Nyström E

Screening for thyroid disease in a primary care unit with a thyroid stimulating hormone assay with a low detection limit.

In a study at a primary care centre in a predominantly rural area of Sweden the records of all patients with established thyroid disease were scrutinised and 2000 consecutive adult patients screened with an immunoenzymometric thyroid stimulating hormone assay. The aims of the study were fourfold: firstly, to assess the total burden of thyroid disease in primary care centres in Sweden; secondly, to assess the efficacy of clinical diagnosis of the disease in unselected populations of patients; thirdly, to assess the efficacy of clinical evaluation of treatment with thyroxine; and, lastly, to see whether a single analysis of the serum thyroid stimulating hormone concentration by recent methods would be enough to identify an abnormality of thyroid function. Of the roughly 17,400 adults in the study community, 111 women and 10 men were being treated for thyroid disease. Screening detected 68 patients (3.5%) not receiving thyroxine who had a serum thyroid stimulating hormone concentration of 0.20 mU/l or less, all of whom were followed up clinically. Fifty of these patients were also studied biochemically during follow up. Only nine of the 68 patients had thyroid disease (three with thyrotoxicosis requiring treatment), no evidence of the disease being found in the remainder. Sixteen patients had spontaneous hypothyroidism requiring treatment, and neither these nor three patients with thyrotoxicosis had been detected at the preceding clinical examination. Of 35 patients in whom thyroid disease was suspected clinically at screening, none had laboratory evidence of thyroid dysfunction. In this series 1.3% of all women in the study community (2.6% of all 50-59 year olds) and 0.1% of the men were being treated for thyroid disease at the primary care centre, roughly 1.0% of adults subjected to screening were found to have thyroid disease requiring treatment, and most patients with a thyroid stimulating hormone concentration of 0.20 mU/l or less did not have thyroid dysfunction. It is concluded that measuring the basal serum thyroid stimulating hormone concentration by present methods is insufficient for the biochemical assessment of thyroid dysfunction in unselected populations.

Clinical outcome of radioiodine treatment of hyperthyroidism: a follow‐up study

Objectives. To study the clinical outcome of treatment of hyperthyroid patients with radioiodine.

Urinary iodine and thyroid volume in a Swedish population

Objective.  To evaluate the present efficacy of an iodine supplementation programme working in Sweden since 1936 by studying the iodine excretion in urine and determining the thyroid volume in a population in a semi‐rural community.

Thyroid volume in Swedish school children: a national, stratified, population-based survey

Background/Objectives:Sweden has had a salt iodination program since 1936. This first national surveillance study on iodine nutrition infers an adequate level of urinary iodine concentration (UIC 125 μg/l) and the aim is now to evaluate thyroid volume (Tvol) in the same national sample.Subjects/Methods:A stratified probability proportionate to size cluster sampling was used to obtain a representative national sample of Swedish children aged 6–12 years. Median Tvol obtained ultrasonographically and the prevalence of enlarged thyroid glands were compared with an international reference standard. Regional differences were evaluated through comparisons of Tvol between coastal and inland areas, urban and rural regions, and former goitre and non-goitre regions.Results:Tvol was correlated with age, body surface area (BSA), weight, height and body mass index for both sexes (P<0.0001) but not with UIC. The most important predictors for Tvol were age (girls: P<0.0001, boys: P=0.001) and BSA (girls: P<0.0001, boys: P<0.01). Median Tvol was higher in Sweden than in the reference study (P<0.0001). The prevalence of goitre was higher in Sweden (correlated to age 22.3%, BSA 15.7%, weight 17.6%, height 12.9%) than in the international reference (correlated to age 2.5%, BSA 2.5%, weight 2.5%, height 2.5%) (P<0.0001). Thyroids were larger in boys from urban and former non-goitre areas.Conclusions:Tvols were higher in Swedish school children than in the international reference study although iodine intake is considered optimal in Sweden. These findings underline the importance of regular monitoring of iodine intake, especially with regard to the decreased intake of table salt that is likely to follow initiation of health campaigns.

Consequences of inadvertent radioiodine treatment of Graves' disease and thyroid cancer in undiagnosed pregnancy. Can we rely on routine pregnancy testing?

Introduction. Radioiodine and most cytostatic treatments are contraindicated in pregnancy. Still, inadvertent therapy does occur. Radioiodine was given to two pregnant women with Graves’ disease and thyroid cancer respectively, both in their 20th gestational week. Routine pregnancy tests based on urinary β-hCG had failed to indicate pregnancy in both cases. Methods. Estimation of doses to the foetuses and foetal thyroids. Scrutiny of pregnancy testing. Results and Conclusions. Doses to foetal thyroids were ablative (250–600 Gy). Total foetal dose in the Graves’ patient was 100 mGy and compatible with survival, whereas a foetal dose of approximately 700 mGy together with induced hypothyroidism was fatal for the foetus of the cancer patient. Routine pregnancy tests may fail early and late in pregnancy. The possibility of pregnancy should be considered in all fertile women before therapy with radionuclides or cytostatic regimens, and a clinical investigation undertaken on wide indications with determination of serum β-hCG, preferably together with an ultrasound examination.

