Pathophysiology

Pathophysiology Study Guide

©2018 of 131 Prerenal Acute Renal Failure Prerenal acute kidney failure is the most common type of acute kidney injury. This is when the blood flow to the kidneys is not adequate for the purpose of filtration, which causes them to clean blood insufficiently. Causes of prerenal acute kidney failure include dehydration due to vomiting, diarrhea, water pills, or loss of blood; a post-surgery drastic fall in blood pressure along with blood loss, sepsis, severe injury, or burns; blocking or narrowing of blood vessels that carry blood to the kidney; low blood flow due to heart failure or attack; and changes in hormones with liver failure that affects the flow of blood and poses pressure to the kidney. At this stage, the kidneys are not damaged and it is still possible to reverse the dysfunction, but a prolonged fall in blood flow has the potential to cause permanent damage to the tissues of the kidney. Intrarenal Acute Renal Failure Intrarenal or intrinsic acute renal failure is the condition characterized by damage or injury to both the kidneys, which causes a loss in kidney functioning. Causes of this type of acute renal failure include vascular diseases, like acute glomerulonephritis and vasculitis; obstruction of the renal artery, obstruction of the renal vein, low blood platelet, and low red blood cell counts; diseases of tubules and interstitium, like amyloidosis and interstitial nephritis; and acute tubular necrosis caused by ischemia and toxins. Postrenal Acute Renal Failure Also known as obstructive renal failure, postrenal acute renal failure is characterized by a blockage of the elimination of urine produced by the kidneys. This is one of the most uncommon conditions of acute renal failure. Causes of postrenal acute renal failure include kidney stones, cancer of organs in the urinary tract, cancer or tumor in the kidney, other structures that obstruct the outflow of urine from kidney, certain medications, bladder stones, enlarged prostate, blood clot, bladder cancer, and neurologic disorders of the bladder that hinder its normal functioning of contraction. This disorder can be corrected by eliminating the reason causing obstruction, and in a few weeks, the normal functioning of kidneys is restored. 5.5 Chronic Renal Failure Also known as chronic renal disease, chronic renal failure is characterized by the gradual loss of normal functioning of the kidneys. The main function of kidneys is to filter the waste substances and excess fluids from blood, which are excreted out of the body through urine. When this functioning mechanism of the kidneys gets impaired, the person suffers from chronic kidney failure. In this condition, dangerous fluids, waste substances, and electrolytes accumulate in the body. The main causes of chronic kidney failure include type 1 and 2 diabetes, hypertension, glomerulonephritis, interstitial nephritis, polycystic kidney disease, prolonged obstruction of the urinary tract, vesicoureteral, and pyelonephritis. There are five stages of chronic renal failure. In stage 1, the kidney gets damaged with an elevated glomerular filtration rate (GFR) that is above 90. In the second stage, the GFR mildly falls and ranges between 60 and 89, along with damage to the kidney. The third stage Achieve Page 82