Giovanna Weber

A 7-year experience with low blood TSH cutoff levels for neonatal screening reveals an unsuspected frequency of congenital hypothyroidism (CH)

Context  The guidelines of the National Academy of Clinical Biochemistry advocated the use of low bloodspot TSH (b‐TSH) threshold for newborn screening of congenital hypothyroidism (CH). The impact generated by the application of this indication is largely unknown.

Bone density and bone metabolism are normal after long-term gluten-free diet in young celiac patients

Objectives:Osteoporosis and alterations of bone metabolism are frequent complications of celiac disease. We evaluated the impact of long-term gluten-free diet (GFD) initiated during childhood and adolescence on bone mineralization and bone metabolism.Methods:We studied 30 celiac patients on GFD for ≥5 yr. The mean age at diagnosis was 11.4 ± 5.0 yr, and the mean duration of GFD was 10.7 ± 4.3 yr. Results were compared with those obtained in 240 healthy controls. Bone mineral density (BMD) was measured in the lumbar spine and in the whole skeleton by dual-energy x-ray absorptiometry. Serum levels of bone-specific alkaline phosphatase (BALP) and N-terminal propeptide of type I procollagen (PINP) were measured as bone formation indices, and urine levels of N-telopeptide of type I collagen (NTx) as bone resorption index.Results:BMD measurements of celiac patients (lumbar spine: 1.131 ± 0.121 g/cm2; total body: 1.145 ± 0.184 g/cm2) did not differ from those of control subjects (lumbar spine: 1.131 ± 0.184 g/cm2; total body: 1.159 ± 0.118 g/cm2). The levels of BALP, PINP, and NTx of celiac patients did not differ from those of controls. Patients who started GFD before puberty had BMD and bone metabolism measurements comparable to those of patients who started GFD during puberty.Conclusions:Our data show that long-term dietary treatment ensures normal mineralization and bone turnover.

Bone Density in Young Patients with Congenital Adrenal Hyperplasia

One of the major complications of glucocorticoid treatment is bone loss. 21-Hydroxylase deficiency is the most frequent inborn error of steroidogenesis, leading to congenital adrenal hyperplasia (CAH): synthesis of cortisol is impaired and replacement therapy is therefore mandatory. We studied the bone mineral density in a group of patients with congenital adrenal hyperplasia (CAH) on long-term glucocorticoid replacement therapy. We selected 30 Caucasian patients with CAH due to 21-hydroxylase deficiency (mean +/- SD age = 17.45 +/- 2.49 years). 22 patients had the classical CAH form and the remaining 8 had the nonclassical (late-onset) form. The mean duration of therapy was 15.20 +/- 4.04 years. Bone mineral density (BMD) was evaluated with a dual-energy X-ray absorptiometer. BMD was also measured in 73 healthy white volunteers of comparable age (17.35 +/- 2.99 years). BMD values of the spine (sBMD), total body (TBBMD), legs, and arms of CAH patients, adjusted for confounding variables (age, gender, body mass index), did not differ from those of control subjects (p = 0.86; p = 0.17; p = 0.06 and p = 0.26, respectively). sBMD and TBBMD values did not show relationships with the duration of treatment and the dose of corticosteroids. Patients with the classical form of CAH had bone density values comparable with those of patients with the nonclassical form (sBMD: p = 0.33; TBBMD: p = 0.97). Our data show that, despite long-term treatment with glucocorticoids, CAH patients have bone density values comparable with controls.

Neonatal transient hypothyroidism: aetiological study

AIMS To define the aetiology of neonatal transient hypothyroidism (NTH) and recommend preventive measures. METHODS Maternal and perinatal clinical data on the use of antiseptics, drugs, and contrast agents containing iodine were collected from 40 subjects. Thyroid stimulating hormone (TSH), free thyroxine (FT4), thyroxine (T4), thyroglobulin (TG), TSH receptor antibodies, thyroid peroxidase antibodies and urinary iodine were measured in random neonatal samples. In the mothers with known or suspected thyroid disorders, TSH, FT4, TSH receptor antibodies and thyroid peroxidase antibodies were also measured. RESULTS The NTH aetiology was identified in 85% of cases. More than 50% of the babies with transient hypothyroidism had been exposed to iodine; maternal transfer of antibodies had occurred in a third of them. CONCLUSIONS It is suggested that the practice of using iodine containing disinfectants should be withdrawn, and chlorhexidine substituted instead; that pregnant women should be advised of the adverse effects of using iodine products; and that thyroid function should be monitored whenever iodine is used.

