Renal Pathology — MCQs

Renal Pathology Indian Medical PG Practice Questions and MCQs

Question 11: Most common mutation in Alport syndrome is in COL4A5, which is transmitted as?

A. Autosomal dominant
B. Autosomal recessive
C. X-linked (Correct Answer)
D. Variable, autosomal dominant or autosomal recessive

Explanation: **Explanation:** Alport Syndrome is a hereditary nephritis caused by mutations in the genes encoding the **Type IV collagen** chains, which are essential components of the glomerular basement membrane (GBM), cochlea, and lens [1]. **1. Why X-linked is correct:** The most common form of Alport Syndrome (approximately **80% of cases**) is caused by a mutation in the **COL4A5** gene, located on the **X chromosome** [1]. This gene encodes the $\alpha$5 chain of Type IV collagen. Because it is X-linked, males are typically more severely affected, often progressing to end-stage renal disease (ESRD), while females are often carriers with milder symptoms (like isolated hematuria) [1]. **2. Why other options are incorrect:** * **Autosomal Recessive (Option B):** This accounts for about 15% of cases and involves mutations in **COL4A3 or COL4A4** (located on Chromosome 2). It presents with early-onset renal failure in both genders. * **Autosomal Dominant (Option A):** This is the rarest form (approx. 5%) and also involves mutations in **COL4A3 or COL4A4**, but follows a dominant inheritance pattern with slower progression. * **Variable (Option D):** While Alport syndrome is genetically heterogeneous, the specific question asks for the transmission of the **COL4A5** mutation, which is strictly X-linked. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad:** Hereditary nephritis (hematuria/ESRD), Sensorineural deafness, and Ocular defects (e.g., **Anterior Lenticonus**). * **Electron Microscopy (Gold Standard):** Shows characteristic **"Basket-weave appearance"** due to irregular thickening, thinning, and splitting of the lamina densa. * **Immunofluorescence:** Shows a "negative" or "loss of expression" for $\alpha$3, $\alpha$4, and $\alpha$5 collagen chains in the GBM [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 929-930.

Question 12: Alport syndrome is due to defective-

A. Collagen (Correct Answer)
B. Elastin
C. Fibrillin
D. Proteoglycan

Explanation: **Explanation:** **Alport Syndrome** is a hereditary nephropathy caused by mutations in the genes encoding the **Type IV collagen** chains (specifically α3, α4, or α5) [1]. Type IV collagen is a crucial structural component of the basement membranes in the glomerulus, the cochlea, and the lens of the eye. 1. **Why Collagen is Correct:** The defect leads to an abnormal glomerular basement membrane (GBM). Under electron microscopy, this manifests as a characteristic **"basket-weave" appearance** due to irregular thinning and thickening with longitudinal splitting of the lamina densa. 2. **Why other options are incorrect:** * **Elastin:** Defects in elastin are associated with conditions like Williams syndrome or cutis laxa, not Alport syndrome. * **Fibrillin:** Mutations in Fibrillin-1 lead to **Marfan Syndrome**, characterized by skeletal, ocular (ectopia lentis), and cardiovascular issues. * **Proteoglycan:** While proteoglycans are part of the extracellular matrix, they are not the primary structural defect in Alport syndrome. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** Most commonly **X-linked Dominant** (COL4A5 mutation) [1]. * **Classic Triad:** 1. **Hereditary Nephritis:** Progressing to end-stage renal disease (ESRD) [1]. 2. **Sensorineural Hearing Loss:** Bilateral, high-frequency [1]. 3. **Ocular Defects:** Anterior lenticonus (pathognomonic) and maculopathy. * **Diagnosis:** Electron microscopy is the gold standard (Basket-weave appearance). Immunohistochemistry showing absence of α5 collagen staining in the GBM can also be helpful [1]. * **Note:** If the question asks for the specific collagen type, it is **Type IV** ("Can't see, can't pee, can't hear a high-C"). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 929-930.

Question 13: Which of the following conditions is characterized by Type III Rapidly Progressive Glomerulonephritis (RPGN)?

