Nephrology — MCQs

Nephrology Indian Medical PG Practice Questions and MCQs

Question 381: Metabolic complications in chronic renal failure (CRF) include all of the following EXCEPT?

A. Hyperkalemia
B. Hypophosphatemia (Correct Answer)
C. Hypocalcemia
D. Hypokalemia

Explanation: In Chronic Renal Failure (CRF), the progressive loss of functioning nephrons leads to significant derangements in electrolyte and acid-base balance. **Explanation of the Correct Answer:** **B. Hypophosphatemia:** This is the correct answer because CRF characteristically causes **Hyperphosphatemia**, not hypophosphatemia. As the Glomerular Filtration Rate (GFR) declines, the kidneys' ability to excrete phosphate decreases. This leads to phosphate retention, which plays a central role in the development of secondary hyperparathyroidism and renal osteodystrophy [2]. **Explanation of Incorrect Options:** * **A. Hyperkalemia:** This is a classic feature of advanced CRF (usually when GFR <15-20 mL/min). Decreased distal delivery of sodium and reduced tubular secretion of potassium lead to its accumulation. * **C. Hypocalcemia:** This occurs due to two main reasons: (1) Hyperphosphatemia leads to calcium-phosphate precipitation, and (2) Failure of the kidneys to convert Vitamin D to its active form (1,25-dihydroxyvitamin D3) results in decreased intestinal calcium absorption [2]. * **D. Hypokalemia:** While hyperkalemia is the rule, hypokalemia can occasionally occur in specific types of renal failure, such as Renal Tubular Acidosis (RTA) or during the diuretic phase of recovery, making it a recognized (though less common) metabolic complication compared to the "normal" state of health. *Note: In the context of this specific MCQ, Hyperphosphatemia is the definitive "wrong" clinical finding.* **High-Yield Clinical Pearls for NEET-PG:** * **Metabolic Acidosis:** CRF typically presents with a **High Anion Gap Metabolic Acidosis** due to the failure to excrete organic acids (phosphates, sulfates) [1]. * **Renal Osteodystrophy Triad:** Hyperphosphatemia + Hypocalcemia + Secondary Hyperparathyroidism [2]. * **Early Sign:** The earliest metabolic change in CRF is often a rise in **FGF-23**, which attempts to maintain phosphate balance before overt hyperphosphatemia develops [2].

Question 382: A patient develops gross hematuria 3 days after an upper respiratory infection. Which of the following is responsible?

A. Acute glomerulonephritis
B. Minimal change disease
C. IgA nephropathy (Correct Answer)
D. Drug abuse

Explanation: ### Explanation **Correct Option: C. IgA nephropathy** The hallmark of **IgA nephropathy (Berger’s disease)** is **synpharyngitic hematuria**—gross hematuria occurring concurrently or within 1–3 days of an upper respiratory tract infection (URTI) [1]. The underlying mechanism involves the overproduction of galactose-deficient IgA1 in response to mucosal triggers, which forms immune complexes that deposit in the glomerular mesangium, leading to inflammation and hematuria [3]. **Why other options are incorrect:** * **A. Acute Glomerulonephritis (PSGN):** Post-Streptococcal Glomerulonephritis typically has a **latent period** of 1–3 weeks after a sore throat (pharyngitis) or 3–6 weeks after a skin infection (impetigo). It does not occur within 3 days of the trigger. * **B. Minimal Change Disease:** This typically presents as **Nephrotic Syndrome** (massive proteinuria, edema, hypoalbuminemia) rather than gross hematuria [2]. It is not classically triggered by an infection within a 3-day window. * **D. Drug abuse:** While certain drugs (like NSAIDs or heroin) can cause interstitial nephritis or secondary FSGS, they do not present with the classic "infection-to-hematuria" temporal relationship seen in this case. **High-Yield Clinical Pearls for NEET-PG:** * **IgA Nephropathy** is the most common cause of primary glomerulonephritis worldwide. * **Complement levels (C3, C4):** Are **normal** in IgA nephropathy but **decreased** in PSGN. * **Prognosis:** The most important prognostic factor is the degree of proteinuria and hypertension. * **Henoch-Schönlein Purpura (HSP):** Is considered the systemic vasculitic form of IgA nephropathy, presenting with a tetrad of palpable purpura, arthralgia, abdominal pain, and renal involvement.

