Nephrology — MCQs

A 71-year-old man presents with blurry vision and blood-tinged urine. He has a history of hypertension treated with a beta-blocker, an ACE inhibitor, and a calcium channel blocker. His symptoms began 3 days ago when he stopped his medications. His blood pressure is 200/110 mmHg, funduscopic examination reveals flame hemorrhages and papilledema, and urinalysis shows red blood cells with dysmorphic red blood cell casts. He has an abdominal bruit. What is the most appropriate next step in management?

Q529Easy

Which of the following is NOT an indication for dialysis?

Q530Medium

Which of the following improves after dialysis?

Nephrology Indian Medical PG Practice Questions and MCQs

Question 521: What is the major cause of death in patients with end-stage renal disease?

A. Cardiovascular disease (Correct Answer)
B. Infection
C. Uremia
D. Respiratory failure

Explanation: **Explanation:** **Cardiovascular disease (CVD)** is the leading cause of mortality in patients with End-Stage Renal Disease (ESRD), accounting for approximately **40–50% of all deaths**. The risk of cardiovascular death in dialysis patients is 10 to 20 times higher than in the general population. This is due to a combination of "traditional" risk factors (hypertension, diabetes, dyslipidemia) [1] and "non-traditional" uremia-related factors, such as chronic inflammation, oxidative stress, hyperphosphatemia, and secondary hyperparathyroidism leading to extensive **vascular and valvular calcification** [1]. **Analysis of Incorrect Options:** * **Infection:** This is the **second most common** cause of death in ESRD [1]. Patients are immunocompromised due to uremia and have frequent breaches in skin barriers (hemodialysis catheters/fistulas), making them prone to sepsis and pneumonia. * **Uremia:** While uremia [1] is the hallmark of untreated renal failure, it is rarely the direct cause of death in the modern era due to the availability of Renal Replacement Therapy (RRT). * **Respiratory failure:** While pulmonary edema (due to fluid overload) is a common complication, it is usually managed with dialysis and is not the primary statistical cause of mortality compared to CVD. **Clinical Pearls for NEET-PG:** * The most common specific cardiovascular cause of death in ESRD is **Sudden Cardiac Death (SCD)**, often due to arrhythmias secondary to electrolyte shifts and left ventricular hypertrophy (LVH). * **Target Blood Pressure** in ESRD: Generally <140/90 mmHg (pre-dialysis) or <130/80 mmHg (post-dialysis). * **Hyperphosphatemia** is a major driver of vascular calcification; maintaining phosphate balance is crucial for reducing CV risk [1].

Question 522: A 60-year-old diabetic male developed renal failure and was initiated on Chronic Ambulatory Peritoneal Dialysis (CAPD). After 4 months of CAPD, the patient developed peritonitis. What is the most common organism responsible?

A. Staphylococcus aureus
B. Staphylococcus epidermidis (Correct Answer)
C. Escherichia coli
D. Bacteroides

Explanation: **Explanation:** Peritonitis is the most common complication of Chronic Ambulatory Peritoneal Dialysis (CAPD). The primary route of infection is **intraluminal or periluminal**, occurring during the manipulation of the catheter or through the exit site. **1. Why Staphylococcus epidermidis is correct:** Coagulase-negative Staphylococci (CoNS), specifically **Staphylococcus epidermidis**, is the most common cause of CAPD-associated peritonitis [1]. These organisms are normal skin commensals [1]. They gain entry into the peritoneal cavity during bag changes or through the catheter tunnel [1]. Their ability to form **biofilms** on the prosthetic material of the catheter makes them particularly persistent [1]. **2. Analysis of Incorrect Options:** * **Staphylococcus aureus:** While it is the second most common cause and often leads to more severe clinical symptoms (including catheter-site infections), it is less frequent than *S. epidermidis* [1]. * **Escherichia coli:** Gram-negative organisms like *E. coli* account for about 15-25% of cases. They usually suggest a bowel-related source (transmigration) or poor hygiene. * **Bacteroides:** Anaerobic peritonitis is rare in CAPD. If present, it strongly suggests a surgical cause, such as bowel perforation or intra-abdominal pathology. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** Cloudy effluent with a WBC count **>100/μL** (with >50% neutrophils). * **Most common route:** Touch contamination during exchange. * **Empiric Treatment:** A combination of a first-generation cephalosporin (or Vancomycin) and an aminoglycoside (or third-generation cephalosporin) to cover both Gram-positive and Gram-negative organisms. * **Fungal Peritonitis:** Usually caused by *Candida* species; it requires immediate catheter removal.

