Assessment of renal osteodystrophy in hemodialysis patients.

We performed a prospective study of 30 patients undergoing chronic hemodialysis to determine which of 6 generally available diagnostic procedures provided the most useful information for the assessment of bone disease in hemodialysis patients. The 6 procedures were: routine biochemical measurements, N-terminal parathyroid hormone (N-PTH), radiographic analysis of hands and clavicles, bone density determination by dual photon absorptiometry (DPA), deferoxamine stimulation test, and iliac crest bone biopsy. Serum N-PTH was elevated in 83% of patients but was not significantly associated with abnormalities of other biochemical parameters. No significant relationship was demonstrated between biochemical data and radiographic findings or between biochemical data and bone density by DPA. All patients with abnormal DPA had an elevation of N-PTH; therefore, DPA did not reveal any unsuspected disease. Bone biopsies were done in 20 patients and findings in each were consistent with uremic osteodystrophy, including osteitis fibrosa cystica in 11 patients and aluminum-associated bone disease in 2 patients. Six patients had mixed disease, and 1 patient had osteoporosis. Despite 11 positive deferoxamine tests, bone biopsy revealed aluminum deposition in only 7 of these patients, suggesting extraosseous aluminum accumulation in the remaining 4. Evaluation of the positive and negative predictive accuracies of DPA, x-ray analysis, N-PTH levels, and aluminum bone deposition revealed that normal DPA or x-ray findings do not exclude bone disease, that N-PTH level is a good marker for secondary hyperparathyroidism, and that a negative deferoxamine test excludes aluminum-associated bone disease. Discriminant analysis also reinforced these conclusions.(ABSTRACT TRUNCATED AT 250 WORDS)

Incidence and etiology of hyponatremia in an intensive care unit.

To evaluate the incidence and causes of hyponatremia in intensive care unit (ICU) patients, retrospective and prospective studies were done. Hyponatremia was defined as a serum sodium concentration equal to or less than 134 mmol/l (134 mEq/l). Prospectively, 29.6% of patients displayed hyponatremia. Relevant data were obtained in twelve patients. Two patients did not have serum hypoosmolality. In the ten patients with serum hypoosmolality, urine osmolality was not maximally dilute and urine sodium concentration was greater than 30 mmol/l (30 mEq/l) suggesting inappropriate antidiuretic hormone secretion (SIADH). However, three patients exhibited suppressed ADH levels despite absence of maximal urinary dilution. The data suggest that hyponatremia is common in ICU patients and that renal diluting defects are frequent. Therefore, hypotonic fluid should be administered cautiously.

Frequency of hyponatremia and nonosmolar vasopressin release in the acquired immunodeficiency syndrome.

The frequency and pathophysiology of hyponatremia were studied in the acquired immunodeficiency syndrome. Of 71 hospitalized patients surveyed retrospectively, hyponatremia was observed in 37 (52%). Of 48 patients studied prospectively, 27 (56%) were hyponatremic. In 16 hyponatremic patients, volume status; serum and urine osmolalities; renal, adrenal, and thyroid function; and plasma vasopressin levels were assessed. Urine osmolalities were inappropriately elevated (mean, 377 mmol/kg of water) relative to serum osmolalities (mean, 268 mmol/kg of water). Four patients had moderate renal insufficiency. Plasma vasopressin levels were elevated in 15 patients, with the highest levels seen in patients who died (median, 7.08 pmol/L). Hyponatremia of multiple etiologies occurred in a majority of inpatients with the acquired immunodeficiency syndrome, often following the administration of hypotonic fluids, and was associated with a 30% (8/27) short-term mortality.

Increased levels of plasma renin, aldosterone, catecholamines and vasopressin in chronic ambulatory peritoneal dialysis (CAPD) patients.

Fluid excess can cause hyporeninemia and hypoaldosteronemia in hemodialysis patients. In six patients on CAPD, plasma renin activity (PRA) and plasma aldosterone (PA) were elevated to levels of : PRA 10.2 +/- 2.9 nl (1-5 ng/ml/h), and PA: 47.4 +/- 16.2 (normal 5-20 ng/dl). In 4 patients, data posthemodialysis and later during CAPD revealed that PRA increased from 0.9 +/- 0.3 to 14.1 +/- 4.6 and PA increased from 3.4 +/- 0.3 to 67.4 +/- 24.9 on CAPD (p less than 0.05). Mean arterial pressure was lower on CAPD and serum glucose was higher. No significant difference was seen in weight, hematocrit, BUN, or potassium, however. Plasma volume was not decreased in five CAPD patients: 3619 +/- 358 ml (predicted 3083 +/- 201 ml). Elevated catecholamine levels were seen in CAPD patients: norepinephrine 868.0 +/- 104.1 (normal 358.4 +/- 41.5 pg/ml), epinephrine 386.3 +/- 49.2 (normal 58.3 +/- 10.6 pg/ml). Plasma vasopressin levels were elevated to the range usually seen with hyperosmolality. In eight patients who lost or gained weight on CAPD, levels of PRA and PA changed as expected, but catecholamine levels did not correlate with weight changes. The data suggest that in CAPD patients, PRA and PA may be elevated in association with augmented sympathetic stimulation and elevated vasopressin levels. Serial observations demonstrated that PRA and PA can respond appropriately to changes in body weight, while catecholamine and vasopressin levels seem to be influenced by other factors.

Renal disease in patients with AIDS: a clinicopathologic study.

To determine the nature and frequency of renal disorders in AIDS we reviewed the records of thirty-two patients hospitalized over a twenty-two month period. Group I, including all patients with AIDS who demonstrated proteinuria and/or renal insufficiency, numbered thirteen patients, in ten of whom renal tissue was available. Renal abnormalities included proteinuria in twelve patients, which exceeded two grams per day in seven. The glomerular histologic lesions included focal glomerulosclerosis, diffuse mesangial hypercellularity, diffuse proliferative glomerulonephritis, and membranoproliferative glomerulonephritis. The nonglomerular histologic lesions included acute tubular necrosis, nephrocalcinosis, focal interstitial nephritis, and one case each of intrarenal cryptococcal infection and renal cell carcinoma. Nine of these thirteen patients developed renal insufficiency, and four of them required dialysis. Their mortality by the end of the study period was eleven of thirteen patients (85 percent), significantly worse in the short term than AIDS patients without renal problems. The patients in Group I were compared to the nineteen AIDS patients without renal abnormalities in Group II. The Group I patients had a higher incidence of oral and esophageal candidiasis, other fungal infections, and infections with Mycobacterium avium-intracellulare. They also had a higher incidence of exposure to aminoglycoside antibiotics and amphotericin B, and experienced more clinical shock than their Group II counterparts. It is concluded that patients with AIDS may demonstrate renal abnormalities on the basis of immune, hemodynamic, infectious, and neoplastic derangements.

Renal vein thrombosis.

Diagnosis of renal vein thrombosis, a disease of subtle or dramatic onset, depends largely on clinical suspicion confirmed by renal venography. The principles of management are changing as diagnostic advances resolve the "chicken-or-egg" quandary over the causal relationship between renal vein thrombosis and the nephrotic syndrome.