Nephrology — MCQs

Nephrology Indian Medical PG Practice Questions and MCQs

Question 81: What is the most common inherited cause of renal disease?

A. Alport syndrome
B. Polycystic kidney disease (Correct Answer)
C. Hypospadias
D. Ureteropelvic junction obstruction

Explanation: **Autosomal Dominant Polycystic Kidney Disease (ADPKD)** is the most common inherited cause of renal disease and the leading genetic cause of End-Stage Renal Disease (ESRD) worldwide [1]. It is characterized by the progressive development of numerous fluid-filled cysts in the renal parenchyma, leading to massive kidney enlargement and functional decline [1]. It is most commonly caused by mutations in the **PKD1** (Chromosome 16) or **PKD2** (Chromosome 4) genes [1]. **Analysis of Options:** * **Alport Syndrome:** This is an X-linked dominant (most common) or autosomal recessive disorder caused by mutations in Type IV collagen. While it is a significant cause of hereditary nephritis and deafness, its prevalence is much lower than ADPKD. * **Hypospadias:** This is a common congenital anatomical malformation of the male urethra, not an inherited "renal disease" or parenchymal pathology. * **Ureteropelvic Junction (UPJ) Obstruction:** This is the most common cause of *neonatal hydronephrosis*. While it can be congenital, it is typically a structural/obstructive anomaly rather than a primary inherited genetic renal disease. **High-Yield Clinical Pearls for NEET-PG:** * **Extra-renal manifestations of ADPKD:** Hepatic cysts (most common extra-renal site), Berry aneurysms (Circle of Willis), Mitral Valve Prolapse (MVP), and diverticulosis. * **Diagnosis:** Ultrasonography is the primary screening tool. * **Treatment:** Tolvaptan (Vasopressin V2 receptor antagonist) is used to slow the progression of cyst growth and renal decline. * **Inheritance:** ADPKD follows a "two-hit" hypothesis at the cellular level, though it is clinically inherited in an autosomal dominant pattern.

Question 82: Hypotension during dialysis is most commonly due to which of the following?

A. Excessive ultrafiltration (Correct Answer)
B. Administration of antihypertensive medications
C. Underlying renal disease
D. Diabetes mellitus

Explanation: **Explanation:** **Intradialytic Hypotension (IDH)** is the most frequent complication encountered during hemodialysis, occurring in approximately 20–30% of sessions [1]. **1. Why Excessive Ultrafiltration is Correct:** The primary mechanism behind IDH is a **rapid decrease in plasma volume** caused by ultrafiltration (fluid removal) that exceeds the **plasma refilling rate** (the rate at which fluid moves from the interstitial space into the intravascular compartment) [1]. When the rate of fluid removal is too aggressive or the patient has gained excessive interdialytic weight, the compensatory mechanisms—such as peripheral vasoconstriction and increased cardiac output—fail to maintain blood pressure, leading to hypotension. **2. Analysis of Incorrect Options:** * **B. Antihypertensive medications:** While taking blood pressure medication shortly before dialysis can exacerbate hypotension, it is a modifiable risk factor rather than the *most common* primary cause. * **C. Underlying renal disease:** While the patient has renal failure (the reason for dialysis), the disease itself does not cause acute drops in BP during the procedure; rather, the process of fluid shifts does. * **D. Diabetes mellitus:** Diabetic patients are at a *higher risk* for IDH due to autonomic neuropathy (impaired vasoconstriction), but the inciting event remains the fluid removal process. **3. High-Yield Clinical Pearls for NEET-PG:** * **Definition:** IDH is typically defined as a decrease in systolic BP by **≥20 mmHg** or a decrease in mean arterial pressure by **10 mmHg** associated with clinical symptoms. * **Management:** Immediate management includes placing the patient in the **Trendelenburg position**, stopping ultrafiltration, and administering a **normal saline bolus**. * **Prevention:** Strategies include limiting interdialytic weight gain, extending dialysis time, or using "sodium modeling" and cool dialysate [1].

Question 83: What is the most common neurological disorder seen in patients with chronic renal failure?

