Thyroidology最新文献

Hyperthyroidism is a common endocrinologic disorder affecting many organ systems. Musculoskeletal and neurological involvement present themselves as fatigue, muscle weakness and paralysis. Electromyography (EMG) is essential for differential diagnosis of muscle weakness. Well defined neuropathy and myopathy have been described in these patients. In the present study 17 hyperthyroid patients were evaluated with electrophysiological tests in addition to physical and neurological examinations and biochemical laboratory studies. Needle EMG, motor and sensory conduction velocities, median and tibial somatosensory evoked potentials (SEP) were studied. For assessment of the activity of disease clinical status, neurological symptom and disability scores and serum T3, T4 and TSH levels were examined. Statistical analysis of neuroelectrophysiological findings of the patient and the control groups yielded meaningful difference in the needle EMG, sensory conduction velocity and evoked potential findings. Abnormalities were observed in 80% of the proximal muscles besides polyphasic potentials that were seen in 20% of the extensor digitorum brevis muscle. Median, ulnar and sural nerve sensory action potential amplitudes were found to be lower than that of the control group. Sural sensory nerve conduction velocity of patients was decreased in 35.5%, prolongation of median SEP latencies and increase in the amplitudes were not however statistically significant. Prolongation of Tibial SEP N1, P2 latencies were seen in 47%, amplitudes of N1 were increased in 88.2%, P2 in 58.8%, N2 in 47%. The thyroid clinical status score was correlated with Tibial SEPs amplitude. These findings suggest the presence of an initial axonal type of mild polyneuropathy. As a conclusion electrophysiological studies can be useful in the diagnosis of asymptomatic polyneuropathy in hyperthyroid patients.

A fixed population of about 120,000 subjects was selected from those A-bomb survivors and unexposed controls for the purpose of follow-up studies on their late health effects. One hundred twelve cases of thyroid cancer were found in the study period between 1958 to 1979. The relative risk increased with thyroid dose: the excess relative risk per Gray was 1.1. The prevalence of thyroid diseases was evaluated in 2,587 subjects in Nagasaki: one or more diagnoses for thyroid diseases were made in 447.

From 1980 to 1990 4,229 consecutive euthyroid patients with thyroid nodule (73% with single and 27% with multiple nodules) were examined by FNA cytology for preoperative selection. One thousand four hundred and eight of these patients (33%) had nodules also suitable for evaluation by large needle biopsy histology (Aspiration Needle Biopsy, ANB). No significant complications occurred following ANB. The proportion of inadequate specimens was 25% for ANB and 15% for FNA, however a definite diagnosis was obtained with ANB in 62 patients with inadequate FNA finding. Diagnostic sensitivity was higher (93%) for FNA than for ANB whereas specificity was better (82%) for ANB diagnoses. Nonetheless ANB contributed to the increase of overall sensitivity as four of all the malignant nodules diagnosed as benign by FNA were correctly identified by ANB. Analysis of the postoperative results of 102 nodules with FNA and ANB finding of benign nodule or of suspected cancer showed that the addition to the same FNA finding (benign nodule or suspected cancer) of a different ANB diagnosis (suspected cancer or benign nodule) greatly changed the probability of finding a malignant nodule at postoperative histology. ANB was also useful in showing a macrofollicular component in 52% of 150 nodules diagnosed by FNA as pure microfollicular nodules.(ABSTRACT TRUNCATED AT 250 WORDS)

Objective: To study whether premenopausal women with nontoxic goiter, but reduced serum TSH as a sign of spontaneous subclinical hyperthyroidism have decreased bone mass or other indications of increased bone turnover.

Design and subjects: In a cross-sectional study, bone mass measurements were performed in the distal forearm and the lumbar spine in 11 premenopausal women with nontoxic goiter and a stable reduction in serum TSH (median (range) 8 months (6-108 months)), and in 22 matched controls. In a longitudinal study, measurements were repeated every 3 months for a maximum period of 2 years in 9 of the patients (6 completed 9 months, 4 completed 2 years follow-up).

