Nephrology — MCQs

Nephrology Indian Medical PG Practice Questions and MCQs

Question 21: Retroperitoneal fibrosis most commonly presents with?

A. Pedal edema
B. Ascites
C. Ureteric obstruction
D. Back pain (Correct Answer)

Explanation: **Explanation:** **Retroperitoneal Fibrosis (Ormond’s Disease)** is characterized by the proliferation of aberrant fibro-inflammatory tissue in the retroperitoneum, typically centered around the infrarenal abdominal aorta and iliac arteries. **Why Back Pain is the Correct Answer:** Dull, poorly localized **back or flank pain** is the most common presenting symptom, occurring in over 80–90% of patients. The pain is typically insidious in onset, non-colicky, and results from the mass effect of the fibrotic plaque or the entrapment of retroperitoneal sensory nerves. It often radiates to the lower abdomen or groins. **Analysis of Incorrect Options:** * **Ureteric Obstruction (Option C):** While ureteric involvement is the most common *complication* and a hallmark of the disease (leading to hydronephrosis and renal failure), it is usually a consequence of the disease progression rather than the initial presenting symptom. Patients often present with pain long before obstructive uropathy becomes clinically evident. * **Pedal Edema (Option A):** This occurs due to the compression of the inferior vena cava (IVC) or lymphatic vessels by the fibrotic mass. While a known feature, it is less frequent than back pain. * **Ascites (Option B):** This is an uncommon presentation and usually suggests advanced portal vein involvement or secondary systemic causes, which are rare in isolated retroperitoneal fibrosis. **High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** 70% are idiopathic; others are associated with drugs (Methysergide, Ergotamine, Beta-blockers) or **IgG4-related disease**. * **Imaging:** CT/MRI shows a "mantle-like" mass encasing the aorta. A classic finding on IVP is **medial deviation of the ureters**. * **Treatment:** Corticosteroids are the first-line medical management; Tamoxifen or Mycophenolate Mofetil are used in refractory cases. Ureterolysis is the surgical intervention of choice.

Question 22: Dialysis allows for the exchange of particles across a semipermeable membrane by which of the following actions?

A. Osmosis and diffusion (Correct Answer)
B. Passage of fluid toward a solution with a lower solute concentration
C. Allowing the passage of blood cells and protein molecules through it.
D. Passage of solute particles toward a solution with a higher concentration.

Explanation: **Explanation:** Dialysis is a life-sustaining process used in renal failure to remove metabolic waste products and excess fluid from the blood [1], [4]. It relies on the movement of solutes and solvents across a semipermeable membrane based on two primary physical principles: 1. **Diffusion:** This is the movement of **solutes** (such as urea, creatinine, and potassium) from an area of higher concentration (blood) to an area of lower concentration (dialysate) across the membrane [1], [4]. 2. **Osmosis:** This is the movement of **solvent (water)** across the membrane from an area of lower solute concentration to an area of higher solute concentration [2]. In hemodialysis, fluid removal is further enhanced by **ultrafiltration** (hydrostatic pressure), while in peritoneal dialysis, osmotic gradients are created using glucose [1]. **Analysis of Incorrect Options:** * **Option B:** This is incorrect because fluid (water) moves toward a solution with a **higher** solute concentration (osmosis), not lower [2]. * **Option C:** The semipermeable membrane is designed to be selective. It prevents the loss of essential large molecules like **albumin (proteins)** and **blood cells**, allowing only small solutes and water to pass. * **Option D:** Solute particles move toward a solution with a **lower** concentration (diffusion) to achieve equilibrium, not higher [4]. **High-Yield Clinical Pearls for NEET-PG:** * **Efficiency:** Diffusion is most efficient for small molecules (Urea < Creatinine < Phosphate). * **Convection:** In techniques like Hemofiltration, "solvent drag" (convection) is used to remove larger middle molecules (e.g., $̢β_2$-microglobulin) [3]. * **Dialysate Composition:** To prevent the removal of essential electrolytes, the dialysate concentration of substances like Calcium and Bicarbonate is kept similar to or higher than normal plasma levels [4].

Question 23: Goodpasture's syndrome is characterized by which of the following?