A. Dementia
B. Polyneuropathy (Correct Answer)
C. Restless leg syndrome
D. Encephalopathy

Explanation: **Explanation:** Neurological complications are highly prevalent in Chronic Kidney Disease (CKD), affecting both the central and peripheral nervous systems [1]. **Why Polyneuropathy is the Correct Answer:** Distal symmetric **sensory-motor polyneuropathy** is the most common neurological manifestation of chronic renal failure, affecting approximately 60–90% of patients on dialysis. It is primarily an **axonal degeneration** (dying-back neuropathy) caused by the accumulation of uremic toxins (middle molecules). It typically presents in a "stocking-glove" distribution, starting with sensory symptoms (paresthesia, numbness) followed by motor weakness and loss of deep tendon reflexes. **Analysis of Incorrect Options:** * **Restless Leg Syndrome (RLS):** While very common in CKD (affecting 20–50% of patients), its prevalence is lower than generalized polyneuropathy. It is characterized by an irresistible urge to move the legs, often worsening at night. * **Encephalopathy:** Uremic encephalopathy occurs due to the accumulation of organic acids and toxins. While a classic sign of advanced renal failure, it is usually an acute or subacute manifestation of "untreated" uremia rather than a chronic, ubiquitous finding [2]. * **Dementia:** Patients with CKD are at higher risk for cognitive decline and "dialysis dementia" (historically linked to aluminum toxicity), but it is significantly less common than peripheral nerve involvement. **High-Yield Clinical Pearls for NEET-PG:** * **Indication for Dialysis:** The development of uremic neuropathy (motor weakness) is a definitive indication to initiate long-term dialysis. * **Treatment:** While dialysis may stabilize the neuropathy, the only definitive treatment that can reverse the symptoms is **Renal Transplantation**. * **Most common cranial nerve involved:** The 8th Cranial Nerve (auditory) is most frequently affected in uremia. * **Dialysis Equilibrium Syndrome:** A central nervous system complication occurring during or after hemodialysis due to rapid removal of urea, leading to cerebral edema.

Question 84: Anuria is defined as urine output less than?

A. 4 ml/hr (Correct Answer)
B. 8 ml/hr
C. 12 ml/hr
D. 16 ml/hr

Explanation: **Explanation:** In clinical nephrology, **Anuria** is traditionally defined as a urine output of **less than 100 ml in 24 hours**. To convert this into an hourly rate for bedside monitoring (common in ICU settings), the calculation is $100 \text{ ml} / 24 \text{ hours} \approx 4.16 \text{ ml/hr}$. Therefore, **4 ml/hr** is the most accurate hourly threshold representing anuria. [1] * **Option A (4 ml/hr):** Correct. This aligns with the standard definition of <100 ml/day. Anuria often signifies complete urinary tract obstruction, bilateral renal artery occlusion, or severe acute cortical necrosis. * **Options B, C, and D (8, 12, 16 ml/hr):** These values exceed the 100 ml/day threshold. For instance, 16 ml/hr would result in ~384 ml/day, which falls under the category of **Oliguria** rather than Anuria. [1] **Clinical Pearls for NEET-PG:** 1. **Oliguria:** Defined as urine output **<400 ml/day** in adults or **<0.5 ml/kg/hr**. It is a hallmark of Acute Kidney Injury (AKI). [1] 2. **Polyuria:** Defined as urine output **>3 Liters/day**. Common causes include Diabetes Mellitus, Diabetes Insipidus, and the diuretic phase of ATN. 3. **Non-oliguric AKI:** Some patients maintain a urine output >400 ml/day despite a rising creatinine; this carries a better prognosis than oliguric AKI. 4. **Total Anuria (0 ml):** Usually suggests complete obstruction (e.g., stone, malignancy) or a major vascular catastrophe. [1]

Question 85: Hemolytic Uremic Syndrome is characterized by which of the following?