A. Systemic Lupus Erythematosus (SLE)
B. IgA nephropathy
C. Granulomatosis with polyangitis (Correct Answer)
D. Cryoglobulinemia

Explanation: **Explanation:** Rapidly Progressive Glomerulonephritis (RPGN) is a clinical syndrome characterized by a rapid decline in renal function and the presence of **crescents** in more than 50% of glomeruli. It is classified into three types based on Immunofluorescence (IF) findings: * **Type I:** Anti-GBM disease (Linear deposits) [3]. * **Type II:** Immune-complex mediated (Granular deposits) [3]. * **Type III:** Pauci-immune (Negative/scant IF deposits) [1]. **Why Option C is correct:** **Granulomatosis with Polyangiitis (GPA)** is the classic example of **Type III (Pauci-immune) RPGN** [2]. It is characterized by the absence of significant antibody deposits on IF and is strongly associated with **c-ANCA (PR3-ANCA)** [1]. Other examples include Microscopic Polyangiitis (p-ANCA) and Eosinophilic Granulomatosis with Polyangiitis (Churg-Strauss). **Why other options are incorrect:** * **Option A (SLE):** Lupus nephritis is a **Type II RPGN**. It shows a "full house" pattern on IF with granular deposits of IgG, IgA, IgM, C3, and C1q. * **Option B (IgA Nephropathy):** This is a **Type II RPGN** characterized by prominent granular IgA deposits in the mesangium. * **Option D (Cryoglobulinemia):** This is an immune-complex mediated disease (often associated with Hepatitis C) and falls under **Type II RPGN**. **High-Yield Pearls for NEET-PG:** 1. **Crescent Composition:** Crescents are formed by the proliferation of **parietal epithelial cells** and the migration of monocytes/macrophages into Bowman’s space. 2. **Fibrin:** The presence of fibrin in Bowman’s space is the key stimulus for crescent formation. 3. **ANCA Association:** Type III RPGN is almost always ANCA-positive [1]. If ANCA is negative, it is termed "ANCA-negative pauci-immune glomerulonephritis." 4. **Goodpasture Syndrome:** This is Type I RPGN + Pulmonary hemorrhage. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 917-918. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 536-537. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 526-527.

Question 14: What is the most common lesion in diabetic nephropathy?

A. Fibrin caps
B. Capsular drops
C. Diffuse glomerulosclerosis (Correct Answer)
D. Kimmelstiel Wilson nodule

Explanation: **Explanation:** Diabetic nephropathy is a leading cause of end-stage renal disease. Understanding the distinction between the most common and the most specific lesion is a frequent high-yield topic in NEET-PG. **1. Why Diffuse Glomerulosclerosis is Correct:** Diffuse glomerulosclerosis is the **most common** histological change in diabetic nephropathy [1]. It is characterized by a global increase in mesangial matrix and thickening of the glomerular basement membrane (GBM) [3]. This process is driven by non-enzymatic glycosylation of proteins, leading to the accumulation of advanced glycation end-products (AGEs) [2]. Almost all patients with long-standing diabetes (both Type 1 and Type 2) develop this lesion [1]. **2. Analysis of Incorrect Options:** * **Kimmelstiel-Wilson (KW) Nodule:** While these are the **most specific** (pathognomonic) lesions for diabetes, they are not the most common [3]. They appear as ovoid, laminated hyaline masses in the periphery of the glomerulus. They occur in only about 15-30% of diabetic patients. * **Fibrin Caps:** These are hyaline accumulations located on the surface of capillary loops. They are non-specific and can be seen in other forms of glomerular injury. * **Capsular Drops:** These are eosinophilic wax-like deposits on the inner surface of Bowman’s capsule. While highly suggestive of diabetes, they are less frequent than diffuse sclerosis. **Clinical Pearls for NEET-PG:** * **Earliest Change:** Thickening of the Glomerular Basement Membrane (GBM) [1]. * **Earliest Clinical Sign:** Microalbuminuria (30–300 mg/day). * **Pathognomonic Lesion:** Kimmelstiel-Wilson (Nodular) Glomerulosclerosis [3]. * **Most Common Lesion:** Diffuse Glomerulosclerosis [1]. * **Vascular Change:** Hyaline arteriolosclerosis affecting **both** afferent and efferent arterioles (highly characteristic of DM). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, p. 1121. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1119-1121. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1121-1122.

