Nephrology — MCQs

Nephrology Indian Medical PG Practice Questions and MCQs

Question 221: Hypokalemia is a feature of all the following conditions except?

A. Baer syndrome
B. Gitelman syndrome
C. Gordon syndrome (Correct Answer)
D. Renal tubular acidosis Type 1

Explanation: The correct answer is **Gordon syndrome** because it is characterized by **hyperkalemia**, not hypokalemia. [1] **1. Why Gordon Syndrome is the correct answer:** Gordon syndrome (also known as Pseudohypoaldosteronism Type II) is a rare genetic disorder caused by mutations in WNK kinases (WNK1 or WNK4). This leads to increased activity of the Na-Cl cotransporter (NCC) in the distal convoluted tubule. The resulting volume expansion suppresses aldosterone, but the primary defect causes decreased potassium secretion, leading to the triad of **Hypertension, Hyperkalemia, and Metabolic Acidosis**. It is essentially the "mirror image" of Gitelman syndrome. **2. Why the other options are incorrect:** * **Bartter syndrome:** A defect in the thick ascending limb of the Loop of Henle (mimicking loop diuretics). It presents with metabolic alkalosis and significant **hypokalemia**. * **Gitelman syndrome:** A defect in the Na-Cl cotransporter in the distal tubule (mimicking thiazide diuretics). It presents with metabolic alkalosis, **hypokalemia**, and hypomagnesemia. * **Renal Tubular Acidosis (RTA) Type 1:** A distal tubule defect in H+ secretion. To maintain electrical neutrality, the kidney excretes potassium instead of hydrogen, leading to severe **hypokalemia**. **High-Yield Clinical Pearls for NEET-PG:** * **The "Rule of Hyperkalemia":** Most RTAs cause hypokalemia, **except Type 4 RTA** (Hyporeninemic hypoaldosteronism). * **Gordon vs. Liddle:** Both have hypertension. However, **Liddle syndrome** has hypokalemia (ENaC overactivity), while **Gordon syndrome** has hyperkalemia. * **Treatment of Gordon Syndrome:** Low-dose **Thiazide diuretics** are highly effective as they directly block the overactive NCC transporter.

Question 222: Glomerulonephritis is a feature of all EXCEPT:

A. Infective endocarditis
B. Diabetic nephropathy (Correct Answer)
C. Nail patella syndrome
D. Alport syndrome

Explanation: **Explanation:** The core concept tested here is the distinction between **Glomerulonephritis (GN)**—which involves inflammatory changes in the glomerulus—and **Glomerulopathy**, which refers to non-inflammatory glomerular damage. **Why Diabetic Nephropathy is the correct answer:** Diabetic nephropathy is a **non-inflammatory** metabolic/hemodynamic glomerular disease [1]. It is characterized by basement membrane thickening, mesangial expansion, and the pathognomonic **Kimmelstiel-Wilson (KW) nodules** [1]. It does not involve cellular infiltration or inflammatory crescents typical of glomerulonephritis [1]. **Analysis of other options:** * **Infective Endocarditis:** This is a classic cause of **immune-complex mediated GN**. It typically presents as focal, segmental, or diffuse proliferative GN due to the deposition of circulating immune complexes [1]. * **Nail-Patella Syndrome:** This is a genetic disorder (LMX1B mutation) that causes "moth-eaten" appearances on the glomerular basement membrane (GBM) due to irregular collagen deposition. While primarily a structural defect, it is classified under the broader umbrella of hereditary glomerulonephritides. * **Alport Syndrome:** This is a hereditary **Type IV Collagen defect** [2]. It presents with a "basket-weave" appearance of the GBM [2]. Like Nail-Patella, it is categorized as a hereditary glomerulonephritis/nephropathy. **High-Yield Clinical Pearls for NEET-PG:** * **Kimmelstiel-Wilson nodules** are ovoid, hyaline, PAS-positive nodules in the glomerular periphery. * **Infective Endocarditis** is associated with **low serum C3 levels** (hypocomplementemia) when GN is present. * **Alport Syndrome Triad:** Sensorineural deafness, ocular defects (anterior lenticonus), and hereditary nephritis [2]. * **Nail-Patella Syndrome** key features: Absent/hypoplastic patella, dystrophic nails, and **iliac horns** (pathognomonic on X-ray).