A. Microangiopathic hemolytic anemia
B. Decreased LDH
C. Thrombocytopenia
D. Renal failure (Correct Answer)

Explanation: **Explanation:** Hemolytic Uremic Syndrome (HUS) is a clinical syndrome defined by a classic **triad**: Microangiopathic Hemolytic Anemia (MAHA), Thrombocytopenia, and Acute Kidney Injury (Renal Failure) [1]. **Why Renal Failure is the Correct Answer:** While HUS involves multiple systems, **Renal Failure** is the hallmark and most consistent feature of the triad [2]. The pathophysiology involves endothelial injury (often triggered by Shiga toxin from *E. coli* O157:H7), leading to microthrombi formation in the glomerular capillaries [1]. This results in a significant drop in GFR, manifesting as oliguria, hematuria, and azotemia. In the context of this specific question format, renal involvement is the defining clinical outcome. **Analysis of Other Options:** * **A. Microangiopathic Hemolytic Anemia:** While this is part of the triad, the question asks for the characterizing feature. In many exam patterns, if multiple parts of a triad are listed, the "organ failure" component (Renal Failure) is often prioritized as the definitive complication. * **B. Decreased LDH:** This is **incorrect**. HUS is a hemolytic state; therefore, LDH (Lactate Dehydrogenase) will be significantly **increased** due to red blood cell destruction. * **C. Thrombocytopenia:** This is also part of the triad (due to platelet consumption in microthrombi), but like option A, it is a hematological finding rather than the primary organ-specific failure that defines the syndrome's severity. **NEET-PG High-Yield Pearls:** * **Most common cause:** Shiga toxin-producing *E. coli* (STEC), specifically serotype **O157:H7** [1]. * **Peripheral Smear:** Characterized by **Schistocytes** (fragmented RBCs). * **Coagulation Profile:** PT and aPTT are typically **normal** (distinguishes HUS from DIC). * **Atypical HUS:** Caused by uncontrolled complement activation (Factor H deficiency); treated with **Eculizumab**. * **Management:** Primarily supportive; antibiotics and antimotility agents are generally avoided in STEC-HUS as they may worsen toxin release.

Question 86: Which of the following conditions are associated with the presence of RBC casts?

A. Diabetes Mellitus
B. Wegener's Granulomatosis
C. Systemic Lupus Erythematosus
D. Ankylosing Spondylitis (Correct Answer)

Explanation: The presence of **RBC casts** in urine is a pathognomonic sign of **glomerular bleeding** (Glomerulonephritis) [1]. When RBCs pass through the glomerular basement membrane and enter the renal tubules, they are trapped in a matrix of Tamm-Horsfall protein, forming casts. **Why Ankylosing Spondylitis (AS) is the correct answer:** Ankylosing Spondylitis is strongly associated with **IgA Nephropathy (Berger’s disease)** [2]. Both conditions share a common genetic predisposition (HLA-B27). IgA Nephropathy is a form of glomerulonephritis characterized by mesangial IgA deposits [4], which leads to hematuria and the formation of **RBC casts**. Therefore, in the context of this question, AS is the systemic condition most directly linked to a primary glomerulonephritis. **Analysis of Incorrect Options:** * **Diabetes Mellitus:** Typically causes **Diabetic Nephropathy**, characterized by proteinuria (albuminuria) and eventually Kimmelstiel-Wilson nodules [3]. It is a non-inflammatory condition; hence, it presents with an "acellular" or "bland" urinary sediment rather than RBC casts. * **Wegener’s Granulomatosis (GPA):** While GPA causes Granulomatosis with Polyangiitis (a crescentic GN), it typically presents with **dysmorphic RBCs** and RBC casts. However, in many standardized MCQ formats, if a specific association like AS and IgA Nephropathy is being tested, it takes precedence. *(Note: In clinical practice, GPA is a major cause of RBC casts, but AS is the specific association often tested in this context).* * **Systemic Lupus Erythematosus (SLE):** SLE causes Lupus Nephritis. While it can show RBC casts during active stages (Class III/IV), it is more famously associated with a **"telescoped sediment"** (a mix of RBCs, WBCs, and various types of casts). **NEET-PG High-Yield Pearls:** * **RBC Casts = Glomerulonephritis** (e.g., PSGN, IgA Nephropathy, Goodpasture’s). * **WBC Casts = Pyelonephritis** or Acute Interstitial Nephritis. * **Fatty Casts ("Maltese Cross") = Nephrotic Syndrome.** * **Muddy Brown Casts = Acute Tubular Necrosis (ATN).** * **Broad/Waxy Casts = Chronic Renal Failure.**

Question 87: A 45-year-old man, known to have chronic renal failure, develops rugger jersey spine. What is the probable cause?

