Nephrology — MCQs

Nephrology Indian Medical PG Practice Questions and MCQs

Question 331: Low complement levels are seen in which of the following conditions?

A. Post-streptococcal glomerulonephritis (PSGN) (Correct Answer)
B. Membranoproliferative glomerulonephritis (MPGN)
C. Goodpasture's syndrome
D. Wegener's granulomatosis

Explanation: **Explanation:** Low serum complement levels (hypocomplementemia) in renal disease indicate the activation of the complement cascade via either the classical or alternative pathway. **1. Why PSGN is correct:** In **Post-streptococcal glomerulonephritis (PSGN)**, there is a significant consumption of complement factors due to the deposition of immune complexes in the glomerular basement membrane [3]. Specifically, **C3 is characteristically low**, while C4 may be normal or slightly decreased. This is a hallmark diagnostic feature; complement levels typically return to normal within 6–8 weeks [3]. **2. Why the other options are incorrect:** * **Membranoproliferative glomerulonephritis (MPGN):** While MPGN *also* presents with low complement levels (Type I: low C3 and C4; Type II: low C3), in the context of standard NEET-PG questions, PSGN is the classic prototype for "low complement" unless specified otherwise [3]. However, if this were a "Multiple Correct" type, MPGN would also be right. In single-choice questions, PSGN is the most common association tested. * **Goodpasture’s Syndrome:** This is caused by anti-GBM antibodies (Type II hypersensitivity). It does not involve systemic immune complex consumption, so complement levels remain **normal** [1]. * **Wegener’s Granulomatosis (GPA):** This is a pauci-immune vasculitis associated with ANCA. By definition, "pauci-immune" means there is little to no complement or antibody deposition in the vessels; thus, serum complement levels are **normal**. **High-Yield Clinical Pearls for NEET-PG:** * **Low Complement (C3) Differential:** PSGN, MPGN, Systemic Lupus Erythematosus (SLE), Subacute Bacterial Endocarditis (SBE), and Cryoglobulinemia. * **Normal Complement Differential:** IgA Nephropathy, Henoch-Schönlein Purpura (HSP), Goodpasture’s, and ANCA-associated vasculitis (Wegener’s) [2]. * **PSGN Rule:** If C3 remains low for **>8 weeks**, consider a diagnosis of MPGN or SLE rather than PSGN.

Question 332: All of the following are true about Goodpasture's syndrome, EXCEPT:

A. It appears in two age groups: men in their late 40s and men and women in their 20s. (Correct Answer)
B. Disease in the younger age group is usually explosive.
C. Hemoptysis is largely confined to smokers, and those who present with lung hemorrhage do better than older populations.
D. The performance of an urgent kidney biopsy is mandatory.

Explanation: Explanation: Goodpasture’s syndrome (Anti-GBM disease) is a rare autoimmune disorder characterized by the triad of glomerulonephritis, pulmonary hemorrhage, and anti-GBM antibodies [1]. 1. Why Option A is the correct answer (The Exception): The epidemiological distribution described is incorrect. Goodpasture’s syndrome typically presents in a bimodal distribution, but the demographics are: * Younger group (20s–30s): Predominantly males, often presenting with combined lung and kidney involvement. * Older group (60s–70s): Affects men and women equally, often presenting with isolated glomerulonephritis. The option incorrectly swaps the age/gender demographics (stating men in their 40s instead of both genders in their 60s-70s). 2. Analysis of other options: * Option B: In younger patients, the disease often presents as an explosive, life-threatening pulmonary-renal syndrome requiring immediate intervention. * Option C: Smoking is a major risk factor for pulmonary hemorrhage in anti-GBM disease (due to increased alveolar capillary permeability). Younger patients with lung hemorrhage often have a better renal prognosis because the respiratory symptoms lead to earlier diagnosis before irreversible renal scarring occurs. * Option D: An urgent kidney biopsy is mandatory to confirm the diagnosis (showing linear IgG deposits) and to assess the degree of crescent formation, which guides prognosis and treatment [1]. High-Yield NEET-PG Pearls: * Immunofluorescence: Characterized by Linear IgG deposits along the glomerular basement membrane. * HLA Association: Strongly associated with HLA-DR2 (specifically DRB1*1501). * Treatment: The mainstay is Plasmapheresis (to remove circulating antibodies) combined with prednisolone and cyclophosphamide [1]. * Target Antigen: The non-collagenous (NC1) domain of the alpha-3 chain of Type IV collagen.

