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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypothalamic-pituitary function was studied in 4 patients with anorexia nervosa of different degree of severity before and after refeeding. Gonadotrophin secretion was low in all subjects and improved in two after a prolonged period of feeding. In one subject there was a failure of pituitary gonadotrophin secretion after the administration of hypothalamic gonadotrophin-releasing hormone but the response was restored to normal after treatment. Thyroid function was reduced in one patient only but returned to normal after intravenous therapy for 6 days. Growth hormone and cortisol levels were elevated in all patients, and in one severe case the growth hormone values were extremely high. There was also a disturbance of the hypothalamic control of growth hormone and pituitary-adrenal function, which returned to normal after refeeding. One patient with severe hypothermia was resistant to the administration of a pyrogen, but developed a normal febrile response after treatment.
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PMID:Hypothalamic-pituitary function in anorexia nervosa. 109 Jan

Thyroid storm is a rapid decompensation of severe hyperthyroidism which can best be described by the three criteria of hyperthermia, tachycardia and altered mental state with severe agitation. There has to be a precipitating factor such as infection, iodine contamination, surgery or even I-131 treatment. Severe hyperthyroidism not fulfilling the criteria of thyroid storm can also be an indication for emergency treatment, particularly in the elderly with heart disease. Suppressed serum TSH and elevated free T4 levels are essential to confirm the diagnosis. When rapidly available, radioiodine uptake of the thyroid can be useful. Therapy aims at rapidly reducing the active circulating hormone pool, hypermetabolic state, tachycardia, and finally hormone synthesis. Thyroid secretion can be blocked by ioipanoic acid or ipodate while hypermetabolic state can be reduced with beta-blockers or calcium channel-blockers. Treatment of hyperthyroidism in patients with iodine contamination is a real therapeutic challenge. Myxoedema coma, a complication of severe hypothyroidism, is defined by hypothermia (rectal temperature less than 36 degrees C), bradycardia, slow mentation, precipitating factor such as infection or drug overdose, and increased serum creatine phosphokinase levels. Diagnosis of severe hypothyroidism should be confirmed by serum measurements of TSH and free T4. Treatment consists of general supporting measures including rewarming, correction of serum electrolyte disturbances, and adequate alimentation. Thyroid hormone treatment should initially be aggressive using either 300-400 micrograms of T4 or 20-40 micrograms of T3 intravenously. Cortisone therapy may be added. Patients should be under close monitoring as arrhythmias and myocardial infarction are frequent complications of myxoedema coma and/or its treatment with thyroid hormones.
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PMID:Thyroid emergencies. 173 98

Measurements of basal body temperature obtained from first-morning voided urine were followed longitudinally in 23 individuals with anorexia nervosa. In each of 10 hypothermic individuals, we found that basal body temperature was significantly correlated with weight gain, whereas in most normothermic individuals, no relationship was found. This suggests that measurement of basal body temperature may provide a convenient means of assessing clinical improvement and nutritional rehabilitation in some patients with anorexia nervosa. Differences in neuroendocrine measures and weight gain were also studied. Thyroid functions did not differ significantly between groups, and no differences were found in dexamethasone suppression or in the thyrotropin-releasing hormone (TRH) stimulation test. Hypothermic individuals, however, were significantly younger and significantly more likely to gain weight in response to treatment.
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PMID:Urinary basal body temperature in anorexia nervosa. 274 44

Thyroid hormone serum concentrations, the thyrotropin (TSH) and prolactin (PRL) response to thyrotropin-releasing hormone (TRH) were evaluated in patients undergoing cardiopulmonary bypass (CPB) conducted in hypothermia. During CPB a marked decrease of thyroxine (T4) and triiodothyronine (T3) concentration with a concomitant increase of reverse T3 (rT3) were observed similarly to other clinical states associated with the 'low T3 syndrome'. Furthermore, in the present study elevated FT4 and FT3 concentrations were observed. In a group of patients, TRH administered during CPB at 26 degrees C elicited a markedly blunted TSH response. In these patients, PRL concentration was elevated but did not significantly increase after TRH. The increased concentrations of FT4 and FT3 were probably due to the large doses of heparin administered to these patients. Thus, the blunted response of TSH to TRH might be the consequence of the elevation of FT4 and FT3 in serum, however, other factors might play a role since also the PRL response to TRH was blocked.
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PMID:Cardiopulmonary bypass: a low T4 and T3 syndrome with blunted thyrotropin (TSH) response to thyrotropin-releasing hormone (TRH). 308 19