Thyroid nodules and cancer in children and adolescents affected by autoimmune thyroiditis

OBJECTIVE To investigate the association between juvenile autoimmune thyroiditis (JAT) and thyroid cancer in pediatric patients. DESIGN We conducted a retrospective study among children and adolescents affected by JAT. SETTINGS Data from 6 Italian pediatric endocrinology centers were collected. PARTICIPANTS Three hundred sixty-five children and adolescents affected by JAT diagnosed at 3.6 to 17.0 years of age. INTERVENTIONS All patients underwent clinical examination and thyroid function test every 6 to 12 months and thyroid echography every 12 to 24 months. Fine-needle aspiration biopsy was performed in 39 patients with nodule diameter of 1 cm or larger, as well as in 4 patients with nodule diameter of less than 1 cm and echographic findings suspicious for neoplasm. Twenty-three patients underwent surgery. MAIN OUTCOME MEASURES Thyroid function, echographic pattern, nodule diameter, the presence of lymphadenopathy, and cytologic and histologic diagnoses were considered. RESULTS Thyroid nodules were found in 115 patients; findings in 11 of these were consistent with papillary carcinoma, with 5 exhibiting lymph node metastasis. The prevalence of male sex among patients with cancer was greater than that among patients with JAT (odds ratio [OR], 2.95; 95% confidence interval [CI], 1.44-6.20). The growth of nodules during levothyroxine sodium therapy (OR, 15.60; 95% CI, 1.87-181.90) and the finding of lymphadenopathy (OR, 5.44; 95% CI, 1.05-30.50) were statistically significantly associated with the presence of cancer, while uninodularity and hypoechogenicity were not. CONCLUSIONS The observed prevalences of thyroid nodules and thyroid cancer in our JAT case series were 31.5% and 3.0%, respectively. Papillary carcinoma was the only histotype detected. The finding of lymphadenopathy, a lack of response to levothyroxine therapy, and nodule hypoechogenicity suggested malignancy. Fine-needle aspiration biopsy was reliable in selecting patients for referral to surgery.

Genetics and phenomics of hypothyroidism due to TSH resistance.

The resistance to thyrotropin (TSH) action is the disease associated with molecular defects hampering the adequate transmission of TSH stimulatory signal into thyroid cells. The defect may in principle affect every step along the cascade of events following the binding of TSH to its receptor (TSHR) on thyroid cell membranes. After the description of the first family affected with loss-of-function (LOF) TSHR mutations in 1995, there is now evidence that TSH resistance is a disease with a broad range of expressivity going from severe congenital hypothyroidism (CH) with thyroid hypoplasia to mild hyperthyrotropinemia (hyperTSH) associated with an apparent euthyroid state. More severe forms occur in patients with disrupting biallelic TSHR mutations and follow a recessive pattern of inheritance. Differential diagnosis in these cases includes the exclusion of other causes of thyroid dysgenesis, such as mutations in thyroid transcription factors. More mild forms may instead occur in patients with monoallelic TSHR defects following a dominant mode of inheritance. In these cases we described the dominant negative effect exerted by some LOF mutants on the activity of the wild-type TSHR. Differential diagnosis involves the exclusion of mild hypothyroidism in autoimmune thyroid disease or pseudohypoparathyroidism associated with genetic or epigenetic defects at the GNAS locus. This review will focus on the prevalence of TSHR mutations, on the molecular mechanisms leading to TSH resistance and on the variable clinical expression of this disease.

STUDY OF THE EFFECTS OF BROMOCRIPTINE ON SEXUAL IMPOTENCE

Serum testosterone, prolactin, LH, FSH and plasma 17β‐oestradiol levels were determined in forty‐seven male patients with sexual impotence. Low testosterone values and slightly elevated prolactin levels were observed in 19% and in 17% of cases, respectively. Since sexual function in the male seems to be controlled by both dopaminergic stimulatory and serotoninergic inhibitory mechanisms, bromocriptine was given orally to seventeen patients. As the preliminary results appeared encouraging, a double blind study was undertaken in the other thirty patients. No appreciable difference in hormonal pattern was noticed between bromocriptine and placebo treatment. As far as sexual function was concerned, good results were obtained in 52% of cases treated with bromocriptine and in 44% of patients given placebo.

