Relationship between the Thyroid Function and Cognitive Impairment in the Elderly in Japan.

Objective The reference ranges of serum thyroid hormone levels are determined by the values of normal subjects aged 15 or 20 to 60 years old in Japan and may differ from the values in elderly patients. In addition, the relationship between the thyroid function and cognitive function remains controversial. We assessed the thyroid function of elderly subjects ≥60 years old and its impact on the cognitive function in Japanese adults. Methods We compared the thyroid function by age group and gender and investigated the effects of cognitive impairment on the thyroid function. This study was a cross-sectional, multi-institutional joint study. Patients The serum concentrations of thyroid hormones in 1,136 patients were measured; however, those taking thyroid hormones, anti-thyroid drugs, and steroid hormones were excluded. Among them, 1,016 cases in which the cognitive function was evaluated were divided into five groups according to their free thyroxine (FT4) levels. Results Excluding overt thyroid dysfunction (5.8%), the average age of the 1,070 remaining patients was 77.5 years old. The rate of cognitive impairment was lowest at FT4 levels of 1.1-1.2 ng/dL and highest at FT4 levels <0.9 ng/dL for both genders. Thyroid-stimulating hormone (TSH) levels in the elderly varied widely by age group and gender. The upper limit of the reference range of TSH for those ≥60 years old may be higher (7.7-9.2 mIU/L for men; 8.2-8.6 mIU/L for women) than the current range for those <60 years old (4.23 mIU/L). Conclusion The thyroid function seemed to be slightly higher (lower TSH and higher FT4) in the population without cognitive impairment than in those with cognitive impairment, except for men in their 90s.

Primary hyperparathyroidism presumably caused by chronic parathyroiditis manifesting from hypocalcemia to severe hypercalcemia.

A 67-year-old woman who presented with hypocalcemia compatible with idiopathic hypoparathyroidism gradually changed into a state of primary hyperparathyroidism. The left upper parathyroid gland, which was larger and harder than other glands, was resected. Despite the operation, hypercalcemia and high levels of intact PTH persisted. Six weeks later total parathyroidectomy was done to induce remission. The resected gland in the first operation had clusters of lymphoid follicles with germinal centers indicating a chronic autoimmune inflammation. This case suggests a transition from hypoparathyroidim to hyperparathyroidism associated with chronic parathyroiditis, possibly by a mechanism analogous to that observed in chronic thyroiditis.

Bright pituitary stalk on MR T1-weighted image: damming up phenomenon of the neurosecretory granules.

Characteristic findings of the pituitary stalk on magnetic resonance (MR) imaging, which suggest a damming-up phenomenon of neurosecretory granules, were reported. Neurosecretory granules containing vasopressin influence the signal intensity on MR T1-weighted image (T1WI). The normal posterior lobe of the pituitary gland appears as a bright signal on T1WI. The bright signal of the posterior lobe represents the normal content of neurosecretory granules and disappears in patients with central diabetes insipidus. The normal pituitary stalk appears as a low-intermediate intensity signal on sagittal and coronal T1WIs with 3 mm-slice thickness. The pituitary stalk appeared as a bright signal in 20 patients; 13 with pituitary adenoma, 4 with an intrasellar cystic lesion, one with cavernous sinus mass, and 2 with no abnormal MR findings. The pituitary stalk was not severed in any of the cases. The normal bright signal of the posterior lobe disappeared in 17 patients. No patients suffered from symptoms of central diabetes insipidus when the bright pituitary stalk appeared. It is suggested that the origin of the bright signal in the pituitary stalk is the damming up and accumulation of neurosecretory granules in the nerve fibers of the hypothalamohypophyseal tract obstructed by adenoma, postoperative scarring, cystic mass and so on. Probably, the damming-up phenomenon on MR imaging represents the functional integrity of the hypothalamo-neurohypophyseal system, and should be distinguished from an ectopic posterior lobe formation which is caused by stalk transection.