Acute Kidney Injury Overview

What is the most common category of causes for Acute Kidney Injury?

Which condition is NOT a prerenal cause of Acute Kidney Injury?

What can lead to acute tubular necrosis as an intrarenal cause of AKI?

Which of the following is considered a postrenal cause of Acute Kidney Injury?

What is the primary pathophysiological event associated with prerenal Acute Kidney Injury?

What sequence of events can occur if prerenal AKI is left untreated?

Which type of injury is primarily involved in intrarenal Acute Kidney Injury?

Which scenario is likely to lead to a prerenal cause of AKI?

What effect do nephrotoxins have on the kidneys?

What is a possible outcome of prolonged urinary obstruction?

Which of the following infections can lead to prerenal acute kidney injury (AKI)?

Which risk factor for AKI is particularly significant for older adults?

What condition can occur due to kidney stones?

Which medication type is a risk factor for intrarenal AKI?

How does heart failure contribute to prerenal AKI?

What is one primary reason for developing postrenal AKI?

Acute Kidney Injury (AKI)

AKI is a sudden decrease in kidney function, leading to reduced glomerular filtration, fluid and electrolyte imbalances, and accumulation of nitrogenous waste products in the blood.

Causes of AKI

Classified into three categories:
- Prerenal: Most common, caused by reduced blood flow to the kidneys. This can be due to low blood pressure (hypotension), low blood volume (hypovolemia), or heart problems causing inadequate blood flow.
- Intrarenal: Damage within the kidney itself. This can include direct damage to kidney structures (e.g., acute tubular necrosis from ischemia or nephrotoxins), inflammatory conditions (glomerulonephritis). Acute interstitial nephritis and allergic reactions to drugs.
- Postrenal: Blockage of urine flow. This can be due to obstructions like kidney stones, enlarged prostate, or tumors.

Pathophysiology

The sequence of events depends on the type of AKI.
- Prerenal: Reduced blood flow to the kidneys reduces glomerular filtration rate (GFR). Hypoxia (lack of oxygen) in the kidney tissue can injure cells and potentially lead to acute tubular necrosis (ATN) if not treated. GFR can recover if blood flow is restored.
- Intrarenal: Damage directly to the kidney tissue, often followed by ischemia (lack of blood flow) and necrosis of renal tubular cells. Nephrotoxins can directly damage proximal tubular cells which are crucial for reabsorption.
- Postrenal: Blockage of urine outflow increases pressure within the nephrons, which reduces filtration. Prolonged blockage can lead to hydronephrosis (swelling of the kidney) and damage to the nephrons. Casts formed by damaged tubular cells can block urine flow, further injuring the kidney.

Transmission

Not transmissible. AKI is not an infectious disease.

Risk Factors

Prerenal: Dehydration, hemorrhage, shock, heart failure
Intrarenal: Nephrotoxins (certain antibiotics, NSAIDs), glomerulonephritis, sepsis
Postrenal: Kidney stones, prostatic hypertrophy, tumors

This quiz covers the essential concepts of Acute Kidney Injury (AKI), including its definition, causes, and pathophysiology. Learn about the distinctions between prerenal, intrarenal, and postrenal causes of AKI and understand their impact on kidney function.