Osmar Monte

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

OBJECTIVEnTo 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.nnnMETHODSnFourteen 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.nnnRESULTSnBasal 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.nnnCONCLUSIONSnChildren 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.

Antiproliferative and apoptotic potencies of glucocorticoids: nonconcordance with their antiinflammatory and immunossuppressive properties

Relative antiinflammatory and immunosuppressive potencies of glucocorticoids (GC) were previously well defined. Nonetheless, GC also regulate cell proliferation and programmed death (apoptosis). The aim of this study was to determine the relative potency of different GC on the modulation of cell survival. The GC-sensitive lymphoblast cell line CEM-c7/14 was submitted to 48 h-exposure to GC (dose-response curve from 10(-8) to 10(-5) M). Cell survival was analyzed employing the DimethylTiazol-Tetrazolium (MTT) test. For each GC at least 4 experiments were performed in quadruplicate. Responses to different GC at the same molarity were analyzed by ANOVA on Ranks. Cell responses to the same GC in different concentrations were tested by repeated measures ANOVA. The EC50 for each GC was calculated with the GraphPad Prism 3.0 software. The use of low concentrations (10(-8) and 10(-7) M) of hydrocortisone and methylprednisolone determined a similar effects on cell survival, which was less prominent than that observed with betamethasone, budesonide or momethasone. Momethasone was the most potent GC, inducing the most intense dexamethasone reduction on cell survival at the lowest concentration (10(-8) M). Momethasone and methylprednisolone were the two GC with the strongest impact on cell survival. Our findings suggest that antiproliferative and apoptotic potencies of GC are different from those previously reported antiinflammatory and immunosuppressive actions.

Utilização do 131I no tratamento da doença de Basedow-Graves na infância e adolescência

While the diagnosis of Graves disease in childhood and adolescence is relatively straightforward, its treatment remains controversial. The first choice therapy is the use of anti-thyroid drugs, although side effects are more frequent than in adults and remission is low. Surgery is not usually indicated as initial treatment. Instead, it is generally recommended after recidive of the disease or due to side effects of medical treatment. The use of radioiodine therapy is increasing in this age group, especially in North America, and control of the hyperthyroidism is achieved in 3 to 6 months in 90% of the cases. There is no evidence that radioiodine therapy is associated with a higher risk of thyroid cancer, and the occurrence of side effects is lower than surgery. Based on the positive results obtained with this therapy, patients with poor responsiveness to medical treatment should be considered for early radioiodine therapy.

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.

Puberdade precoce: dilemas no diagnóstico e tratamento

New criteria have been proposed for the diagnosis and treatment of patients with central precocious puberty (PP) (GnRH-dependent). In girls, breast and pubic hair development are occurring significantly earlier than previously suggested. Usually, the age limit to consider puberty as normal is 9 years for boys and 8 years for girls. Between ages 6 and 8 years, some girls show isolated telarche or pubarche with absent or slightly elevated growth velocity (GV) and bone age (BA). This represents a constitutional acceleration of growth and puberty, and when compared to familial target, it presents no influence on predicted final height. Long-term clinical follow-up is recommended, but usually no treatment is required. On the other hand, pathologic GnRH-dependent PP is associated to progressive pubertal manifestation, increased GV and accelerated bone maturation, with consequent negative impact on the final height. The age of clinical manifestation is variable, and in part dependent on the etiology. When starting between the ages 6 and 8 the puberty is rapidly progressive. The cause for early hypothalamic-pituitary activation should be investigated by cranial MR. GnRH-dependent PP is best treated with slow-release GnRH analogues (leuprolide or tryptorelin). The initial recommended dose is 3.75mg IM, every four weeks. With this schedule, pubertal characteristics are efficiently controlled. The results on final height are influenced by the age of diagnosis and therapy, and the best outcome is observed when treatment begins before the age of 6. During GnRHa therapy, some patients show intense decrease in GV and substantial reduction in predicted final height. In this condition, additional use of growth hormone should be considered.

