The BUN:Cr in prerenal azotemia is greater than 15. The reason for this lies in the mechanism of filtration of BUN and creatinine. GFR levels are decreased due to hypoperfusion, leading to a general increase in BUN and creatinine levels. However, since some of the filtered BUN is reabsorbed from the proximal tubules of the kidney back into the blood, whereas very little of the filtered creatinine is, more BUN builds up in the blood relative to creatinine.
The BUN:Cr in renal azotemia is normal--less than 15. Although the GFR is decreased and both BUN and creatinine levels are increased in the blood, because of the damaged proximal tubules, no BUN is reabsorbed from the filtrate. Thus, BUN is lost into the urine just like creatinine, preserving the normal ratio.
The BUN:Cr in postrenal azotemia is greater than 15. The increased nephron tubular pressure causes increased reabsorption of BUN, elevating it abnormally relative to creatinine.
A urinalysis will typically show a decreased urine sodium level, a high urine creatinine-to-serum creatinine ratio, a high urine urea-to-serum urea ratio, and concentrated urine (determined by osmolality and specific gravity). None of these is particularly useful in diagnosis.
In pre-renal and post-renal azotemias, elevation of the BUN exceeds that of the creatinine (i.e., BUN>12*creatinine). This is because BUN is readily absorbed while creatinine is not. In congestive heart failure (a cause of pre-renal azotemia) or any other condition that causes poor perfusion of kidneys, the sluggish flow of glomerular filtrate results in excessive absorption of BUN and elevation of its value in blood. Creatinine, however, is not absorbable and therefore does not rise significantly. Stasis of urine in post-renal azotemia has the same effect.
Prompt treatment of some causes of azotemia can result in restoration of kidney function; delayed treatment may result in permanent loss of renal function. Treatment may include hemodialysis or peritoneal dialysis, medications to increase cardiac output and increase blood pressure, and the treatment of the condition that caused the azotemia.
WIPO ASSIGNS PATENT TO CARESMILE FOR "BODY-WASTE PROCESSING DEVICE HAVING IMPROVED DISCHARGE ABILITY" (SOUTH KOREAN INVENTOR)
May 09, 2011; GENEVA, May 9 -- Publication No. WO/2011/052999 was published on May 05. Title of the invention: "BODY-WASTE PROCESSING DEVICE...