Question 223: Which of the following drugs is NOT useful in the management of hepatorenal syndrome?

A. Octreotide
B. Midodrine
C. Intravenous albumin
D. Alpha blockers (Correct Answer)

Explanation: **Explanation:** **Hepatorenal Syndrome (HRS)** is characterized by intense renal vasoconstriction occurring in the setting of advanced cirrhosis and portal hypertension. [1] The pathophysiology involves splanchnic vasodilation (mediated by nitric oxide), which leads to a decrease in effective arterial blood volume. This triggers a compensatory activation of the renin-angiotensin-aldosterone system (RAAS) and the sympathetic nervous system, causing profound renal artery constriction. [1] **Why Alpha Blockers are NOT useful:** Alpha blockers (like Prazosin or Tamsulosin) cause systemic vasodilation. In HRS, the patient is already in a state of systemic hypotension and splanchnic vasodilation. Administering alpha blockers would further decrease the effective arterial blood volume and worsen renal perfusion, potentially exacerbating the syndrome. **Why the other options are used (The Standard Medical Management):** The goal of treatment is to reverse splanchnic vasodilation and increase renal perfusion: * **Octreotide (A):** A somatostatin analogue that causes splanchnic vasoconstriction. * **Midodrine (B):** An alpha-1 agonist that increases systemic vascular resistance and blood pressure. * **Intravenous Albumin (C):** Acts as a plasma expander to increase effective circulatory volume and improve the efficacy of vasoconstrictors. [1] **Clinical Pearls for NEET-PG:** * **Gold Standard Treatment:** The combination of **Terlipressin** (a vasopressin analogue) and **Albumin** is considered the most effective medical therapy for HRS. [1] * **Definitive Treatment:** Liver transplantation is the only curative treatment. [1] * **TIPS:** Transjugular Intrahepatic Portosystemic Shunt can be used in selected patients as a bridge to transplant. * **Diagnostic Criteria:** HRS is a diagnosis of exclusion; one must first rule out shock, nephrotoxic drugs, and organic kidney disease (proteinuria <500mg/day). [1]

Question 224: Which of the following is not steroid-resistant?

A. Post-streptococcal glomerulonephritis
B. Minimal change glomerulonephritis (Correct Answer)
C. Rapidly progressive glomerulonephritis (RPGN)
D. Recurrent hematuria

Explanation: **Explanation:** The core concept behind this question is the **steroid responsiveness** of various glomerular diseases. **1. Why Minimal Change Disease (MCD) is the correct answer:** Minimal Change Disease is the most common cause of nephrotic syndrome in children. It is characterized by the effacement of podocyte foot processes. The hallmark of MCD is its **exquisite sensitivity to corticosteroids** [1]. Over 90% of children and a significant majority of adults achieve complete remission with Prednisolone therapy. Therefore, it is classified as **steroid-sensitive**, not steroid-resistant. **2. Analysis of incorrect options:** * **Post-streptococcal Glomerulonephritis (PSGN):** This is an immune-complex-mediated disease that follows a streptococcal infection. It is typically **self-limiting** [1]. Management is supportive (diuretics, antihypertensives); steroids have no proven role in its treatment and do not alter the outcome. * **Rapidly Progressive Glomerulonephritis (RPGN):** While high-dose "pulse" steroids are used in RPGN, the condition is defined by a rapid decline in GFR and crescent formation [2]. Many forms (especially Type II and certain Type III) are notoriously difficult to treat and often progress despite steroids, requiring aggressive immunosuppression like Cyclophosphamide or Plasmapheresis. * **Recurrent Hematuria:** This is a clinical presentation (often seen in IgA Nephropathy or Alport Syndrome). In many cases, such as thin basement membrane disease or mild IgA nephropathy, steroids are either not indicated or the condition does not respond to them [1]. **Clinical Pearls for NEET-PG:** * **MCD:** Most common cause of Nephrotic Syndrome in children; associated with Hodgkin’s Lymphoma in adults. * **FSGS (Focal Segmental Glomerulosclerosis):** Often the "opposite" of MCD in exams—it is frequently **steroid-resistant** and the most common cause of primary nephrotic syndrome in adults. * **Steroid Resistance in MCD:** If a child with suspected MCD does not respond to 8 weeks of steroids, a renal biopsy is indicated to rule out FSGS.

