High-dose thyroid hormone replacement has been recommended for treatment of myxedema coma (MC) while questions of safety of the therapy and of efficacy of low-dose thyroid hormone replacement have not been systematically addressed. We treated 8 patients with MC in a period of 18 years, the first 3 with high-dose intravenous injections of levotriiodothyronine (LT3) and the other 5 patients with a smaller amount of either LT3 or levothyroxine (LT4). Two of the first 3 patients died of pneumonia and the other 5 recovered despite pulmonary abnormalities at the outset. To find factors associated with fatal outcome after treatment, the MEDLINE database was searched for MC cases with data of thyroid hormone replacement and outcome within 1 month of therapy. Clinical data for our 5 patients and 82 cases from the MEDLINE search were pooled and factors associated with mortality were sought among age, gender, presence of cardiac or pulmonary complications, and doses of thyroid hormone by multiple logistic regression analysis. It revealed that greater age, cardiac complications, and high-dose thyroid hormone replacement (LT4 > or = 500 microg/d or LT3 > or = 75 microg/d) were significantly associated with a fatal outcome within 1 month of treatment. Elderly MC patients can be treated with low-dose hormone replacement. A bolus of 500 microg LT4, especially by mouth or via nasogastric tube, appears to be tolerated by younger patients (< 55 years) without cardiac complication. The conclusion remains to be confirmed in more patients.
The clinical and laboratory findings in 76 patients with isolated corticotropin deficiency (10 of our own and 66 from literature) were analyzed with the following observations. With the exceptions of hyperpigmentation and hyperkalemia, the similarity of symptoms and signs to those of Addison's disease and their reversibility by glucocorticoids indicate that most, but not all, manifestation of isolated corticotropin deficiency is caused by glucocorticoid deficiency. Isolated corticotropin deficiency seems to be of pituitary origin in most patients, as shown by lack of corticotropin response to insulin-induced hypoglycemia, vasopressin, or corticotropin-releasing factor. Secretion of other pituitary hormones is frequently abnormal, which is mostly attributable to glucocorticoid deficiency. Although the pathogenesis of isolated corticotropin deficiency is unknown in most patients, association with other autoimmune endocrinopathies, postpartum onset in women, or serum antipituitary antibodies suggests an autoimmune pathogenesis in some patients. In two of our 10 patients, cancer developed during glucocorticoid treatment. More observations of complications and long-term prognosis following glucocorticoid therapy are needed for optimal clinical decision making.
Patients with untreated ACTH deficiency may have either of two kinds of hyponatraemia--i.e. borderline hyponatraemia associated with subclinical hypovolaemia, or dilutional hyponatraemia. Similarity of plasma AVP levels in two hyponatraemic states suggests their AVP secretion is regulated by non-osmotic, non-volume mechanisms, possibly released from GC suppression at low plasma osmolality.
Nine elderly patients, some with preceding dementia, presented with adipsia, progressive dehydration, impaired consciousness, and hypernatremia following common acute infections without gastrointestinal disturbance. Studies before rehydration revealed inappropriately low plasma arginine-vasopressin (AVP) levels for plasma osmolality, insufficiently concentrated urine, absolutely or relatively low plasma angiotensin II (A-II) concentrations (compared with plasma renin activity and plasma angiotensin I concentrations), and low serum angiotensin I-converting enzyme activities. The plasma AVP concentrations were positively correlated with the plasma A-II concentrations (r = .677) but not with plasma osmolality. The plasma AVP level was raised by an intravenous infusion of A-II in one patient. These findings suggest the following sequence of events: impaired A-II production caused impairment of thirst perception, renal-concentrating capacity, and AVP secretion and contributed to development of hypernatremic dehydration in these elderly patients.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.