Question 383: All of the following are indicated in the management of acute hyperkalemia except?

A. Intravenous Calcium gluconate
B. Intravenous Glucose and Insulin
C. Beta2 agonist inhalation
D. Sodium polystyrene sulfonate (Correct Answer)

Explanation: **Explanation:** The management of **acute hyperkalemia** (typically defined as $K^+ > 6.5$ mEq/L or presence of ECG changes) focuses on three immediate goals: stabilizing the cardiac membrane, shifting potassium into cells, and removing potassium from the body [1]. **Why Option D is the correct answer:** **Sodium polystyrene sulfonate (Kayexalate)** is a cation-exchange resin. While it does remove potassium from the body via the GI tract, its onset of action is very slow (several hours to days). Therefore, it has **no role in the emergency/acute management** of life-threatening hyperkalemia. Furthermore, recent guidelines discourage its use due to the risk of intestinal necrosis. **Analysis of Incorrect Options (Indicated Treatments):** * **A. IV Calcium Gluconate:** This is the first-line treatment if ECG changes are present [1]. It **stabilizes the cardiac myocyte membrane** (antagonizes the membrane effect of hyperkalemia) without lowering serum potassium levels [1]. * **B. IV Glucose and Insulin:** This is the most reliable method to **shift potassium intracellularly**. Insulin stimulates the Na-K ATPase pump; glucose is co-administered to prevent hypoglycemia [2]. * **C. Beta-2 Agonist Inhalation:** Salbutamol (Albuterol) nebulization also promotes the **intracellular shift** of potassium [2]. It acts synergistically with insulin. **NEET-PG High-Yield Pearls:** 1. **Fastest acting:** IV Calcium Gluconate (onset 1-3 mins) – but it does *not* lower $K^+$. 2. **Most effective for shifting $K^+$:** Insulin + Glucose. 3. **Definitive management:** Hemodialysis is the fastest way to *remove* potassium in patients with renal failure. 4. **ECG Sequence:** Tall peaked T-waves $→$ PR prolongation $→$ Loss of P-wave $→$ Widening of QRS $→$ Sine wave pattern $→$ Asystole.

Question 384: Clinical features of chronic renal failure (CRF) appear when renal function is reduced to what percentage of normal?

A. 70%
B. 50%
C. 30%
D. 20% (Correct Answer)

Explanation: **Explanation:** The kidneys possess a remarkable functional reserve, meaning they can maintain homeostasis even when a significant portion of nephrons is lost. Clinical features of Chronic Renal Failure (CRF) typically do not manifest until the **Glomerular Filtration Rate (GFR) falls below 20-25% of its normal value.** [1] 1. **Why 20% is correct:** This threshold marks the transition from "Renal Insufficiency" to "Renal Failure." At this stage, the remaining nephrons can no longer compensate for the loss. Patients begin to develop overt symptoms such as azotemia (elevation of BUN/Creatinine), anemia (due to decreased erythropoietin), and impaired concentrating ability (isosthenuria) [1]. 2. **Why other options are incorrect:** * **70% & 50%:** At these levels, the kidney is in the stage of **Decreased Renal Reserve.** Patients are asymptomatic, and routine blood tests (BUN/Creatinine) are often within normal limits because the surviving nephrons undergo compensatory hypertrophy. * **30%:** This represents moderate renal insufficiency. While biochemical abnormalities may be detectable, many patients remain relatively asymptomatic or have very mild, non-specific symptoms [1]. **High-Yield NEET-PG Pearls:** * **Stages of CKD:** Defined by GFR. Stage 1 (>90), Stage 2 (60-89), Stage 3 (30-59), Stage 4 (15-29), and Stage 5 (<15 ml/min) [1]. * **Earliest Clinical Sign:** Polyuria and nocturia (due to loss of urinary concentrating ability). * **Earliest Biochemical Sign:** Increase in serum Creatinine (though it only rises significantly after 50% nephron loss). * **Uremic Syndrome:** Usually occurs when GFR drops below 5-10% (End-Stage Renal Disease) [1].

Question 385: Nephrocalcinosis is seen in which of the following conditions?