Question 523: What is the metabolic defect in accelerated hypertension?

A. Normal non-ionic metabolic acidosis
B. Ionic gap metabolic acidosis
C. Hypomagnesemia
D. Metabolic alkalosis (Correct Answer)

Explanation: In accelerated or malignant hypertension, the pathophysiology is driven by the **activation of the Renin-Angiotensin-Aldosterone System (RAAS)**. ### Why Metabolic Alkalosis is Correct Severe hypertension causes pressure natriuresis and renal ischemia, which triggers the release of Renin. This leads to high levels of Angiotensin II and **Aldosterone**. Aldosterone acts on the cortical collecting ducts of the kidney to [2]: 1. Increase sodium reabsorption. 2. Increase the secretion of **Potassium (K+)** and **Hydrogen ions (H+)** into the urine. The excessive loss of H+ ions leads to **metabolic alkalosis**, typically accompanied by **hypokalemia** [1]. This is often referred to as "secondary hyperaldosteronism." ### Why Other Options are Incorrect * **A & B (Metabolic Acidosis):** Metabolic acidosis is generally seen in chronic kidney disease (CKD) or acute kidney injury (AKI) due to the failure of the kidneys to excrete fixed acids. While accelerated hypertension can cause renal failure, the primary metabolic defect driven by the hormonal response (RAAS) is alkalosis. * **C (Hypomagnesemia):** While electrolyte imbalances occur, hypomagnesemia is not a hallmark or specific metabolic defect of accelerated hypertension; it is more commonly associated with diuretic use or chronic alcoholism. ### NEET-PG High-Yield Pearls * **Definition:** Accelerated hypertension is characterized by a sudden increase in BP (usually >180/120 mmHg) with Grade III hypertensive retinopathy (flame-shaped hemorrhages, cotton wool spots). * **Malignant Hypertension:** Includes the above plus **Papilledema** (Grade IV retinopathy). * **The "Aldosterone Paradox":** Even though the body is hypertensive, the kidneys perceive "low volume" due to ischemia, leading to paradoxically high renin and aldosterone levels [3]. * **Treatment Goal:** Reduce Mean Arterial Pressure (MAP) by no more than 25% within the first hour to prevent cerebral hypoperfusion.

Question 524: What type of renal stone is typically formed in a patient with regional enteritis?

A. Calcium oxalate (Correct Answer)
B. Cysteine
C. Struvite
D. Urate

Explanation: **Explanation:** The correct answer is **Calcium oxalate**. The association between regional enteritis (Crohn’s disease) and calcium oxalate stones is a high-yield medical concept rooted in **enteric hyperoxaluria**. **Pathophysiology:** In a healthy individual, dietary calcium binds to oxalate in the gut to form insoluble calcium oxalate, which is excreted in the feces. In patients with regional enteritis (especially those with terminal ileal disease or resection), fat malabsorption occurs. The unabsorbed free fatty acids bind to calcium (saponification), leaving oxalate "free" and unbound. This free oxalate is highly soluble and is excessively absorbed in the colon, leading to hyperoxaluria and the subsequent formation of calcium oxalate stones in the kidneys. **Analysis of Incorrect Options:** * **B. Cysteine:** These are caused by an autosomal recessive defect in the transport of dibasic amino acids (COAL: Cystine, Ornithine, Arginine, Lysine). They are not associated with malabsorption. * **C. Struvite:** Also known as "triple phosphate" or staghorn calculi, these are associated with chronic urinary tract infections caused by urease-producing bacteria (e.g., *Proteus*, *Klebsiella*) [1]. * **D. Urate:** While patients with inflammatory bowel disease (IBD) can develop uric acid stones due to dehydration and low urine pH (especially after a total colectomy/ileostomy), calcium oxalate remains the most classic association with small bowel involvement in Crohn’s [2]. **High-Yield Clinical Pearls for NEET-PG:** * **The "Colon" Requirement:** Enteric hyperoxaluria only occurs if the **colon is intact**, as that is the primary site of excess oxalate absorption. * **Treatment:** Management includes a low-oxalate diet, increased fluid intake, and calcium supplements (to bind oxalate in the gut). * **Other Associations:** Crohn’s disease is also associated with **gallstones** due to the depletion of the bile acid pool from ileal malabsorption.

