A case of idiopathic hypothalamic hypothyroidism

The availability of thyrotropin hormone (TRH) has made it possible to determine whether tropic hormone deficiency is caused by pituitary or hypothalamic dysfunction. A case of hypothalamic hypothyroidism was described ina a 17 year old woman. This patient was admitted for the evaluation of hypothyroidism and secondary amenorrhea. Her T3 and T4 were decreased, with an undetectable level of base line thyrotropin. the TRH test revealed normal but delayed response of TSH. Her base line prolactin and its response to TRH were normal. Adenocorticotropic hormone (ACTH), cortisol, growth hormone (GH), and urinary 17-hydroxysteroids were also normal. ACTH response to metyrapone was normal. Evaluation of the pituitary-gonadal axis revealed a normal increase in both lutenizing hormone (LH) and follicle stimulating hormone (FSH) following the intravenous administration of lutenizing hormone releasing hormone (LHRH). These results suggest that she had hypothalamic hypothyroidism as an isolated disturbance in the hypothalamic-pituitary axis. A deficiency of TRH is probably caused by a disorder of hypothalamic function of unknown etiology since the extensive studies did not reveal any secondary causes. It is recommended that patients with amenorrhea and hypothyroidism be evaluated for possible hypothalamic hypothyroidism.

Acid-base disturbance in patients with fulminant hepatic failure

Forty-two arterial blood pH and gas determinations were carried out on 11 patients with fulminant hepatic failure. The most common type of acid-base disturbance was that of respiratory alkalosis in 22 cases (52.4%). This was partially compensated in 13 subjects (31.0%) while an accompanying metabolic alkalosis was present in 9 (21.5%). Partially compensated metabolic acidosis was observed on 15 occasions (35.7%), all of which were in patients with laboratory evidence of impaired renal failure. The mental status of the patients was evaluated in each of the categories of acid-base disturbances. Some degree of correlation was evident between the PCO2 and the magnitude of base excess and that of the severity of the encephalopathy. The lower PCO2 and greater negative base excess values tended to be nearly always present in totally comatose subjects. By contrast, there was no clear cut relationship between pH and mental state.

The depressant effect of halothane and sodium thiopental on the spontaneous and evoked activity of dorsal horn cells: lamina specificity, time course and dose dependence

The effects of halothane and sodium thiopental on dorsal horn cell unit activity were studied in the lumbar spinal cord of decerebrate, low thoracic spinal cats. Both halothane (0.5, 1 and 1.5%) and sodium thiopental (2.5, 5 and 10 mg/kg) depressed, in a dose-dependent manner, the spontaneous firing frequency of cells in Rexed laminae I, V and VI and the evoked firing frequency of cells in laminae I and V. They, however, had no effect on cells in lamina IV. The maximum depression of cell activity occurred 5 to 8 minutes after inhalation of halothane and 2 to 3 minutes after the intravenous administration of sodium thiopental. The recovery of cell activity occurred within 15 to 30 minutes after discontinuation of halothane and within 10 to 30 minutes after intravenous administration of sodium thiopental. The depressive effect of halothane and sodium thiopental, both primarily hypnotic anesthetics, on lamina VI cells is in contrast to our previous finding that morphine sulfate, nitrous oxide and ketamine hydrochloride, primarily analgesic agents, had no significant effect on this lamina.