Diurnal variations in renal excretion of electrolytes, uric acid and total amino nitrogen in various renal diseases and in essential hypertension

Abstract

Results of earlier investigations and observations from clinical practice indicate that diurnal variations in renal excretion of different urinary constituents diminish when kidney is damaged. Consequently the diagnostic value of the so-called “clearance indices” ( C x ) has been studied. Performed as 24-h tests, C x was estimated every 3 h taking into account the maximum oscillations of C x ( VC max ). The tests were performed in 63 patients who were classified into the following groups: ( I) acute glomerulonephritis (9); ( 2) chronic glomcrulonephritis (13); ( 3) pyelonephritis (8); ( 4) nephrosis (5); ( 5) other renal diseases (low nephron syndrome, polycystic degeneration of the kidney, post-nephrectomy states, etc.) (9); ( 6) essential hypertension (19); ( 7) controls (healthy medical students) (10). The following conclusions were drawn: ( 1) Kidney functional disturbances in most cases are characterised by decrease in C x and VC x max. (2) In the healthy controls low water intake causes a decrease of C x and VC x max.