Supplementary iodine fails to reverse hypothyroidism in adolescents and adults with endemic cretinism.

The efficacy of supplemental iodine in correcting hypothyroidism in adults and older children with endemic myxedematous cretinism is not known. To investigate this issue we administered im iodized oil (1.5 mL) to 28 hypothyroid endemic cretins (TSH, greater than 5 mIU/L) from western China, aged 14-52 yr (mean = 29 SD = 11 yr). Clinical examination, intelligence testing (Hiskey Nebraska Test of Learning Aptitude and the Griffiths Mental Development Scales), and thyroid function tests were performed before and 6 months after iodine supplementation. We found that signs of thyroid hormone deficiency, dwarfism, and delayed sexual maturity persisted after iodine supplementation. Further, mental disability and other clinical features of neurological damage were not altered by treatment. The mean serum concentration of total T4 before treatment was 75 nmol/L (SD = 40) and fell after iodized oil administration to 56 nmol/L (SD = 29; P less than 0.001). Mean serum levels of TSH before and after iodine showed a paradoxical fall [85 mIU/L (SD = 102) and 46 mIU/L (SD = 46), respectively]. Serum TSH levels decreased into the normal range (less than 5 mIU/L) in only 1 of 28 patients (4%). We conclude that iodine supplementation does not reverse thyroid hormone deficiency or its sequelae in adolescents and adults with endemic myxedematous cretinism. Iodized oil in this age group of patients with endemic cretinism does not appear to be beneficial and should be used with caution.

Glycometabolic status and acute myocardial infarction: has the time come for glucose-insulin-(potassium) therapy?

Glucose-insulin-potassium infusion as a metabolic therapy was first advocated for the management of acute myocardial infarction (AMI) in 1960s. Over the subsequent decades, enthusiasm for its use has been patchy, especially with the availability of other effective treatments such as reperfusion therapy for AMI. Several clinical studies in the mid-1990s revived the interest in the glycometabolic aspects of patients with AMI. The somewhat conflicting results of these recent studies have generated debate over the significance of the glycometabolic state following acute coronary occlusion and the role of insulin-based infusion therapy. Although most of the available evidence is in favour of an insulin-based therapy, there are still many aspects of this therapy that require clarification. More evidence will be required from further clinical trials before it is adopted in routine clinical practice.

Re-emergence of iodine deficiency in Australia.

Iodine is an essential nutrient for human growth and development. The thyroid gland is dependent upon iodine for production of thyroid hormone. It is a common perception that iodine deficiency is not a major public health concern in mainland Australia, with sporadic studies carried out about a decade ago showing average urinary iodine excretion levels of around 200 microg/day. Recent evidence, however, has shown that the consumption of iodine is declining in Australia. A similar situation has occurred in the USA. The present study was designed to evaluate the urinary iodine excretion (UIE), as the indicator of iodine nutrition, in samples obtained from various demographic groups in the Sydney metropolitian area, namely: schoolchildren, healthy adult volunteers. pregnant women and patients with diabetes. Urinary iodine in spot urine sample was measured in a Technicon II autoanalyser using an in-house, semiautomated method. The results in this communication show that all four study groups had the median UIE below 100 microg/L. the criteria set by the World Health Organization for iodine repletion, and confirm what has been described previously, that iodine deficiency has reemerged in Sydney, Australia. One of the major causes of the reduced iodine intake is the reduction of iodine in milk since the dairy industry replaced iodine-rich cleaning solutions with other sanitisers. Secondly, less than 10% of the population are currently using iodised salt. A national survey into the iodine nutrition status in Australia is urgently required as part of the establishment of a systematic surveillance and legislation is required to iodise all edible salt.