[Thyreotoxic hypokalemic paralysis; presentation of symptoms in three case reports].
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Biomedical subjects
Publications and source records attributed to K H Rudorff.
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A patient with a ganglioglioma of the neurohypophysis developed the syndrome of inappropriate antidiuretic hormone secretion (SIADH). We present the case and describe its microscopic and ultrastructural features. Malignant neoplasms were thought to be the main cause of ectopic production of vasopressin. Head trauma, infection, or drugs, however, can also induce hypersecretion of vasopressin. Mechanical compression of the pituitary stalk can lead to an excessive antidiuretic hormone (ADH) release by affecting the inhibitory system. Primary neuroendocrine tumors of the hypothalamic-neurohypophyseal system are extremely rare. We demonstrate the presence of vasopressin in the tumor cells by immunocytochemistry. This represents the first case of SIADH caused by a tumor of the neurohypophysis.
OBJECTIVE: Several studies have suggested that iodine may influence thyroid hormone status, and perhaps antibody production, in patients with autoimmune thyroid disease. To date, studies have been carried out using large amounts of iodine. Therefore, we evaluated the effect of small doses of iodine on thyroid function and thyroid antibody levels in euthyroid patients with Hashimoto's thyroiditis who were living in an area of mild dietary iodine deficiency. METHODS: Forty patients who tested positive for anti-thyroid (TPO) antibodies or with a moderate to severe hypoechogenic pattern on ultrasound received 250 microg potassium iodide daily for 4 months (range 2-13 months). An additional 43 patients positive for TPO antibodies or with hypoechogenicity on ultrasound served as a control group. All patients were TBII negative. RESULTS: Seven patients in the iodine-treated group developed subclinical hypothyroidism and one patient became hypothyroid. Three of the seven who were subclinically hypothyroid became euthyroid again when iodine treatment was stopped. One patient developed hyperthyroidism with a concomitant increase in TBII titre to 17 U/l, but after iodine withdrawal this patient became euthyroid again. Only one patient in the control group developed subclinical hypothyroidism during the same time period. All nine patients who developed thyroid dysfunction had reduced echogenicity on ultrasound. Four of the eight patients who developed subclinical hypothyroidism had TSH concentrations greater than 3 mU/l. In 32 patients in the iodine-treated group and 42 in the control group, no significant changes in thyroid function, antibody titres or thyroid volume were observed. CONCLUSIONS: Small amounts of supplementary iodine (250 microg) cause slight but significant changes in thyroid hormone function in predisposed individuals.
A heterogeneous enzyme immunoassay for the determination of thyroxine binding globulin (TBG) was developed and assessed in clinical trials in 12 laboratories. The assay is based on the competition principle and employs plastic tubes coated with goat anti-TBG. CV's between 1.4-8.9% for intra-assay precision and 2.9-8.6% for inter-assay precision were found over the concentration range of 4-40 mg/l TBG. In comparative studies using highly purified TBG as standard, values with Enzymun-Test TBG were found to be on average 30% lower than those obtained by various TBG-RIAs. A broad-base study, to determine reference values, was carried out on a group of control persons 18 to 50 years old without previous history of thyroid disease. This study revealed a median of 14.33 mg/l TBG, with 95% of all values between 9.6 and 18.5 mg/l TBG. The median in women of 14.5 mg/l TBG was significantly higher than in men (13.4 mg/l TBG). TBG values in hyperthyroid patients were within the reference range while those in hypothyroid individuals were elevated. Highly elevated TBG values were seen in women receiving oestrogen (median: 22.2 mg/l TBG) and in pregnant women (median: 28.5 mg/l TBG). The T4/TBG ratios made it possible to distinguish between euthyroid, hyperthyroid and hypothyroic subjects (median: 4.9, 11.3 and 1.0, respectively). These ratios were significantly lower in pregnant women (median: 3.1) than in the control persons.
Because of the slow lingering course of this disease, the diagnosis of hypothyroidism is generally made by chance particularly because the euthyroidism can change unobserved into manifest hypothyroidism. In old age the course of hypothyroidism may be oligosymptomatic: only adynamia and abnormal susceptibility to cold may be diagnosed. Because of the augmented oxygen requirement of tissues during therapy with thyroid hormones the medical treatment of hypothyroidism has to start - especially in old age - with a fractional part of the final dose. In old age bland struma more and more changes to nodular struma, where small autonomic areas are often developed. Conservative therapy with thyroid hormones predominates in this case. Radioiodotherapy is indicated when medical treatment has been without success and operation is contraindicated because of high risk. Cancer of the thyroid is important - with respect to differential diagnosis - especially in older patients. Cancer of the thyroid is most common in patients aged between 50-70 years, and the anaplastic carcinoma is the most frequently observed malignant growth of old age. Concerning therapy, a radical operation comes into consideration; if radical operation is combined with too high risks, remaining tissue may be treated by radioiodotherapy without danger.