Hypothyroidism produces major derangements of normal physiology. Depression of myocardial function, decreased hypoxic and hypercapnic ventilatory responses, abnormal baroreceptor function, and reductions in plasma volume may all be present. In addition, the presence of anemia, hypoglycemia, hyponatremia, decreased free water excretion, and impaired hepatic drug metabolism may all adversely influence responses to anesthesia. Most reported complications have occurred in patients with unrecognized hypothyroidism. Preoperative recognition of hypothyroidism is essential for the safe anesthetic management of these patients. Elective surgical procedures should not be undertaken in the presence of untreated hypothyroidism. Thyroid supplements should be untreated hypothyroidism. Thyroid supplements should be given preoperatively to hypothyroid patients before emergency surgery. Intraoperative and postoperative hypothermia and electrolyte disturbances are relatively common and must be guarded against.
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PMID:Anesthesia and hypothyroidism: a review of thyroxine physiology, pharmacology, and anesthetic implications. 703 17

All adult patients (102 cases) presenting to Bellevue Hospital Medical Center over a calendar year (1978) with core temperatures less than 35 C were studied. Statistically significant correlations between hypothermia and mortality were identified according to mental status, hypoxia, hypotension, hyperamylasemia, duration and severity of hypothermia, and history of exposure and alcohol ingestion. Mortality could not be predicted on the basis of season, age (if greater than 40 years old), sex, presence of infection, or presenting temperature (if greater than 26 C). Thyroid and adrenal function were not significantly altered. Of only nine diabetic patients, four died in ketoacidosis or hyperosmolar states. There were no cases of meningitis, and the incidence of "occult" bacteremia was less than 1%. Prolonged hypothermia was uniformly associated with profound underlying medical disease. In patients presenting with temperatures less than 26 C, 50% of deaths resulted from temperature-induced ventricular arrhythmias. Alcoholics hypothermic from exposure had excellent prognoses; however, temperatures less than 26 C were associated with a marked and statistically significant incidence of death.
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PMID:Hypothermia: the Bellevue Experience. 710 59

Thyroid hormone has numerous effects on cardiovascular function in the adult. The present study was undertaken to evaluate the effects of cardiopulmonary bypass and deep hypothermia on thyroid function in the neonate. Ten newborns were studied preoperatively and postoperatively. The total and free triiodothyronine, total and free thyroxine, thyroid-stimulating hormone, and thyroglobulin levels were measured by immunoassays. The data demonstrated a transient rise in the free thyroxine level associated with and followed by significant reductions in the free and total triiodothyronine, total thyroxine, thyroid-stimulating hormone, and thyroglobulin levels in the early postoperative period. By the fifth postoperative day, the free and total triiodothyronine and total thyroxine levels were returning toward the preoperative levels under the influence of an elevated thyroid-stimulating hormone level. These results suggest that the combination of cardiopulmonary bypass and deep hypothermia can result in a transient suppression of the pituitary-thyroid axis in the neonate.
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PMID:Suppression of the pituitary thyroid axis after cardiopulmonary bypass in the neonate. 767 26

Total triiodothyronine and thyroxine were measured in the blood plasma during different stages of surgery and after it in 26 patients operated on the open heart under conditions of hypothermia without perfusion. Cooling without perfusion did not appreciably affect the levels of thyroid hormones. Only their ratio was evidently changed at cooling below 30 degrees C with the predominant content of thyroxine. After surgery functional hypothyrosis developed. The shifts were the most expressed on day 3 after the operation. Thyroid status normalized by day 10 postoperation.
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PMID:[Thyroid hormones during the correction of acquired mitral defects under perfusion-free hypothermia]. 896 9

