Germán Ramírez

Cholesterol embolization is not widely recognized as a complication of major arteriographic procedures. In a retrospective study of 71 autopsies of patients who underwent diagnostic arteriographic procedures (20 with aortograms, 51 with cardiac catheterization and coronary angiography), we found an incidence of cholesterol embolization of 30% and 25.5%, respectively, in comparison with 4.3% in an age and disease-matched control population. The organs most frequently affected are the kidney and spleen following aortogram, and the myocardium following cardiac catheterization. The clinical importance of these findings cannot be ascertained from this study, but our experience with a single case demonstrates that radiographic studies may produce substantial morbidity. (<i>Arch Intern Med</i>138:1430-1432, 1978)

Disturbances in thyroid function and a high prevalence of goiter develop in patients on chronic hemodialysis. This study shows that in patients on dialysis, mean serum thyroxine and triiodothyronine levels are lower than normal. Patients with chronic renal failure not on dialysis, have mean serum thyroxine levels similar to normal subjects and low mean serum triiodothyronine levels. However, both serum thyroxine and triiodothyronine concentrations decrease as the renal failure worsens. In addition, both groups of patients with renal failure have a decreased serum thyroxine response to oxogenous thyrotrophin and a diminished serum thyrotrophin response to thyrotrophin-releasing hormone. These data suggest the presence of an intrathyroidal and an hypophyseal defect in uremic patients. Although serum iodide concentrations are elevated, there is no correlation between the level of serum iodide and the degree of renal failure. Therefore, we have no direct evidence that iodide excess is responsible for the abnormalities observed.

Fifty-three patients with renal failure on chronic hemodialysis were screened for the presence of goiter. Thirty-one had enlarged thyroid glands, a prevalence of goiter of 58% not previously reported. Thyroid function studies showed low131I uptakes, low serum thyroxine and normal serum triiodothyronine and thyrotrophic hormone levels. Serum concentrations of thyroxine-binding globulin were normal; serum albumin concentration was only slightly reduced. Administration of synthetic thyrotrophin-releasing hormone was followed by a rise in serum thyrotrophin and triiodothyronine levels. The cause of the goiter is not known. The possibility that goitrogenic substances are involved is discussed.

A high incidence (40%) of cardiac arrhythmias was found in patients while on dialysis. This incidence was significantly higher than on nondialysis days. A comparison study of patients with significant cardiac arrhythmia and patients with cardiac arrhythmia was made. There was no difference in the echocardiogram, total body potassium, plasma renin activity, aldosterone, catecholamines, serum sodium, potassium and calcium between the two groups. Significant alkalinization occurred in all patients at the end of dialysis. Blood levels of total PTH and C peptide were higher in the arrhythmic patients versus the nonarrhythmic patients. No explanation was found as to why patients developed arrhythmias or what differentiated the two groups.

Several alterations are present in the hypothalamic hypophyseal regulation of many hormones in patients with chronic renal failure. Evaluation of the hypothalamic hypophyseal adrenal axis in these groups of patients demonstrated normal levels of plasma cortisol. Dexamethasone suppression is abnormal after administration of 1 mg of oral dexamethasone, but normal after 3 mg. Dexamethasone blood levels were lower than the control after administration of 1 mg of oral dexamethasone. A dexamethasone metabolic clearance showed a similar half-life between the patients and controls. Oral absorption study showed poor absorption of the drug. Therefore, there is a problem of gastrointestinal absorption producing the abnormal dexamethasone suppression test in patients with renal failure. Results of metyrapone tests were normal. Corticotropin stimulation tests elicited a normal response. Insulin-induced hypoglycemia does not produce an increment in plasma cortisol or adrenocorticotropic hormone levels.