Renal Pathology — MCQs

Renal Pathology Indian Medical PG Practice Questions and MCQs

Question 461: What is the diagnosis for pulmonary hypoplasia associated with uropathy?

A. Potter syndrome (Correct Answer)
B. Patau syndrome
C. Pehe disease
D. All of the above

Explanation: **Explanation:** **Potter Syndrome (Correct Answer):** Potter syndrome (or Potter sequence) refers to a constellation of physical findings caused by **oligohydramnios** (low amniotic fluid). In the context of uropathy—such as bilateral renal agenesis, posterior urethral valves, or polycystic kidney disease—the fetus fails to excrete urine into the amniotic sac. Amniotic fluid is essential for lung development; it stretches the airways and provides the necessary pressure for alveolar growth. Its absence leads to **pulmonary hypoplasia**, which is the most common cause of death in these neonates. Characteristic physical features include flattened "Potter facies" (low-set ears, flattened nose, recessed chin) and limb deformities due to uterine compression. **Incorrect Options:** * **Patau Syndrome (Trisomy 13):** This is a chromosomal anomaly characterized by midline defects such as holoprosencephaly, cleft lip/palate, polydactyly, and microphthalmia. While renal cysts can occur, it is not the primary cause of pulmonary hypoplasia via uropathy. * **Pehe Disease:** This is an obsolete term sometimes historically associated with infantile scurvy or specific metabolic bone conditions; it has no clinical relevance to renal-pulmonary pathology. **High-Yield Clinical Pearls for NEET-PG:** * **The "Sequence" Concept:** Potter syndrome is technically a *sequence*, where a single primary trigger (renal failure/leakage) leads to a cascade of secondary effects [1]. * **Mnemonic (POTTER):** **P**ulmonary hypoplasia, **O**ligohydramnios, **T**wisted face, **T**wisted skin, **E**xtremity defects, **R**enal failure. * **Most common cause:** Bilateral renal agenesis is the classic cause, but obstructive uropathy (like Posterior Urethral Valves) is a frequent trigger in males. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 460-462.

Question 462: Distal and collecting duct cysts are seen in which condition?

A. Autosomal Dominant Polycystic Kidney Disease (ADPKD)
B. Autosomal Recessive Polycystic Kidney Disease (ARPKD) (Correct Answer)
C. Tuberous Sclerosis
D. Nephronophthisis

Explanation: **Explanation:** **Autosomal Recessive Polycystic Kidney Disease (ARPKD)** is the correct answer because it is characterized by the **fusiform (cylindrical) dilation of the distal tubules and collecting ducts**. This condition is caused by a mutation in the **PKHD1 gene** on chromosome 6, which encodes **fibrocystin** [1]. Unlike other cystic diseases, the cysts in ARPKD are arranged radially, extending from the medulla to the cortex, giving the kidney a "sponge-like" appearance on gross examination. **Analysis of Incorrect Options:** * **ADPKD (Option A):** Cysts in ADPKD are derived from **all segments of the nephron** (proximal tubule, Loop of Henle, and distal segments) [2]. They are typically large, spherical, and involve only a fraction of the nephrons. * **Tuberous Sclerosis (Option C):** While associated with renal cysts and angiomyolipomas, the cysts are not specific to the distal/collecting ducts and often resemble those seen in ADPKD. * **Nephronophthisis (Option D):** This condition typically presents with cysts at the **corticomedullary junction**, primarily involving the distal convoluted tubules and collecting ducts, but it is characterized by small, shrunken kidneys and tubulointerstitial fibrosis, rather than the massive bilateral enlargement seen in ARPKD [3]. **High-Yield Clinical Pearls for NEET-PG:** * **Liver Involvement:** ARPKD is universally associated with **Congenital Hepatic Fibrosis** [1]. If a child presents with renal cysts and portal hypertension, think ARPKD. * **Potter Sequence:** Severe ARPKD in utero leads to oligohydramnios, resulting in pulmonary hypoplasia, flattened facies, and clubfoot. * **Imaging:** On ultrasound, the kidneys appear bilaterally enlarged and **hyperechoic** due to the numerous small interfaces of the microcysts. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 952-953. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 950-951. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 953-954.