Results: Serum TSH in the patients were (median (range)) 0.025 mU/l (< 0.005-0.256 mU/l). Patients had a bone mineral content of the distal forearm and a bone mineral density of the lumbar spine similar to those of controls, medians of controls: 98.4% and 93.8%, respectively. The risk of a type 2 error for over-looking a 10% difference was 2% for the distal forearm and 20% for the spine. TSH correlated negatively with marginal significance (p < 0.10) with markers of bone turnover: plasma osteocalcin, serum alkaline phosphatase, and fasting urinary hydroxyproline corrected for creatinine, although all patients had absolute values of these parameters within normal range. During follow-up bone mass measurements did not tend to decrease, but serum alkaline phosphatase and fasting urinary hydroxyproline showed increasing trends (p < 0.05).

Conclusions: Premenopausal women with nontoxic goiter and reduced serum TSH do not seem to have reduced bone mass but seem to demonstrate signs of increased bone turnover.

An increase of muscle enzymes in hypothyroidism has sometimes been correlated with a polymyositis-like syndrome and hypothyroid patients have been misdiagnosed and mismanaged as suffering from polymyositis. Actually, muscle symptoms, such as aches and pain, stiffness, weakness and cramps or, more rarely, hypertrophy, are observed in hypothyroidism and increased serum muscle enzyme values, particularly the level of creatine phosphokinase (CPK), indeed seem to suggest polymyositis. The muscular groups most commonly affected by the above mentioned symptomatology are those of the shoulder and pelvic girdles. In this report two hypothyroid patients complaining of muscle symptoms, whose serum muscle enzymes were particularly elevated, are described. In the first case the patient had been suffering from pain and weakness of the thenar eminence for about 4 months. The clinical features suggested a diagnosis of Carpal Tunnel Syndrome, but thyroid function tests revealed primary hypothyroidism. In the second case the patient had been afflicted with muscular weakness of the shoulder girdle for 2 months and was unable to keep his arms raised over his head. A study of thyroid function demonstrated a picture of hypothyroidism. Both patients were treated with L-thyroxine and in a relatively short time biochemical parameters improved remarkably, and the symptoms disappeared. The hypothesis that a muscular effort of long duration by hypothyroid patients may have been responsible for the muscular damage and the symptoms may explain why only a few hypothyroid patients develop a clinical picture similar to polymyositis.

At Columbia Presbyterian Medical Center, CPMC, the incidence of thyroid cancer found at surgery (CI) has recently changed. CI prior to 1950 was 3-4%. The CI gradually increased to 29% in 1975 without the use of needle biopsy. Fine needle biopsy (FNB) was introduced in 1976. The CI did not change during the next 7 years but remained stable at 27% in patients who did not undergo coarse needle biopsy (CNB). The overall CI using both FNB and CNB in 1982 was 42% and with CNB alone, 47%. Since that time, extensive experience using both CNB and FNB has led to a CI of 51%. The CI in patients who only received FNB remains at 28%. The increase in CI seen in patients undergoing CNB are a result of better distinction between hyperplastic lesions and microfollicular neoplasms. 78 patients, referred for surgery because of suspicion of a follicular neoplasm determined on FNB alone, underwent CNB. 35 of these patients were shown to have benign macro-micro follicular lesions (hyperplastic). In a review of 1,625 patients who have undergone CNB there were 3 complications which required surgical intervention (.018%). All of these were for bleeding 6-72 hours after CNB. These 3 patients underwent total thyroidectomy for follicular cancer without complications. There were no other significant complications. These experiences demonstrate that CNB is extremely useful in evaluating thyroid nodules. The complication rate is low and is offset by a large decrease (40%) in the number of patients referred for operation. The primary value of CNB is in differentiating between true microfollicular neoplasms and hyperplastic ones.

