The role of thyroid tests in handling of patients in general practice. A phenomenologic study.

During a period of 2 months thyroid function tests, performed on out-patients referred to the laboratory from general practitioners, were studied. The relative informative value of the tests was estimated in relation to the reasons given for requesting the tests. In 86% of the samples from patients with no history of earlier thyroid disease the conventional thyroid tests were found within the reference intervals. 3% showed a definite abnormal pattern of values. In 11% the results were in some way abnormal. In the group of patients with earlier history of thyroid disease 50% of the tests were abnormal. The relative merits of adding a sensitive TSH assay test were analyzed, and it was estimated whether using the sensitive TSH as a first-line discrimination test would add or subtract information compared to the conventional thyroid function tests. It was concluded that in the situation where the general practitioner wants laboratory information of thyroid parameters on patients in order to make decisions on the further handling of the patient, the sensitive TSH test is of limited value as a first-line discrimination test and should be supplemented by other tests.

Goitre size and outcome of medical treatment of Graves' disease.

One hundred and twenty-four patients with newly diagnosed hyperthyroidism received a combined thionamid-thyroxine medical therapy for approximately 2 years. According to the estimated goitre size before therapy and the type of goitre the patients were divided into 4 groups: Graves' disease no goitre (n = 19), Graves' disease small goitre (n = 57), Graves' disease medium or large goitre (n = 23), multinodular goitre (n = 25). The median follow-up period after cessation of medication was 64 (range 11-141) months. The remission rates in the different groups during follow-up were calculated using life table analysis. Graves' patients with no goitre or a small goitre had a significantly better outcome (remission % after 5 years 82.5 +/- 15.4 (SE) and 71.5 +/- 7.8, respectively) than Graves' patients with a medium size or large goitre (remission % after 5 years 37.0 +/- 11.1)(P less than 0.025). Most patients with multinodular goitre had a relapse within the first year after stop of medication (remission % after 5 years 15.5 +/- 10.1). Hence patients with Graves' disease having a small thyroid gland should be treated medically while surgery or radioiodine may be a more reasonable choice in Graves' patients with medium size or large goitres. Medically treated patients with toxic multinodular goitres have a very small chance of prolonged remission if medication is stopped.

A longitudinal study of serum TSH, and total and free iodothyronines during normal pregnancy.

Serum T4, T3, rT3, free T4, free T3 and TSH were measured during and after normal pregnancy in 20 women. Special methodological precautions were taken to avoid interference of other hormones and protein alterations in the assays. Serum T4 and T3 were steadily increasing during the last part of the 1st trimester, and remained high and nearly stable during the 2nd and 3rd trimester of the gestation period. The high levels were approximately 1.5 times the values measured 10 weeks post-partum. Serum rT3 was elevated already during the last part of the 1st trimester and remained high throughout pregnancy, compared to the post-partum value. Serum free T4 and free T3 were slightly elevated in early pregnancy. The values decreased gradually during pregnancy and were slightly depressed during the 3rd trimester. A gradual increase in serum TSH was observed during pregnancy and the 2nd and 3rd trimester values were significantly higher than the post-partum value. The mean values for serum TSH, free T4 and free T3 remained always well within the normal range. Thus small variations in serum free iodothyronines and TSH occur during normal pregnancy, the alterations observed in the last trimester of the gestation period resembling those of a slight thyroid insufficiency. These trends in variation of the reference values are worth to remember in the diagnosis of borderline hypo- or hyperthyroidism and in the balanced treatment of pregnant women with thyroid dysfunction.

Occurrence of goitre during lithium treatment.

Of 330 patients given lithium for recurrent manic-depressive disorder 12 developed goitre after treatment periods of five months to two years. All the patients remained clinically euthyroid. Pressure symptoms necessitated subtotal thyroidectomy in two patients. In 9 out of 10 patients with goitre, and in two out of seven without goitre study with radioactive iodine showed abnormal findings in iodine metabolism. Discontinuance of lithium led to disappearance of goitres, while thyroid metabolism returned to normal. Thyroxine or desiccated thyroid produced shrinkage of the gland in spite of continued lithium medication.