A. Anti-GBM antibodies
B. Crescenteric glomerulonephritis
C. Diffuse alveolar haemorrhage
D. All of the above (Correct Answer)

Explanation: **Explanation:** Goodpasture’s Syndrome (also known as Anti-GBM Disease) is a rare but life-threatening autoimmune disorder characterized by the triad of **Anti-GBM antibodies**, **Crescentic Glomerulonephritis**, and **Diffuse Alveolar Hemorrhage**. [1] 1. **Anti-GBM Antibodies (Option A):** The pathogenesis involves the formation of autoantibodies against the **alpha-3 chain of Type IV collagen**. This antigen is primarily expressed in the basement membranes of the renal glomeruli and pulmonary alveoli. 2. **Crescentic Glomerulonephritis (Option B):** The binding of these antibodies triggers a severe inflammatory response, leading to **Rapidly Progressive Glomerulonephritis (RPGN)**. Histologically, this is characterized by the formation of "crescents" in Bowman’s space, representing severe glomerular injury. [2] 3. **Diffuse Alveolar Hemorrhage (Option C):** Cross-reactivity with the alveolar basement membrane leads to pulmonary capillaritis, resulting in hemoptysis and pulmonary infiltrates. [1] **Why "All of the above" is correct:** Since Goodpasture’s syndrome is defined by the clinical combination of pulmonary hemorrhage and glomerulonephritis mediated by specific anti-GBM antibodies, all three individual options are hallmark features of the disease. [1] **High-Yield Clinical Pearls for NEET-PG:** * **Immunofluorescence (Gold Standard):** Shows **Linear IgG deposits** along the glomerular basement membrane (unlike the granular pattern seen in Post-Streptococcal GN). [2] * **Demographics:** Typically shows a bimodal age distribution (young men in their 20s and older women in their 60s). * **Risk Factors:** Smoking and exposure to hydrocarbons/solvents can trigger pulmonary symptoms. * **Treatment:** The mainstay is **Plasmapheresis** (to remove circulating antibodies) combined with corticosteroids and cyclophosphamide. [1] * **Note:** If only the kidneys are involved without pulmonary hemorrhage, the condition is simply called **Anti-GBM Disease**.

Question 24: Which of the following is NOT a complication of hemodialysis?

A. Altered cardiovascular dynamics
B. Anaphylactoid reaction
C. Hypertension (Correct Answer)
D. Muscle cramps

Explanation: The correct answer is **C. Hypertension**. In fact, **hypotension** is the most common acute complication of hemodialysis, occurring in approximately 20–30% of sessions. **Why Hypertension is the correct answer:** While chronic hypertension is a common reason patients *require* dialysis, the procedure itself typically causes a drop in blood pressure due to rapid fluid removal (ultrafiltration) and shifts in serum osmolality. While "intradialytic hypertension" can occur in a small subset of patients (due to renin-angiotensin activation or sympathetic overactivity), it is considered a paradoxical event rather than a standard expected complication of the procedure [1]. **Analysis of Incorrect Options:** * **A. Altered cardiovascular dynamics:** Hemodialysis causes significant shifts in blood volume and electrolytes. This leads to decreased cardiac output, arrhythmias, and potential myocardial "stunning" due to transient ischemia during fluid removal. * **B. Anaphylactoid reaction:** This is a known acute complication, often referred to as "First-use syndrome." It is typically caused by hypersensitivity to the dialyzer membrane (e.g., cuprophane) or sterilizing agents like ethylene oxide. * **D. Muscle cramps:** These are very common (5–20% of sessions). The etiology is multifactorial, involving rapid fluid removal, tissue hypoxia, and electrolyte imbalances (hypomagnesemia or hypocalcemia) [1]. **High-Yield NEET-PG Pearls:** * **Most common acute complication:** Hypotension. * **Disequilibrium Syndrome:** Caused by rapid removal of urea, leading to cerebral edema. Symptoms include headache, confusion, and seizures. Prevented by slow initial dialysis. * **First-use Syndrome:** Type A (Anaphylactic, IgE-mediated) occurs within minutes; Type B (Non-specific, chest/back pain) occurs later in the session. * **Commonest cause of death in ESRD patients on dialysis:** Cardiovascular disease (Arrhythmias/MI).

