Hypothyroidism
	The epidemiological and clinical aspects of adult-onset hypothyroidism was evaluated by Vargas and co-workers (Lima, Peru). They have, retrospectively, analyzed 208 patients (females 179, males 29) with a mean age of 44.7 years. In this cohort the majority of patients were 40-50y old. The diagnosis of primary hypothyroidism was established in 202 patients and only 6 cases were secondary to hypothalamic-pituitary disorders. The major cause for diminished thyroid function were a previous history of treated Graves' disease (27.1%), thyroidectomy for other reasons (10.7%) and thyroid dysgenesis (2.5%). The authors could not find a definite cause in 125 patients, assuming an association with autoimune disorders. Treatment of myxedematous pre-coma was evaluated by Diaz and co-workers from Buenos Aires, Argentina. Three old patients (2 females, one male, age > 70y) were admitted to the hospital during the winter with a clinical picture of severe hypothyroidism and a pre-comatous state (Glasgow score 8/15). Treatment was started with hemodynamic procedures, LT4 (0.1 mg per day, i.v.) and 300 mg of hydrocortisone. One patient had chronic atrial fibrillation and cardiac failure. All three patients had signs and symptoms of acute respiratory infection (treated with antibiotics). Serum TSH was elevated 44.5-57.6 µU/mL and mean serum total T4 very low 1.92 µg/dL. All patients were maintained on the same doses of LT4 and on assisted ventilatory respiration and recovered fully. The authors argue that low doses of LT4 are efficient in treating myxedematous pre-coma. Subclinical hypothyroidism in infertility and sterility was evaluated by Sciovra et al. from Buenos Aires, Argentina. A cohort of 73 females complaining of infertility or sterility was evaluated (infertility 18, sterility 55), with a mean age of 31.2y (21-44). Goiter was present in 8 patients. Serum TSH levels were in the normal range in 72 patients (98.6%) but the TSH response to TRH disclosed 8 patients with an exaggerated response of TSH. In this group, in 2 patients anti-TPO autoantibodies were present in the serum. The authors comment that evaluation of thyroid function should be conducted in all patients complaining of infertility or sterility. The actual doses of LT4 for treatment of primary hypothyroidism was discussed by Escobar, from Bogota, Colombia. The author analyzed, retrospectively, 76 patients with primary hypothyroidism (ages between 11-68 years) with an initial serum TSH level between 5.1 and 270 µU/mL. The patients were started on a LT4 doses of 1.3 µg/kg/day. In 51 patients the mean LT4 doses to maintain serum TSH within the normal range was 1.1 µg/kg/day. However, individuals with very elevated initial serum TSH levels (> 20 µU/mL) needed a higher LT4 daily doses (1.6 µg/kg/day). Also older patients (> 50y) needed a lower LT4 doses (0.9 µg/kg/day). Only 9 patients needed a LT4 dosis higher than 150 µg/day. The authors concluded that LT4 treatment should be individualized and kept at the lower possible doses to keep serum TSH within normal range. The impact of subclinical hypothyroidism in clinical practice was discussed by de la Torre and colleagues from Quito, Ecuador. They retrospectively analyzed the records of patients seen between 1991-1995 in a general hospital. All patients with serum TSH higher than 4.5 µU/mL or, alternatively, with a TSH response to TRH higher than 27 µU/mL were considered as possible candidates for subclinical hypothyroidism. A total of 495 patients were analyzed who met one of the above criteria. In these patients the final diagnosis of actual hypothyroidism was made in 47% of the patients either with goiter or without. A number of other pathologies was associated with subclinical hypothyroidism such as Turner's syndrome, dyslipidemias, growth retardation and menstrual disorders. The authors claim that systematic evaluation of subclinical hypothyroidism should be proposed for the adult population of a general hospital. The influence of iodinated desinfectants (I.D.) on TSH values in screening for congenital hypothyroidism was evaluated by Dratler and colleagues from Buenos Aires, Argentina. TSH was measured in dried blood spots (DBS) collected on filter paper by a immunofluorometric assay (DELFIA) and the results were expressed as µU/mL of serum (cut-off value 20 µU/mL of serum). Group 1) DBS samples from a NICU (neonates) population: n = 161; ages (days, X ± SD) 19.2 ± 22.4, range = 0 to 104; weight (grams, X ± SD) 264 ± 962.4. Within group 1, 65/161 patients were exposed to iodinated disinfectant (ID) (Group 1a) and 69/161 patients were not exposed to ID (Group 1b). In 27/161 data of ID-exposure were not available. The degree of iodine exposure was registered as: a) only one exposure; b) repeated exposures; c) exposed body surface: 25%, 50%, or > 50%. A group of DBS samples from a screening program was considered as control. (Group 2), n = 748. The results were as follows: TSH (X ± SD): Group 1: 4.4 ± 4.; range: 1.1 to 25.6; Group 1a: 5.1 ± 5.4; range: 1.1 to 25.6; Group 1b: 4.3 ± 3.5; range: 1.1 to 21.4. (G1a vs. G1b): p: ns. G2: 2.7 ± 2.2; range: 0.5 to 15.5 (G1 vs. G2); 2p <0.001. Group 1 was also evaluated according to prematurity, weight (<="1500" or> 1500 grams), age (<= 24 or> 24 hrs), diagnosis and presence of illness. Age was the only factor with significant influence on the TSH levels in the NICU population (p <0.01). Three cases in Group 1 had higher values than the cutoff level: G 1a: 2/65 (20.4 and 25.6) and G 1b: 1/69 (21.4). (G 1a vs. G 1b): Fisher Exact Test: ns. The 69 patients without reference to ID use had all normal TSH values. The authors concluded that: 1) TSH levels were not significatively different between exposed and not exposed to ID groups in the neonates. 2) Even if the neonate population as a whole showed significantly higher TSH values than the control population, they were independent of the use and extent of ID exposure. 3) Prematurity, weight or presence of illness do not influence TSH values neither in exposed nor in non-exposed patients. 4) As expected, the DBS samples obtained within the first 24 hrs of life showed higher TSH values in the neonate population, exposed or not to ID. Therefore, use of ID would not be a risk factor to elevate TSH levels above the cutoff level in congenital hypothyroidism screening in the neonate population.