Screening for thyroid disease of 15-17-year-old schoolchildren in an area with normal iodine intake.

Abstract. Milakovic M, Berg G, Eggersten R, Lindstedt G, Nyström E (Sahlgrenska University Hospital, Göteborg, Sweden). Screening for thyroid disease of 15–17‐year‐old schoolchildren in an area with normal iodine intake. J Intern Med 2001; 250: 208–212.

The liquorice effect on the RAAS differs between the genders

Objective. Liquorice‐induced increase in blood pressure (BP) is more profound in subjects with essential hypertension (HT) than in healthy individuals. Liquorice induces pseudohyperaldosteronism by inhibiting the 11β‐hydroxysteroid dehydrogenase type 2 and is also known to inhibit the renin–angiotensin–aldosterone system (RAAS). We explored the difference in response in BP, considering the RAAS and the genders. Design. Patients with HT (eight men and three women, mean age 40.7 years) and healthy controls (13 men and 12 women, mean age 31.2 years) consumed 100 g of liquorice (150 mg glycyrrhetinic acid) daily for 4 weeks. Methods. Blood, urine samples and BP were evaluated before and after 4 weeks of liquorice consumption and 4 weeks after cessation of liquorice consumption. Results. The relative change in serum aldosterone levels differed between the genders (p<0.02), men being more responsive than women, but not between patients with HT and healthy subjects. Conclusion. The liquorice‐induced inhibition of aldosterone secretion differs between the genders and is not influenced by the BP levels. This difference between the genders has not been exposed before.

The relations of microalbuminuria to ambulatory blood pressure and myocardial wall thickness in a population

. Nilsson T, Svensson A, Lapidus L, Lindstedt G, Nyström E, Eggertsen R (Mölnlycke Primary Health Care and Research Centre; Göteborg University, Göteborg, Sweden). The relations of microalbuminuria to ambulatory blood pressure and myocardial wall thickness in a population. J Intern Med 1998; 244: 55–9.

Wrong biochemistry results - Information on incidents with consequences for health should be collected centrally

Editor—In their editorial Ismail and Barth discuss the possibility of getting wrong biochemistry results, particularly when immunoassays are done.1 Laboratories try to detect these problems and provide an accurate, clinically relevant result. But the large number of assays done has resulted in widespread reliance on automation, particularly for hormones, and the “one size fits all” approach inherent in this makes the likelihood of inaccurate results quite high. What is needed is fit-for-purpose assays on these automated platforms. We are aware, though, of the problems that this may present: we have experienced difficulty in persuading a company that the female testosterone values that its machine produces are analytically incorrect and may lead to inappropriate clinical action if preceded by an oestradiol assay (table). The fact that we elicited similar findings from other centres through a computer mailbase and added this weight of evidence to ours did not matter to the company or, worryingly, to the Medical Devices Agency. Until companies recognise that, in a clinical governance setting, no-blame reporting is constructive criticism requiring positive action, then inappropriate interventions will continue to affect patients. More critical oversight of analysis and its clinical implications by the Medical Devices Agency is vital. We need confidence that any problem will be addressed either cooperatively or by effective monitoring.

Exploring the use of recombinant human TSH in the diagnosis of central hypothyroidism

CONTEXT The diagnosis of central hypothyroidism (CH) is often difficult to establish as serum TSH levels may be low, normal, or slightly increased. OBJECTIVE To explore the use of recombinant human TSH (rhTSH) in the diagnosis of CH. DESIGN Randomized single-blind clinical trial. SETTING Outpatient clinic of a tertiary care referral center. INTERVENTION A single intramuscular injection of 0.1 and 0.9 mg rhTSH in random order with 1-week interval. PARTICIPANTS Eighteen adult patients with pituitary insufficiency and six healthy age-, sex-, and body mass index-matched controls. Six patients had untreated CH (newCH), six had treated CH (CH), and six patients were TSH sufficient (nonCH). Five weeks before TSH stimulation, levothyroxine was replaced with tri-iodothyronine (T(3)) for 4 weeks. One week before stimulation, treatment was withdrawn. MAIN OUTCOME MEASURES Thyroid hormones and thyroglobulin (Tg) before and 2, 3(1/2), 7, 24, 48, and 72 h after each injection. RESULTS In the newCH group, basal free thyroxine (FT(4)) levels were lower than in controls (P<0.05). After 0.9 mg rhTSH, the increases in FT(4) and reverse T(3) (rT(3)) were less marked in the newCH group than in controls (FT(4)+/-s.e.m. 9.2+/-0.5 to 19.7+/-1.2 vs 11.3+/-0.5 to 27.8.2+/-2.4 pmol/l, P<0.05). The CH group exhibited reduced basal and stimulated FT(4) compared with the TSH-sufficient groups. Tg increased similarly among all study groups after rhTSH injection. CONCLUSION In this pilot study, patients with untreated CH had lower response to 0.9 mg rhTSH in FT(4) and rT(3) than controls. An rhTSH test may be useful in the diagnosis of CH, but further studies are required.