-five obese children and adolescents and 17 controls were studied. The patients were submitted to four 12-h urine collections, starting at 22:00 h; dexamethasone was administered orally at the end of the second urine sample. Patients were divided in the following groups: group Ob75 (n = 29) and the control group (n = 17) received dexamethasone 75 microg/m2, and group Ob150 (n = 26) received dexamethasone 150 microg/m2. Urinary cortisol was determined by RIA and expressed as microg/m2/12 h. All patients and controls showed a circadian rhythm before GC, which was maintained after dexamethasone only in controls. In the obese patients the circadian rhythm was abolished following both doses of dexamethasone, but more prominently with the dose of 150 microg/m2. In the obese group given 75 microg/m2, urinary cortisol inhibition was only observed in the first 12 h after dexamethasone, suggesting a partial and shorter suppression of the hypothalamic-pituitary axis. In both control and obese patients, the very low dose of dexamethasone was able to create a gradient of cortisol suppression that could be useful to identify an individuals sensitivity to glucocorticoids.

Near-final height in patients with congenital adrenal hyperplasia treated with combined therapy using GH and GnRHa

INTRODUCTION Intrinsic limitations of glucocorticoid therapy in patients with congenital adrenal hyperplasia (CAH) determine frequent loss in final height. The association of secondary central precocious puberty and early epiphyseal fusion is also frequent. In these conditions, GnRHa treatment alone or in combination with GH has been indicated. OBJECTIVES This is a retrospective study, describing the estatural findings of CAH patients with significant decrease in height prediction, who were submitted to combined GH plus GnRHa therapy up to near-final height. SUBJECTS AND METHODS We studied 13 patients, eight females and five males, eight with the classical and five with the nonclassical form of the disorder. Treatment with hydrocortisone (10-20 mg/m(2)/day) or prednisolone (3-6 mg/kg/day) was associated with GnRHa (3.75 mg/months) for 4.0 (1.5) years, and GH (0.05 mg/kg/day) for 3.6 (1.4) years. RESULTS Stature standard deviation score for bone age improved significantly after GH treatment, becoming similar to target height at the end of the second year of GH treatment. CONCLUSION We conclude that combined GH plus GnRHa therapy can be useful in a subset of CAH patients with significant reduction of predicted final height associated with poor hormonal control and central precocious puberty.

Update on diagnosis and monitoring of cystic fibrosis-related diabetes mellitus (CFRD)

Cystic fibrosis (CF) is the most common recessive autosomal disease among Caucasian. Children with CF have benefitted from advances in medical and nutritional treatments, and this can be gleaned from the improvement in the survival of these patients. The increase in the survival rate brought with it the appearance of co-morbidities related to CF. Nowadays cystic fibrosis-related diabetes (CFRD) is considered the most common complication associated with CF. It can appear as early as infancy or adolescence, and its prevalence can be as high as 50% in adult patients. Because of its high prevalence, difficulties in early detection and the risks involved, in recent years several studies and consensuses have focused on this condition, adding information about the epidemiology, pathophysiology, prognosis and treatment of CFRD. The main aspects of these new concepts, as well as the current recommendations for its diagnosis and follow-up, will be presented in this study.

Thyroid function and autoimmunity in children and adolescents with Type 1 Diabetes Mellitus.

We evaluated 233 children and adolescents with T1 Diabetes to analyze the prevalence and characteristics of Autoimmune Thyroid Disease. AITD was found in 23%, the majority being female and patients older than 5 years of age. Screening is mandatory, and the best approach could be guided by gender and age.

A novel glucokinase deletion (p.Lys32del) and five previously described mutations co-segregate with the phenotype of mild familial hyperglycaemia (MODY2) in Brazilian families.

Six Brazilian families with mild familial hyperglycaemia have been screened for glucokinase (GCK) mutations. All had mutations that co-segregated with the phenotype. One of the mutations, the deletion 96_98delAAG (p.Lys32del), had not been previously described, reinforcing the worldwide prevalence of GCK MODY and widespread existence of undetected new mutations.