Question 333: Which of the following statements is NOT true regarding dialysis dementia syndrome?

A. Presenting symptoms include dysarthria, apraxia, and slurred speech.
B. Aluminum chelation with deferoxamine is helpful in improving symptoms.
C. Seizures and frank psychosis are early symptoms of the disease. (Correct Answer)
D. Its incidence has decreased with the use of aluminum-free water for dialysis.

Explanation: ### Explanation: Dialysis Dementia Syndrome **Dialysis Dementia Syndrome** (also known as Dialysis Encephalopathy) is a progressive, often fatal neurological disorder historically associated with long-term hemodialysis. It is primarily caused by the accumulation of **aluminum** in the brain, originating from aluminum-contaminated dialysate or aluminum-containing phosphate binders. #### Why Option C is the Correct Answer (The "NOT True" Statement) The clinical progression of dialysis dementia is typically insidious. **Seizures and frank psychosis are late-stage manifestations**, not early symptoms. The disease begins subtly with intermittent speech disturbances and progresses over months to more severe neurological decline. #### Analysis of Other Options * **Option A:** This is **true**. The earliest and most characteristic signs are speech disorders, specifically **stuttering, dysarthria, and apraxia**. These symptoms are initially intermittent (often worsening during or after a dialysis session) but eventually become permanent. * **Option B:** This is **true**. Since aluminum toxicity is the underlying cause, chelation therapy with **deferoxamine** can help remove aluminum from tissue stores and may improve or stabilize symptoms if initiated early. * **Option C:** This is **true**. The incidence has plummeted in modern nephrology due to the strict use of **reverse osmosis (RO)** water treatment systems and the replacement of aluminum-based phosphate binders with non-aluminum alternatives (like sevelamer). #### High-Yield Clinical Pearls for NEET-PG * **Key Culprit:** Aluminum toxicity (Dialysate water or phosphate binders). * **Classic Triad:** Speech disturbances (earliest), myoclonus, and progressive dementia. * **EEG Finding:** Characteristic paroxysmal bursts of high-voltage delta waves with spikes (often precedes clinical symptoms). * **Prevention:** The most effective "treatment" is prevention through purified water (RO) and avoiding aluminum-containing medications.

Question 334: A 60-year-old man presents with pain over his toes. He previously underwent coronary stenting for acute STEMI. Local examination of his feet reveals colored skin lesions with tenderness, and his renal function has been gradually declining. What is the most probable diagnosis?

A. Sharp syndrome
B. Antiphospholipid antibody syndrome
C. Aortic dissection
D. Atheroembolism (Correct Answer)

Explanation: ### Explanation The correct diagnosis is **Atheroembolism** (also known as Cholesterol Crystal Embolization). **Why Atheroembolism is correct:** This condition occurs when cholesterol crystals break off from atherosclerotic plaques in large arteries (like the aorta) and lodge in small distal vessels. [1] * **Trigger:** The most common trigger is an invasive vascular procedure, such as **coronary stenting** or angiography, where the catheter mechanically disrupts the plaque. [1] * **Clinical Presentation:** It typically presents with a triad of: 1. **Cutaneous signs:** "Blue toe syndrome" (painful, cyanotic toes with intact pulses) and *Livedo reticularis*. [1] 2. **Acute/Subacute Kidney Injury:** Gradual decline in renal function due to occlusion of renal arterioles. [1] 3. **Systemic symptoms:** Fever, eosinophilia, and low complement levels. **Why other options are incorrect:** * **Sharp Syndrome:** Also known as Mixed Connective Tissue Disease (MCTD). It presents with features of SLE, scleroderma, and polymyositis (e.g., Raynaud’s, puffy fingers). It is not triggered by vascular interventions. * **Antiphospholipid Antibody Syndrome (APS):** While it causes thrombosis, it usually presents with venous/arterial clots or pregnancy loss. It lacks the specific association with post-procedural "blue toes." * **Aortic Dissection:** This presents with sudden, tearing chest or back pain and acute hemodynamic instability, rather than a gradual decline in renal function and localized toe lesions. **NEET-PG High-Yield Pearls:** * **Classic Triad:** Recent vascular procedure + Livedo reticularis/Blue toes + Eosinophilia/Eosinophiluria. [1] * **Pathognomonic Histology:** Renal biopsy shows **"Biconvex needle-shaped clefts"** (ghost cells) within the lumen of small arteries, representing dissolved cholesterol crystals. * **Management:** Primarily supportive; statins are used for plaque stabilization. Avoid anticoagulation as it may prevent the "healing" of the plaque and worsen embolization. [1]

Question 335: What is the major cause of death in patients with chronic renal failure?

