Renal Failures

Question 1

What is the definition of renal failure?

Answer 1

A condition where the kidneys fail to maintain hydroelectrolytic and acid-base balance, leading to accumulation of metabolic waste (urea, creatinine, uric acid).

Question 2

What are the two types of renal failure?

Answer 2

• Acute Kidney Injury (AKI) – Sudden onset, potentially reversible.
  
  • Chronic Kidney Disease (CKD) – Progressive and irreversible kidney dysfunction.

Question 3

What is acute kidney injury (AKI)?

Answer 3

A sudden loss of kidney function over hours to days, leading to electrolyte imbalances and waste accumulation.

Question 4

What is oligoanuria, and how is it related to AKI?

Answer 4

• Oliguria: Urine output < 400 mL/24h
  
  • Anuria: No urine output
  • Important in AKI diagnosis!

Question 5

What are the three main types of AKI?

Answer 5

• Prerenal (Functional) – Due to decreased kidney perfusion.
  
  • Intrinsic (Renal/Parenchymal) – Due to direct kidney damage.
  • Postrenal (Obstructive) – Due to urinary obstruction.

Question 6

What are common causes of prerenal AKI?

Answer 6

Hypoperfusion due to dehydration, heart failure, shock, nephrotic syndrome, cirrhosis.

Question 7

Can prerenal AKI be reversed?

Answer 7

Yes, if fluid balance is restored in time.
Intrinsic AKI (Renal)

Question 8

What are common causes of intrinsic AKI?

Answer 8

Glomerulonephritis, infections, toxins, autoimmune diseases (ANCA, Anti-GBM), multiple myeloma, ischemia.

Question 9

What investigations help diagnose intrinsic AKI?

Answer 9

• Hemolysis markers (LDH, haptoglobin).
  
  • Autoimmune markers (ANCA, Anti-GBM, ANA).
  • Renal biopsy (definitive test).

Question 10

What are the main causes of postrenal AKI?

Answer 10

Urinary stones, prostate hypertrophy, bladder tumors, retroperitoneal fibrosis.

Question 11

What are the main biochemical markers of AKI?

Answer 11

• Elevated creatinine (>50% increase).
  
  • Increased blood urea nitrogen (BUN).
  • Hyperkalemia, metabolic acidosis.

Question 12

What electrolyte imbalances occur in AKI?

Answer 12

Hyperkalemia, hyponatremia, hyperchloremia.

Question 13

What are the acid-base disturbances in AKI?

Answer 13

Metabolic acidosis (pH < 7.38).

Question 14

What is the definition of chronic kidney disease (CKD)?

Answer 14

GFR < 60 mL/min/1.73m² for >3 months due to irreversible structural kidney damage.

Question 15

What are the most common causes of CKD?

Answer 15

• Hypertension
  
  • Diabetes (Diabetic Nephropathy)
  • Glomerulonephritis
  • Polycystic Kidney Disease (PKD)

Question 16

Why is CKD a major public health issue?


Answer 16

Requires long-term management and can progress to dialysis or kidney transplant.

Question 17

What are the key biochemical markers in CKD?

Answer 17

• Elevated serum creatinine.
  
  • Reduced GFR (<60 mL/min).
  • Proteinuria.
  • Hyperkalemia, metabolic acidosis.

Question 18

What is the best method for estimating GFR?

Answer 18

CKD-EPI formula (more accurate than MDRD).

Question 19

What is the role of Cystatin C in CKD diagnosis?

Answer 19

Proposed as a better GFR marker but less commonly used than creatinine.

Question 20

What is nephrotic syndrome?

Answer 20

A glomerular disease causing protein loss in urine due to increased glomerular permeability.

Question 21

What are the four key biochemical features of nephrotic syndrome?

Answer 21

• Heavy proteinuria (>3g/24h).
  
  • Hypoalbuminemia (<30 g/L).
  • Hyperlipoproteinemia (high cholesterol & triglycerides).
  • Edema (due to low oncotic pressure).

Question 22

What are the key urinary findings in nephrotic syndrome?

Answer 22

Massive proteinuria (>3g/24h in adults, >50 mg/kg/day in children).

Question 23

What are common blood findings in nephrotic syndrome?

Answer 23

• Hypoalbuminemia (<30 g/L).
  
  • Hyperlipidemia.
  • Hypercoagulability (high fibrinogen).

Question 24

What are the most common symptoms of nephrotic syndrome?

Answer 24

• Generalized edema (soft, pitting).
  
  • Fluid effusions (ascites, pleural effusion).
  • Weight gain & oliguria.

Question 25

Why do nephrotic patients have a high risk of thrombosis?

Answer 25

Increased fibrinogen and loss of anticoagulants in urine.

Question 26

Why do nephrotic patients develop infections?

Answer 26

Loss of immunoglobulins in urine leads to immunodeficiency.

Question 27

What are the key characteristics of pure nephrotic syndrome?

Answer 27

• Affects children (+).
  
  • Selective proteinuria (Albumin >85%).
  • Highly corticosteroid-sensitive (+++).
  • No hypertension, hematuria, or renal failure.

Question 28

What are the key characteristics of mixed nephrotic syndrome? (Glomerulonephritis, Systemic Disease)

Answer 28

• Corticosteroid-resistant.
  
  • Non-selective proteinuria (includes albumin & other proteins).
  • Associated with hypertension & renal insufficiency.

Question 29

What systemic diseases can cause mixed nephrotic syndrome?

Answer 29

Diabetes, Lupus, Amyloidosis, Rheumatoid Purpura.

Question 30

A 45-year-old male presents with severe edema, proteinuria (6 g/24h), and hypoalbuminemia (20 g/L). He has no hematuria or hypertension.
* What is the most likely diagnosis?
* What is the next step?

Answer 30

Diagnosis: Pure nephrotic syndrome (Minimal Change Disease).
Next step: Start corticosteroids. If resistant, consider renal biopsy.