Nephrology — MCQs

Nephrology Indian Medical PG Practice Questions and MCQs

Question 791: Which of the following is NOT a common cause of acute renal failure?

A. Chronic kidney disease due to analgesic nephropathy (Correct Answer)
B. Acute pyelonephritis
C. Acute kidney injury from snakebite
D. Acute kidney injury due to rhabdomyolysis

Explanation: Chronic kidney disease due to analgesic nephropathy - This is a cause of chronic kidney disease, characterized by gradual, irreversible kidney damage over a long period due to prolonged use of certain analgesics. [1] - It does not present as an acute, sudden decline in kidney function, which is the hallmark of acute renal failure. [1] Acute pyelonephritis - Severe cases of acute pyelonephritis (kidney infection) can lead to acute kidney injury due to sepsis, inflammation, and potential obstruction. [1] - The systemic inflammatory response and direct tissue damage can impair kidney function rapidly. [1] Acute kidney injury from snakebite - Snake envenomation can cause acute kidney injury through various mechanisms, including hemolysis, rhabdomyolysis, direct nephrotoxicity, and systemic hypotension. - These effects can lead to rapid and severe kidney damage. Acute kidney injury due to rhabdomyolysis - Rhabdomyolysis involves the breakdown of skeletal muscle tissue, releasing large amounts of myoglobin into the bloodstream. [1] - Myoglobin is toxic to the renal tubules, leading to acute tubular necrosis and rapid onset of acute kidney injury. [1]

Question 792: All are true about GFR except:

A. 30-40% decrease after 70 years of age
B. GFR is dependent on height in children
C. Chronic Kidney Disease (CKD) is defined as GFR < 60 ml/min/1.73 m² for 3 months or more.
D. Best estimated by creatinine clearance (Correct Answer)

Explanation: ***Best estimated by creatinine clearance*** - While **creatinine clearance** can be used as a measure of GFR, it is not the *best* estimate; it tends to slightly **overestimate** GFR due to tubular secretion of creatinine. [1] - The gold standard for measuring GFR involves methods like **inulin clearance**, but in clinical practice, GFR is often *estimated* using equations based on **serum creatinine** (e.g., CKD-EPI, MDRD). [2] *30-40% decrease after 70 years of age* - **Aging** is associated with a physiological decline in GFR, with a general decrease often cited as 30-40% after the age of 70 years. - This decline is part of the normal **age-related changes in renal function**. *GFR is dependent on height in children* - In children, GFR is often adjusted for **body surface area (BSA)**, which is calculated based on both **height and weight**, making height an important factor. [1] - This adjustment is crucial for accurate assessment of renal function in a growing pediatric population. *Chronic Kidney Disease (CKD) is defined as GFR < 60 ml/min/1.73 m² for 3 months or more.* - This statement accurately reflects the widely accepted definition of **Chronic Kidney Disease (CKD)** according to clinical guidelines. [3] - A GFR below this threshold sustained for more than three months indicates persistent kidney damage or dysfunction.

Question 793: What condition is characterized by hypertension and hypokalemia?

A. Gitelman's Syndrome
B. Liddle's Syndrome (Correct Answer)
C. Bartter Syndrome
D. All of the options

Explanation: ***Liddle's Syndrome*** - This syndrome is characterized by **overactivity of the epithelial sodium channel (ENaC)** in the collecting ducts, leading to increased sodium reabsorption and potassium excretion. [1] - The resulting **sodium retention causes hypertension**, while the **potassium excretion leads to hypokalemia**. *Gitelman's Syndrome* - This is an **autosomal recessive kidney disorder** causing a defect in the **thiazide-sensitive NaCl cotransporter** in the distal convoluted tubule. - It presents with **hypokalemia and hypomagnesemia**, but typically with **normal or low blood pressure**, not hypertension. *Bartter Syndrome* - This is a group of **autosomal recessive salt-wasting tubulopathies** affecting the **Na-K-2Cl cotransporter** in the thick ascending limb of the loop of Henle. - It leads to **hypokalemia, metabolic alkalosis, and normal or low blood pressure**, similar to chronic loop diuretic use. *All of the options* - While all mentioned conditions involve **hypokalemia**, only **Liddle's Syndrome** is consistently associated with **hypertension**. - **Gitelman's and Bartter syndromes** typically present with **normal or low blood pressure**.

Question 794: What does the measurement of Glomerular Filtration Rate (GFR) help determine in kidney function?