Question 25: All are true about Alport syndrome, EXCEPT:

A. Hereditary nephropathy
B. Sensorineural hearing loss
C. Microscopic hematuria during early childhood
D. Renal failure occurs in 50% of affected males (Correct Answer)

Explanation: Explanation: Alport Syndrome is a hereditary basement membrane disorder caused by mutations in the genes encoding the Type IV collagen alpha chains (α3, α4, or α5) [2]. Why Option D is the correct answer (The Exception): In the most common form, X-linked Alport Syndrome (XLAS), renal involvement is progressive and severe in males. It is not limited to 50%; rather, virtually 100% of affected males will develop End-Stage Renal Disease (ESRD) by the age of 40. The 50% figure is inaccurate as it significantly underestimates the penetrance and severity of the disease in males. Analysis of other options: * Option A (Hereditary nephropathy): True. It is the most common hereditary glomerular disease, most frequently inherited in an X-linked dominant pattern (85%), followed by autosomal recessive and dominant forms. * Option B (Sensorineural hearing loss): True. This is a classic extra-renal manifestation. It is typically bilateral, high-frequency, and usually manifests during late childhood or adolescence. * Option C (Microscopic hematuria): True. Persistent microscopic hematuria is the earliest and most common sign of Alport syndrome, often appearing in early childhood. NEET-PG High-Yield Pearls: * Pathology: Electron microscopy shows a characteristic "Basket-weave appearance" due to irregular thickening, thinning, and splitting of the Glomerular Basement Membrane (GBM) [2]. * Ocular Findings: Anterior Lenticonus (pathognomonic) and "dot-and-fleck" retinopathy. * Molecular Defect: Mutation in COL4A5 (X-linked) or COL4A3/COL4A4 (Autosomal) [2]. * Post-Transplant Complication: Patients are at risk of developing Anti-GBM disease (Goodpasture-like syndrome) in the graft because their immune system recognizes the normal Type IV collagen in the donor kidney as foreign [1].

Question 26: What is the most sensitive and specific investigation for screening of renovascular hypertension?

A. MRI
B. Captopril enhanced radionuclide scan
C. Spiral CT Scan (Correct Answer)
D. Duplex – Doppler flow study

Explanation: Renovascular hypertension (RVH) is most commonly caused by atherosclerosis or fibromuscular dysplasia. While **Digital Subtraction Angiography (DSA)** remains the "Gold Standard" for diagnosis, it is invasive. For screening and non-invasive diagnosis, **Spiral CT Angiography (CTA)** is currently considered the most sensitive and specific investigation [1]. **Why Spiral CT Scan is Correct:** Spiral CT (specifically Multidetector CT) offers high spatial resolution, allowing for excellent visualization of the renal artery anatomy and the detection of stenotic lesions [1]. It has a sensitivity and specificity often exceeding 90-95%, making it superior to ultrasound and nuclear medicine for identifying anatomical narrowing. **Analysis of Incorrect Options:** * **MRI (MRA):** While highly accurate and avoiding ionizing radiation, Gadolinium-enhanced MRA is contraindicated in patients with significant renal impairment (eGFR <30) due to the risk of Nephrogenic Systemic Fibrosis (NSF) [3]. It is generally slightly less sensitive than CTA for distal or accessory renal artery stenosis. * **Captopril Enhanced Radionuclide Scan:** Once a popular screening tool, its utility has declined. It is less reliable in patients with bilateral disease or impaired baseline renal function, leading to lower sensitivity compared to CTA. * **Duplex – Doppler Flow Study:** This is highly operator-dependent and technically challenging in obese patients or those with excessive bowel gas [2]. While useful for follow-up, it lacks the consistent sensitivity required to be the "most" reliable screening tool compared to CTA. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** Digital Subtraction Angiography (DSA). * **Best Initial Screening (Non-invasive):** Spiral CT Angiography (CTA) [1]. * **Classic Presentation:** Sudden onset hypertension in a young female (Fibromuscular dysplasia) or refractory hypertension in an elderly patient with generalized atherosclerosis. * **Key Sign:** An abdominal bruit heard on auscultation. * **Contraindication:** Avoid ACE inhibitors/ARBs in patients with bilateral renal artery stenosis as it can precipitate acute renal failure.