Question 225: Clinical features of uremia will appear when the Glomerular Filtration Rate (GFR) is less than what value (ml/min/1.73 m2)?

A. 15 (Correct Answer)
B. 30
C. 45
D. 60

Explanation: **Explanation:** The correct answer is **A (15 ml/min/1.73 m²)**. **Medical Concept:** Uremia is a clinical syndrome characterized by the accumulation of nitrogenous waste products (urea, creatinine) and toxins that are normally excreted by the kidneys [1]. According to the KDIGO classification of Chronic Kidney Disease (CKD), Stage 5 is defined by a **GFR <15 ml/min/1.73 m²**, also known as **End-Stage Renal Disease (ESRD)** [1]. While mild symptoms like nocturia or hypertension may appear earlier, the full constellation of uremic symptoms—including uremic encephalopathy, pericarditis, asterixis, symptoms such as nausea and vomiting, and respiratory depth changes—typically manifests only when the GFR falls below this critical threshold [1]. **Analysis of Incorrect Options:** * **B (30 ml/min/1.73 m²):** This marks the transition from Stage 3b to Stage 4 CKD. While patients may show anemia and secondary hyperparathyroidism, they are usually asymptomatic regarding uremic toxins. * **C (45 ml/min/1.73 m²):** This is the threshold for Stage 3b. Complications like bone mineral disorders begin here, but uremia does not occur. * **D (60 ml/min/1.73 m²):** This is the cutoff for diagnosing CKD (Stage 3a). At this level, kidney function is reduced, but the remaining nephrons compensate sufficiently to prevent toxin buildup [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Indications for Urgent Dialysis (AEIOU):** **A**cidosis (refractory), **E**lectrolytes (Hyperkalemia), **I**ngestion (Toxins), **O**verload (Fluid), **U**remia (Pericarditis/Encephalopathy). * **Earliest sign of CKD:** Often hypertension or albuminuria. * **Most common cause of death in CKD:** Cardiovascular disease (not uremia itself). * **Uremic Bleeding:** Due to platelet dysfunction (defective adhesion/aggregation); treated with Desmopressin (DDAVP).

Question 226: What is the first line of management for hyperkalemia presenting with ECG changes?

A. Glucose insulin drip
B. Calcium gluconate (Correct Answer)
C. Hemodialysis
D. Potassium chelating resins

Explanation: **Explanation:** The management of hyperkalemia is a high-yield topic for NEET-PG, prioritized based on the urgency of the patient's condition. When **ECG changes** (such as peaked T-waves, PR prolongation, or QRS widening) are present, the immediate priority is to prevent life-threatening arrhythmias [1], [2]. **1. Why Calcium Gluconate is Correct:** Calcium gluconate is the **first-line treatment** because it acts as a **membrane stabilizer** [1]. It antagonizes the effect of potassium on the cardiac cell membrane by shifting the threshold potential, thereby reducing myocardial excitability and preventing cardiac arrest. It does *not* lower serum potassium levels; its role is purely cardioprotective. **2. Why Other Options are Incorrect:** * **Glucose-Insulin Drip:** This is the next step after membrane stabilization. It works by shifting potassium from the extracellular space into the intracellular space. It is effective for lowering serum levels but does not provide immediate cardiac protection. * **Hemodialysis:** This is the most definitive method for removing potassium from the body, but it is time-consuming to initiate and is reserved for refractory cases or patients with renal failure. * **Potassium Chelating Resins:** These (e.g., Kayexalate) remove potassium via the GI tract. They have a slow onset of action (hours to days) and are never used for acute management with ECG changes. **Clinical Pearls for NEET-PG:** * **The "C-Big-K" Mnemonic for Order of Treatment:** **C**alcium (Stabilize) → **B**eta-agonists/Bicarbonate/Insulin-**G**lucose (Shift) → **K**ayexalate/Diuretics/Kidney dialysis (Remove). * **Dose:** Usually 10 ml of 10% Calcium Gluconate IV over 2–5 minutes [1]. * **Caution:** Use with extreme care in patients taking **Digoxin**, as hypercalcemia can precipitate digoxin toxicity ("stone heart").

Question 227: Which of the following is characteristic of Renal Tubular Acidosis (RTA) type 1?