Question 463: Which of the following is NOT true about the condition shown?

A. Cysts increase in size with age
B. Spider leg deformity
C. Anemia
D. Low Renin due to pressure atrophy of Juxtaglomerular apparatus (Correct Answer)

Explanation: ***Low Renin due to pressure atrophy of Juxtaglomerular apparatus*** - This is **NOT true** - ADPKD actually causes **high renin levels** due to compression of intrarenal arteries by cysts, leading to **renal ischemia** and activation of the renin-angiotensin system. - The **juxtaglomerular apparatus** responds to decreased perfusion pressure by **increasing renin secretion**, not decreasing it. *Cysts increase in size with age* - This **IS true** - cysts in ADPKD progressively enlarge throughout life due to continued **fluid secretion** and **cell proliferation**. - The **total kidney volume** increases significantly over time, often reaching massive proportions in advanced disease. *Spider leg deformity* - This **IS true** - refers to the characteristic **radiologic appearance** on intravenous pyelogram (IVP) showing stretched and distorted calyces. - The **collecting system** appears elongated and narrowed, resembling spider legs due to compression by multiple cysts. *Anemia* - This **IS true** - occurs in advanced ADPKD due to **chronic kidney disease** and decreased **erythropoietin production**. - **Progressive renal failure** leads to reduced EPO synthesis, resulting in **normocytic normochromic anemia**.

Question 464: What is the characteristic pathological finding in the kidney in malignant hypertension?

A. Flea-bitten kidney (Correct Answer)
B. Irregular granular contracted kidney
C. Large white kidney
D. No change in the kidney

Explanation: **Explanation** **Malignant Hypertension** is a medical emergency characterized by a sudden, severe rise in blood pressure (typically >200/120 mmHg). The characteristic gross appearance of the kidney in this condition is the **Flea-bitten kidney** [2]. 1. **Why "Flea-bitten kidney" is correct:** The rapid rise in pressure causes severe vascular injury, specifically **fibrinoid necrosis** [1] of the arterioles and **hyperplastic arteriolosclerosis** (onion-skinning) [1]. This leads to the rupture of glomerular capillaries and small arterioles, resulting in multiple pinpoint, petechial hemorrhages on the cortical surface. These tiny red spots resemble flea bites. 2. **Analysis of Incorrect Options:** * **B. Irregular granular contracted kidney:** This is characteristic of **Chronic Glomerulonephritis** or **Benign Nephrosclerosis**. In benign hypertension, long-term hyaline arteriolosclerosis leads to ischemic atrophy and fibrosis, resulting in a symmetrical, fine "leathery" granularity [3]. * **C. Large white kidney:** This is classically seen in **Nephrotic Syndrome** (e.g., Membranous Nephropathy) or **Amyloidosis** due to lipid accumulation or protein deposition. * **D. No change:** Malignant hypertension always causes significant morphological changes due to acute vascular damage. **High-Yield Clinical Pearls for NEET-PG:** * **Microscopic Hallmarks:** Look for **Fibrinoid necrosis** (necrotizing arteriolitis) and **Onion-skinning** (proliferation of smooth muscle cells) [1]. * **Differential Diagnosis for Flea-bitten Kidney:** 1. Malignant Hypertension 2. PSGN (Post-Streptococcal Glomerulonephritis) 3. Infective Endocarditis (SBE) 4. Polyarteritis Nodosa (PAN) 5. Wegener’s Granulomatosis * **Clinical Presentation:** Patients often present with papilledema, encephalopathy, and acute renal failure [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, p. 945. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Cardiovascular Disease, pp. 276-277. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 541-542.

Question 465: What is the most common viral infection in the kidney?