A. Uremia
B. Malignant hypertension
C. Hyperkalemia-induced arrhythmias
D. Myocardial infarction (Correct Answer)

Explanation: **Explanation:** **1. Why Myocardial Infarction (MI) is the correct answer:** Cardiovascular disease (CVD) is the leading cause of mortality in patients with Chronic Kidney Disease (CKD), accounting for nearly 50% of all deaths [1]. Patients with CKD have a significantly higher prevalence of traditional risk factors (hypertension, diabetes, dyslipidemia) and non-traditional risk factors (chronic inflammation, oxidative stress, hyperphosphatemia, and vascular calcification). This leads to accelerated atherosclerosis and left ventricular hypertrophy (LVH), making **Myocardial Infarction** and sudden cardiac death the most common terminal events [2]. **2. Analysis of Incorrect Options:** * **A. Uremia:** While uremia causes significant morbidity (encephalopathy, pericarditis, platelet dysfunction), it is rarely the direct cause of death in the modern era due to the availability of renal replacement therapy (dialysis) [1]. * **B. Malignant Hypertension:** Although hypertension is a hallmark of CKD and contributes to renal decline, it is usually a manageable risk factor rather than the primary cause of acute mortality. * **C. Hyperkalemia-induced arrhythmias:** Hyperkalemia is a life-threatening emergency in CKD/ESRD; however, with dietary restrictions and dialysis, it is a less frequent cause of death compared to chronic ischemic heart disease. **3. High-Yield Clinical Pearls for NEET-PG:** * **The "Cardio-Renal" Link:** CKD is considered an independent risk factor for CAD. Even a mild decrease in GFR increases cardiovascular risk. * **Vascular Calcification:** High phosphorus levels in CKD lead to the transformation of vascular smooth muscle cells into osteoblast-like cells, causing "Mönckeberg-like" medial calcification [3]. * **Most common cause of ESRD:** Diabetes Mellitus (followed by Hypertension) [1]. * **Most common cause of death in Dialysis patients:** Cardiovascular disease (specifically sudden cardiac death/arrhythmia).

Question 336: What is the earliest abnormality in diabetic nephropathy?

A. Hyperfiltration (Correct Answer)
B. Microalbuminuria
C. Hypertension
D. Proteinuria

Explanation: ### Explanation **Correct Answer: A. Hyperfiltration** In the natural history of Diabetic Nephropathy (DN), the earliest functional change is **Glomerular Hyperfiltration**, characterized by an increase in the Glomerular Filtration Rate (GFR). This occurs due to hyperglycemia-induced vasodilation of the afferent arteriole and vasoconstriction of the efferent arteriole (mediated by Angiotensin II). This creates high intraglomerular pressure, leading to an initial rise in GFR (Stage 1 of Mogensen’s classification) before any structural damage or protein leakage is detectable. **Analysis of Incorrect Options:** * **B. Microalbuminuria (30–300 mg/day):** This is the **earliest clinical sign** and the first detectable marker of DN in routine screening [1], [2]. However, it occurs after the initial hyperfiltration and basement membrane thickening phase (Stage 3). Pathologically, the first changes coincide with the onset of microalbuminuria and include thickening of the glomerular basement membrane [2]. * **C. Hypertension:** This usually develops alongside microalbuminuria and worsens as the GFR begins to decline. It is a consequence and a progression factor, not the initiating event. * **D. Proteinuria (Macroalbuminuria >300 mg/day):** This represents "Overt Nephropathy" (Stage 4). It signifies significant glomerular damage and is a late feature compared to hyperfiltration [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Mogensen’s Stages:** Stage 1 is Hyperfiltration; Stage 2 is Silent phase (structural changes like GBM thickening); Stage 3 is Incipient DN (Microalbuminuria). * **Pathological Hallmark:** Kimmelstiel-Wilson (KW) nodules (nodular glomerulosclerosis) are pathognomonic for DN [2]. * **Size of Kidneys:** Unlike most causes of Chronic Kidney Disease (CKD), kidneys in diabetic nephropathy are typically **enlarged** or normal-sized, even in advanced stages. * **Drug of Choice:** ACE inhibitors or ARBs are used to reduce intraglomerular pressure by dilating the efferent arteriole.

