Hyperthyroidism after treatment with lithium.

The association between treatment with lithium and hypothyroidism is well documented. Reports of hyperthyroidism are rare and it is less well known among patients treated with lithium. It may be overlooked simply because the clinician will be watching for hypothyroidism, the reverse phenomenon. This paper describes the cases of four patients who have been on long term lithium treatment, all of whom developed Graves' disease, or an atypical form of hyperthyroidism. Some suggestions are offered to account for the mechanism underlying this unusual association. Although hyperthyroidism may be rare among patients receiving lithium, astute clinical observation and appropriate laboratory tests are called for to detect the early stages of such thyroid dysfunction and to provide appropriate intervention.

Lithiumogenic disorders of the thyroid and parathyroid glands as surgical disease.

Little notice has been paid in the surgical literature to problems with psychoeffective lithium, which by interfering with adenylate cyclase affects thyroid and parathyroid function, causing hypercalcemia, hyperparathyroidism, and hypothyroidism. Seven patients with lithiumogenic hyperparathyroidism occurring after years of lithium therapy underwent treatment and manifested osteoporosis (n = 2), hypertension (n = 2), nephrolithiasis (n = 1), coma (n = 1), rising hypercalcemia (n = 1), goitrous myxedema (n = 4), nephrogenic diabetes insipidus (n = 2), renal failure (n = 2), and hyperlipidemia (n = 1). Disease-directed parathyroidectomy (without morbidity) was curative. Unique laboratory findings included normal serum phosphorus and reduced urinary calcium and cyclic adenosine monophosphate values. Three separate cases of thyroid carcinoma after long-term lithium therapy were also treated, being preceded by myxedema (n = 2) and concurrent with hyperparathyroidism (n = 1). There has been only one previous report of lithium-associated thyroid carcinoma. All patients taking lithium should undergo surveillance for thyroid and parathyroid dysfunction and neoplasia, and appropriate surgical and medical treatment should be considered in each situation. Although hyperparathyroidism may be reversible with lithium discontinuance, such therapy may be obligatory for patient well-being, thus dictating parathyroidectomy.

Hyperparathyroidism, hypothyroidism, and impaired renal function after 10 to 20 years of lithium treatment.

Of 19 patients who had been receiving a therapeutic dosage of lithium carbonate for 10 to 20 years, 8 (42%) were found to have some laboratory evidence of hyperparathyroidism. Of the 3 who had parathyroid surgery, 2 had hyperplasia and 1 had a solitary adenoma, an unusually high incidence of hyperparathyroidism. Unusual features of lithium-induced hyperparathyroidism in this series include (1) low urinary calcium excretion and the absence of nephrolithiasis, (2) normal urinary cyclic adenosine monophosphate excretion, and (3) normal plasma inorganic phosphate. Eight patients (42%) required treatment for hypothyroidism. Three patients (16%) had impaired kidney function. While these observations do not contraindicate the continued use of lithium carbonate in manic depression, they strongly emphasize the need for close laboratory surveillance.

Cardiac assessment for patients undergoing noncardiac surgery. A multifactorial clinical risk index.

In this article, we describe a multifactorial cardiac risk index that can be used to assess patients undergoing noncardiac surgery. The index is a modified version of an index that was previously generated by Goldman and coworkers on a set of 1001 consecutive patients and prospectively validated in our clinical setting (a general medical consultation service in a large teaching hospital) on 455 patients. We present a Bayesian approach to assessing cardiac risks by converting average risks for patients undergoing particular surgical procedures (pretest probabilities) to average risks for patients with each index score (posttest probabilities). A simple nomogram is presented for performing such a calculation.

Predicting cardiac complications in patients undergoing non-cardiac surgery.

The authors prospectively studied 455 consecutive patients referred to the general medical consultation service for cardiac risk assessment prior to non-cardiac surgery, in order to validate a previously derived multifactorial index in their clinical setting. They also tested a version of the index that they had modified to reflect factors they believed to be important. For patients undergoing major surgery, the original index performed less well in the validation data set than in the original derivation set (p less than 0.05), but still added predictive information to a statistically significant degree (p less than 0.05). The modified index also added predictive information for patients undergoing both major and minor surgery, demonstrating an area under the Receiver Operating Characteristic curve of 0.75 (95% confidence interval of 0.70 to 0.80). A simple nomogram is presented which will enable conversion of pretest probabilities into posttest probabilities using the likelihood ratios associated with each risk score. It is recommended that clinicians estimate local overall complication rates (pretest probabilities) for the clinically relevant populations in their settings before they apply the predictive properties (likelihood ratios) demonstrated in this study in order to calculate cardiac risks for individual patients (posttest probabilities).

Clinically unrecognized ventricular dysfunction in young diabetic patients.

Left ventricular function at rest and during supine bicycle exercise was assessed by gated radionuclide angiography in 20 diabetic patients and 18 normal control subjects without clinical evidence of heart disease. The diabetic patients were aged 21 to 44 years and all except one used insulin. No subject developed chest pain or electrocardiographic changes during exercise. Both groups had a similar rest and exercise heart rate and blood pressure, and both achieved similar work loads. The control group had an ejection fraction at rest of 65.4 +/- 6.2% (mean +/- SD) and only 1 of 18 showed a decrease with exercise; peak exercise ejection fraction averaged 77.1 +/- 7.8%. The diabetic group had a mean ejection fraction at rest of 63.7 +/- 6.5%, similar to that of the control group, but 7 of 20 showed a decrease during exercise; the exercise ejection fraction averaged 67.7 +/- 9.7%, significantly lower than that of the control group (p less than 0.01). The diabetic patients varied widely in ejection fraction response to exercise, ranging from an increase of 25% to a decrease of 21%. This response did not correlate with age, sex, duration of diabetes, smoking, retinopathy, exercise heart rate, blood pressure or rate-pressure product, work load attained or ejection fraction at rest. These data suggest that approximately one-third of patients with diabetes have subclinical left ventricular dysfunction without correlation to risk factors for atherosclerosis or other diabetic complications. Whether this is due to unrecognized coronary artery disease or primary myocardial disease remains unknown.

Hypokalemic metabolic alkalosis caused by surreptitious vomiting: report of four cases.

Four women, aged 22 to 40 years, presented with severe hypokalemia and metabolic alkalosis. Three had related neuromuscular symptoms. All four patients denied vomiting or diuretic ingestion, and a diagnosis of Bartter's syndrome was entertained. A diagnosis of surreptitious vomiting was suspected from the characteristic urine electrolyte pattern: high values for sodium and potassium, and a chloride concentration of less than 5 mmol/l. Three patients excreted sodium and potassium primarily with bicarbonate and had an alkaline urine; the fourth patient excreted these cations primarily with an organic anion and had an acid urine (pH 5.5). Since self-induced vomiting may be a common method of weight reduction in young women, recognition of this characteristic urine electrolyte pattern will assist in the rapid diagnosis of hypokalemia and metabolic alkalosis of obscure cause.

Oral hypoglycemic agents.

Oral agents should not be used in the treatment of patients with asymptomatic maturity-onset diabetes. The indication for sulfonylureas is symptomatic maturity-onset diabetes or excessive hyperglycemia--fasting blood sugar over 300 mg per 100 ml--in the elderly patient who cannot or will not take insulin. The use of biguanides cannot be recommended.