A. Hyperkalemia.
B. Decreased ammonium excretion. (Correct Answer)
C. Acidosis with normal anion gap.
D. None of the above.

Explanation: **Explanation:** Renal Tubular Acidosis (RTA) Type 1, also known as **Distal RTA**, is characterized by a defect in the alpha-intercalated cells of the distal tubule, leading to an inability to secrete hydrogen ions ($H^+$) into the tubular lumen. **Why Option B is correct:** In a healthy kidney, $H^+$ ions are buffered by ammonia ($NH_3$) to form ammonium ($NH_4^+$) for excretion. In Type 1 RTA, the primary defect is the failure of distal $H^+$ secretion. Because $H^+$ cannot be secreted, $NH_4^+$ cannot be formed or trapped in the tubular lumen. Consequently, **decreased urinary ammonium excretion** is a hallmark of this condition, reflected clinically by a **positive urinary anion gap**. **Analysis of Incorrect Options:** * **Option A (Hyperkalemia):** This is incorrect. Type 1 RTA is typically associated with **hypokalemia** [2]. The failure to secrete $H^+$ leads to increased potassium ($K^+$) excretion to maintain electrical neutrality. Hyperkalemia is characteristic of Type 4 RTA. * **Option C (Acidosis with normal anion gap):** While Type 1 RTA *does* cause a Normal Anion Gap Metabolic Acidosis (NAGMA), this feature is common to **all** types of RTA (Type 1, 2, and 4) [1]. Therefore, while true, it is not the most specific "characteristic" distinguishing feature when compared to the specific defect in ammonium excretion. **High-Yield Clinical Pearls for NEET-PG:** * **Urinary pH:** In Type 1 RTA, the urinary pH is persistently **high (> 5.5)** because the distal tubule cannot acidify the urine [1]. * **Complications:** It is frequently associated with **nephrocalcinosis and calcium phosphate stones** due to hypercalciuria and alkaline urine. * **Associations:** Often linked to autoimmune diseases like Sjögren’s syndrome or drugs like Amphotericin B.

Question 228: Which of the following statements is false regarding renal artery stenosis?

A. Hypertension is a common presentation.
B. Renin levels are typically elevated.
C. Kidneys may show asymmetrical sizes.
D. Renal function improves with angiotensin II receptor blockers. (Correct Answer)

Explanation: **Explanation:** Renal Artery Stenosis (RAS) leads to decreased renal perfusion pressure, which activates the **Renin-Angiotensin-Aldosterone System (RAAS)** [3]. In a stenosed kidney, glomerular filtration rate (GFR) is maintained by Angiotensin II-mediated vasoconstriction of the **efferent arteriole**. **Why Option D is False (Correct Answer):** When Angiotensin II Receptor Blockers (ARBs) or ACE inhibitors are administered, they cause vasodilation of the efferent arteriole. This drops the intraglomerular pressure sharply, leading to a **decline in GFR** and potential acute kidney injury, especially in patients with bilateral RAS or stenosis in a solitary functioning kidney. Therefore, renal function typically worsens rather than improves. **Analysis of Other Options:** * **Option A:** Hypertension (Renovascular HTN) is the most common clinical presentation due to chronic RAAS activation [1]. * **Option B:** Decreased perfusion to the juxtaglomerular apparatus triggers the release of renin; thus, plasma renin levels are typically elevated [1], [2]. * **Option C:** Chronic ischemia leads to renal atrophy. A size discrepancy of **>1.5 cm** between the two kidneys is a classic diagnostic clue for unilateral RAS [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** Atherosclerosis (common in elderly) and Fibromuscular Dysplasia (common in young females; "string of beads" appearance). * **Clinical Clue:** An abdominal bruit or a sudden worsening of renal function after starting an ACE inhibitor/ARB. * **Gold Standard Diagnosis:** Renal Arteriography. * **Screening:** Duplex Doppler Ultrasound or CT/MR Angiography [1].

Question 229: Which of the following is NOT an absolute indication for dialysis?