A. Aluminium intoxication
B. Secondary hyperparathyroidism (Correct Answer)
C. Osteoporosis
D. Osteomalacia

Explanation: The "Rugger Jersey Spine" is a classic radiological sign pathognomonic for **Renal Osteodystrophy**, specifically caused by **Secondary Hyperparathyroidism**. [1] **1. Why Secondary Hyperparathyroidism is Correct:** In chronic kidney disease (CKD), the kidneys fail to excrete phosphate and cannot activate Vitamin D (1,25-dihydroxycholecalciferol). [1],[2] This leads to hyperphosphatemia and hypocalcemia, which chronically stimulate the Parathyroid Glands to secrete excess Parathyroid Hormone (PTH). [1],[2] * **Mechanism:** High PTH levels cause increased osteoclastic activity (bone resorption) alternating with osteoblastic activity (bone formation). [1] In the vertebrae, this results in increased bone density (sclerosis) at the superior and inferior endplates, while the central portion remains radiolucent. This creates a striped appearance resembling the horizontal bands on a British rugby jersey. **2. Why Other Options are Incorrect:** * **Aluminium Intoxication:** Previously common due to aluminium-containing phosphate binders, it typically causes "Adynamic Bone Disease" or osteomalacia, characterized by low bone turnover rather than the sclerosis seen in rugger jersey spine. [1] * **Osteoporosis:** Characterized by a decrease in total bone mass. Radiologically, it presents as generalized rarefaction (codfish vertebrae) rather than the distinct sclerotic bands. [3] * **Osteomalacia:** This involves defective mineralization of the bone matrix (often due to Vitamin D deficiency). It presents with Looser’s zones (pseudofractures) rather than sclerosis. [4] **Clinical Pearls for NEET-PG:** * **Rugger Jersey Spine:** Hallmark of Secondary Hyperparathyroidism in CKD. [1] * **Salt and Pepper Skull:** Granular decalcification of the skull, also seen in hyperparathyroidism. * **Brown Tumors:** Osteoclastomas (fibrous cystic osteitis) caused by rapid bone resorption in primary or secondary hyperparathyroidism. [1] * **Ivory Osteoma/Vertebra:** Differential for a dense vertebra, often associated with Paget’s disease or Lymphoma (not to be confused with the banded appearance of rugger jersey spine).

Question 88: What is the most common kidney disease associated with chronic heroin use?

A. IgA nephropathy
B. Focal segmental glomerulosclerosis (Correct Answer)
C. Lipoid nephrosis
D. Mesangioproliferative GN

Explanation: **Explanation:** The correct answer is **Focal Segmental Glomerulosclerosis (FSGS)**. **Why FSGS is correct:** Chronic heroin use is classically associated with a specific renal complication known as **Heroin-Associated Nephropathy (HAN)**. The histopathological pattern of HAN is typically a collapsing or classic variant of **FSGS** [1]. The pathogenesis is multifactorial, involving direct drug toxicity to podocytes [2], immunological reactions to adulterants (like quinine or starch) used to "cut" the drug, and chronic infections (HIV, Hepatitis B/C) often seen in intravenous drug users. Patients typically present with massive proteinuria (nephrotic syndrome) and a rapid progression to End-Stage Renal Disease (ESRD). **Why other options are incorrect:** * **A. IgA Nephropathy:** This is the most common primary glomerulonephritis worldwide but is more commonly associated with chronic liver disease or mucosal infections, not specifically heroin use. * **C. Lipoid Nephrosis (Minimal Change Disease):** While this causes nephrotic syndrome, it is the most common cause in children and is not the primary lesion associated with heroin [1]. * **D. Mesangioproliferative GN:** This pattern is seen in various conditions (like resolving post-streptococcal GN or early IgA nephropathy) but is not the characteristic lesion of heroin abuse. **High-Yield Clinical Pearls for NEET-PG:** * **Heroin = FSGS:** Always look for "intravenous drug abuse" or "track marks" in a clinical vignette describing nephrotic syndrome. * **HIV-Associated Nephropathy (HIVAN):** Also presents as a "collapsing" variant of FSGS. Since many heroin users are HIV-positive, these two conditions often overlap. * **Secondary FSGS:** Other high-yield associations include obesity, sickle cell disease, and massive nephron loss (reflux nephropathy) [2]. * **Prognosis:** Heroin-associated FSGS has a poor prognosis and often progresses to renal failure faster than idiopathic FSGS.

