Prevalência do hipotiroidismo subclínico e repercussões sobre o perfil lipídico e massa óssea em mulheres na pós-menopausa

OBJETIVO: avaliar a prevalência do hipotiroidismo subclínico e suas repercussões sobre o perfil lipídico e a densidade mineral óssea (DMO) em mulheres na pós-menopausa. Métodos: trata-se de estudo transversal com recuperação de dados de prontuários de pacientes acompanhadas em ambulatório de climatério. Critérios de inclusão: mulheres na pós-menopausa com dosagem do hormônio estimulador da tiróide (TSH) e de tiroxina livre (T4-L). Critérios de exclusão: hipertiroidismo e carcinoma de tiróide. Considerou-se hipotiroidismo subclínico valores de TSH superiores a 5,0 mUI/mL e T4-L normal. Foram selecionadas 320 pacientes (idade 55,2±6,4 anos) divididas em 3 grupos: função tiroideana normal (n=208), hipotiroidismo subclínico (n=53) e hipotiroidismo clínico sob tratamento (n=59). Foram analisados dados clínicos, uso de terapia hormonal, índice de massa corpórea (IMC=kg/m²), perfil lipídico (colesterol total, HDL, LDL, triglicerídeos) e DMO da coluna lombar e fêmur. Na análise estatística, as diferenças entre as médias dos grupos foram comparadas utilizando-se a análise de variância (ANOVA). Para múltipla comparação, assumindo que a variância era diferente entre os grupos, utilizou-se o método de Tukey. RESULTADOS: o hipotiroidismo subclínico foi diagnosticado em 16,1% dos casos. Os grupos foram homogêneos quanto às características clínicas, IMC e perfil lipídico e uso de terapêutica hormonal. Nas pacientes com hipotiroidismo subclínico ou clínico encontrou-se menor freqüência de osteopenia na coluna lombar e fêmur quando comparadas às eutiroidianas (p<0,001). Houve correlação negativa entre os valores de TSH e DMO da coluna lombar e fêmur (p<0,001). Não se constatou correlação entre os valores de TSH e idade, tempo de menopausa, IMC e perfil lipídico. O total de usuárias de terapia hormonal foi de 65,1%, duração média de 3,43±2,42 anos, não diferindo entre os grupos. CONCLUSÃO: o hipotiroidismo subclínico com prevalência de 16,1% na pós-menopausa associou-se à baixa DMO, mas sem repercussões sobre o perfil lipídico.

A novel mutation (Q40P) in PAX8 associated with congenital hypothyroidism and thyroid hypoplasia: Evidence for phenotypic variability in mother and child

Congenital hypothyroidism associated with thyroid hypoplasia can be caused by several genetic defects, including mutations in the TSH beta -subunit, the TSH receptor, the G(A)alpha -subunit, and the transcription factor PAX8. Four girls with sporadic congenital hypothyroidism and hypoplastic thyroid glands were analyzed for mutations in PAX8 and TTF2 (FKHL15). Mutations in the coding region of the TSH beta -subunit gene, the TSH receptor gene, and exons 8 and 9 of G(mu)alpha had been excluded previously. Serum TSH concentrations were 150 mU/liter or more, TG levels were within normal limits, and thyroid autoantibodies were absent. Technetium scintigraphies did not reveal the presence of thyroid tissue, but ultrasonography documented hypoplastic, normally located glands.One patient was found to harbor a heterozygous transversion 119A -->C in exon 3 of PAX8 replacing a conserved glutamine by proline in the paired box domain (Q40P). Analysis of her family members revealed that her mother, who has a thyroid gland of normal size and mild, adult-onset autoimmune hypothyroidism, is also heterozygous for this mutation. Functional analyses of the PAX8 Q40P mutation showed impaired binding to a PAX8 response element and absent transactivation of a thyroid peroxidase promoter luciferase reporter gene.These findings confirm the important role of PAX8 in the development of the thyroid, but they indicate that PAX8 gene mutations may have a variable penetrance or expressivity. The absence of mutations in the coding sequences of the analyzed genes in the three other patients supports the concept that the pathogenesis of congenital hypothyroidism associated with thyroid hypoplasia is diverse.

Clinical and laboratory evaluation of hyperlipemic and hypothyroid patients

OBJECTIVE: To determine the frequency of hypothyroidism in a sample of hyperlipemic patients and evaluate clinical and laboratory factors indicative of thyropathy among them. METHODS: Fifty-one hyperlipemic patients, grouped according to an earlier or recent diagnosis of their thyroid function into euthyroid and hypothyroid, were evaluated with clinical and laboratory examinations of blood levels of free T4 and TSH (by radioimmunoassay). Patients were on average 46.8±11.7 years old, predominantly of the female sex (62.5%); 31% had a previous diagnosis of hypothyroidism and were under treatment with thyroxin. RESULTS: Fourteen three percent of patients analyzed had hypothyroidism, which had not been detected before. Differentiating attributes of the groups analyzed were: a predominance of females among the hypothyroid patients and a higher HDL serum concentration among those recently diagnosed. CONCLUSION: In the present study, new cases of hypothyroidism in hyperlipemic patients were a frequent occurrence, yet few clinical and laboratory data except tests evaluating free T4 and TSH in the blood indicated which patients had thyroid dysfunction.

Facial paralysis associated to hypothyroidism in a dog

The hypothyroidism is the most commonly endocrinopathy in dogs, that occurs preferentially in middle-aged pure breed. The clinical signs associated with hypothyroidism are variable, many times non-specific, including metabolical, dermatological or cardiovascular. The main laboratorial findings are non-regenerative anemia and hypercholesterolemia. Hyponatremia, increase on alanine transferase and alkaline phosphatase activity also can be observed in a lower frequency. There are some reports of peripheral neuropathies caused by hypothyroidism, but the pathophysiology of this process is still unknown. There are specific diagnostic tests that can be used to help diagnose hypothyroidism, and those should be aligned together with the animal's clinical symptoms. The thyroxine stimulating hormone, and free and total thyroxine concentrations are the most used tests. A Pit Bull dog, female, over weighted, was treated presenting left facial paralysis. Thyroid function tests confirmed hypothyroidism. The animal was treated with hormonal replacement and there was improvement in clinical signs in 40 days, confirming that hypothyroidism was facial paralysis' cause.