A. Heart rate
B. Recovery from shock
C. Stage of kidney disease (Correct Answer)
D. Blood volume

Explanation: Stage of kidney disease - A low GFR indicates impaired kidney function, helping to classify the severity and stage of chronic kidney disease (CKD) [1]. - Monitoring GFR over time is crucial for assessing disease progression and guiding treatment strategies [1]. *Heart rate* - Heart rate is a measure of cardiac function and is not directly assessed by GFR. - Kidney function can indirectly affect heart rate over time (e.g., in advanced kidney disease with fluid overload), but GFR itself doesn't measure it. *Recovery from shock* - While kidney function is important during shock, GFR primarily measures the kidney's filtration capacity at a given moment. - Recovery from shock involves many physiological parameters beyond just kidney filtration, such as blood pressure and organ perfusion. *Blood volume* - Blood volume is regulated by many mechanisms, including hormonal systems (e.g., renin-angiotensin-aldosterone system) and fluid intake/excretion. - Although kidneys play a role in fluid balance, GFR specifically measures the rate of filtration of blood plasma, not the overall blood volume [1].

Question 795: Which of the following is a cause of post-transplantation hypertension? I. Rejection II. Cyclosporine nephrotoxicity III. Renal transplant artery stenosis (RTAS) IV. Recurrent disease in the allograft. Select the correct option.

A. None of the above are correct causes.
B. I, II, and IV are correct causes.
C. I and III are correct causes.
D. All of the options are correct causes of post-transplantation hypertension. (Correct Answer)

Explanation: ***All of the options are correct causes of post-transplantation hypertension.*** - Post-transplantation hypertension often has a multifactorial etiology, with **rejection**, **cyclosporine nephrotoxicity**, **renal transplant artery stenosis (RTAS)**, and **recurrent disease in the allograft** all being significant contributors. - Each of these conditions can lead to mechanisms that elevate blood pressure, such as **renal ischemia**, activation of the **renin-angiotensin system**, and inflammatory responses affecting renal function. *I, II, and IV are correct causes.* - This option is incorrect because it excludes **renal transplant artery stenosis (RTAS)** (III), which is a well-established cause of secondary hypertension in transplant recipients due to reduced blood flow to the allograft. - **RTAS** activates the renin-angiotensin-aldosterone system (RAAS), leading to **vasoconstriction** and **sodium retention**, contributing to hypertension. *I and III are correct causes.* - This option is incorrect as it omits other crucial causes like **cyclosporine nephrotoxicity** (II) and **recurrent disease in the allograft** (IV), both of which are documented contributors to post-transplantation hypertension. - **Cyclosporine nephrotoxicity** causes afferent arteriolar vasoconstriction and glomerulosclerosis, directly increasing blood pressure. *None of the above are correct causes.* - This option is incorrect because **rejection**, **cyclosporine nephrotoxicity**, **renal transplant artery stenosis (RTAS)**, and **recurrent disease in the allograft** are all recognized and significant causes of post-transplantation hypertension. - Each condition has distinct pathological mechanisms that contribute to **elevated blood pressure** in transplant recipients.

Question 796: Which of the following is not a feature of Poststreptococcal Glomerulonephritis (PSGN)?

A. HTN
B. Increased urea
C. Increased creatinine
D. Normal C3 level (Correct Answer)

Explanation: ***Normal C3 level*** - In Post-streptococcal glomerulonephritis (PSGN), **C3 levels are typically decreased** due to complement consumption during the inflammatory process. [1] - A **normal C3 level** would not be consistent with PSGN, as it suggests no significant complement activation. *Increased urea* - Increased urea can occur due to **impaired renal function**, which is common in PSGN due to glomerular inflammation. [1] - It's a typical finding reflecting the kidneys' inability to excrete waste products properly. *HTN* - Hypertension is frequently associated with PSGN due to **volume overload** and activation of the renin-angiotensin system. [1] [2] - It is a common clinical feature that results from increased fluid retention. *Increased creatinine* - Increased creatinine levels indicate **renal impairment**, which is characteristic of PSGN as kidney function is affected during this condition. [1] - This finding highlights the reduction in glomerular filtration rate (GFR), typical in glomerulonephritis. [2]

Question 797: Which of the following is not a feature of distal renal tubular acidosis

A. Renal hypercalciuria
B. Normal anion gap
C. Hyperkalemia (Correct Answer)
D. Alkaline urine

Explanation: ***Hyperkalemia*** - **Distal renal tubular acidosis (dRTA)** is characterized by impaired acid excretion, leading to metabolic acidosis. The impaired excretion of acid is often accompanied by impaired potassium secretion, resulting in **hypokalemia**, not hyperkalemia. - While hyperkalemia is a feature of **type 4 RTA**, which is characterized by hypoaldosteronism or renal tubular unresponsiveness to aldosterone, it is not a feature of **distal RTA (type 1)**. [1] *Normal anion gap* - **Distal RTA** is a form of **normal anion gap metabolic acidosis**, also known as **hyperchloremic metabolic acidosis**. [1] - The anion gap is calculated as [Na+] - ([Cl-] + [HCO3-]), and in dRTA, the bicarbonate loss is compensated by an increase in chloride, maintaining a normal anion gap. *Renal hypercalciuria* - **Distal RTA** is associated with **impaired acid excretion**, which leads to chronic metabolic acidosis. - This **acidosis** promotes the dissolution of bone, releasing calcium, and decreases tubular reabsorption of calcium, resulting in **hypercalciuria**. *Alkaline urine* - In **distal RTA**, the distal tubule is unable to acidify the urine due to a defect in hydrogen ion secretion. - This leads to a persistent **urine pH > 5.5** (typically alkaline or inappropriately normal) despite systemic acidosis, making it a key diagnostic feature. [1]

