A case of thyrotropin-secreting pituitary macroadenoma.

We present a 49 year old male patient with thyroid stimulating hormone (TSH) producing pituitary macroadenoma. He had been mistakenly diagnosed and treated as Graves' disease for 1 year. Serum TSH level was inappropriately elevated in the presence of high serum total and free thyroid hormone concentrations. Thyrotropin releasing hormone stimulation showed blunt response of TSH but good response for prolactin. The alpha-subunit level and alpha-subunit to TSH molar ratio were measured and found to be high before surgery. The sex hormone-binding globulin level was also high. MRI demonstrated a pituitary macroadenoma. Insulin tolerance test and GnRH revealed normal response. The patient was given a high dose of PTU combined with lugol's solution for controlling hyperthyroidism preoperatively. Transfrontal surgery was performed and the tumor was partially removed. The diagnosis was confirmed by tissue pathology and immunohistochemistry staining of the tumor. The immunohistochemistry staining was performed and found that tumor cells were strongly reactive to TSH with a relatively mild degree for follicular stimulating hormone and leutinizing hormone. The tumor cells were not stained for prolactin, growth hormone and ACTH. Supervoltage irradiation by 60Co was delivered to the pituitary area because of persistence of hyperthyroidism. While waiting for the remote effect of radiotherapy, the patient was given an antithyroid drug to control hyperthyroidism.

An identical neo-mutation in the thyroid hormone receptor beta gene (A317T) in 2 unrelated Thai families with resistance to thyroid hormone.

We reported two unrelated Thai girls with resistance to thyroid hormone. The affected patients presented with goiter and no other stigmata of hyperthyroidism. Their serum T4, T3, free T4 and free T3 concentrations were high and they had normal levels of TSH. The affected girl in family 1 was treated with an antithyroid drug for 1-9/12 years. The affected girl in family 2 was only observed her thyroid function tests. TRH test showed normal TSH response in both girls. Analysis of the thyroid hormone receptor beta gene of both affected girls revealed the same missense mutation, changing the guanine in nucleotide 1234 to an adenine which results in the replacement of the normal alanine (GCT) with a threonine (ACT) at codon 317. Two proposita were heterozygous, and this mutation was not present in their parents compatible with a neo-mutation.

Lack of association between a polymorphism of human thyrotropin receptor gene and autoimmune thyroid disease.

A polymorphism in codon 52 of the human thyrotropin receptor results in a proline to threonine substitution in the extracellular domain of the receptor, but the association with autoimmune thyroid disease has been uncertain and there is no report the prevalence of this polymorphism in Orientals. To investigate this polymorphism and the association with autoimmune thyroid disease, we studied 113 normal unrelated individuals, 142 autoimmune thyroid disease patients including 112 Graves' disease and 30 Hashimoto's thyroiditis in the Thai population. We screened genomic DNAs of these subjects for the presence of A253 by PCR amplification using a degenerate oligonucleotide primer which produces a Tth111 I restriction site only in the presence of A253. The variant allele was present in 5.3 per cent of normal and 3.5 per cent of autoimmune thyroid disease, 2.7 per cent of Graves' disease and 6.7 per cent of Hashimoto's thyroiditis. The allele distribution in autoimmune thyroid disease patients did not differ significantly from that observed in controls. No association was found between this TSH-R polymorphism and the occurrence of autoimmune thyroid disease.

Neonatal screening program in Rajavithi Hospital, Thailand.

A pilot study was conducted in order to identify the cases and determine the incidence of congenital hypothyroidism, phenylketonuria (PKU) and glucose-6 phosphate dehydrogenase (G6PD) deficiency in the newborn infants born at Rajavithi Hospital. During May 1995 - July 1998, 32,407 out of 49,092 (66%) infants were screened for congenital hypothyroidism by measuring thyroid stimulating hormone (TSH) by radioimmunometric assay method. Seven cases of congenital hypothyroidism were identified (incidence of 1 : 4,629 live births). The recall rate was 0.66%. The screening for PKU was done on 17,421 out of 29,443 (59.14%) infants by measuring phenylalanine level by Guthrie method during June 1996 to July 1998. There was no PKU found. From January 1996 to July 1998. 24,714 newborn infants were screened for G6PD deficiency by fluorescent screening technique. The total incidence of 5.13% was found. The incidence in males and females was 9.13% and 1.66% respectively. This study confirms the benefit of the screening program in early detection and treatment of the disorders.