Importance of screening with oral glucose tolerance test for early diagnosis of cystic fibrosis-related diabetes mellitus

To evaluate (a) the prevalence of cystic fibrosis‐related diabetes mellitus (CFRD) in a non‐Caucasian population treated in a University Hospital in São Paulo, Brazil; and (b) if annual screening of patients with cystic fibrosis (CF) ≥ 10 yr of age, with oral glucose tolerance test (OGTT), resulted in early detection of CFRD.

Fast acquisition sagittal T1 magnetic resonance imaging (FAST1-MRI): A new imaging approach for the diagnosis of growth hormone deficiency

Routine magnetic resonance imaging (MRI) is an established standard method to investigate the etiology of pituitary insufficiency. Among the anatomic abnormalities usually observed, ectopic hyperintense signal on T1 sequence is the most frequently associated with pituitary dysfunction. We developed a new protocol (FAST1-MRI) which is able to detect anatomic hypothalamic-pituitary abnormalities with 100% concordance when compared to the routine MRI protocol. FAST1-MRI takes only 3.25 minutes, and is performed without contrast, sedation or anesthesia. We studied 17 controls and 31 patients with growth hormone (GH) deficiency (18/31 with abnormal MRI). Patients with ectopic hyperintense signal were shorter in height, had lower IGF-I and IGFBP-3 levels, and reduced GH response after clonidine. In conclusion, we describe a new simplified MRI protocol that we propose should be used in the diagnosis of GH deficiency.

Dyslipidemia in young patients with type 1 diabetes mellitus

OBJECTIVE The association between type 1 diabetes mellitus (T1D) and dyslipidemia (DLP) increases the risk of cardiovascular disease (CVD). The aim of this study was to evaluate the presence of dyslipidemia in young T1D patients. MATERIALS AND METHODS The study design was cross-sectional and descriptive. We reviewed medical records of T1D patients followed at an endocrinology service, from 1998-2012. DATA COLLECTED gender, actual age and age at diagnosis, duration of T1D since diagnosis, body mass index (BMI), pubertal stage, glycemic control (GC) determined by glycated hemoglobin (HbA1c), total cholesterol (TC), HDL, LDL, triglycerides (TG). To analyze lipid profile and metabolic control, we used the Brazilian Society of Diabetes Guidelines. RESULTS Were included 239 T1D patients, 136 (56.9%) females; mean ± SD: actual age 15.7 ± 5.0 years and at T1D diagnosis 7.3 ± 3.9; T1D duration 10.6 ± 6.4 years, 86.6% puberty, 15.1% overweight. The prevalence of DLP was 72.5%, 63.3% females, 86.6% puberty, mean ± SD: actual age 15.4 ± 4.8 years and at T1D diagnosis 7.2 ± 4.1 years, duration of T1D 10.7 ± 6.1 years. We found high-CT in 56.7%, low-HDL = 21.7%, high LDL = 44.0%, high-TG = 11.8%. Between females with DLP, 83.5% was in puberty. We find correlation between the presence of DLP, a poor GC and BMC. CONCLUSION We found a high prevalence of DLP in young patients with T1D, particularly in puberty females. Programs targeting the prevention of dyslipidemia should be adopted, especially for this group, in order to prevent/delay chronic complications and cardiovascular disease.

Three unreported glucokinase (GCK) missense mutations detected in the screening of thirty-two Brazilian kindreds for GCK and HNF1A-MODY

Thirty-two Brazilian families with MODY phenotype were screened for GCK and HNF1A mutations. GCK mutations were found in 8 families, all patients with mild asymptomatic hyperglycaemia; 3 of them are novel: p.Asp365Asn, p.Gly81Asp and p.Val253Leu. Previously described mutations in HNF1A were found in 2 families.