Hypothermic hyperkalemic circulatory arrest has been widely used for myocardial protection during heart surgery. Recent data showed that administration of triiodo-L-thyronine (T3) postoperatively enhanced ventricular function. The effect of hyperkalemic arrest in conjunction with thyroid hormone on the plasma membrane enzyme sodium/potassium-adenosine triphosphatase (Na/K-ATPase), was determined in cultured neonatal rat atrial and ventricular myocytes. Exposure of ventricular myocytes to hyperkalemic medium (50 mM KCl) in the absence of T3 increased expression of the Na/K-ATPase catalytic subunit mRNAs, alpha1 and alpha3 isoforms, by 1.9- and 1.5-fold, respectively (p<0.01), which were accompanied by similar increases (1.4- and 1.8-fold) in protein content. Addition of T3 to the hyperkalemic cultures attenuated these increases in Na/K-ATPase mRNA isoforms to levels of expression observed in cells treated with T3 (10(-8) M) alone. Similarly, expression of the alpha1 mRNA isoform in atrial myocytes was increased (p<0.05) by hyperkalemic conditions, and T3 treatment attenuated this effect. In contrast, although expression of the Na/K-ATPase beta1 mRNA in both atrial and ventricular myocytes was significantly increased by hyperkalemia, addition of T3 did not prevent the hyperkalemic response, and in atrial myocytes T3 significantly increased beta1 mRNA expression 1.8-fold. These results show that expression of cardiac Na/K-ATPase is regulated by T3 and hyperkalemia in an isoform and chamber specific manner, and suggest that use of hyperkalemic cardioplegia during heart surgery may alter plasma membrane ion function.
Thyroid 1999 Jan
PMID:Regulation of Na/K-ATPase gene expression by thyroid hormone and hyperkalemia in the heart. 1003 77

Since the introduction of neonatal mass screening for congenital hypothyroidism (CH), numerous cases have been detected. It is of interest that even severely hypothyroid neonates rarely exhibit bradycardia, hypothermia, or inactivity, which have been recognized as typical signs of CH. Regarding neonates and young infants, few reported data are available on the effects of thyroid hormones on energy expenditure. Plasma free fatty acids (FFAs), markers for lipolysis, play essential roles in maintaining physiologic homeostasis. To study fuel utilization in CH neonates, we measured heart rates, plasma FFA, and thyroid hormones before and after levothryoxine (LT4) replacement therapy. Fifty-five screen-detected CH neonates and 29 age-matched normal neonates for controls were enrolled. The CH neonates were divided into two groups according to serum thyroid hormone levels: a mildly hypothyroid group (n = 37), serum thyrotropin (TSH) less than 100 microIU/mL and free thyroxine (FT4) 0.6 ng/dL or more; and a severely hypothyroid group (n = 18), TSH 100 microIU/mL or more and FT4 less than 0.6 ng/dL. Twenty-four of the 55 patients had their heart rates measured by electrocardiography. Fasting blood samples were taken from the subjects during physical movements. Serum levels of TSH, FT4, FFA, and other blood chemicals, measured on an autoanalyzer system in our hospital, were compared before and after LT4 substitution therapy. The following results were obtained. The mean plasma FFA values before LT4 replacement were 208.5 +/- 89.4 microEq/L in the mildly hypothyroid group, 228.5 +/- 114.7 microEq/L in the severely hypothyroid group, and 213.9 +/- 97.7 microEq/L in controls. No statistical differences were noted among the three values. Two months after LT4 replacement therapy, at the age of 3 months, plasma FFA concentrations significantly increased in both groups compared with those before the therapy. Control infants also showed a significant increase in plasma FFA concentrations from 1 to 3 months of age. There were no significant differences in plasma FFA concentrations among the three groups at the age of 3 months. No significant correlations were found between plasma FFA and serum thyroid hormones. From these results it is suggested that in neonates and young infants, thyroid hormones do not play major roles in mobilization of fats through the adrenergic regulation of lipolysis for energy supply. This may be one of the reasons for the unexpectedly mild signs and symptoms in the screen-detected hypothyroid neonates.
Thyroid 2001 Jan
PMID:Plasma free fatty acids in neonates with congenital hypothyroidism. 1127 1


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