Question 27: Absent P waves with wide QRS complex indicates serum potassium of what level?

A. 5.4 meq/L
B. 6.5 meq/L
C. More than 8 meq/L (Correct Answer)
D. More than 10 meq/L

Explanation: **Explanation:** Hyperkalemia is a critical electrolyte abnormality that causes progressive changes in cardiac conduction [1]. The ECG manifestations follow a predictable sequence as serum potassium levels rise: 1. **Serum K+ 5.5–6.5 mEq/L:** The earliest sign is the appearance of **Tall, peaked T waves** (narrow base, "tent-shaped") in most leads [1]. 2. **Serum K+ 6.5–8.0 mEq/L:** As levels increase, there is paralysis of the atria [1]. This leads to **prolongation of the PR interval**, flattening/decreased amplitude of the P wave, and eventually **disappearance of the P wave**. Concurrently, the **QRS complex begins to widen** [1]. 3. **Serum K+ >8.0 mEq/L:** At this severe level, the P wave is typically **absent**, and the QRS complex becomes **markedly wide**, eventually merging with the T wave to form a **Sine Wave pattern**. This is a pre-terminal rhythm that can rapidly progress to ventricular fibrillation or asystole. **Analysis of Options:** * **Option A (5.4 mEq/L):** This is near the upper limit of normal; ECG is usually normal or shows very mild T-wave peaking. * **Option B (6.5 mEq/L):** At this level, peaked T waves are prominent, but P waves are usually still present, and QRS widening is just beginning. * **Option D (>10 mEq/L):** While ECG changes would be severe here, the classic threshold for the disappearance of P waves and significant QRS widening in medical literature and exams is >8 mEq/L. **Clinical Pearls for NEET-PG:** * **Treatment Priority:** The first step in managing hyperkalemia with ECG changes is **Intravenous Calcium Gluconate** (to stabilize the cardiac membrane), followed by agents to shift K+ intracellularly (Insulin+Dextrose, Salbutamol). * **Pseudohyperkalemia:** Always rule out hemolysis during blood collection if ECG is normal despite high lab values. * **Hypokalemia:** Look for U waves, flattened T waves, and ST depression.

Question 28: Renal artery stenosis is caused by all of the following except:

A. Atherosclerosis
B. Fibromuscular dysplasia
C. Takayasu arteritis
D. Buerger's disease (Correct Answer)

Explanation: **Explanation:** Renal Artery Stenosis (RAS) is the narrowing of one or both renal arteries, leading to renovascular hypertension. The correct answer is **Buerger’s disease** because it is a peripheral vascular disease that does not typically involve the renal arteries. **1. Why Buerger’s Disease is the Correct Answer:** Buerger’s disease (Thromboangiitis obliterans) is a non-atherosclerotic, inflammatory occlusive disease that primarily affects **small and medium-sized arteries and veins of the distal extremities** (hands and feet). It is strongly associated with heavy tobacco use. It does not involve visceral arteries like the renal artery. **2. Analysis of Other Options:** * **Atherosclerosis:** The **most common cause** of RAS (approx. 90%), typically involving the proximal third or the ostium of the renal artery. It is usually seen in elderly patients with cardiovascular risk factors. * **Fibromuscular Dysplasia (FMD):** The second most common cause, typically seen in **young females**. It involves the distal two-thirds of the renal artery, often presenting with a "string of beads" appearance on angiography. * **Takayasu Arteritis:** A large-vessel vasculitis ("pulseless disease") that involves the aorta and its primary branches. It is a significant cause of RAS in young patients, particularly in Asian populations. **Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Digital Subtraction Angiography (DSA). * **Screening Test of Choice:** Duplex Doppler Ultrasound or CT/MR Angiography. * **Classic Sign:** Abdominal bruit heard on auscultation. * **ACE Inhibitor Warning:** ACE inhibitors are contraindicated in **bilateral** renal artery stenosis (or stenosis in a solitary kidney) as they can precipitate acute renal failure by reducing intraglomerular pressure.

Question 29: What is the definitive treatment for hypermagnesemia?

