Renal pathophysiology Practice Questions
20 free Renal pathophysiology practice questions for the Physiology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Acute kidney injury (AKI) is best defined as:
- A Slow progressive loss of kidney function over many years
- B Sudden decline in renal function over hours to days
- C Reduced urine output with a normal GFR
- D Irreversible loss of functioning nephrons
Correct answer: Sudden decline in renal function over hours to days
AKI is characterized by a rapid decrease in glomerular filtration rate occurring over hours to days. It leads to accumulation of nitrogenous wastes and disturbances in fluid and electrolyte balance.
Prerenal acute kidney injury is primarily caused by:
- A Intrinsic tubular damage
- B Obstruction of urinary tract
- C Reduced renal perfusion
- D Autoimmune glomerular injury
Correct answer: Reduced renal perfusion
Prerenal AKI results from decreased renal blood flow, commonly due to hypovolemia or heart failure. The renal parenchyma is initially structurally normal.
Which finding is typical of prerenal acute kidney injury?
- A Elevated urinary sodium concentration above 40 mEq/L
- B Low blood urea nitrogen with normal creatinine
- C Low fractional excretion of sodium
- D Muddy brown granular casts on urine microscopy
Correct answer: Low fractional excretion of sodium
In prerenal AKI, the kidneys conserve sodium to maintain volume. This results in a low fractional excretion of sodium.
Acute tubular necrosis is most commonly caused by:
- A Renal artery stenosis
- B Ischemia or nephrotoxins
- C Ureteral obstruction
- D Immune complex deposition
Correct answer: Ischemia or nephrotoxins
Acute tubular necrosis results from ischemic injury or exposure to nephrotoxic agents. Tubular epithelial cell damage impairs reabsorption and filtration.
Postrenal acute kidney injury results from:
- A Immune-mediated glomerular inflammation
- B Reduced cardiac output and renal hypoperfusion
- C Obstruction to urine flow
- D Ischemic tubular injury
Correct answer: Obstruction to urine flow
Postrenal AKI occurs due to obstruction of urine flow at any level of the urinary tract. This leads to increased tubular pressure and reduced GFR.
Chronic kidney disease (CKD) is characterized by:
- A Sudden reversible loss of renal function
- B Progressive irreversible nephron loss
- C Acute inflammation of tubules
- D Normal electrolyte balance
Correct answer: Progressive irreversible nephron loss
CKD involves gradual and irreversible loss of functional nephrons. It results in persistent reduction in GFR and systemic complications.
Which condition is a common cause of chronic kidney disease?
- A Diabetes mellitus
- B Acute dehydration
- C Urinary tract infection
- D Transient hypotension
Correct answer: Diabetes mellitus
Diabetes mellitus is a leading cause of CKD worldwide. Chronic hyperglycemia damages glomerular capillaries.
Proteinuria in glomerular disease is primarily due to:
- A Increased tubular secretion
- B Reduced renal blood flow
- C Increased glomerular permeability
- D Decreased plasma protein synthesis
Correct answer: Increased glomerular permeability
Glomerular damage increases permeability of the filtration barrier. This allows proteins to leak into the urine.
Which change commonly occurs in chronic kidney disease?
- A Metabolic alkalosis
- B Hyperkalemia
- C Hypophosphatemia
- D Increased erythropoietin production
Correct answer: Hyperkalemia
Reduced renal excretion of potassium leads to hyperkalemia in CKD. This can cause serious cardiac complications.
Anemia in chronic kidney disease is mainly due to:
- A Coexisting iron and folate deficiency
- B Chronic blood loss through the urinary tract
- C Reduced erythropoietin production
- D Accelerated red cell hemolysis
Correct answer: Reduced erythropoietin production
The kidneys produce erythropoietin, which stimulates red blood cell production. CKD reduces erythropoietin synthesis, leading to anemia.
Which renal disorder is characterized by hematuria, proteinuria, and hypertension?
- A Acute glomerulonephritis
- B Nephrotic syndrome with heavy proteinuria
- C Acute tubular necrosis from ischemia
- D Obstructing renal calculi
Correct answer: Acute glomerulonephritis
Acute glomerulonephritis presents with hematuria, proteinuria, and hypertension. It is caused by inflammatory injury to glomeruli.
Nephrotic syndrome is defined by all EXCEPT:
- A Massive proteinuria
- B Hypoalbuminemia
- C Edema
- D Hematuria
Correct answer: Hematuria
Nephrotic syndrome is characterized by heavy proteinuria, low serum albumin, and edema. Hematuria is not a defining feature.
Edema in nephrotic syndrome primarily results from:
- A Increased capillary hydrostatic pressure
- B Reduced plasma oncotic pressure
- C Increased lymphatic drainage
- D Sodium loss in urine
Correct answer: Reduced plasma oncotic pressure
Loss of albumin in urine reduces plasma oncotic pressure. This promotes fluid movement into interstitial spaces.
Renal tubular acidosis is characterized by:
- A Respiratory acidosis
- B Inability to acidify urine
- C Excess bicarbonate reabsorption
- D Hyperventilation
Correct answer: Inability to acidify urine
Renal tubular acidosis involves defective acid secretion or bicarbonate handling by tubules. This leads to metabolic acidosis.
Which substance accumulates in uremia?
- A Creatinine and urea
- B Filtered glucose reabsorbed by tubules
- C Serum albumin lost in urine
- D Ionized calcium bound to protein
Correct answer: Creatinine and urea
Uremia results from accumulation of nitrogenous wastes such as urea and creatinine. These toxins cause systemic symptoms.
Polycystic kidney disease is primarily characterized by:
- A Immune-mediated nephron destruction
- B Formation of multiple renal cysts
- C Acute tubular necrosis
- D Renal artery obstruction
Correct answer: Formation of multiple renal cysts
Polycystic kidney disease involves progressive development of multiple cysts in the kidneys. These cysts impair normal renal function.
Which electrolyte imbalance is commonly seen in advanced renal failure?
- A Hypokalemia from renal potassium wasting
- B Hypercalcemia with metastatic calcification
- C Hyperphosphatemia
- D Hypomagnesemia from tubular loss
Correct answer: Hyperphosphatemia
Reduced phosphate excretion leads to hyperphosphatemia in renal failure. This contributes to bone and mineral disorders.
Secondary hyperparathyroidism in CKD is mainly due to:
- A Increased renal vitamin D synthesis
- B Persistent hypercalcemia
- C Phosphate retention and low calcium
- D Elevated calcitonin secretion from the thyroid
Correct answer: Phosphate retention and low calcium
Phosphate retention and reduced vitamin D activation lower serum calcium. This stimulates parathyroid hormone secretion.
Which feature differentiates acute kidney injury from chronic kidney disease?
- A Reduced daily urine output
- B Elevated serum creatinine on presentation
- C Small shrunken kidneys on imaging
- D Multiple coexisting electrolyte disturbances
Correct answer: Small shrunken kidneys on imaging
Chronically diseased kidneys are often small and shrunken on imaging. AKI usually presents with normal-sized kidneys.
The most important determinant of progression of chronic kidney disease is:
- A Advancing age of the patient
- B Persistent proteinuria
- C Patient sex
- D Fluctuating body temperature
Correct answer: Persistent proteinuria
Persistent proteinuria reflects ongoing glomerular damage. It is a strong predictor of CKD progression.