Congenital hypothyroidism treatment in infants: a comparative study between liquid and tablet formulations of levothyroxine.

AIMS: To compare the effects of liquid and tablet formulations of levothyroxine (L-T4) in 78 newborns with congenital hypothyroidism (CH). METHODS: 39 patients received liquid L-T4 (group A) and 39 patients received tablets (group B). Thyroid-stimulating hormone (TSH) and free thyroxine (fT4) were measured and L-T4 dose recorded at onset of therapy and during the first year of treatment. Developmental quotient (DQ) was assessed by Griffiths' mental development scales at 12 months of age. RESULTS: Gestational age, birth weight, screening TSH, etiology and severity of CH, age at onset of therapy and median initial L-T4 dose were similar in both groups. fT4 concentration normalized before 10 days of treatment in all patients. Normalization of TSH concentration was achieved after 7-10 days of therapy in 87% of group A patients and in 82% of group B patients. Group A patients had significantly lower TSH values compared with those of group B at 7-10 days (p = 0.05) and 6-8 months (p = 0.043) of treatment, despite similar L-T4 dose and fT4 concentration. Mean DQ scores were within normal range in all patients. CONCLUSION: We confirmed the efficacy and safety of both formulations. The TSH inhibition trend when using liquid L-T4 may be linked to a higher absorption in comparison to the tablets.

Difficult treatment of consumptive hypothyroidism in a child with massive parotid hemangioma.

Consumptive hypothyroidism is a rare condition related to massive infantile hemangiomas producing an excess of the thyroid-hormone-inactivating enzyme type 3 iodothyronine deiodinase. We report the first case of consumptive hypothyroidism secondary to a large parotid hemangioma, highlighting the difficulties in selecting an adequate therapeutic strategy. The affected child was initially referred to our center for congenital hypothyroidism with a hypoplastic thyroid gland. L-Thyroxine (L-T4) replacement therapy was started at seven days of life. In the following weeks, the hemangioma rapidly increased in volume and the child developed severe hypothyroidism refractory to high doses of L-T4 therapy. The concentration of reverse triiodothyronine was elevated, suggesting that the underlying cause was an excessive conversion of thyroid hormones by high type 3 iodothyronine deiodinase levels in the tumor. Corticosteroid treatment showed only partial benefit. Introduction of propranolol instead led to normalization of thyroid hormones along with a dramatic involution of the hemangioma.

Newborn of mothers affected by autoimmune thyroiditis: the importance of thyroid function monitoring in the first months of life.

BACKGROUND: Evaluation of thyroid function in neonates born from mothers affected by autoimmune thyroiditis in order to define if a precise follow-up is necessary for these children. The influence of maternal thyroid peroxidase antibody (TPOAb) and L-thyroxine therapy during pregnancy on neonatal thyroid function was also investigated. METHODS: 129 neonates were tested for thyroid function by measurement of free thyroxine (FT4) and thyroid stimulating hormone (TSH) in 3th day, 15th day and at one month of life. TPOAb were measured in all patients; periodical control of thyroid function were performed until 6 months of life if Ab were positive. Data concerning etiology of maternal hypothyroidism and maternal replacement therapy with L-thyroxine during pregnancy were retrospectively collected. RESULTS: 28% neonates showed at least a mild increase of TSH value at the different determinations. In the majority of them, a spontaneous completely normalisation of TSH value was observed within the first month life. L-thyroxine replacement therapy was started in 3 neonates. TPOAb titer and maternal L-thyroxine replacement therapy were not related to alteration of thyroid hormone function in our study population. CONCLUSIONS: Transient mild elevation of serum TSH above the normal reference value for age is frequently observed in the first month of life in infants born from mothers affected by autoimmune thyroiditis. Persistent hyperthyrotropinemia requiring replacement therapy is observed in 2.2% of these neonates. According to our experience, follow-up is recommended in these newborns; the most accurate and not invasive way to carefully monitor these infants after neonatal screening for CH seems to be serum-testing TSH between 2nd and 4th week of life.

Bilateral cavo-ilio-femoral thrombosis in an adolescent with transient anti-phospholipid antibodies and factor V heterozygous mutation: a case report.

We report a case of bilateral cavo-ilio-femoral thrombosis in an adolescent with factor V heterozygous mutation and transient antiphospholipid antibodies secondary Varicella infection.The clinical significance of finding transient antiphospholipid antibodies in the sera of infectious disease is unclear. We here report a case of bilateral cavo-ilio-femoral thrombosis in an adolescent with newly diagnosed factor V heterozygous mutation and transient antiphospholipid antibodies secondary to Varicella infection.

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. OBJECTIVE: To determine the impact on CH epidemiology and classification generated by the introduction of low b-TSH cutoff. DESIGN: Retrospective study of 629,042 newborns screened with b-TSH cutoffs of 12 (years 1999-2002) or 10 mU/l (2003-2005). MEASUREMENTS: Congenital hypothyroidism incidence and classification. Results were compared with those virtually obtained with the previous cutoff (20 mU/l). Clinical re-evaluation after L-T4 withdrawal of a representative group of 140 CH children at 3-5 years. RESULTS: Low b-TSH cutoffs allowed the detection of 435 newborns with confirmed CH (incidence 1:1446). Forty-five percent of CH infants, including 12/141 dysgenesis, would have been missed using the 20 mU/l cutoff. In contrast to current classification, 32% CH newborns had thyroid dysgenesis and 68% had a gland in situ (GIS). Premature birth was present in 20% of cases being associated with a 3-5 fold increased risk of GIS CH. Re-evaluation at 3-5 years showed a permanent thyroid dysfunction in 78% of 59 CH toddlers with GIS. CONCLUSIONS: The use of low b-TSH cutoff allowed the detection of an unsuspected number of children with neonatal hypothyroidism, evolving in mild permanent thyroid dysfunction later in life. The incidence of CH in this Italian population appears to be double than previously thought with a clear-cut prevalence of functional defects over dysgenetic ones.

Persistent mild hypothyroidism associated with novel sequence variants of the DUOX2 gene in two siblings.

One of the steps in thyroid hormone biosynthesis is the generation of hydrogen peroxide by dual oxidases (DUOX). Only one study reported mutations in DUOX2 gene in congenital hypothyroidism (CH) associated with total iodide organification defect (TIOD) in homozygosity or with partial iodide organification defect (PIOD) in heterozygous patients. We report genetic and phenotypic characterization of a family affected with isolated CH. The proband was positive at neonatal TSH screening. High serum TSH with low FT4 confirmed the diagnosis. At 4 years, TSH was high after L-T(4) withdrawal and (123)I scintigraphy with perchlorate discharge test revealed a PIOD. His brother was negative at TSH screening, but perinatal iodine overload was documented by urinary test. Serum TSH was elevated at postnatal day 11 and progressively increased together with a decline in urinary iodine. Reevaluation at 4 years confirmed a persistent hyperthyrotropinemia associated with PIOD. Both siblings resulted compound heterozygotes for two novel DUOX2 variants, a nonsense mutation (c.2524C>T, p.Arg842X) and a missense substitution (c.1126C>T, p.Arg376Trp), undetected in 140 control alleles. The parents had normal thyroid function and were heterozygous carriers of mutant alleles. In conclusion, we report two novel sequence variants in DUOX2 gene that are associated with persistent mild hypothyroidism and PIOD in two siblings. Different neonatal iodine supply apparently acted as disease modifier, justifying the discrepant results at TSH screening in the two siblings with same DUOX2 genotype and suggesting that mild dyshormonogenic defects may remain undisclosed in areas characterized by elevated iodine intake.