A. Epstein-Barr virus (EBV)
B. Herpes simplex virus (HSV)
C. Cytomegalovirus (CMV) (Correct Answer)
D. Hepatitis B virus (HBV)

Explanation: **Explanation:** **Cytomegalovirus (CMV)** is the most common viral infection affecting the kidney, particularly in immunocompromised individuals and renal transplant recipients. In the kidney, CMV typically infects the **tubular epithelial cells**. Histologically, it is characterized by the presence of large, eosinophilic intranuclear inclusions surrounded by a clear halo, giving the classic **"Owl’s eye" appearance**. It can lead to tubulointerstitial nephritis and is a significant cause of graft dysfunction in transplant patients. **Analysis of Incorrect Options:** * **Epstein-Barr virus (EBV):** While EBV is associated with Post-Transplant Lymphoproliferative Disorder (PTLD) which can involve the kidney, it is not the most common primary viral infection of the renal parenchyma itself. * **Herpes simplex virus (HSV):** HSV rarely involves the kidney; it more commonly causes mucocutaneous lesions or encephalitis. Renal involvement is usually seen only in cases of severe disseminated viremia. * **Hepatitis B virus (HBV):** HBV is a major cause of **secondary glomerular diseases**, most notably **Membranous Nephropathy (MN)**, but it is not the most common direct viral infection of the kidney tissue. **High-Yield Pearls for NEET-PG:** * **BK Virus:** Another high-yield virus in renal pathology. It causes **BK Virus-associated Nephropathy (BKVAN)** in transplant patients, characterized by "decoy cells" in urine and intranuclear inclusions (Basophilic/Homogenous) that can mimic CMV [1]. * **HIV:** Associated with **HIV-Associated Nephropathy (HIVAN)**, which typically presents as a collapsing variant of Focal Segmental Glomerulosclerosis (FSGS). * **HCV:** Strongly associated with **Cryoglobulinemic Membranoproliferative Glomerulonephritis (MPGN)**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 935-937.

Question 466: The characteristic feature of benign nephrosclerosis is

A. Leather grain appearance (Correct Answer)
B. Flea bitten kidney
C. Onion skin appearance
D. Hyperplastic arteriosclerosis

Explanation: ### Explanation **Correct Answer: A. Leather grain appearance** **Benign nephrosclerosis** is the renal pathology associated with long-standing, well-controlled essential hypertension [2]. The chronic ischemia leads to symmetrical atrophy of the kidneys. * **Mechanism:** Chronic hypertension causes **hyaline arteriolosclerosis** (deposition of pink hyaline material in arteriolar walls) [1]. This results in narrowing of the lumen, leading to patchy ischemic atrophy of the parenchyma and interstitial fibrosis [1]. * **Gross Appearance:** The kidney surface becomes finely granular and scarred, resembling **"leather grain."** This is due to the alternation of depressed areas (scarred glomeruli) and raised areas (compensatory hypertrophied nephrons) [1]. **Why other options are incorrect:** * **B. Flea-bitten kidney:** This refers to multiple pinpoint subcapsular hemorrhages. It is characteristic of **Malignant Hypertension**, Infective Endocarditis, or PSGN. * **C. Onion skin appearance:** This is a histological hallmark of **Malignant Hypertension** [3]. It refers to concentric laminated thickening of arteriolar walls due to proliferation of smooth muscle cells [3]. * **D. Hyperplastic arteriolosclerosis:** This is the microscopic correlate of Malignant Hypertension (along with necrotizing arteriolitis), not benign nephrosclerosis [3]. **High-Yield Clinical Pearls for NEET-PG:** * **Benign Nephrosclerosis:** Hyaline arteriolosclerosis + Leather grain kidney. * **Malignant Nephrosclerosis:** Hyperplastic arteriolosclerosis (Onion skinning) + Necrotizing arteriolitis + Flea-bitten kidney [3]. * **Key Distinction:** Benign nephrosclerosis rarely leads to renal failure unless combined with diabetes; Malignant nephrosclerosis is a medical emergency presenting with papilledema and acute renal failure [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 943-945. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 541-542. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 498-499.

