Renal Pathology Practice Questions

Q: Increased BP, proteinuria, and RBC casts are the features of which type of Glomerulonephritis?

Rapidly progressive glomerulonephritis (RPGN). **Explanation:** The clinical triad of **Hypertension (Increased BP), Proteinuria, and RBC casts** is the hallmark of **Nephritic Syndrome** [1]. Among the given options, **Rapidly Progressive Glomerulonephritis (RPGN)** is the most severe clinical manifestation of nephritic syndrome, characterized by a rapid decline in GFR (usually >50% within weeks to months) and the presence of **crescents** on histology [1]. * **Why RPGN is correct:** RBC casts are pathognomonic for glomerular bleeding (nephritis). In RPGN, severe glomerular inflammation leads to the leakage of RBCs and proteins into the urine, while decreased salt/water excretion causes hypertension [1]. * **Why other options are incorrect:** * **Membranous GN:** This is a classic **Nephrotic Syndrome**. It presents with massive proteinuria (>3.5g/day) and edema, but typically lacks RBC casts and significant hypertension in early stages [1]. * **FSGS:** Another primary cause of **Nephrotic Syndrome**. While it can occasionally present with mild hematuria or hypertension, it is primarily characterized by heavy proteinuria rather than an active nephritic sediment (RBC casts) [1]. * **Membranoproliferative GN (MPGN):** This is a "mixed" pattern that can present with both nephritic and nephrotic features. However, RPGN is the more definitive answer when focusing on the acute presentation of RBC casts and rapid clinical deterioration. **Clinical Pearls for NEET-PG:** * **RBC Casts:** Always signify **Glomerulonephritis** (not lower urinary tract bleeding). * **RPGN Histology:** Characterized by **Crescents** (formed by proliferation of parietal epithelial cells and infiltration of monocytes/fibrin) [1]. * **Classification:** RPGN is divided into Type I (Anti-GBM/Goodpasture), Type II (Immune complex), and Type III (Pauci-immune/ANCA-associated) [1].

Q: A condition presenting as nephritic syndrome with features of loss of foot processes on electron microscopy and poor response to corticosteroid therapy is:

Focal segmental glomerulosclerosis. ### Explanation The correct answer is **Focal Segmental Glomerulosclerosis (FSGS)**. **Why FSGS is correct:** FSGS is a common cause of nephrotic syndrome in adults, but it frequently presents with **nephritic features** such as hypertension, hematuria, and azotemia. On **Electron Microscopy (EM)**, it characteristically shows the **effacement (loss) of podocyte foot processes**, similar to Minimal Change Disease (MCD) [1]. However, unlike MCD, FSGS is notorious for its **poor response to corticosteroid therapy**, often progressing to chronic kidney disease [1]. **Why the other options are incorrect:** * **Postinfectious Glomerulonephritis (PSGN):** While it presents with nephritic syndrome, EM shows characteristic **subepithelial "humps"** (immune complexes), not simple foot process effacement [1]. * **Membranoproliferative Glomerulonephritis (MPGN) Type I:** This presents with a mixed nephritic/nephrotic picture, but EM shows **subendothelial deposits** and a "tram-track" appearance on light microscopy due to mesangial interposition. * **Minimal Change Disease (MCD):** Although MCD shows loss of foot processes on EM, it presents as a **pure nephrotic syndrome** (no hematuria/hypertension) and is highly **corticosteroid-sensitive**, especially in children [1]. **High-Yield Clinical Pearls for NEET-PG:** * **FSGS Hallmark:** Segmental sclerosis in some (focal) glomeruli on Light Microscopy; Foot process effacement on EM [1]. * **Collapsing Variant:** The most severe form of FSGS, strongly associated with **HIV infection** and IV drug use. * **Genetic Mutation:** Mutations in the **NPHS2 gene** (encoding podocin) are associated with steroid-resistant FSGS. * **Recurrence:** FSGS has a high rate of recurrence in renal transplants (up to 30-50%).

Q: Which of the following is true about the light microscopic changes in Minimal Change Glomerulonephritis?

No abnormality. ### Explanation: Minimal Change Disease (MCD) **1. Why "No abnormality" is the correct answer:** Minimal Change Disease (MCD) is defined by its name: the changes are so "minimal" that the glomeruli appear **completely normal under Light Microscopy (LM)** [1]. The glomerular basement membrane (GBM) thickness is normal, and there is no hypercellularity or inflammatory infiltrate. This is why it was historically called "Nil Disease." **2. Analysis of Incorrect Options:** * **B. Fusion of foot processes:** While this is the hallmark finding of MCD, it is **only visible under Electron Microscopy (EM)** [1]. Under LM, these changes are below the resolution limit. Foot process effacement is a result of cytokine-mediated injury to podocytes. * **C & D. Absence of immunoglobulins/complement:** These findings are characteristic of **Immunofluorescence (IF)**, which is typically negative in MCD [1]. While true that they are absent, the question specifically asks for **Light Microscopic (LM)** changes. "No abnormality" is the most accurate description of the LM morphology itself. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most Common Cause:** MCD is the most common cause of Nephrotic Syndrome in children (peak age 2–6 years) [1]. * **Pathogenesis:** T-cell dysfunction leads to the production of a "glomerular permeability factor" (cytokines) that destroys the negative charge (polyanionic charge) of the GBM, leading to selective albuminuria. * **Electron Microscopy (Gold Standard):** Shows diffuse effacement (fusion) of podocyte foot processes [1]. * **Clinical Feature:** Sudden onset of massive edema; highly responsive to **Steroid therapy** (Prednisone) [1]. * **Selective Proteinuria:** Unlike other nephrotic syndromes, MCD typically presents with selective loss of Albumin only. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 921-928.