Question 798: Interstitial nephritis is common with

A. Black water fever
B. Rhabdomyolysis
C. Tumor lysis syndrome
D. Nonsteroidal anti-inflammatory drugs (NSAIDs) (Correct Answer)

Explanation: ***Nonsteroidal anti-inflammatory drugs (NSAIDs)*** - **NSAIDs** are a known cause of **acute interstitial nephritis** (AIN), an inflammatory condition affecting the tubules and interstitium of the kidney [1]. - This adverse reaction often manifests as **fever**, **rash**, **eosinophilia**, and **acute kidney injury**, typically 7-10 days after drug exposure. *Black water fever* - **Blackwater fever** is a severe complication of **malaria**, characterized by massive hemolysis leading to **hemoglobinuria**, which darkens the urine. - It primarily causes **acute kidney injury** through **acute tubular necrosis** due to hemoglobin precipitation in the renal tubules, not interstitial nephritis. *Rhabdomyolysis* - **Rhabdomyolysis** involves the breakdown of muscle tissue, releasing myoglobin into the bloodstream, which is toxic to the kidneys. [1] - This condition leads to **acute kidney injury** predominantly through **acute tubular necrosis** due to myoglobin casts obstructing tubules and direct toxicity, not interstitial inflammation. *Tumor lysis syndrome* - **Tumor lysis syndrome** occurs when large numbers of cancer cells are rapidly destroyed, releasing intracellular contents like potassium, phosphate, and nucleic acids. - The high concentration of **uric acid** and **phosphate** in the renal tubules leads to crystal formation, causing **acute kidney injury** primarily through **acute uric acid nephropathy** and **phosphate nephropathy**, rather than interstitial nephritis [1].

Question 799: Which of the following is a characteristic finding in distal RTA?

A. Urine pH < 5.5
B. Hypokalemia
C. Hypercalciuria (Correct Answer)
D. Nephrolithiasis

Explanation: ***Hypercalciuria*** - **Hypercalciuria** is a characteristic finding in distal RTA (Type 1), leading to increased calcium in the urine. - This occurs due to reduced **distal tubular reabsorption of calcium** and increased bone resorption from chronic acidosis. *Urine pH < 5.5* - In distal RTA, the kidneys are unable to acidify the urine properly, leading to a **urine pH > 5.5** [1]. - A urine pH < 5.5 would suggest a normal kidney response to systemic acidosis, ruling out distal RTA. *Hypokalemia* - While hypokalemia can occur in distal RTA, it is not always present and is not the most definitive characteristic finding. - **Hypokalemia** is more characteristic of Type 1 RTA due to increased potassium excretion in an attempt to excrete H+ ions. *Nephrolithiasis* - **Nephrolithiasis** (kidney stones) is a common complication of distal RTA due to hypercalciuria and alkaline urine [2]. - However, hypercalciuria is the *reason* for the increased risk of nephrolithiasis, making it a more fundamental characteristic finding.

Question 800: Which of the following is a sign of Bartter's syndrome?

A. High potassium levels
B. Acidic blood
C. Low potassium levels (Correct Answer)
D. High sodium levels

Explanation: ***Low potassium levels*** * Bartter's syndrome is characterized by **renal salt wasting** and subsequent volume depletion, which activates the **renin-angiotensin-aldosterone system** [1]. * This leads to increased aldosterone levels, causing increased potassium secretion in the collecting ducts, resulting in **hypokalemia** [2]. *High potassium levels* * **Hyperkalemia** is not a feature of Bartter's syndrome; instead, it is marked by persistent potassium loss [1]. * Conditions causing hyperkalemia typically involve impaired renal potassium excretion or increased potassium release from cells. *Acidic blood* * Bartter's syndrome usually presents with **metabolic alkalosis** due to hydrogen ion loss in the urine, not acidic blood [2]. * Acidic blood (**acidemia**) would imply a state of respiratory or metabolic acidosis. *High sodium levels* * Bartter's syndrome primarily involves **renal salt wasting**, leading to **normal or low sodium levels** rather than high sodium levels. * High sodium levels (**hypernatremia**) are usually due to inadequate water intake or excessive water loss.

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Acute Kidney Injury

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Chronic Kidney Disease

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Glomerular Diseases

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Tubulointerstitial Diseases

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Nephrotic and Nephritic Syndromes

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Urinary Tract Infections

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Renal Replacement Therapy

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Fluid and Electrolyte Disorders

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Acid-Base Disorders

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Kidney in Systemic Diseases

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Kidney Stones and Obstructive Uropathy

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Hypertension in Kidney Disease

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Nephrology — MCQs

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