A. Sarcoidosis
B. Medullary cystic disease
C. Milk alkali syndrome
D. All the above (Correct Answer)

Explanation: Explanation: Nephrocalcinosis refers to the generalized deposition of calcium salts (calcium phosphate or calcium oxalate) within the renal parenchyma, most commonly in the renal medulla. It is primarily driven by states of hypercalcemia, hypercalciuria, or hyperoxaluria. Breakdown of Options: * **Sarcoidosis (Option A):** This is a granulomatous disease where macrophages within the granulomas produce 1-alpha-hydroxylase. This enzyme converts Vitamin D into its active form (1,25-dihydroxyvitamin D), leading to increased intestinal calcium absorption, hypercalcemia, and subsequent hypercalciuria, which causes calcium deposition in the kidneys [2]. * **Medullary Cystic Disease (Option B):** While often confused with Medullary Sponge Kidney (MSK), both can be associated with nephrocalcinosis [1]. In MSK, urinary stasis in dilated collecting ducts promotes stone formation; in certain cystic diseases, metabolic derangements and structural changes facilitate calcification. * **Milk-Alkali Syndrome (Option C):** This results from excessive ingestion of calcium and absorbable alkali [2]. It leads to the triad of hypercalcemia, metabolic alkalosis, and renal insufficiency. The high serum calcium levels directly lead to metastatic calcification within the renal tissue [2]. Clinical Pearls for NEET-PG: 1. **Most Common Cause:** Primary Hyperparathyroidism is the most frequent cause of nephrocalcinosis [2]. 2. **Distal Renal Tubular Acidosis (Type 1 RTA):** A high-yield association. It causes nephrocalcinosis due to alkaline urine, hypercalciuria, and hypocitraturia. 3. **Imaging:** Ultrasonography is the most sensitive initial screening tool, showing "hyperechoic pyramids" [1]. 4. **Differential:** Do not confuse nephrocalcinosis (parenchymal calcification) with nephrolithiasis (stones within the pelvicalyceal system).

Question 386: Which of the following conditions does NOT cause contracted kidney?

A. Diabetic nephropathy (Correct Answer)
B. Chronic glomerulonephritis
C. Chronic pyelonephritis
D. Benign nephrosclerosis

Explanation: In chronic kidney disease (CKD), the hallmark finding is typically **contracted kidneys** (small, shrunken, and scarred) due to progressive fibrosis and loss of nephrons [1]. However, certain conditions are notable exceptions where the kidneys remain normal-sized or even enlarged despite renal failure. ### **Why Diabetic Nephropathy is the Correct Answer** In **Diabetic Nephropathy**, the kidneys are characteristically **enlarged or normal-sized**, even in advanced stages of chronic renal failure. This occurs due to: * **Hyperfiltration and hypertrophy:** Early stages involve glomerular hyperfiltration. * **Matrix expansion:** Accumulation of basement membrane material and mesangial matrix (Kimmelstiel-Wilson nodules) [2]. * **Glycation products:** Deposition of advanced glycation end-products (AGEs) leads to structural bulk. ### **Why the Other Options are Incorrect** * **Chronic Glomerulonephritis (B):** This is the classic cause of bilateral, symmetrically contracted kidneys with a granular surface due to global glomerular scarring. * **Chronic Pyelonephritis (C):** Leads to asymmetrical contraction with characteristic **U-shaped cortical scars** overlying blunted calyces [1]. * **Benign Nephrosclerosis (D):** Long-standing hypertension causes hyaline arteriolosclerosis, leading to ischemic atrophy and finely granular, shrunken kidneys. ### **High-Yield Clinical Pearls for NEET-PG** To excel in questions regarding "Large Kidneys in CKD," remember the mnemonic **"DAPAM"**: 1. **D**iabetic Nephropathy (Most common cause) 2. **A**myloidosis (Due to extracellular protein deposition) 3. **P**olycystic Kidney Disease (ADPKD - due to multiple expanding cysts) 4. **A**IV (HIV-associated nephropathy) 5. **M**yeloma Kidney (Light chain deposition) *Note: In Diabetic Nephropathy, kidneys only begin to shrink in the very terminal stages if there is significant superimposed atherosclerotic renovascular disease.*

Question 387: Which of the following conditions causes euvolemic hyponatremia?