Q: In a pathological examination of a renal biopsy specimen, what percentage of glomeruli defines focal change?

Less than 50% of glomeruli. In renal pathology, specific terminology is used to describe the distribution of lesions within a biopsy specimen. These definitions are crucial for diagnosing various glomerulonephritides. ### **Explanation of the Correct Answer** The term **Focal** refers to a lesion that involves **less than 50% of the total number of glomeruli** sampled in the biopsy [1]. Conversely, if the lesion involves **50% or more** of the glomeruli, it is termed **Diffuse**. This distinction is a fundamental classification criterion used in the ISN/RPS classification of Lupus Nephritis and in defining Focal Segmental Glomerulosclerosis (FSGS) [1]. ### **Analysis of Incorrect Options** * **Options A, B, and D:** While these percentages represent a "portion" of the kidney, they do not align with the standardized pathological threshold. In renal pathology, the 50% mark is the universal "cut-off" point used by pathologists to differentiate between focal and diffuse processes. There are no major renal classifications that utilize 10%, 25%, or 30% as the primary defining threshold for focal change. ### **High-Yield Clinical Pearls for NEET-PG** * **Focal vs. Diffuse:** Refers to the **number of glomeruli** involved (Threshold: 50%) [1]. * **Segmental vs. Global:** Refers to the **extent of involvement within a single glomerulus**. * **Segmental:** Involves only a portion of the glomerular tuft (e.g., FSGS) [1]. * **Global:** Involves the entire glomerulus [1]. * **Minimum Requirement:** For an adequate renal biopsy interpretation, at least **10 glomeruli** should be present (though 15-20 is preferred for evaluating focal diseases like FSGS to avoid sampling error). * **Lupus Nephritis:** Class III is Focal (<50%), while Class IV is Diffuse (≥50%) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 230-232.

Question 1

A 25-year-old woman presents with new symptoms of decreased urine output, leg edema, and facial swelling. Laboratory investigations reveal acute kidney injury. A renal biopsy shows a granular pattern of immune complex-mediated glomerulonephritis on immunofluorescence. Which of the following conditions is most likely to cause this pattern of renal injury?

Accepted Answer

Postinfectious glomerulonephritis

Answer

Acute tubular necrosis (ATN)

Answer

Wegener granulomatosis

Answer

Hemolytic uremic syndrome (HUS)

Question 2

Increased BP, proteinuria, and RBC casts are the features of which type of Glomerulonephritis?

Accepted Answer

Rapidly progressive glomerulonephritis (RPGN)

Answer

Membranous glomerulonephritis (GN)

Answer

Membranoproliferative glomerulonephritis (GN)

Answer

Focal segmental glomerulosclerosis (FSGS)

Question 3

Which of the following is characteristic of acute glomerulonephritis?

Accepted Answer

FeNa < 1%

Answer

Muddy brown casts

Answer

Hematuria and proteinuria

Answer

WBC casts

Question 4

A condition presenting as nephritic syndrome with features of loss of foot processes on electron microscopy and poor response to corticosteroid therapy is:

Accepted Answer

Focal segmental glomerulosclerosis

Answer

Postinfectious glomerulonephritis

Answer

Membranoproliferative glomerulonephritis type I

Answer

Minimal change disease

Question 5

Which of the following is true about the light microscopic changes in Minimal Change Glomerulonephritis?

Accepted Answer

No abnormality

Answer

Fusion of foot processes

Answer

Absence of immunoglobulins

Answer

Absence of complement

Question 6

An 8-year-old boy presents with periorbital edema and throbbing headaches. His parents report that the boy had a 'strep throat' 2 weeks ago. Urinalysis shows 3+ hematuria. A renal biopsy shows hypercellular glomeruli, and electron microscopic examination of glomeruli discloses subepithelial 'humps.' Which of the following best explains the pathogenesis of glomerulonephritis in this patient?

Accepted Answer

Deposition of circulating immune complexes

Answer

Antineutrophil cytoplasmic autoantibodies

Answer

Directly cytotoxic IgG and IgM antibodies

Answer

IgE-mediated mast cell degranulation

Question 7

IgA nephropathic deposits are seen in which of the following conditions?

Accepted Answer

Henoch-Schonlein Purpura (HSP)

Answer

Systemic Lupus Erythematosus (SLE)

Answer

Kawasaki disease

Answer

Wegener's granulomatosis

Question 8

Which is not a feature of benign hypertension in the kidney?

Accepted Answer

Fibrinoid necrosis

Answer

Hyaline arteriosclerosis

Answer

Interstitial lobular fibrosis

Answer

Medial hypertrophy of small vessels

Question 9

In a pathological examination of a renal biopsy specimen, what percentage of glomeruli defines focal change?

Accepted Answer

Less than 50% of glomeruli

Answer

Less than 10% of glomeruli

Answer

Less than 30% of glomeruli

Answer

Less than 25% of glomeruli

Question 10

A child presented with edema, massive proteinuria, and hyperlipidemia. Which statement about this condition is true?

Accepted Answer

Glomerular function is lost due to the loss of the polyanionic charge on both sites of the glomerular foot process.

Answer

Type of focal segmental glomerulosclerosis.

Answer

IgA deposition on the basement membrane.

Answer

Foot processes of the glomerular membrane are normal.

Renal Pathology — MCQs

Renal Pathology — MCQs

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