Question 337: Type 1A diabetes is characterized by:

A. High anion gap acidosis
B. Low serum potassium (Correct Answer)
C. Hyperkalemia
D. Negative urine anion gap

Explanation: **Explanation:** The question refers to **Distal Renal Tubular Acidosis (Type 1 RTA)**. In Type 1 RTA, the primary defect is the inability of the alpha-intercalated cells in the distal tubule to secrete hydrogen ions ($H^+$) into the tubular lumen. **Why Option B is Correct:** In Type 1 RTA, the failure to secrete $H^+$ leads to a compensatory increase in potassium ($K^+$) excretion. To maintain electrical neutrality, the kidney excretes $K^+$ instead of $H^+$. Additionally, the resulting systemic acidosis and volume depletion trigger aldosterone, which further promotes potassium wasting [1]. This leads to **hypokalemia** (low serum potassium), a hallmark of Type 1 RTA. **Analysis of Incorrect Options:** * **A. High anion gap acidosis:** RTAs are classic causes of **Normal Anion Gap Metabolic Acidosis (NAGMA)** or hyperchloremic metabolic acidosis [1]. High anion gap acidosis is seen in conditions like DKA, Lactic acidosis, or Uremia. * **C. Hyperkalemia:** This is characteristic of **Type 4 RTA** (Hypoaldosteronism), not Type 1. * **D. Negative urine anion gap:** A negative UAG indicates the presence of ammonium ($NH_4^+$) and is seen in diarrhea. In Type 1 RTA, the **Urine Anion Gap is Positive** because the kidney cannot excrete $NH_4^+$ effectively due to the distal acidification defect. **High-Yield Clinical Pearls for NEET-PG:** * **Urinary pH:** In Type 1 RTA, the urine pH is characteristically **high (> 5.5)** because the distal tubule cannot acidify the urine [1]. * **Complications:** Chronic Type 1 RTA often leads to **nephrocalcinosis** and calcium phosphate stones (due to hypercalciuria and alkaline urine). * **Mnemonic:** Type **1** is **D**istal (1D), Type **2** is **P**roximal (2P). Type 1 is the only RTA where urine pH cannot be lowered below 5.5.

Question 338: Convulsions are commonly precipitated in terminal renal failure by:

A. Hyperkalemia
B. Hypokalemia
C. Water intoxication (Correct Answer)
D. Hypermagnesemia

Explanation: In terminal renal failure (End-Stage Renal Disease), the kidneys lose their ability to excrete free water and maintain osmolality [2]. This leads to **Water Intoxication**, characterized by dilutional hyponatremia [3]. **Why Water Intoxication is the Correct Answer:** As the Glomerular Filtration Rate (GFR) drops significantly, the kidneys cannot effectively dilute urine [3]. Excessive water intake (iatrogenic or oral) leads to a rapid fall in serum sodium levels [2]. This creates an osmotic gradient that shifts water into brain cells, causing **cerebral edema**. The resulting increased intracranial pressure and neuronal irritability are the primary triggers for convulsions (seizures) and encephalopathy in these patients [1]. **Analysis of Incorrect Options:** * **Hyperkalemia (A):** While life-threatening, hyperkalemia primarily causes cardiac conduction defects (peaked T-waves, widened QRS) and arrhythmias/cardiac arrest, not typically convulsions. * **Hypokalemia (B):** Rare in terminal renal failure (unless due to aggressive dialysis or diuretics); it typically causes muscle weakness, ileus, and U-waves on ECG. * **Hypermagnesemia (D):** High magnesium levels actually act as a CNS depressant and neuromuscular blocker. It leads to loss of deep tendon reflexes and respiratory depression, rather than convulsions. **NEET-PG High-Yield Pearls:** 1. **Dialysis Equilibrium Syndrome:** A specific cause of seizures occurring *during* or shortly after dialysis due to the rapid removal of urea, leading to cerebral edema. 2. **Hyponatremia Rule:** Rapid correction of hyponatremia can lead to **Central Pontine Myelinolysis** (Osmotic Demyelination Syndrome). 3. **Most common cause of death in ESRD:** Cardiovascular disease (not electrolyte imbalance).