Question 15: A 37-year-old man develops pulmonary hemorrhage and glomerulonephritis. Lung biopsy with immunofluorescence demonstrates IgG deposition along the basement membrane. These antibodies are most likely directed against which of the following types of collagen?

A. Type I
B. Type II
C. Type III
D. Type IV (Correct Answer)

Explanation: The clinical presentation of pulmonary hemorrhage and glomerulonephritis (pulmonary-renal syndrome) combined with linear IgG deposition on immunofluorescence is diagnostic of **Goodpasture Syndrome** (Anti-GBM disease) [1, 2]. **Why Type IV Collagen is Correct:** Goodpasture syndrome is caused by autoantibodies directed against the **non-collagenous domain (NC1)** of the **α3 chain of Type IV collagen** [1]. Type IV collagen is a major structural component of basement membranes [1]. Because these antigens are intrinsic to the basement membrane and evenly distributed, immunofluorescence reveals a characteristic **smooth, linear pattern** of IgG deposition along the glomerular and alveolar capillaries [1, 2]. **Why Other Options are Incorrect:** * **Type I Collagen:** The most abundant collagen found in bone, skin, and tendons. It provides tensile strength but is not the target in Goodpasture syndrome. * **Type II Collagen:** Primarily found in hyaline and elastic cartilage (e.g., vitreous humor, intervertebral discs). * **Type III Collagen:** Known as "reticulin," it is found in extensible soft tissues like blood vessels, uterus, and fetal skin. It is also involved in early wound healing (granulation tissue). **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad:** Glomerulonephritis, pulmonary hemorrhage, and anti-GBM antibodies [2]. * **Immunofluorescence (IF):** Linear IgG (and C3) deposition [1]. This distinguishes it from Post-Streptococcal GN (lumpy-bumpy/granular) or Alport Syndrome (split basement membrane). * **Light Microscopy:** Often shows **crescentic glomerulonephritis** (RPGN Type I). * **HLA Association:** Strongly associated with **HLA-DRB1** [2]. * **Treatment:** Plasmapheresis (to remove circulating antibodies) plus corticosteroids and cyclophosphamide [2]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 526-527, 537-538. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 322-323.

Question 16: Hemodialysis-associated amyloid is deposited in which of the following?

A. Knee joint (Correct Answer)
B. Tongue
C. Liver
D. Tongue

Explanation: **Explanation:** **Hemodialysis-associated amyloidosis** is a form of systemic amyloidosis that occurs in patients with end-stage renal disease (ESRD) on long-term dialysis. 1. **Why Option A is Correct:** The precursor protein in this condition is **$\beta_2$-microglobulin**. In healthy individuals, this protein is filtered by the renal glomeruli and catabolized by tubules. In patients with renal failure, it cannot be filtered, and standard dialysis membranes are inefficient at removing it [2]. This leads to high serum levels, causing the protein to deposit as amyloid fibrils specifically in **osteoarticular structures**. Common sites include the **knee joint**, carpal ligaments (leading to Carpal Tunnel Syndrome), and the spine (spondylarthropathy) [2]. 2. **Why Other Options are Incorrect:** * **Options B & D (Tongue):** Macroglossia (enlargement of the tongue) is a classic feature of **AL Amyloidosis** (Primary Amyloidosis), associated with plasma cell dyscrasias [2],[3]. It is not a characteristic feature of $\beta_2$-microglobulin deposition. * **Option C (Liver):** While the liver is frequently involved in **AA Amyloidosis** (Secondary Amyloidosis) and AL Amyloidosis, it is typically spared in dialysis-associated amyloidosis, which has a strong predilection for the musculoskeletal system [2],[4]. **High-Yield Clinical Pearls for NEET-PG:** * **Precursor Protein:** $\beta_2$-microglobulin (A$\beta_2$M). * **Most Common Presentation:** Carpal Tunnel Syndrome (often the first symptom) [2]. * **Staining:** Like all amyloid, it shows **Apple-green birefringence** under polarized light after Congo Red staining [1]. * **Risk Factor:** Duration of dialysis; the risk increases significantly after 5–10 years of treatment. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 268-269. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 269-270. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 135-136. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 136-140.