A. Persistent or severe hyperkalemia
B. Congestive cardiac failure
C. Hyperphosphatemia (Correct Answer)
D. Severe acidosis

Explanation: ### Explanation In nephrology, the decision to initiate urgent dialysis is based on life-threatening complications of renal failure that cannot be managed with conservative medical therapy. These are often remembered by the mnemonic **AEIOU**. **Why Hyperphosphatemia is the Correct Answer:** Hyperphosphatemia (Option C) is a common feature of both acute and chronic kidney disease, but it is **not** an absolute indication for dialysis [1]. It is typically managed through dietary restriction and oral phosphate binders (e.g., calcium acetate, sevelamer) [1]. While severe, prolonged hyperphosphatemia contributes to secondary hyperparathyroidism and vascular calcification, it does not pose an immediate, acute threat to life compared to the other options. **Analysis of Incorrect Options (Absolute Indications):** * **A. Persistent/Severe Hyperkalemia:** Potassium levels >6.5 mEq/L or ECG changes refractory to medical therapy (insulin/glucose, calcium gluconate) are absolute indications due to the risk of fatal arrhythmias. * **B. Congestive Cardiac Failure (Fluid Overload):** Diuretic-resistant pulmonary edema or fluid overload causing respiratory distress is a critical indication for emergent ultrafiltration/dialysis. * **D. Severe Acidosis:** Metabolic acidosis with a pH <7.1–7.2 that does not respond to bicarbonate therapy or where bicarbonate is contraindicated (e.g., fluid overload) requires dialysis. **NEET-PG High-Yield Pearls: The "AEIOU" Indications** 1. **A**cidosis: Metabolic acidosis (pH <7.1). 2. **E**lectrolytes: Refractory Hyperkalemia (>6.5 mEq/L). 3. **I**ngestion: Toxic alcohols (methanol, ethylene glycol), Salicylates, Lithium, Theophylline. 4. **O**verload: Refractory pulmonary edema. 5. **U**remia: Symptomatic uremia (Uremic pericarditis, encephalopathy, or neuropathy). *Note: A high BUN/Creatinine level alone, without symptoms, is generally considered a relative rather than an absolute indication.*

Question 230: Which of the following is NOT a feature of hepatorenal syndrome?

A. Low GFR with serum creatinine level >1.5 mg/dL
B. Plasma osmolality > Urine osmolality (Correct Answer)
C. Urine sodium level <10 mEq/L
D. Urine red blood cell count <50/HPF

Explanation: **Explanation:** Hepatorenal Syndrome (HRS) is a form of functional renal failure occurring in patients with advanced cirrhosis or fulminant hepatic failure. It is characterized by intense renal vasoconstriction despite histologically normal kidneys [1]. **Why Option B is the Correct Answer:** In HRS, the kidneys are structurally intact and retain their ability to concentrate urine. Due to severe renal hypoperfusion, the kidneys maximally reabsorb water and sodium. This results in **hypersthenuria**, where the **Urine Osmolality is significantly higher than Plasma Osmolality** (typically >1.5:1) [1]. Therefore, the statement "Plasma osmolality > Urine osmolality" is incorrect and characteristic of acute tubular necrosis (ATN), not HRS. **Analysis of Incorrect Options:** * **Option A:** A low GFR is the hallmark of HRS. The International Club of Ascites (ICA) criteria traditionally used a serum creatinine >1.5 mg/dL, though newer definitions (HRS-AKI) focus on a rise in creatinine from baseline [1]. * **Option C:** Due to secondary hyperaldosteronism and maximal sodium retention, the **Urine Sodium is typically <10 mEq/L**, distinguishing it from ATN (where UNa is >20-40 mEq/L) [1]. * **Option D:** HRS is a functional failure without structural damage; therefore, the urinary sediment is "bland." A red blood cell count **<50/HPF** and absence of significant proteinuria are essential diagnostic criteria to rule out intrinsic renal disease [1]. **Clinical Pearls for NEET-PG:** * **Pathophysiology:** Splanchnic vasodilation leads to effective arterial hypovolemia, triggering the RAAS and sympathetic nervous system, causing profound renal vasoconstriction [1]. * **Treatment of Choice:** Vasoconstrictors (**Terlipressin** is preferred) plus **Albumin** infusion [1]. * **Definitive Treatment:** Liver Transplantation [1]. * **Diagnostic Rule-out:** HRS is a diagnosis of exclusion; it is only diagnosed if there is no improvement in renal function after 48 hours of diuretic withdrawal and volume expansion with albumin [1].

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Glomerular 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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Nephrology — MCQs

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