The clinical signs of thyroid disease in older people may differ considerably from those in younger patients. The symptoms are often incorrectly interpreted and attributed to old age. The age is also important to the kind of therapy. The normal clinical hyperthyroidism-indices are not relevant in the diagnosis of hyperthyroidism in older patients. Organic symptoms predominate in old age (loss of weight, muscular asthenia, tremor, cardiac arrhythmia, stenocardia, congestive cardiomyopathy). Most of the time they are wrongly interpreted as additional symptoms of old age. Probably it is not the age that causes the difficulties in hyperthyroidism-diagnostics in old age, but the atypical symptoms of solitary or multilocular adenomas, which increase with advancing age. A special symptom of hyperthyroidism in old age, often misinterpreted, is "apathetic" hyperthyroidism. Radioiodotherapy is indicated in older patients with hyperthyroidism.
T4-, T3- and reverse-T3 concentrations were measured in the sera of 365 subjects beyond the age of 65 in order to evaluate if the decrease of serum T3 frequently observed in old age can be attributed to old age per se or to concomitant nonthyroidal disease. The results obtained from a carefully selected healthy group of elderly people show that 1) total and free T3 levels are lower in senescence but well within the range for euthyroidism in younger healty controls;2) the decrease of serum T3 is more pronounced and occurs earlier in healthy old males than in females, so that for subjects over the age of 75, the upper limit for euthyroidism has to be adjusted by 10% in women and by 20% in men; and 3) there is no low T3 syndrome characterized by decreased serum T3 and increased serum reverse T3, solely due to old age. Turnover kinetics have shown the daily production of T4 and T3 in old age to decrease by 20 micrograms and 10 micrograms, respectively, and an increased T3 metabolic clearance not to account for the reduction of serum T3 concentrations. Combined stimulation tests with TSH and TRH showed that the functional reserve of the thyroid gland to produce T3 is maintained in old age. The first step in the sequence of events may be seen in an impairment of TSH secretion leading to an adaptation of the amount of thyroid hormones to a reduced mass of metabolically active body tissue in old age.
1. The radioimmunoassay (RIA) and the competitive ligand binding assay (CLBA) are convenient routine methods for the precise and reproducible measurement of TBG in large numbers of serum samples. 2. There is an age dependent variation of the TBG-concentration in serum. There is a steady decrease of TBG with increasing age with a minimum between the 20th and 50th year. In higher age TBG increases again significantly. 3. There are significantly negative correlation between TBG-serum levels on the one hand and free T4- and T3- fractions on the other. The low TBG-level in hyperthyroid patients increases gradually to normal during treatment with thyroid blocking drugs, the elevated TBG-concentrations in hypothyroid patients decrease to normal during treatment with thyroid hormones. 4. Estrogen stimulates TBG-synthesis in the liver. During enhanced endogenous estrogen production (pregnancy) as well as during exogenous estrogen application a rise occurs in TBG-concentration in serum, which seems to be dose related. 5. Androgens induces a decrease of the TBG-concentration in serum. 6. During viral hepatitis and in compensated cirrhosis of the liver TBG-concentration is significantly elevated. In cirrhosis of the liver with poor hepatic function the TBG-concentration is decreased. 7. The T4/TBG-quotient is a good parameter to estimate free T4-concentration in serum.
A functional diagnosis of the diencephalohypophyseal system was carried out in patients with Sheehan syndrome, chromophobic adenoma, craniopharyngioma, prolactin-producing pituitary tumours, acromegaly, hypothalamo-pituitary dwarfism and constitutional retardation. A combined insulin hypoglycaemia/LH-RH/TSH test was performed to define frequency and extent of anterior pituitary insufficiency. With these illnesses, almost generally, a somatotropic insufficiency (except in acromegaly) was found. An impairment of gonadotropic function was often present, in general a pathologic LH-RH test correlating with a more or less developed androgen deficiency. An adrenocorticotropic insufficiency was found in most patients with sheehan syndrome, chromophobic adenoma and craniopharyngioma while in acromegaly and hypothalamo-pituitary dwarfism it was present less frequently, necessitating a substitution with corticoids. The TRH test reflects only incompletely a secondary hypothyroidism, and can be normal with organic processes of the diencephalo-hypophyseal region, making a T3 and T4 estimation in the blood decisive for a thyroid hormone substitution. A clear-cut separation of the hypothalamic from the pituitary cause of the insufficiency is neither possible with the LH-RH nor with the TRH test.
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During enhanced endogen estrogen production (pregnancy) as well as during exogen estrogen application a rise occurs in TBG concentration in serum, which seems to be dose related. Simultaneously with the TBG there is an increase in total T4 and T3; the concentrations of the free T4 and T3 however decrease. Towards the end of pregnancy AFT4 is significantly decreased, compared to the controls, AFT3 being in the lower normal range. The lower concentrations of the free hormones are also documented by a decline in the T4/TBG and T3/TBG ratios. Normal basal TSH concentration in serum suggest a metabolic state which is still compensated. Oral contraceptives with low estrogen content have no influence on TBG, T4 and T3 concentrations.
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