Initial Thyroid Stimulating Hormone Concentration Research Articles

Evaluation of Predictors for the Diagnosis of Hyperthyroidism in Cats

In humans, subclinical hyperthyroidism is diagnosed when serum thyroid hormone concentrations are within the reference range but thyroid stimulating hormone (TSH) concentration is subnormal. In a previous study, a higher prevalence of thyroid nodular disease was found in euthyroid geriatric cats with undetectable TSH (<0.03 ng/mL) compared to those with detectable TSH concentrations, suggesting subclinical hyperthyroidism might also exist in cats. Euthyroid cats with undetectable TSH concentrations have subclinical hyperthyroidism and may subsequently develop overt signs of hyperthyroidism. One-hundred four client-owned cats. In this prospective cohort study, euthyroid geriatric (≥ 9 years) cats were recruited during routine health checks. Plasma biochemistry was performed at baseline and every 6 months thereafter. Total thyroxine and TSH concentrations were determined annually. Short-term follow-up data (within 14 months of recruitment) were used to detect variables at entry that were predictive of the diagnosis of hyperthyroidism, using univariable analysis followed by multivariable logistic regression analysis. Log rank analysis was used to test the association of initial TSH concentration with diagnosis of hyperthyroidism during the total available follow-up. Median (range) follow-up was 26 (0-54) months and annual incidence of hyperthyroidism during the study was 7.4%. Cats that became hyperthyroid within 14 months had higher ALKP activity (P = 0.02) and higher prevalence of goiter (P = .03) at baseline than controls. Cats with undetectable TSH at baseline (29/104; 28%) were significantly (P < .001) more likely to be diagnosed with hyperthyroidism. However, not all cats with undetectable TSH became hyperthyroid during the study.

Repeat testing of TSH in preterm infant for congenital hypothyroidism

BackgroundThe recommended screening cut-off for congenital hypothyroidisim (CHT) in the UK is a blood spot Thyroid Stimulating Hormone (TSH) of 10 μ/l but centres use values ranging from 5–10 μ/l....

Repeat testing for congenital hypothyroidism in preterm infants is unnecessary with an appropriate thyroid stimulating hormone threshold

Background:Revised UK neonatal screening guidelines recommend that a second blood sample for assay of thyroid stimulating hormone (TSH) be taken when preterm infants reach a postmenstrual age of 36 weeks.Objective:To...

Factors involved in the rate of fall of thyroid stimulating hormone in treated hypothyroidism

The rate of fall of serum thyroid stimulating hormone (TSH) concentrations in 32 hypothyroid infants (11 boys, 21 girls) was studied after starting treatment with thyroxine to determine whether it...

Survey of neonatal screening for primary hypothyroidism in England, Wales, and Northern Ireland 1982-4

National screening for congenital hypothyroidism was established in the United Kingdom in 1982. During 1982-4, 488 infants with primary congenital hypothyroidism were detected by the 25 regional screening laboratories in England, Wales, and Northern Ireland. In addition, one infant had signs of cretinism at birth and was investigated before the screening test was done and four infants were known to have been missed by the screening programme; among these four infants the initial thyroid stimulating hormone concentrations were normal in two with inherited defects of synthesis of thyroxine, not measured in one, and false negative in one. The overall incidence of primary hypothyroidism was 1:3937 births (boys 1:6640, girls 1:2756). The incidence seemed to be reduced in infants born to black mothers (two cases only) and increased in those born to Asian mothers (61 cases). Congenital anomalies other than those of the thyroid glands were reported in 36 children (7%), and 15 (3%) died from various causes before the age of 4. Infants who were considered to show unequivocal evidence of hypothyroidism started treatment at a median age of 17 days (5th and 95th centiles 10 and 42 days) compared with a median age of 14 days (5th and 95th centiles 9 and 21 days) for infants with classic phenylketonuria also detected by national screening.