Renal Pathology Practice Questions

Q: Wire loop lesions are often characteristic for which class of lupus nephritis?

Diffuse proliferative glomerulonephritis (WHO class IV). **Explanation:** **Diffuse Proliferative Glomerulonephritis (Class IV)** is the most common and severe form of lupus nephritis [1]. The hallmark **"wire loop lesion"** occurs due to massive **subendothelial immune complex deposits** (DNA-anti-DNA complexes) [1]. These deposits cause circumferential thickening of the glomerular capillary wall, making it appear rigid and thickened like a wire under light microscopy [1]. This class involves >50% of glomeruli and is associated with the worst prognosis if untreated [1]. **Analysis of Incorrect Options:** * **Class II (Mesangial Proliferative):** Characterized by mild clinical symptoms and immune complexes restricted to the **mesangium** only. Capillary loops remain thin. * **Class III (Focal Proliferative):** Similar to Class IV but involves **<50% of glomeruli** [1]. While wire loops can occasionally be seen, they are the defining characteristic of the more extensive Class IV. * **Class IV (Membranous):** Characterized by **subepithelial deposits** (not subendothelial). It presents with nephrotic syndrome and shows uniform "spikes and domes" on silver stain, rather than wire loops. **High-Yield Clinical Pearls for NEET-PG:** * **Most common and most severe form:** Class IV (DPGN) [1]. * **Most common cause of death in SLE:** Renal failure (specifically Class IV). * **Immunofluorescence:** Shows a **"Full House" pattern** (IgG, IgA, IgM, C3, and C1q positivity). * **Electron Microscopy (EM):** Subendothelial deposits are the key to wire loops; "Fingerprint" patterns may also be seen. * **Lab Correlation:** Class IV is associated with high anti-dsDNA titers and low serum complement (C3, C4) levels. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, p. 232.

Q: A patient presented with pus in urine. Urine culture was negative. Following a sudden onset of renal failure, the patient died. An autopsy revealed the following finding in the kidney. What is the most likely diagnosis?

TB kidney. ***TB kidney*** - **Sterile pyuria** (pus in urine with negative standard culture) is the classic hallmark of **renal tuberculosis**, as TB organisms require special culture media. - Autopsy findings typically show **caseous necrosis**, **cavitation**, and **epithelioid granulomas** with **Langhans giant cells** in the kidney parenchyma. *Infected renal cysts* - Would show **positive bacterial culture** on routine urine culture, not sterile pyuria. - Autopsy would reveal **cystic structures** with **purulent material** but no granulomatous inflammation or caseous necrosis. *Renal cell carcinoma* - Typically presents with **hematuria**, not pyuria, and doesn't cause sterile pyuria. - Autopsy would show **solid tumor mass** with **clear cell** or **papillary architecture**, not inflammatory changes. *Renal stones* - May cause **secondary bacterial infection** leading to positive urine culture, not sterile pyuria. - Autopsy findings would include **calcium oxalate** or **uric acid crystals** with possible **hydronephrosis**, but no granulomatous inflammation.

Q: RBC casts in the microscopic examination of urine are an indicator of which of the following conditions?

Acute glomerulonephritis. **Explanation:** **1. Why Acute Glomerulonephritis is Correct:** The presence of **RBC casts** is a pathognomonic finding for **glomerular hematuria**, most commonly seen in **Acute Glomerulonephritis (AGN)** [1]. When there is inflammation or damage to the glomerular basement membrane, red blood cells leak into the nephron [1]. As they pass through the distal convoluted tubule and collecting duct, they are trapped within a matrix of **Tamm-Horsfall mucoprotein**. The cylindrical shape of the tubule molds these cells into "casts." Their presence confirms that the source of bleeding is the renal parenchyma (specifically the glomerulus) rather than the lower urinary tract [1]. **2. Why the Other Options are Incorrect:** * **Acute Pyelonephritis:** This is characterized by **WBC casts** and bacteria in the urine, reflecting an infectious/inflammatory process in the renal pelvis and interstitium. * **Chronic Glomerulonephritis:** While hematuria can occur, the characteristic finding in chronic renal failure or advanced stages is **Broad, Waxy casts**, which indicate dilated, atrophic tubules with low flow. * **Nephrotic Syndrome:** This is primarily characterized by heavy proteinuria [1]. The classic microscopic findings are **Fatty casts**, "Maltese cross" appearance under polarized light, and oval fat bodies. **3. NEET-PG High-Yield Clinical Pearls:** * **RBC Casts:** Glomerulonephritis (e.g., Post-streptococcal GN) or Vasculitis [1]. * **WBC Casts:** Pyelonephritis or Acute Interstitial Nephritis. * **Eosinophil Casts:** Highly suggestive of Drug-induced Acute Interstitial Nephritis. * **Muddy Brown (Granular) Casts:** Diagnostic of Acute Tubular Necrosis (ATN). * **Hyaline Casts:** Can be normal (seen in dehydration or after intense exercise).