Question 525: Which of the following is NOT an indication for dialysis in a case of acute renal failure?

A. Uremia
B. Hyponatremia (Correct Answer)
C. Hyperkalemia
D. Metabolic acidosis

Explanation: In management of Acute Kidney Injury (AKI), the decision to initiate Renal Replacement Therapy (RRT) is based on life-threatening metabolic derangements that cannot be managed medically [1]. ### **Why Hyponatremia is the Correct Answer** **Hyponatremia (Option B)** is generally **not** a primary indication for dialysis. While fluid overload (which can cause dilutional hyponatremia) is an indication, mild to moderate low sodium is typically managed through fluid restriction [1]. Dialysis is reserved for severe, symptomatic electrolyte imbalances, primarily **Hyperkalemia**, because it poses an immediate risk of cardiac arrest. ### **Analysis of Other Options (Indications for Dialysis)** * **Uremia (Option A):** Specifically symptomatic uremia. This includes uremic encephalopathy (confusion/seizures), uremic pericarditis (friction rub), or uremic coagulopathy (bleeding). * **Hyperkalemia (Option C):** Refractory hyperkalemia (typically K+ >6.5 mEq/L) or hyperkalemia with associated ECG changes that does not respond to medical "shifting" therapy (Insulin/Glucose, Calcium gluconate). * **Metabolic Acidosis (Option D):** Severe metabolic acidosis (typically pH <7.1) that is refractory to medical management or where bicarbonate administration is contraindicated (e.g., due to volume overload). ### **High-Yield Clinical Pearl: The "AEIOU" Mnemonic** For NEET-PG, remember the classic indications for urgent dialysis in AKI: * **A – Acidosis:** Refractory metabolic acidosis (pH <7.1). * **E – Electrolytes:** Refractory Hyperkalemia (K+ >6.5 mEq/L). * **I – Intoxications:** Poisoning with SLIME (Salicylates, Lithium, Isopropanol, Methanol, Ethylene glycol). * **O – Overload:** Refractory pulmonary edema/volume overload. * **U – Uremia:** Symptomatic (Pericarditis, Encephalopathy, Neuropathy).

Question 526: Which of the following is not a feature of Chronic Renal Failure?

A. Hyperparathyroidism
B. Osteomalacia
C. Hyperthyroidism (Correct Answer)
D. Decreased 1,25(OH)2 vitamin D3 level

Explanation: ### Explanation In Chronic Kidney Disease (CKD) or Chronic Renal Failure, the primary metabolic derangement involves the **Calcium-Phosphate-Vitamin D axis**. **Why Hyperthyroidism is the Correct Answer:** Hyperthyroidism is not a feature of Chronic Renal Failure. In fact, CKD is more commonly associated with **"Euthyroid Sick Syndrome"** or occasionally hypothyroidism. While the parathyroid glands are hyperactive, the thyroid gland's function is generally suppressed or altered due to chronic systemic illness, but it does not typically manifest as hyperthyroidism. **Analysis of Incorrect Options:** * **Decreased 1,25(OH)2 Vitamin D3 (Calcitriol):** The kidneys contain the enzyme **1-alpha-hydroxylase**, which converts 25-hydroxyvitamin D into its active form, 1,25-dihydroxyvitamin D3. In CRF, the loss of renal parenchyma leads to a deficiency of this enzyme, resulting in low calcitriol levels [1], [3]. * **Hyperparathyroidism:** Low calcitriol levels and phosphate retention (hyperphosphatemia) lead to hypocalcemia [1]. This triggers the parathyroid glands to secrete excess Parathyroid Hormone (PTH) to maintain calcium levels, a condition known as **Secondary Hyperparathyroidism** [2], [3]. * **Osteomalacia:** This is a component of **Renal Osteodystrophy** [2]. It occurs due to the failure of bone mineralization caused by vitamin D deficiency and chronic metabolic acidosis. **NEET-PG High-Yield Pearls:** 1. **Renal Osteodystrophy Spectrum:** Includes Osteitis fibrosa cystica (high turnover due to PTH), Osteomalacia (low turnover), and Adynamic bone disease [2]. 2. **Phosphate Management:** Hyperphosphatemia is a major driver of mortality in CKD; phosphate binders (like Sevelamer) are mainstay treatments. 3. **FGF-23:** This is the earliest marker of disordered phosphorus metabolism in CKD, rising even before phosphate levels increase [2].

