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The pathologic changes seen on light and electron microscopy of the kidney in paroxysmal nocturnal hemoglobinuria are described in two cases, one at autopsy and the other at biopsy. Intense hemosiderosis of the kidney is the most characteristic pathologic change in paroxysmal nocturnal hemoglobinuria although not specific for this disease. There is no apparent structural or functional reaction to the hemosiderosis. The intensity of ferritin accumulation at various points in the nephron is correlated with current concepts of hemoglobinuria, hemoglobin and ferritin metabolism and large molecule transport.

A powerful procoagulant is normally excreted in large amounts in the urine of man, rats and rabbits. The secretion is not altered in a variety of diseases including hemorrhagic diathesis and thromboembolism. In parenchymatous kidney diseases, however, there is a marked reduction of procoagulant excretion. The procoagulant excretion is negatively correlated with BUN, blood creatinine and degree of proteinuria. With marked proteinuria in human or experimental renal disease, the procoagulant content per ml urine and the 24 h excretion drop to very low or zero values. In man, complete recovery of procoagulant excretion is obtained after homotransplantation of a well functioning kidney.

SummaryNephrotoxic agents temporarily alter the excretion of a procoagulant normally present in the urine. Agents producing tubular necrosis or inducing proteinuria without severe glomerular damage have the most pronounced effect.

Two human kidney biopsy specimens were obtained by needle biopsy from a patient with classical clinical and laboratory evidence of paroxysmal nocturnal hemoglobinuria. Iron, in the form of hemosiderin granules and iron micelles 50–60 A in size was found at all levels of the nephron. The visceral and parietal epithelial cells of Bowman's capsule contained individual 50–60 A iron micelles, and membrane-limited masses of closely packed iron micelles (hemosiderin granules). The proximal convoluted tubule cells contained hyalin droplets, hemosiderin granules, and 50–60 A iron micelles. The hyalin droplets were membrane-limited, spheroid, structures which contained peripherally located electron-dense masses. The hemosiderin granules, sometimes membrane-limited, consisted of tightly packed 50–60 A iron micelles. Iron micelles were also observed in the basement membranes underlying parietal epithelial cells, proximal convoluted tubule cells, and in the peritubular capillary endothelium and lumen. The iron micelles were similar in sub-unit structure throughout all regions of the kidney, consisting of sub-units 15–20 A in size spaced 15–20 A apart, and indistinguishable from the iron micelles of ferritin. A comparison is made between the morphology of the hyalin droplets, and hemosiderin granules observed here and elsewhere, and the localization of iron micelles is discussed with respect to ferritin transport.

Goodner and Brown's 1 report based on autopsy findings in 2 cases of cardiac tamponade in uremic pericarditis emphasized that uremic pericarditis should be considered in the differential diagnosis of cardiac tamponade. Eight months later Guild, Bray, and Merrill 2 reported the first 2 cases of uremic pericarditis in which the diagnosis of pericardial effusion was made before death, and removal of pericardial fluid resulted in striking objective and subjective improvement. Goodner and Brown commented that since uremic pericarditis is such a poor prognostic sign in chronic renal disease, pericardiocentesis would probably not yield more than transient prolongation of life. They suggested, however, that cardiac tamponade might occur in a potentially reversible form of renal failure and that here its recognition and treatment might be life-saving. This report describes the first 2 cases, 1 certain and 1 probable, of massive pericardial effusion complicating a potentially reversible form of renal failure

In eight patients with advanced renal insufficiency (inulin clearance 1.4–9.1 ml/min), concentrations of serum calcium (S[Ca]) and phosphorus (S[P]) were maintained normal (S[Ca] > 9.0 mg/100 ml, (S[P] < 3.5 mg/100 ml) for at least 20 consecutive days with phosphate binding antacids and oral calcium carbonate. The initial serum levels of immunoreactive parathyroid hormone (S-PTH) were elevated in three (426–9230 pg/ml), normal in four (one after subtotal parathyroidectomy), and not available in one. The initial fractional excretion of filtered phosphorus (CpCIN) was high in all and ranged from 0.45–1.05. Following sustained normo-calcemia and normo-phosphatemia, S-PTH was reduced below control levels in all patients; being normal in six and elevated in two. CpCIN decreased below control levels in all patients; it remained high in six (of which five had normal S-PTH) and was normal (CpCIN=0.01) in two (of which one had elevated S-PTH). The observed relationship between S-PTH and CpCIN could either reflect the inability of the radioimmunoassay for PTH employed to measure a circulating molecular species of PTH which was present in which case the actual levels of S-PTH were higher than those measured, and/or it could be indicative of the presence of additional important factor(s) (other than S-PTH) which inhibit tubular reabsorption of phosphorus in advanced chronic renal failure.