A. Nephrotic syndrome
B. Syndrome of Inappropriate Antidiuretic Hormone secretion (SIADH) (Correct Answer)
C. Diarrhea
D. Vomiting

Explanation: Hyponatremia is classified based on the patient’s volume status into hypovolemic, euvolemic, and hypervolemic states [1]. **Correct Answer: B. SIADH** SIADH is the classic cause of **euvolemic hyponatremia** [1]. In this condition, excessive ADH secretion leads to water retention and concentrated urine [2]. While the body retains water, it does not retain sodium; the initial mild volume expansion triggers **atrial natriuretic peptide (ANP)** release and suppresses the Renin-Angiotensin-Aldosterone System (RAAS). This results in "pressure natriuresis" (excretion of sodium in urine), which brings the extracellular fluid volume back toward normal (euvolemia) but worsens the hyponatremia. **Incorrect Options:** * **A. Nephrotic Syndrome:** This causes **hypervolemic hyponatremia** [1]. Low oncotic pressure (due to hypoalbuminemia) leads to fluid shifting into the interstitium (edema), causing a decrease in effective arterial blood volume, which triggers compensatory ADH release. * **C & D. Diarrhea and Vomiting:** These cause **hypovolemic hyponatremia** [1]. There is a loss of both salt and water. The resulting volume depletion stimulates ADH secretion (non-osmotic trigger) to preserve volume at the expense of tonicity. **NEET-PG High-Yield Pearls:** * **Euvolemic Hyponatremia Causes:** Remember the mnemonic **"RASH"**: **R**enal tubular acidosis (proximal), **A**ddison’s disease (secondary/Glucocorticoid deficiency), **S**IADH, and **H**ypothyroidism [1]. * **SIADH Diagnosis:** Characterized by low serum osmolality (<275 mOsm/kg), inappropriately high urine osmolality (>100 mOsm/kg), and high urine sodium (>40 mEq/L). * **Treatment:** Fluid restriction is the first-line treatment for SIADH. For severe symptomatic cases, use 3% hypertonic saline.

Question 388: What is the most common renal condition observed in HIV patients?

A. Mesangial proliferation
B. Focal segmental glomerulosclerosis (Correct Answer)
C. Membranous glomerulonephritis
D. Minimal change disease

Explanation: **Explanation:** The most common renal manifestation of HIV infection is **HIV-Associated Nephropathy (HIVAN)**, which characteristically presents as a **collapsing variant of Focal Segmental Glomerulosclerosis (FSGS)** [1]. 1. **Why FSGS is correct:** HIVAN is caused by the direct infection of renal tubular and glomerular cells by the HIV virus, leading to podocyte dysregulation [1]. It typically presents with heavy proteinuria (nephrotic range), rapidly progressive renal failure, and normal-sized or enlarged kidneys on ultrasound. It is most frequently seen in patients of African descent due to the presence of **APOL1 gene** risk variants. 2. **Why other options are incorrect:** * **Mesangial proliferation:** While seen in some viral infections (like Hepatitis B), it is not the primary or most common lesion associated with HIV [1]. * **Membranous glomerulonephritis:** This is more commonly associated with **Hepatitis B**, syphilis, or gold therapy, rather than HIV. * **Minimal change disease:** This is the most common cause of nephrotic syndrome in children and is associated with NSAIDs or Hodgkin’s lymphoma, but not specifically with HIV [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Pathology Hallmark:** "Collapsing" FSGS (wrinkling and collapse of the glomerular basement membrane). * **Ultrasound Finding:** Unlike most chronic kidney diseases where kidneys shrink, in HIVAN, kidneys are often **large and echogenic**. * **Treatment:** Initiation of **HAART (Highly Active Antiretroviral Therapy)** is the most effective way to slow the progression of HIVAN. * **Immune Complex Disease:** HIV patients can also develop "HIVICK" (HIV-associated immune complex kidney disease), but FSGS remains the most common classic association.

Question 389: A diabetic male presents with hypertension and 24-hour urine showing 200 mg of albumin. In a diabetic patient with microalbuminuria, what is the appropriate drug for the treatment of hypertension to prevent the progression of renal failure?