Question 527: Fluid containing which of the following substances is used in peritoneal dialysis?

A. NaCl
B. Urea
C. Heparin
D. Dextrose (Correct Answer)

Explanation: **Explanation:** The primary goal of peritoneal dialysis (PD) is to remove excess water and metabolic waste products from the blood. This is achieved through the processes of **osmosis** and **diffusion** across the peritoneal membrane [1]. **Why Dextrose is the Correct Answer:** Dextrose (glucose) serves as the **osmotic agent** in the PD fluid [1]. By creating a high osmotic pressure in the peritoneal cavity relative to the blood, it draws excess water out of the intravascular space and into the dialysate (ultrafiltration) [2]. Standard PD fluids contain dextrose in varying concentrations (e.g., 1.5%, 2.5%, or 4.25%) to tailor the amount of fluid removal required. **Analysis of Incorrect Options:** * **A. NaCl:** While PD fluid contains sodium chloride to maintain electrolyte balance and isotonicity, it is not the active substance used to drive the dialysis process or fluid removal. * **B. Urea:** Urea is a metabolic waste product that PD aims to *remove* from the body. Including it in the dialysate would prevent the concentration gradient necessary for its diffusion out of the blood. * **C. Heparin:** Heparin is sometimes added to PD bags to prevent fibrin clots from plugging the catheter (especially during peritonitis), but it is a pharmacological additive, not a constituent of the standard dialysis process itself. **Clinical Pearls for NEET-PG:** * **Icodextrin:** A glucose polymer used as an alternative osmotic agent for long dwells (e.g., overnight) in patients with high transport characteristics or diabetes. * **Peritonitis:** The most common complication of PD; the most frequent causative organism is *Staphylococcus epidermidis*. * **Contraindication:** PD is generally avoided in patients with recent abdominal surgery or extensive intra-abdominal adhesions.

Question 528: A 71-year-old man presents with blurry vision and blood-tinged urine. He has a history of hypertension treated with a beta-blocker, an ACE inhibitor, and a calcium channel blocker. His symptoms began 3 days ago when he stopped his medications. His blood pressure is 200/110 mmHg, funduscopic examination reveals flame hemorrhages and papilledema, and urinalysis shows red blood cells with dysmorphic red blood cell casts. He has an abdominal bruit. What is the most appropriate next step in management?

A. Order an ECG and observe the patient.
B. Order an abdominal CT scan to rule out aortic aneurysm.
C. Administer the patient's usual daily doses of blood pressure medications and observe him.
D. Administer intravenous medication to reduce his blood pressure. (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Administer intravenous medication to reduce his blood pressure.** **Concept:** This patient is presenting with a **Hypertensive Emergency**, defined as severely elevated blood pressure (typically >180/120 mmHg) associated with **acute target organ damage**. [1] In this case, the target organ damage is evidenced by: 1. **Hypertensive Retinopathy:** Papilledema and flame hemorrhages (Grade IV). 2. **Hypertensive Nephropathy:** Hematuria and dysmorphic RBC casts (suggesting acute glomerulonephritis or acute kidney injury). 3. **Renovascular Clues:** The abdominal bruit suggests underlying Renal Artery Stenosis, which likely triggered this crisis upon medication withdrawal. [2] In a hypertensive emergency, the immediate goal is to reduce the Mean Arterial Pressure (MAP) by **no more than 25% within the first hour** using **intravenous (IV) medications** (e.g., Labetalol, Nicardipine, or Nitroprusside) to prevent further organ damage while avoiding cerebral ischemia. [1] **Why incorrect options are wrong:** * **Option A:** While an ECG is part of the workup, "observation" is dangerous. Immediate pharmacological intervention is required to prevent permanent vision loss or renal failure. * **Option B:** An abdominal bruit may suggest an aneurysm, but the priority is stabilizing the blood pressure. A CT scan would delay life-saving treatment. [2] * **Option C:** Oral medications have a slow onset and unpredictable absorption. They are appropriate for Hypertensive *Urgency* (no organ damage), but not for an *Emergency*. **Clinical Pearls for NEET-PG:** * **Hypertensive Emergency vs. Urgency:** The presence of end-organ damage (brain, heart, kidneys, eyes) is the sole clinical differentiator, not the absolute BP number. * **Target BP:** Reduce MAP by 25% in the 1st hour, then to 160/100–110 mmHg over the next 2–6 hours. * **Exception:** In **Aortic Dissection**, BP should be lowered rapidly (SBP <120 mmHg within 20 minutes). * **Drug of Choice:** IV Labetalol is often the first-line agent in many hypertensive emergencies due to its alpha and beta-blocking properties. [1]

Question 529: Which of the following is NOT an indication for dialysis?