A. Calcium gluconate
B. IV fluids
C. Hemodialysis (Correct Answer)
D. Exchange resins

Explanation: **Explanation:** Hypermagnesemia is a rare but potentially life-threatening electrolyte imbalance, typically occurring in patients with advanced chronic kidney disease (CKD) who ingest magnesium-containing medications. **Why Hemodialysis is the Correct Answer:** While initial management involves stopping magnesium intake and promoting excretion, **Hemodialysis** is the **definitive treatment**. Magnesium is primarily an intracellular cation, but its serum levels are effectively reduced by dialysis because the kidneys are the only natural route for significant magnesium clearance. In patients with severe renal failure or those with life-threatening symptoms (e.g., respiratory depression, coma, or cardiac arrhythmias), dialysis is the only way to rapidly and reliably remove the excess magnesium load from the body [2]. **Analysis of Incorrect Options:** * **A. Calcium Gluconate:** This is the **immediate first-line treatment** for symptomatic hypermagnesemia [1]. It acts as a physiological antagonist to magnesium at the neuromuscular junction and cardiac membrane, protecting the heart. However, it does not remove magnesium from the body; it only stabilizes the membrane. * **B. IV Fluids:** Saline diuresis (with or without loop diuretics) can enhance magnesium excretion in patients with **normal renal function**. It is not definitive in the setting of renal failure. * **C. Exchange Resins:** These (like Sodium Polystyrene Sulfonate) are used for hyperkalemia, not hypermagnesemia. There is no specific exchange resin for magnesium. **High-Yield Clinical Pearls for NEET-PG:** * **Early Sign:** Loss of deep tendon reflexes (DTRs) occurs at levels of 4–6 mEq/L. * **Late Signs:** Respiratory paralysis and heart block occur at levels >10 mEq/L. * **Antidote:** 10% Calcium Gluconate (10 mL IV over 10 mins) [1]. * **Classic Scenario:** An elderly patient with CKD taking magnesium-containing antacids or laxatives.

Question 30: Which of the following conditions is characterized by a normal kidney size?

A. Nephronophthisis
B. Autosomal dominant polycystic kidney disease (ADPCKD)
C. Acquired renal cysts
D. Medullary sponge kidney (Correct Answer)

Explanation: **Explanation:** The size of the kidneys is a crucial diagnostic clue in nephrology. While most chronic kidney diseases (CKD) lead to shrunken kidneys due to fibrosis, certain conditions are exceptions where kidney size remains normal or becomes enlarged. **Correct Answer: D. Medullary Sponge Kidney (MSK)** In Medullary Sponge Kidney, there is cystic dilatation of the collecting ducts in the renal pyramids. Despite these structural changes, the overall architecture of the kidney is preserved, and the **kidney size remains normal** [1]. It is typically a benign, non-progressive condition often discovered incidentally or when patients present with nephrolithiasis or UTIs [1]. **Analysis of Incorrect Options:** * **A. Nephronophthisis:** This is a progressive tubulointerstitial disease. It is a classic cause of **shrunken (small) kidneys** with corticomedullary cysts [1]. It is the most common genetic cause of ESRD in children. * **B. ADPCKD:** This condition is characterized by **bilaterally enlarged kidneys** due to the progressive growth of numerous large cysts that replace the renal parenchyma [1]. * **C. Acquired Renal Cysts:** These occur in patients with long-standing CKD or those on dialysis. Because the underlying state is chronic renal failure, the kidneys are typically **small/shrunken**, even though they develop multiple cysts. **High-Yield Clinical Pearls for NEET-PG:** * **CKD with Large/Normal Kidneys (Mnemonic: "SHAM"):** * **S:** **S**ystemic Amyloidosis (Enlarged) * **H:** **H**IV-associated nephropathy (HIVAN) * **A:** **A**DPCKD (Massively enlarged) [1] * **M:** **M**ellitus (Diabetes Mellitus - early stages) * **Medullary Sponge Kidney** is associated with "Paintbrush appearance" or "Bouquet of flowers" on Intravenous Urography (IVU) [1]. * **Nephronophthisis** is associated with the *NPHP* gene and can present with extra-renal features like retinitis pigmentosa (Senior-Løken syndrome) [1].

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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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Nephrology — MCQs

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