Sleep and upper airway obstruction in children with achondroplasia

OBJECTIVE The features of achondroplasia, the most common form of dwarfism, includes short cranial base and midface hypoplasia; both abnormalities increased the risk of upper airway obstruction during sleep. The aim of our study was to evaluate sleep and respiratory function of children with achondroplasia and to differentiate central from obstructive apnea. We also wanted to correlate apneic events with foramen magnum stenosis. STUDY DESIGN Sixteen children with achondroplasia (mean age, 4.7 years) were studied by noctumal polysomnography and brain computed tomography or magnetic resonance imaging. A comparison of sleep and respiratory findings was made between the study group and 25 children with adenotonsillar hypertrophy. RESULTS The study revealed no significant difference between groups with respect to sleep architecture. We also found no relationship between apnea type and foramen magnum stenosis. Twelve children (75%) with achondroplasia had significant upper airway obstruction during sleep, with symptoms of continuous snoring and periods of brief obstructive apnea, hypopnea, or both. The mean apneahypopnea index (per hour of sleep) did not differ significantly between the two groups. However, the breathing rate during sleep was increased in children with achondroplasia. These findings indicate that the most important breathing disorder during sleep in children with achondroplasia is upper airway obstruction. CONCLUSION We conclude that polysomnography with detailed scoring of breathing abnormalities is a useful tool in evaluating sleep-disordered breathing in children with achondroplasia.

Vitamin D in childhood and adolescence: an expert position statement

AbstractVitamin D is a key hormone in the regulation of calcium and phosphorus metabolism and plays a pivotal role in bone health, particularly during pediatric age when nutritional rickets and impaired bone mass acquisition may occur. Great interest has been placed in recent years on vitamin D’s extraskeletal actions. However, while recent data suggest a possible role of vitamin D in the pathogenesis of several pathological conditions, including infectious and autoimmune diseases, the actual impact of vitamin D status on the global health of children and adolescents, other than bone, remains a subject of debate. In the meantime, pediatricians still need to evaluate the determinants of vitamin D status and consider vitamin D supplementation in children and adolescents at risk of deficiency. This review is the result of an expert meeting that was held during the congress “Update on vitamin D and bone disease in childhood” convened in Pisa, Italy, in May 2013. Conclusion: The collaboration of the international group of experts produced this “state of the art” review on vitamin D in childhood and adolescence. After dealing with vitamin D status and its determinants, the review outlines the current debate on vitamin D’s health benefits, concluding with a practical approach to vitamin D supplementation during childhood and adolescence.What is Known:• Vitamin D deficiency is a worldwide health problem.• Vitamin D deficiency affects not only musculoskeletal health but also a potentially wide range of acute and chronic diseases.What is New:• We reviewed the literature focusing on randomized controlled trials of vitamin D supplementation during childhood and adolescence.• This review will help pediatricians to appreciate the clinical relevance of an adequate vitamin D status and it will provide a practical approach to vitamin D supplementation.

Congenital hypothyroidism with eutopic thyroid gland: Analysis of clinical and biochemical features at diagnosis and after re-evaluation

CONTEXT In recent years changes in screening strategies for congenital hypothyroidism (CH) led to an increased detection of mild forms of CH, associated with eutopic thyroid gland. OBJECTIVES We aimed to determine the clinical evolution of CH with eutopic thyroid gland and to find out prognostic factors at diagnosis and follow-up. PATIENTS AND METHODS We retrospectively analyzed a group of 84 children with CH and eutopic thyroid gland treated at our institution. They all underwent clinical re-evaluation after the age of 3, based on thyroid function testing after l-thyroxine therapy withdrawal, thyroid ultrasonography, and (123)I scintigraphy with perchlorate discharge test. Genetic analysis was performed in selected cases. RESULTS At re-evaluation, 34.5% of patients showed permanent hypothyroidism and needed l-thyroxine reintroduction, 27.4% had persistent hyperthyrotropinemia (TSH 5-10 mU/L), and 38.1% had transient hypothyroidism. Major risk factors for permanent CH were prematurity, first-degree familial history of goiter/nodules, thyroid hypoplasia at diagnosis, and high l-thyroxine requirements at follow-up. Iodine organification defects were found in 29.7% of patients, 30% of whom harbored DUOX2 mutations. TSH receptor gene mutations were found in 8.7% of patients with persistent thyroid dysfunction and negative perchlorate discharge test. CONCLUSIONS Only one-third of patients with CH and eutopic thyroid gland needed to continue l-thyroxine therapy after re-evaluation. A frequent finding was the persistence of mild hyperthyrotropinemia. The evolution of CH remains difficult to predict, although different clinical features might suggest different outcomes. Mutations in the genes commonly linked to mild forms of CH were documented in a minority of cases.