RENAL FUNCTION AND ELECTROLYTE METABOLISM IN ACUTE GLOMERULONEPHRITIS 1

Abstract

Eight instances of the first attack of acute glomerulonephritis and 4 of the exacerbation in chronic glomerulonephritis were studied. The typical renal functional disturbances in an acute episode of glomerulonephritis issues from the characteristic glomerular lesion which leads to an excessive reduction in filtration rate and filtration fraction. Excretory and reabsorptive functions, as measured by TmPAH and Tm glucose, respectively, are less extensively reduced. The changes in renal functions are similar in the exacerbation in chronic glomerulonephritis. The typical changes are noted in spite of hypertension or the development of congestive heart failure, conditions otherwise characterized by an increased filtration fraction. The degree of abnormality and altered interrelations of renal functions are of little assistance in arriving at a prognosis. Considerable improvement in all functions usually follows an acute episode, although the rate of recovery is highly variable. Function also improves following an exacerbation, but does not return to normal because of pre-existing impairment effected by chronic disease. Salt and water diuresis during the recovery phase of acute glomerulonephritis may take place without change in filtration rate. Urea clearance is sometimes reduced out of proportion to the filtration rate in acute glomerulonephritis, and during recovery may increase without change in filtration rate. Serum Na concn. is normal or slightly low while plasma chloride, K and inorganic phosphate levels are sometimes above normal. These changes are not related to the degree of abnormality observed in renal functions. Na and chloride excretion more or less parallel one another. K excretion is depressed during the early stages of acute glomerulonephritis and increases during the diuresis of the recovery phase. A greater fraction than normal of filtered K and inorganic phosphate appear in the urine in the majority of patients. Ammonia excretion is greater than normal during the early phases of acute glomerulonephritis but subsequently falls below the usual normal range.