Patofisiologi - Cidera Ginjal Akut Intrarenal / Azotemia / Acute Kidney Injury

Summary

The video covers key aspects of acute kidney injury (AKI), focusing on prerenal, intrarenal, and postrenal causes. It explains how prerenal injury, caused by low blood flow to the kidneys, can lead to decreased kidney function, while intrarenal injury involves damage to the kidney's internal structures like the tubules and glomeruli. The video also highlights diagnostic markers such as BUN-to-creatinine ratios, sodium content in urine, and osmolarity to help identify kidney dysfunction. The speaker encourages interaction and discussion, emphasizing the importance of understanding these mechanisms for diagnosing and treating kidney conditions.

Takeaways

• 😀 Intrarenal kidney injury originates from within the kidney itself, affecting structures like the tubules, glomerulus, or interstitium.
• 😀 Acute tubular necrosis (ATN), glomerulonephritis, and interstitial nephritis are key conditions causing intrarenal injury.
• 😀 When kidneys lose their filtering ability, they struggle with reabsorbing and secreting substances like urea and sodium.
• 😀 A decreased BUN to creatinine ratio (less than 15:1) indicates impaired reabsorption of urea in the kidneys.
• 😀 Elevated urea levels in the blood occur due to the failure to reabsorb urea, causing it to remain in the bloodstream.
• 😀 Damaged kidneys fail to reabsorb sodium, leading to higher sodium concentrations in the urine.
• 😀 Urine sodium concentration can exceed 40 mEq/L in cases of intrarenal injury.
• 😀 The fractional excretion of sodium (FENa) can be greater than 22%, a marker of kidney injury.
• 😀 Decreased urine osmolarity (below 350 mOsm/kg) is a result of less water being reabsorbed into the body.
• 😀 Intrarenal kidney injury involves structural damage within the kidney, leading to impaired filtration, reabsorption, and secretion functions.

Q & A

What is intrarenal kidney injury?

Intrarenal kidney injury refers to damage that occurs directly within the kidneys, affecting structures like the tubules, glomeruli, or interstitial tissue. This damage impairs the kidney's ability to filter and process blood effectively.

What are the main causes of intrarenal kidney injury?

The causes of intrarenal kidney injury can include acute tubular necrosis (ATN), acute interstitial nephritis, and glomerulonephritis. These conditions result in damage to kidney structures, leading to dysfunction.

How does intrarenal injury affect kidney filtration?

In intrarenal injury, the tubules and other kidney structures lose their ability to properly filter blood, reabsorb essential substances like urea and sodium, and regulate the body's fluid balance.

What is the significance of the BUN/Creatinine ratio in diagnosing intrarenal injury?

The BUN/Creatinine ratio typically decreases to less than 15:1 in cases of intrarenal injury. This occurs because the kidneys are unable to reabsorb urea effectively, leading to an increase in blood urea levels and a decrease in the ratio.

What happens to sodium levels in the urine during intrarenal kidney injury?

During intrarenal injury, the kidneys are unable to reabsorb sodium properly, leading to an increase in urinary sodium content. This can be measured using the fractional excretion of sodium (FENa).

What is the fractional excretion of sodium (FENa) and why is it important?

FENa is a diagnostic tool that measures the percentage of filtered sodium that is excreted in the urine. A FENa greater than 2% indicates tubular dysfunction, which is a characteristic of intrarenal injury.

What is the normal range for urine osmolarity in cases of intrarenal injury?

In cases of intrarenal injury, urine osmolarity typically decreases to below 350 mOsm/kg due to impaired reabsorption of water by the kidneys.

How can urine sodium levels indicate intrarenal kidney damage?

In intrarenal injury, urine sodium levels increase and may exceed 40 mEq/L. This is because the kidneys lose their ability to reabsorb sodium effectively, leading to its excessive excretion in the urine.

What role do the tubules play in kidney function, and how does injury affect them?

The tubules in the kidneys are responsible for reabsorbing important substances such as sodium, urea, and water. When injured, these tubules cannot perform their functions properly, leading to imbalances in fluid and electrolyte levels.

Why is it important to monitor both sodium and urea in diagnosing intrarenal kidney injury?

Monitoring both sodium and urea helps identify intrarenal kidney injury. Urea levels rise in the blood because the kidneys fail to reabsorb it, while sodium levels in the urine rise due to impaired tubular function.