Question 17: Which of the following conditions is characterized by highly selective proteinuria?

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

Explanation: Proteinuria is classified as **selective** when the glomerular basement membrane (GBM) loses its negative charge but maintains its structural integrity, allowing only small, negatively charged proteins like **Albumin** to leak through [1]. It is **non-selective** when there is significant structural damage to the GBM, allowing larger proteins (e.g., Globulins) to pass. **1. Why Minimal Change Disease (MCD) is correct:** MCD is the classic example of **highly selective proteinuria** [2]. The primary pathology is the **loss of the polyanionic charge** (heparan sulfate) of the GBM due to T-cell-derived cytokines [1]. Since the physical pores of the filter remain intact (only podocyte effacement is seen on EM), only albumin escapes [2]. This is why MCD typically responds excellently to steroids [2]. **2. Why the other options are incorrect:** * **Membranous Glomerulonephritis (C):** Characterized by subepithelial deposits and GBM thickening [3]. The structural damage is significant, leading to **non-selective proteinuria**. * **Focal Segmental Glomerulosclerosis (FSGS) (D):** Involves sclerosis and hyalinosis of glomerular segments. The physical destruction of the capillary loops results in **non-selective proteinuria** and a poorer response to steroids compared to MCD [2]. * **Mesangial Proliferative Nephritis (B):** This involves cellular proliferation and structural changes that generally result in a non-selective pattern of protein loss. **NEET-PG High-Yield Pearls:** * **MCD Gold Standard:** Light Microscopy (LM) appears **normal**; Electron Microscopy (EM) shows **effacement of podocyte foot processes** [2]. * **Selectivity Index:** A ratio of IgG clearance to Albumin clearance <0.1 indicates highly selective proteinuria. * **Most common cause** of Nephrotic Syndrome in children is MCD [2]; in adults, it is FSGS (globally) or Membranous (historically) [3]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 905-907. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 922-923. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 919-921.

Question 18: Immune complex-mediated glomerular damage is seen in all except?

A. Membranoproliferative GN
B. Goodpasture's syndrome (Correct Answer)
C. Crescentric GN
D. Focal segmental GN

Explanation: **Explanation:** The core concept tested here is the classification of glomerular injury based on immunofluorescence patterns. Glomerular damage is typically divided into **Immune-Complex mediated** (granular pattern), **Anti-GBM antibody-mediated** (linear pattern), and **Pauci-immune** (minimal/no deposits) [1], [2]. **Why Goodpasture’s Syndrome is the correct answer:** Goodpasture’s syndrome is the classic example of **Type II Hypersensitivity**. It is caused by antibodies directed against the non-collagenous domain of the **α3 chain of Type IV collagen** in the glomerular basement membrane (GBM) [3]. On immunofluorescence, this results in a characteristic **smooth, continuous linear pattern**, not an immune-complex (granular) pattern [1], [2]. **Analysis of other options:** * **Membranoproliferative GN (MPGN):** This is a classic immune-complex-mediated disease (Type I) or caused by alternative complement pathway dysregulation (Type II/C3 Glomerulopathy), both showing granular deposits [2], [4]. * **Crescentic GN (RPGN):** This is a clinical-pathological syndrome. While Type I is anti-GBM, **Type II Crescentic GN** is specifically defined by immune-complex deposition (e.g., post-infectious, SLE, or IgA nephropathy). Therefore, immune complexes *can* be the cause. * **Focal Segmental Glomerulosclerosis (FSGS):** While primarily a podocytopathy, FSGS often shows entrapped **IgM and C3** in the areas of sclerosis/hyalinosis, which are considered non-specific immune aggregates/complexes. **High-Yield Clinical Pearls for NEET-PG:** * **Linear Pattern:** Goodpasture’s Syndrome (Anti-GBM) [3]. * **Granular ("Lumpy-Bumpy") Pattern:** PSGN, Membranous GN, MPGN, SLE [4]. * **Pauci-immune:** Wegener’s (GPA), Microscopic Polyangiitis, Churg-Strauss (associated with ANCA). * **Goodpasture Triad:** Glomerulonephritis, Pulmonary hemorrhage, and Anti-GBM antibodies [3]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 526-527. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 911-913. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, p. 915. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, p. 911.