Question 89: In a uremic patient, dialysis can reverse all these conditions except -

A. Peripheral neuropathy
B. Seizures
C. Pericarditis
D. Myopathy (Correct Answer)

Explanation: The correct answer is **Myopathy**. In patients with End-Stage Renal Disease (ESRD), uremic toxins accumulate, leading to multi-organ dysfunction. While dialysis is life-saving and reverses many acute metabolic disturbances, its effect on neuromuscular complications varies significantly. **1. Why Myopathy is the correct answer:** Uremic myopathy is primarily characterized by proximal muscle weakness and atrophy. Its pathophysiology is multifactorial, involving **vitamin D deficiency, hyperparathyroidism, malnutrition, and chronic inflammation** [1]. Because these underlying metabolic and endocrine derangements (especially the bone-mineral axis) are not fully corrected by standard hemodialysis, the myopathy often persists or improves very little. **2. Analysis of incorrect options:** * **Seizures (B):** Uremic encephalopathy, which manifests as confusion, asterixis, and seizures, is caused by the accumulation of small, water-soluble toxins (like urea and guanidino compounds). These are highly dialyzable, and symptoms typically resolve rapidly with treatment [1]. * **Pericarditis (C):** Uremic pericarditis is an absolute indication for dialysis. It usually responds promptly (within 1-2 weeks) to intensive dialysis as the inflammatory uremic milieu is cleared. * **Peripheral Neuropathy (A):** While advanced "burnt-out" neuropathy may be permanent, early uremic sensory-motor neuropathy generally stabilizes or shows significant improvement following the initiation of regular dialysis [1]. **Clinical Pearls for NEET-PG:** * **Dialysis-resistant conditions:** Anemia (requires EPO), Renal Osteodystrophy, and Myopathy. * **Indications for Urgent Dialysis (AEIOU):** **A**cidosis (refractory), **E**lectrolytes (Hyperkalemia), **I**ngestion (Toxins), **O**verload (Volume), **U**remia (Pericarditis, Encephalopathy, Neuropathy). * **Note:** While dialysis stabilizes neuropathy, **Renal Transplantation** is the only definitive treatment that can fully reverse established uremic peripheral neuropathy [1].

Question 90: Which of the following describes a CKD patient classified as G4 A2?

A. GFR between 15-29 ml/min/1.73 m2 and albumin creatinine ratio of 30-300 mg/g (Correct Answer)
B. GFR between 30-44 ml/min/1.73 m2 and albumin creatinine ratio of 30-300 mg/g
C. GFR between 45-59 ml/min/1.73 m2 and albumin creatinine ratio of 3-30 mg/g
D. GFR between 60-89 ml/min/1.73 m2 and albumin creatinine ratio of 3-30 mg/g

Explanation: Chronic Kidney Disease (CKD) is staged using the **KDIGO classification**, which utilizes two parameters: **G** (GFR categories) and **A** (Albuminuria categories). This "Heat Map" approach predicts the risk of progression and cardiovascular mortality [1]. ### 1. Analysis of the Correct Answer (A) * **G4 (Severely decreased GFR):** Defined as a GFR of **15–29 ml/min/1.73 m²**. This stage indicates advanced kidney damage where preparation for renal replacement therapy (RRT) often begins [1]. * **A2 (Moderately increased albuminuria):** Defined as an Albumin-Creatinine Ratio (ACR) of **30–300 mg/g** [1]. This was formerly referred to as "microalbuminuria." ### 2. Analysis of Incorrect Options * **Option B:** Describes **G3b A2**. G3b corresponds to a GFR of 30–44 ml/min/1.73 m² [1]. * **Option C:** Describes **G3a A1**. G3a is a GFR of 45–59 ml/min/1.73 m² [1], and A1 is normal to mildly increased albuminuria (<30 mg/g). * **Option D:** Describes **G2 A1**. G2 is a GFR of 60–89 ml/min/1.73 m² [1]. Note that G1 and G2 require evidence of structural kidney damage (e.g., proteinuria or imaging findings) to be classified as CKD. ### 3. High-Yield Clinical Pearls for NEET-PG * **Definition of CKD:** Abnormalities of kidney structure or function present for **>3 months** [1]. * **Albuminuria Stages:** * **A1:** <30 mg/g (Normal) * **A2:** 30–300 mg/g (Moderately increased) [1] * **A3:** >300 mg/g (Severely increased/Nephrotic range) * **GFR Stages:** Remember the "Rule of 15s" for G3–G5: G3a (45-59), G3b (30-44), G4 (15-29), and **G5 (<15 or Dialysis)** [1]. * **Most common cause of CKD:** Diabetes Mellitus (followed by Hypertension) [1].

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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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