Estudo comparativo do uso de prednisolona versus acetato de hidrocortisona no tratamento da hiperplasia adrenal congênita por deficiência da 21-hidroxilase forma clássica

ABSTRACT Comparative Study of Prednisolone versus Hydrocortisone Acetate for Treatment of Patients with the Classic Congenital Adrenal Hyper-plasia due to 21-Hydroxylase Deficiency. Hydrocortisone acetate is usually employed in the treatment of classic con-genital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. In Brazil, however, oral hydrocortisone acetate is only available from manipulation pharmacies. Prednisolone has stable oral pharmaceutical formulations com-mercially available, with the advantage of a single daily dose. The aim of this study was to compare the efficacy of oral prednisolone and oral hydrocorti-sone in the treatment of CAH due to 21-hydroxylase deficiency. Fifteen pa-tients with mean (SD) chronological age of 7.2 (3.6) years, were evaluated in two consecutive 1-year periods. In the first year, hydrocortisone (17.5mg/m²/day, divided in three doses) was used in the treatment, followed by the use of prednisolone (3 mg/m²/day, once in the morning) in the second year. Thecomparison between the two treatments was assessed after a one-year treat-ment period by: variation of height standard deviation score (SDS) ( Height SDS), variation of height SDS according to bone age ( BA SDS), variation of body mass SDS ( BMI SDS) and serum levels of androstenedione. No sig-nificant difference was observed in relation to the Height SDS, BA SDS

Carcinoma de tireóide na infância e adolescência

Approximately 10% of thyroid cancers are present in patients less than 21 years of age, representing 3% of all cancers of children and adolescents, with predominance in females 2:1 in relation to males. Thyroid cancers in this age group are usually papillary (90%), bilateral, multifocal and bigger in size compared to adults. Capsule invasion and lymphatic and pulmonary metastases are more frequent in children. Radiation sensitivity seems to represent an important factor in prepubertal patients. Familial history is reported in 5% of the cases. Genes such as RET/PTC, RAS and BRAF are usually involved in thyroid carcinogenesis in this age group. Cervical adenomegaly is a common clinical presentation, but does not represent a poor prognostic factor in children. Ultrasound and fine needle aspiration biopsy are valuable diagnostic procedures. Surgery is the preferred treatment including thyroidectomy and ganglionary excision, followed by ablative radioiodine therapy. L-thyroxine replacement with suppressive dosage should be employed targeting chronic TSH suppression. Long-term prognosis is usually better in children when compared with adults. Plasma thyroglobulin measurement is also useful to detect residual thyroid cancer disease.

Abordagem do diabetes melito na primeira infância

The occurrence of type 1 diabetes mellitus in children under 5-years-old is rare, but its incidence has been growing all over the world. The diagnosis is usually delayed and the patient presents advanced states of ketoacidosis. After the diagnosis, it is extremely crucial the involvement of the family in the treatment from the beginning, due to the dependency of the young children. The attention focused on the patient must be intense, since there are no evident hypoglycemic symptoms, the food intake and physical activities are irregular and there is higher insulin sensitivity. Insulin administration has to be individualized, and glucose monitoring is essential to obtain a good control.

Transdermal Estradiol Priming During Clonidine Stimulation Test in Non-Growth Hormone Deficient Children with Short Stature: A Pilot Study

The diagnosis of growth hormone (GH) deficiency is strongly influenced by age, body mass index and presence of gonadal steroids. Priming with oral estradiol (E2) is one possible way to overcome the impact of variable levels of sex steroids. We describe the effects of transdermal estradiol (E2-t) priming on GH response after clonidine stimulation in prepubertal children with familial short stature (group 1, n = 12) or constitutional growth delay (group 2, n = 22). All patients underwent a clonidine test (0.1 mg/m2, p.o.) followed by a clonidine plus E2-t test (50 microg/day) with a 7-day interval. Before E2-t, basal GH and insulin-like growth factor-I (IGF-I) values were similar in the two groups. After E2-t priming, basal GH was significantly higher only in group 2. When compared with group 1, patients from group 2 had a significant increase of GH peak response when submitted to E2-t. The number of patients in both groups with adequate GH peak response was higher after E2-t priming. We conclude that E2-t priming is able to increase GH peak response after clonidine stimulation and also improves the accuracy of the clonidine test in the diagnosis of GH deficiency. Compared to oral administration, E2-t delivery can prevent liver toxicity, providing a more physiological mechanism of GH secretion.