Mechanisms of Kidney Function

Ms. Cornwall is infected by a focal bacteria in her renal pelvis, calyces, and medulla. The invasion of the bacteria has caused an inflammatory mediators. When the pyelonephritis is severe, there will result from the formation of abscess and necrosis in the medulla. In the healing process, scar tissues may form. The urine from the glomeruli which mixes with the inflammatory exudate found in the renal pelvis and calyces or tubules with the extensive infection. As a result, purulent urine which bacteria and white blood cell cast will form (McCance & Huether, 2014). 

Prerenal acute renal failure is a condition where there is a decrease of the renal function with elevated blood urea nitrogen (BUN). The creatinine of plasma is caused by the impaired blood flow to the kidney. There is a low blood pressure reaching the afferent arteriole of the kidney and as a result, a low glomerular filtration rate which eventually becomes renal ischemia. The examples of prerenal acute renal failure causes are hypotension, hemorrhage, hypovolemia, shock, myocardial infarction with poor cardiac output and failure of the left ventricle (In Gilbert et al, 2014). 

Intrarenal Acute Renal failure is caused when there is an impairment of blood flow in the kidney. This is caused when the kidney is directly damaged by ischemia or damaged inflammatorily. Examples of the intrarenal causes includes acute tubular necrosis (ATN), glomerulonephritis, and hypertension, malignant, disseminated intravascular coagulation (DIC) as well as renal vasculitis. 

Postrenal acute renal failure is caused by the impairment of outflow from the kidney. When the passage of urine is blocked or obstructed, the urine backs up into the renal pelvis and pressure in the kidney is altered. Example are the kidney stones, bladder outlet obstruction, and enlarged prostate (Olgaard, Salusky & Silver, 2010). 


In Gilbert, S. J., In Weiner, D. E., In Gipson, D. S., In Perazella, M. A., In Tonelli, M., & National Kidney Foundation. (2014). National Kidney Foundation’s primer on kidney diseases.

McCance, K. L., & Huether, S. E. (2014). Pathophysiology: The biologic basis for disease in adults and children.

Olgaard, K., Salusky, I. B., & Silver, J. (2010). The spectrum of mineral and bone disorders in chronic kidney disease.

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