Question 1

Familial Renal Cell Carcinoma is associated with which of the following genetic syndromes?

Accepted Answer

Von Hippel-Lindau syndrome

Answer

Turner syndrome

Answer

Alport syndrome

Answer

Peutz-Jeghers syndrome

Question 2

What is the most common renal pathology observed in patients experiencing shock?

Accepted Answer

Acute tubular necrosis

Answer

Acute cortical necrosis

Answer

Renal vein thrombosis

Answer

Acute medullar necrosis

Question 3

Goodpasture's disease is characterized by all of the following except:

Accepted Answer

Leukocytoclastic vasculitis

Answer

Glomerulonephritis

Answer

Presence of antibodies to basement membrane

Answer

Diffuse alveolar hemorrhage

Question 4

Which of the following conditions is characterized by occasional breaks in the glomerular basement membrane and subepithelial deposits visible on electron microscopy?

Accepted Answer

Membranous glomerulonephritis (MGN)

Answer

Focal glomerular sclerosis

Answer

Rapidly progressive glomerulonephritis (RPGN)

Answer

Minimal change disease (MCD)

Question 5

Which of the following features characterize Hemolytic Uremic Syndrome?

Accepted Answer

Microangiopathic hemolytic anemia, Thrombocytopenia, Renal failure

Answer

Microangiopathic hemolytic anemia, decreased LDH, Thrombocytopenia

Answer

Microangiopathic hemolytic anemia, Renal failure

Answer

Decreased LDH, Thrombocytopenia, Renal failure

Question 6

What is true about acute post-infective glomerulonephritis?

Accepted Answer

Deposition of IgA

Answer

Crescent formation

Answer

Subepithelial deposits

Answer

Granular deposits of IgG

Question 7

At autopsy, a patient who had died with acute anuria and uremia is found to have ischemic necrosis of the cortex of both kidneys with relative sparing of the medulla. These pathological findings are MOST likely related to which of the following underlying conditions?

Accepted Answer

Disseminated intravascular coagulation

Answer

Multiple myeloma

Answer

Polycystic kidney disease

Answer

Pyelonephritis

Question 8

Wire loop lesions are often characteristic for which class of lupus nephritis?

Accepted Answer

Diffuse proliferative glomerulonephritis (WHO class IV)

Answer

Mesangial proliferative glomerulonephritis (WHO class II)

Answer

Focal proliferative glomerulonephritis (WHO class III)

Answer

Membranous glomerulonephritis (WHO class V)

Question 9

A patient presented with pus in urine. Urine culture was negative. Following a sudden onset of renal failure, the patient died. An autopsy revealed the following finding in the kidney. What is the most likely diagnosis?

Accepted Answer

TB kidney

Answer

Infected renal cysts

Answer

Renal cell carcinoma

Answer

Renal stones

Question 10

RBC casts in the microscopic examination of urine are an indicator of which of the following conditions?

Accepted Answer

Acute glomerulonephritis

Answer

Acute pyelonephritis

Answer

Chronic glomerulonephritis

Answer

Nephrotic syndrome

Renal Pathology — MCQs

Renal Pathology — MCQs

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