What are intrinsic renal causes of acute renal failure characterized by?

Intrinsic renal causes of acute renal failure are characterized by direct injury to the kidney tissue. This category of acute renal failure occurs when there is damage to the nephrons, which can be due to a variety of factors including ischemia, toxins, infections, or inflammatory processes. Conditions that can lead to intrinsic renal failure include acute tubular necrosis, glomerulonephritis, and acute interstitial nephritis.

In contrast, obstruction in the urinary tract refers to post-renal causes of renal failure, where the kidneys are functioning normally but the outflow of urine is obstructed, leading to back pressure and kidney damage. Systemic diseases affecting kidney function are more related to pre-renal causes, where factors outside the kidney itself, such as heart failure or sepsis, reduce blood flow to the kidneys. Decreased blood flow to the kidneys is indicative of pre-renal causes as well, resulting from conditions that impede adequate renal perfusion without intrinsic kidney damage.

Thus, intrinsic renal failure specifically points to a problem that arises directly within the kidney's own structure and function.