A. Beta blocker
B. Thiazide diuretic
C. Angiotensin converting enzyme inhibitor (Correct Answer)
D. Short-acting dihydropyridine calcium channel blocker for precise control (nifedipine)

Explanation: ### Explanation **Correct Answer: C. Angiotensin converting enzyme inhibitor (ACEI)** **Why it is correct:** In diabetic nephropathy, the primary goal is to reduce intraglomerular pressure. ACE inhibitors (and ARBs) are the drugs of choice because they cause **preferential vasodilation of the efferent arteriole** [1]. This reduces the glomerular filtration pressure, thereby decreasing albuminuria and slowing the progression to end-stage renal disease (ESRD) [1]. This "renoprotective" effect is independent of their systemic blood pressure-lowering capabilities. **Why the other options are incorrect:** * **A. Beta blockers:** These are not first-line for diabetic hypertension as they can mask the symptoms of hypoglycemia (except sweating) and may adversely affect lipid profiles. * **B. Thiazide diuretics:** While effective for BP control, they can cause metabolic side effects like hyperglycemia and hyperuricemia, which are undesirable in diabetic patients. They do not offer specific renoprotection. * **D. Short-acting nifedipine:** Short-acting dihydropyridines are contraindicated for routine BP control due to the risk of reflex tachycardia and potential adverse cardiovascular events [3]. While long-acting CCBs (like Amlodipine) are used, they do not provide the same degree of efferent vasodilation as ACEIs. **Clinical Pearls for NEET-PG:** * **Microalbuminuria Definition:** 30–300 mg/24 hours (or an Albumin-to-Creatinine Ratio of 30–300 mg/g) [2]. * **First Sign of Diabetic Nephropathy:** Hyperfiltration (increased GFR), followed by microalbuminuria [2]. * **Management Tip:** If a patient develops a cough on ACEIs, switch to an **Angiotensin Receptor Blocker (ARB)** [3]. * **Contraindication:** Never combine ACEIs and ARBs due to the risk of hyperkalemia and acute kidney injury. * **Monitoring:** Always monitor serum potassium and creatinine within 1–2 weeks of starting an ACEI [3]. A rise in creatinine up to 30% is generally acceptable.

Question 390: What is the drug of choice for stage I hypertension with diabetic nephropathy associated with frank proteinuria?

A. Alpha blocker
B. Beta blocker
C. Calcium channel blocker
D. ACE inhibitor (Correct Answer)

Explanation: **Explanation:** The drug of choice for hypertension in patients with diabetic nephropathy and proteinuria is an **ACE inhibitor (ACEi)** or an **Angiotensin Receptor Blocker (ARB)** [1]. **Why ACE Inhibitors are correct:** The primary mechanism is the **preferential dilation of the efferent arteriole** in the renal glomerulus. This reduces intraglomerular pressure, thereby decreasing the mechanical strain on the basement membrane and reducing proteinuria [1]. Beyond blood pressure control, ACE inhibitors provide **renoprotection** by slowing the progression of diabetic kidney disease (DKD) and reducing the rate of decline in the Glomerular Filtration Rate (GFR) [1][2]. **Why other options are incorrect:** * **Alpha-blockers:** These are not first-line agents for hypertension and lack specific renoprotective benefits. They are primarily used as add-on therapy or in patients with concomitant Benign Prostatic Hyperplasia (BPH). * **Beta-blockers:** While useful in patients with heart failure or post-MI, they can mask hypoglycemic symptoms and potentially worsen insulin sensitivity. They do not offer the same level of antiproteinuric effect as ACE inhibitors. * **Calcium Channel Blockers (CCBs):** Dihydropyridine CCBs (like Amlodipine) are excellent antihypertensives but primarily dilate the *afferent* arteriole, which does not reduce intraglomerular pressure as effectively as ACE inhibitors [2]. **High-Yield Clinical Pearls for NEET-PG:** * **The "ACEi/ARB Rule":** If a patient has diabetes with microalbuminuria (>30mg/day) or frank proteinuria, start an ACEi/ARB even if they are normotensive [1]. * **Monitoring:** Always monitor serum **Potassium** and **Creatinine** levels within 1-2 weeks of starting an ACEi [2]. A rise in creatinine up to 30% is acceptable. * **Contraindication:** ACE inhibitors are strictly contraindicated in **pregnancy** (teratogenic) and **Bilateral Renal Artery Stenosis** [2]. * **Side Effect:** The most common side effect of ACE inhibitors is a dry cough (due to bradykinin accumulation); in such cases, switch the patient to an ARB [2].

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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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