Ultrasonic examination was performed on 120 patients who later underwent surgery. Ultrasonically, among the 64 cases of benign nodules and the 56 of carcinomas, 50 and 46 cases respectively were diagnosed correctly. In making the ultrasonic diagnosis, the following findings were considered; shape, margin, boundary, internal echoes, hyperechoic spots, the echo level of the nodule and the cystic pattern. The sensitivity for carcinoma diagnosis was 0.82, specificity was 0.78 and accuracy was 0.80. The diagnostic accuracy for the same patients using a newly devised diagnostic system that utilized a fuzzy inference was almost as high as that of the conventional method. Furthermore, the diagnostic accuracy of both of these methods did not differ significantly from that obtained by fine needle aspiration cytology. Therefore, non invasive ultrasonic examination is considered to be very useful for the detection and diagnosis of thyroid carcinoma.

Thyroid cancer is a relatively rare cancer (5 new cases/y/10(5) inhabitants). An excess of thyroid carcinoma has been found in some but not in all goiter endemic areas. Follicular and anaplastic carcinomas have been found particularly frequent in regions of goitre endemia. A significant increase of thyroid carcinoma has also been found in iodine sufficient areas (Norway, Iceland, Hawaii). In several surveys a positive correlation has been found between parity and incidence of differentiated thyroid carcinoma. Natural goitrogens and chemotherapeutic agents have been proved to induce hyperplasia but their role in carcinogenesis of exposed populations is not yet definitely ascertained. Exposure to external radiation is carcinogenic for the thyroid both in human and in experimental animals. Patients treated for hyperthyroidism or thyroid cancer or given diagnostic doses of 131-I (0.5 Gy/test) indicate that under these conditions 131-I is not carcinogenic. Findings on population exposed to radioactive fallout showed an increased incidence of thyroid carcinomas compared to unexposed populations. After the Chernobyl accident (1986) particular attention was given to calculate the risk of thyroid cancer caused by the fallout of 131-I. Up to now a considerable increase of thyroid carcinoma has been reported in children of a region near Chernobyl (Belarus).

The physician might happen to play a double role in the clinical setting when he is the caregiver as well as the researcher for a patient at the same time. The dynamics and the ethical profile of the two relationships caregiver-patient and researcher-subject are different, and conflicts might arise: while the main responsibility of the caregiver is directed towards the patient "here and now", the researcher has a primary responsibility for future patients, the scientific community and the society at large. It has been suggested that in the clinical setting the researcher, provided that all the requirements for the ethical conduct of an experimentation be respected, has an "autonomy-in-trust", i.e. a wide discretional space in the decision-making process. While agreeing with such a proposal to some extent, we suggest that a more active and deeper participation of subjects in the experimental process, through an ongoing consent and joint decision-making process, would help in overcoming many possible conflicts.

We have previously demonstrated enhanced daily turnover of thyroid hormones in patients with hypermetabolic symptoms due to malignant haematologic disorders or small cell carcinoma of the lung. We hypothesized that some of these symptoms might be due to enhanced peripheral effects of T3. We therefore studied the nuclear T3 receptor binding in circulating mononuclear blood cells in 5 patients with malignant haematologic disorders, 5 with untreated small cell carcinoma of the lung, and 11 healthy controls. Maximal binding capacity of T3 (MBC) was increased 2.5 times in the diseased patients, (median (range)) 110 fmol/mg DNA (75-519) in the haematologic group (p < 0.01), 106 fmol/mg DNA (47-490) (p < 0.10) in small cell carcinoma patients, as compared to 43 fmol/mg DNA (26-94) in controls. The affinity constant Ka of bound T3 was reduced to one-third in the diseased patients. No differences were found between serum thyroid hormone or TSH levels. It is hypothesized, that previously demonstrated enhanced turnover of thyroid hormones in these states of disease might in part be due to increased peripheral consumption of thyroid hormones, including enhanced receptor binding of T3.