Thyroid function and human chorionic gonadotropin in patients with hydatidiform mole.

Sixty-seven patients with molar pregnancy were studied on admission to Rajvithi Hospital from 1992 to 1996. Thyroid function tests and serum hCG concentrations were measured. On the basis of thyroid function test results, the patients could be subdivided into three groups; Group I (hyperthyroid), Group II (subclinical hyperthyroid) and Group III (nontoxic). We found significant correlation between hCG and T4, T3 and FT4I levels (rho = 0.559, p < 0.001 n = 35; rho = 0.629, p < 0.001 n = 35; and rho = 0.465, p = 0.010 n = 30 respectively). These findings support that a variant hCG is responsible for hyperthyroidism observed in patients with molar pregnancy.

Antitriiodothyronine antibody in patient with Hashimoto's thyroiditis.

We described a 44-year-old female patient with a history of goiter for 2 months. Physical examination revealed a diffusely enlarged thyroid gland weighing 40 g firm to hard in consistency. She was clinically euthyroid and had neither ophthalmopathy nor dermopathy. Serum thyroid hormone levels revealed total T4 (RIA) of 4.8 micrograms/dL (normal, 4-11 micrograms/dL), total T3 (RIA) of above 600 ng/dL (70-175 ng/dL), and TSH (IRMA) of 54 mU/L (0.3-6 mU/L). Antithyroglobulin and antiperoxidase antibody titers were 1:5,120 and 1:409,260, respectively. Because of the discrepancy between the patient's clinical status and laboratory values, assay for thyroid hormone autoantibodies (THAA) was done and subsequently demonstrated antitriiodothyronine antibody with percentage of precipitation by polyethylene of 98.4 per cent (normal range, 3.06 +/- 8.58%). In conclusion, THAA should be suspected in patients whose clinical status is incoherent with the thyroid function test.

Simple and sensitive test for thyroid hormone autoantibodies.

We presented a simple and sensitive test for thyroid hormone autoantibodies. The normal range for T4 and T3 autoantibodies in Thai people considering mean +/- 3 S.D. were 1.8-9.4 per cent and 3.1-8.6 per cent, respectively. Although positive low titer of thyroid hormone autoantibodies had almost no interference of thyroid hormone levels, high titer might cause great interference. This method can be used for screening patients who have unexpectably high levels of serum T4, T3 or discrepancy between thyroid hormone levels and clinical findings.

Gestational diabetes mellitus.

The prevalence of gestational diabetes mellitus by screening 25,997 pregnant women in Rajavithi Hospital during a two-year-period was 2.02 per cent. Of the 312 gestational diabetes patients available for the study, their mean age was 29 years. Risk factors included a BMI before pregnancy of more than 26 (26.5%), family history of diabetes mellitus (23.1%), history of abortion (14.4%), and history of fetal death in utero (3.2%). Macrosomia, congenital anomalies and cesarean delivery were found significantly more common in gestational diabetic patients compared to normal pregnancy.

Lipid disorders in Thai diabetic patients at Rajavithi Hospital.

Lipid abnormalities are common in diabetic patients. In this study, 71 per cent had hyperlipidemia. The incidence of combined hyperlipidemia, hypertriglyceridemia, and hypercholesterolemia were 29.5, 25.8 and 15.5 per cent respectively. Females were found to have higher cholesterol levels than males. Cholesterol and triglycerides levels were correlated with BMI and GHb but showed no correlation with age and duration of diabetes. HDL-C showed no correlation with BMI, GHb, age or duration of diabetes.