Question 339: All of the following are associated with low C3 levels except?

A. Post streptococcal glomerulonephritis
B. Membranoproliferative Glomerulonephritis
C. Goodpasture disease (Correct Answer)
D. Systemic lupus erythematosus

Explanation: **Explanation:** The measurement of serum complement (C3 and C4) is a critical diagnostic step in nephrology to differentiate between various types of glomerulonephritis (GN). **1. Why Goodpasture Disease is the Correct Answer:** Goodpasture disease (Anti-GBM disease) is characterized by the formation of antibodies directly against the glomerular basement membrane [1]. It is a **Type II hypersensitivity reaction** that does not typically involve the systemic activation or consumption of the complement cascade. Therefore, serum complement levels (C3 and C4) remain **normal** [3]. **2. Analysis of Incorrect Options (Low C3 Conditions):** * **Post-streptococcal Glomerulonephritis (PSGN):** Characterized by the activation of the alternative pathway, leading to **low C3** and usually normal C4 [2]. Levels typically normalize within 6–8 weeks. * **Membranoproliferative Glomerulonephritis (MPGN):** * Type I (Classical pathway): Low C3 and Low C4. * Type II (Dense Deposit Disease): Low C3 and Normal C4 (due to C3 nephritic factor) [2]. * **Systemic Lupus Erythematosus (SLE):** Lupus nephritis involves the classical pathway activation, resulting in **low levels of both C3 and C4** [3]. **3. High-Yield Clinical Pearls for NEET-PG:** To quickly solve "Low Complement GN" questions, remember the mnemonic **"PMS"**: * **P** - Post-streptococcal GN * **M** - Membranoproliferative GN * **S** - SLE (Systemic Lupus Erythematosus) * *Other causes include Subacute Bacterial Endocarditis (SBE) and Cryoglobulinemia.* **Key Distinction:** * **Low C3 + Low C4:** SLE, MPGN Type I, Cryoglobulinemia. * **Low C3 + Normal C4:** PSGN, MPGN Type II (Dense Deposit Disease) [2]. * **Normal C3 + Normal C4:** Goodpasture disease, IgA Nephropathy, ANCA-associated vasculitis (GPA/MPA) [3].

Question 340: What is the most important laboratory finding in nephrotic syndrome?

A. Bence Jones protein
B. Hyperkalemia
C. Hypoalbuminemia (Correct Answer)
D. Hypertension

Explanation: Nephrotic syndrome is a clinical triad characterized by massive proteinuria, hypoalbuminemia, and generalized edema [1]. The pathophysiology begins with **heavy proteinuria** (>3.5 g/24h) due to increased glomerular permeability [3]. This massive loss of protein directly leads to **Hypoalbuminemia** (serum albumin <3 g/dL), which is the hallmark laboratory finding [3]. The decrease in plasma oncotic pressure subsequently causes fluid to shift into the interstitium (edema) and triggers the liver to increase lipoprotein synthesis (hyperlipidemia) [3]. **Analysis of Incorrect Options:** * **A. Bence Jones protein:** These are monoclonal immunoglobulin light chains found in the urine of patients with **Multiple Myeloma** [1]. While they cause proteinuria, they are not a feature of primary nephrotic syndrome. * **B. Hyperkalemia:** This is typically a feature of **Acute Kidney Injury (AKI)** or advanced Chronic Kidney Disease (CKD) where GFR is significantly reduced. In pure nephrotic syndrome, potassium levels are usually normal unless there is associated renal failure. * **C. Hypertension:** While hypertension can occur in certain types of nephrotic syndrome (like FSGS), it is more characteristic of **Nephritic Syndrome** [2]. It is a clinical sign, not the defining laboratory finding. **NEET-PG High-Yield Pearls:** * **Mnemonic for Nephrotic Syndrome:** **N**aphrotic (Proteinuria, Hypoalbuminemia, Edema, Hyperlipidemia). * **Most common cause in children:** Minimal Change Disease (MCD) [1]. * **Most common cause in adults:** Focal Segmental Glomerulosclerosis (FSGS) (globally) or Membranous Nephropathy [2]. * **Hypercoagulability:** Patients are at high risk for thromboembolism (especially Renal Vein Thrombosis) due to the loss of Antithrombin III in urine.

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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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Nephrology — MCQs

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