The influence of smoking habits on thyroid gland volume: an ultrasonic approach.

The effects of smoking habits on thyroid function, echo-texture (nodules and/or cysts) and thyroid gland volume were determined by using ultrasound and measuring serum Thyroxin (T4), Triiodothyronine (T3), Thyrotropin (TSH) and TPO antibodies (ab-TPO) in 189 healthy smokers and non-smokers, randomly selected (111 females and 78 males) among the employees of our hospital and their relatives. When the entire group of subjects was considered the mean ratio of thyroid gland volume/body weight was found to be significantly higher in male (P < 0.05) and female (P < 0.05) smokers compared with non-smokers. In female smokers, mean serum thyroid-stimulating hormone (TSH) was lower (P < 0.05) and the degree of smoking was positively correlated with the ratio of thyroid gland volume/body weight (P < 0.05). However, when the subjects with a family history of goitre in first degree relatives were excluded from our study (14 females and 9 males), no significant differences in mean ratio of thyroid volume/weight or TSH between the remaining smokers and non-smokers were detected. In both sexes, the correlation between the degree of smoking and thyroid volume, although positive, did not reach statistical significance. No difference in prevalence of abnormal echogenicity and echo-texture (nodules and cysts) between smokers and non-smokers was detected. It is concluded that smoking habits present a goitrogenic effect only in subjects with a family history of goitre but have no influence on thyroid gland texture.

Imaging of the sella in the syndrome of inappropriate secretion of antidiuretic hormone.

OBJECTIVE: The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) results either from ectopic production or inappropriate release of antidiuretic hormone from the neurohypophysis. Although magnetic resonance imaging (MRI) has provided new insights into the morphological changes of the hypophysis in health and disease, no previous studies have evaluated its use in SIADH: The aim of this study was to evaluate the MRI appearance of the neurohypophysis in patients with SIADH: DESIGN: Retrospective case-control study. SETTING: Tertiary care teaching hospital. SUBJECTS: We studied retrospectively eight patients with SIADH who had been hospitalized in Boston's Beth Israel between 1984 and 1994 and who had MRI scans including the sella turcica. We also evaluated prospectively the MRIs of the heads of 23 consecutive control patients who had no pituitary pathology and no serum osmolality or electrolyte abnormalities. INTERVENTIONS: Clinical evaluation as well as sagittal and axial T1-MR images. MAIN OUTCOME MEASURES: Presence or absence of the high intensity signal of the neurohypophysis. RESULTS: In seven out of eight patients (87.5%) the normal high intensity signal of the neurohypophysis was not present. In one patient (12.5%), two interpreting radiologists disagreed about its presence. The high intensity signal was present in the neurohypophysis of 20 out of 23 controls (87.5%). CONCLUSIONS: Our data indicate an association of SIADH with the absence of the normal hyperintense signal of the neurohypophysis, confirming the usefulness of MRI as a tool to visualize ADH processing. These data also raise the possibility that the absence of the high intensity signal may be useful diagnostic tool in cases of SIADH that are difficult to diagnose clinically. Additional studies to correlate this signal with various forms of SIADH will be needed.