Question 467: Papillary necrosis is seen in all the following conditions except:

A. Sickle cell anemia
B. Analgesic nephropathy
C. Diabetes mellitus
D. Chronic alcoholism (Correct Answer)

Explanation: **Explanation:** Renal Papillary Necrosis (RPN) is a form of nephropathy characterized by ischemic necrosis of the renal papillae. The renal papillae are particularly vulnerable to ischemia because they are located at the distal end of the vasa recta, which is a relatively low-oxygen environment. **Why Chronic Alcoholism is the correct answer:** Chronic alcoholism is not a direct cause of renal papillary necrosis. While alcohol can lead to chronic kidney disease through other mechanisms (like IgA nephropathy or hepatorenal syndrome), it does not typically cause the specific ischemic or toxic insult required to necrose the papillae. **Why the other options are incorrect:** * **Sickle cell anemia:** Sickling of RBCs in the hypertonic, hypoxic environment of the renal medulla causes micro-thrombosis and congestion of the vasa recta, leading to ischemic necrosis [1]. * **Analgesic nephropathy:** Chronic use of NSAIDs (like Phenacetin or Aspirin) inhibits prostaglandin synthesis (vasodilators), leading to vasoconstriction of the vasa recta and direct toxic damage to the papillae [3]. * **Diabetes mellitus:** This is the most common cause of RPN [2]. It occurs due to a combination of ischemic changes (diabetic microangiopathy) and an increased predisposition to severe infections like pyelonephritis [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic "POSTCARDS":** **P**yelonephritis, **O**bstruction (Urinary tract), **S**ickle cell disease, **T**uberculosis, **C**hronic liver disease (rarely), **A**nalgesics, **R**enal transplant rejection, **D**iabetes mellitus, **S**ystemic vasculitis. * **Clinical Presentation:** Often presents with hematuria, flank pain (due to sloughed papillae obstructing the ureter), and features of UTI [2]. * **Radiology:** The "Ring sign" on intravenous pyelography (IVP) is a classic finding representing the sloughed papilla surrounded by contrast. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 948-949. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 543-544. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 934-935.

Question 468: Diabetic glomerulosclerosis is characterized by all of the following EXCEPT:

A. Diffuse glomerulosclerosis
B. Fibrin cap
C. Fibrin clot (Correct Answer)
D. Kimmelstiel-Wilson lesions

Explanation: **Explanation:** Diabetic Nephropathy (Diabetic Glomerulosclerosis) is a progressive kidney disease resulting from chronic hyperglycemia. The correct answer is **Fibrin clot**, as it is not a feature of diabetic pathology; rather, it is typically associated with acute conditions like Disseminated Intravascular Coagulation (DIC) or Thrombotic Microangiopathies (TMA). **Why the other options are incorrect (Features of Diabetes):** * **Diffuse Glomerulosclerosis (Option A):** This is the **most common** histological change in diabetic nephropathy [1]. It involves a generalized increase in mesangial matrix and thickening of the glomerular basement membrane (GBM) [3]. * **Fibrin Cap (Option B):** This is a "hyaline lesion" representing an accumulation of plasma proteins in the peripheral capillary loops [1]. Along with **Capsular drops** (hyaline masses on the inner surface of Bowman’s capsule), these are highly suggestive of diabetic damage [2]. * **Kimmelstiel-Wilson (KW) Lesions (Option D):** Also known as **Nodular Glomerulosclerosis**, these are ovoid, laminated, PAS-positive hyaline nodules in the mesangium [3]. While diffuse sclerosis is more common, KW lesions are **pathognomonic** (highly specific) for diabetes. **NEET-PG High-Yield Pearls:** 1. **Earliest clinical sign:** Microalbuminuria (30–300 mg/day). 2. **Earliest morphological change:** Thickening of the Glomerular Basement Membrane (GBM) [2]. 3. **Vascular hallmark:** Hyaline arteriolosclerosis affecting **both** afferent and efferent arterioles (highly specific for diabetes) [4]. 4. **Armanni-Ebstein Lesions:** Glycogen deposits in the tubular epithelial cells (Pars recta of proximal tubule), seen in severe hyperglycemia. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 907-908. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, p. 1121. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1121-1122. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 498-499.