Question 19: The gross specimen section of kidney depicts which of the following?

A. Renal cell carcinoma
B. Medullary cystic kidney
C. Polycystic kidney (Correct Answer)
D. Hydatid cyst

Explanation: ***Polycystic kidney*** - Shows **multiple cysts** of varying sizes throughout the renal parenchyma, causing significant **kidney enlargement**. - The cysts replace normal kidney tissue and give the characteristic **"bunch of grapes"** appearance on gross examination. *Renal cell carcinoma* - Presents as a **solid mass** with areas of **necrosis** and **hemorrhage**, not multiple cysts. - Typically shows a **golden-yellow color** with variegated appearance due to lipid content. *Medullary cystic kidney* - Features **small cysts** confined to the **corticomedullary junction**, with overall **kidney shrinkage**. - Results in **small, scarred kidneys** rather than the enlarged cystic appearance seen here. *Hydatid cyst* - Appears as a **single, large cyst** with **thick walls** and **daughter cysts** inside. - Caused by **Echinococcus granulosus** infection and typically involves the **liver** more commonly than kidneys.

Question 20: Complement level is reduced in which of the following conditions?

A. Minimal change disease
B. Membranous nephropathy
C. Focal and segmental glomerulosclerosis
D. Membranoproliferative glomerulonephritis (Correct Answer)

Explanation: **Explanation:** The reduction of serum complement levels (hypocomplementemia) in renal disease indicates the activation of the complement cascade via either the classical or alternative pathway. **Why D is Correct:** **Membranoproliferative Glomerulonephritis (MPGN)** is a classic "hypocomplementemic" glomerular disease. [1], [2] * **MPGN Type I:** Primarily involves the classical pathway (low C3 and C4) due to immune complex deposition. [2] * **MPGN Type II (Dense Deposit Disease):** Involves the alternative pathway (low C3, normal C4). [1] It is associated with **C3 Nephritic Factor**, an autoantibody that stabilizes C3 convertase, leading to continuous C3 consumption. [1] **Why Other Options are Incorrect:** * **A, B, and C (MCD, MN, FSGS):** These are primarily **nephrotic syndromes** where the pathogenesis does not involve significant systemic complement consumption. While Membranous Nephropathy involves the formation of the Membrane Attack Complex (C5b-9) in situ, it does not typically result in decreased *serum* complement levels. [3] **High-Yield Clinical Pearls for NEET-PG:** To quickly solve "Low Complement" questions, remember the mnemonic **"MAP"**: 1. **M** – **M**PGN (Types I and II) 2. **A** – **A**cute Post-Streptococcal Glomerulonephritis (PSGN) - (C3 returns to normal in 6-8 weeks). [3] 3. **P** – **P**roliferative Lupus Nephritis (SLE). *Other causes include Subacute Bacterial Endocarditis (SBE) and Cryoglobulinemia.* **Key Distinction:** * **Low C3 + Low C4:** Suggests Classical Pathway (SLE, MPGN Type I). * **Low C3 + Normal C4:** Suggests Alternative Pathway (PSGN, MPGN Type II/Dense Deposit Disease). [1] **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 534-535. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 926-927. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, p. 915.

Practice by Chapter

Congenital Anomalies of the Kidney

Practice Questions

Glomerular Diseases

Practice Questions

Tubular and Interstitial Diseases

Practice Questions

Vascular Diseases of the Kidney

Practice Questions

Cystic Diseases of the Kidney

Practice Questions

Urinary Tract Obstruction and Stones

Practice Questions

Renal Tumors

Practice Questions

Kidney in Systemic Diseases

Practice Questions

Renal Transplantation Pathology

Practice Questions

Urinary Tract Infections

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free