A. Pericarditis
B. Persistent hyperkalemia
C. Uremic encephalopathy
D. Anemia (Correct Answer)

Explanation: In nephrology, the indications for urgent or maintenance dialysis are often summarized by the mnemonic **AEIOU**. Understanding these criteria is crucial for identifying when renal replacement therapy (RRT) is life-saving versus when medical management suffices. ### **Why Anemia is the Correct Answer** **Anemia** in Chronic Kidney Disease (CKD) is primarily due to a deficiency in **Erythropoietin (EPO)** production by the peritubular interstitial cells of the kidney. While it is a common complication of renal failure, it is **not** an indication for dialysis [1]. Anemia is managed medically using Erythropoiesis-Stimulating Agents (ESAs) and iron supplementation. Dialysis does not correct the underlying hormonal deficiency and may even worsen anemia due to blood loss in the circuit. ### **Explanation of Incorrect Options** * **Pericarditis (Option A):** Uremic pericarditis is an absolute indication for urgent dialysis. It signifies severe nitrogenous waste buildup causing inflammation of the serous membranes. Failure to dialyze can lead to pericardial effusion and cardiac tamponade. * **Persistent Hyperkalemia (Option B):** Hyperkalemia ($K^+ > 6.5$ mEq/L) that is refractory to medical therapy (insulin/glucose, calcium gluconate, resins) is a life-threatening emergency due to the risk of fatal arrhythmias and requires immediate dialysis. * **Uremic Encephalopathy (Option C):** Neurological symptoms such as asterixis, seizures, or altered mental status due to uremia are definitive indications for starting RRT [1]. ### **NEET-PG High-Yield Pearls: The "AEIOU" Mnemonic** * **A – Acidosis:** Metabolic acidosis (pH < 7.1) refractory to medical management [1]. * **E – Electrolytes:** Refractory hyperkalemia. * **I – Intoxication:** Poisoning with SLIME (Salicylates, Lithium, Isopropanol, Methanol, Ethylene glycol). * **O – Overload:** Fluid overload (pulmonary edema) unresponsive to diuretics. * **U – Uremia:** Symptomatic uremia (Pericarditis, Encephalopathy, or bleeding diathesis).

Question 530: Which of the following improves after dialysis?

A. Pericarditis
B. Peripheral neuropathy (Correct Answer)
C. Metabolic acidosis
D. All of the above

Explanation: ### Explanation In the management of End-Stage Renal Disease (ESRD), it is crucial to distinguish between uremic symptoms that are reversible with dialysis and those that are not. **Why Peripheral Neuropathy is the Correct Answer:** Uremic peripheral neuropathy (typically a distal, symmetric sensory-motor polyneuropathy) is a classic indication for initiating dialysis. While the recovery is often slow and may require months of adequate dialysis or a renal transplant for full resolution, the **progression of the neuropathy is halted**, and sensory symptoms generally show significant improvement following the stabilization of uremic toxins. [1] **Analysis of Other Options:** * **Pericarditis (Option A):** While uremic pericarditis is an absolute indication for urgent dialysis, it is considered a **complication** of uremia rather than a symptom that simply "improves" like a metabolic derangement. * **Metabolic Acidosis (Option C):** While dialysis corrects the pH acutely [1], metabolic acidosis is a **biochemical abnormality**, not a clinical symptom or a chronic pathological state like neuropathy. In many exam patterns, "improvement" refers to the resolution of a pathological clinical condition. **Clinical Pearls for NEET-PG:** * **Indications for Dialysis (AEIOU):** **A**cidosis (refractory), **E**lectrolytes (refractory hyperkalemia), **I**ngestion (toxins), **O**verload (volume), **U**remia (pericarditis, encephalopathy, neuropathy). [1] * **What Dialysis DOES NOT Improve:** Renal osteodystrophy (bone disease), anemia (requires EPO), and hypertension (often requires multi-drug therapy). * **Most common cause of death in ESRD:** Cardiovascular disease (not uremia itself). * **First sign of uremic neuropathy:** Loss of Vibration sense or "Restless Leg Syndrome."

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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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