Question 469: Which of the following is NOT a typical electron microscopic feature of Alport syndrome?

A. Irregular thickening of the glomerular basement membrane (GBM)
B. Multilamellation of the lamina densa
C. Basket weave pattern of the lamina densa
D. Thickening of the renal tubules (Correct Answer)

Explanation: **Explanation:** Alport syndrome is a hereditary type IV collagen disorder (most commonly X-linked) caused by mutations in the **COL4A3, COL4A4, or COL4A5** genes [1]. These genes encode the alpha chains of type IV collagen, which is a structural hallmark of the **Glomerular Basement Membrane (GBM)**, cochlea, and lens. **Why Option D is correct:** The primary pathology in Alport syndrome is localized to the **basement membranes of the glomeruli**, not the renal tubules. While chronic disease may lead to secondary tubulointerstitial fibrosis, "thickening of the renal tubules" is not a diagnostic or typical electron microscopic (EM) feature of the condition [1]. **Why other options are incorrect:** * **Options A, B, and C:** These represent the classic EM triad of Alport syndrome. The GBM initially appears thin but progresses to show **irregular thickening** and thinning. The hallmark feature is the longitudinal splitting and **multilamellation of the lamina densa**, which creates a characteristic **"basket-weave" appearance**. These findings are pathognomonic for the disease. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Triad:** Hereditary nephritis (hematuria/ESRD), Sensorineural deafness, and Ocular defects (e.g., Anterior lenticonus) [1]. * **Genetics:** 80% are X-linked dominant (COL4A5) [1]. * **Light Microscopy:** Early stages show no specific changes; later stages show focal segmental glomerulosclerosis (FSGS) and interstitial foam cells (lipid-laden macrophages) [1]. * **Immunofluorescence:** Characteristically shows a "negative" or "absent" staining for Type IV collagen alpha chains [1]. * **Differential:** Thin Basement Membrane Disease (Benign Familial Hematuria) shows only diffuse thinning of the GBM without the basket-weave pattern. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 929-930.

Question 470: Which glomerular lesion is seen in cases of reflux nephropathy?

A. Rapidly progressive glomerulonephritis (RPGN)
B. Membranoproliferative glomerulonephritis (MPGN)
C. Membranous glomerulonephritis (MGN)
D. Focal segmental glomerulosclerosis (FSGS) (Correct Answer)

Explanation: Reflux nephropathy is a form of chronic pyelonephritis caused by vesicoureteral reflux (VUR) [1]. The correct answer is **Focal Segmental Glomerulosclerosis (FSGS)** because it represents the secondary glomerular response to chronic parenchymal scarring and nephron loss. **1. Why FSGS is correct:** In reflux nephropathy, chronic inflammation leads to significant renal scarring and a reduction in the total number of functional nephrons [1]. To compensate, the remaining healthy nephrons undergo **hypertrophy and hyperfiltration** [3]. This hemodynamic stress causes endothelial and epithelial injury, eventually leading to the development of **secondary FSGS** [3]. This is the primary reason why patients with reflux nephropathy often develop significant proteinuria and progressive renal failure even after the reflux is surgically corrected. **2. Why other options are incorrect:** * **RPGN (Option A):** Characterized by "crescents" on histology, this is an aggressive clinical syndrome associated with systemic vasculitis or anti-GBM disease, not chronic scarring. * **MPGN (Option B):** Involves immune complex deposition or complement dysregulation leading to a "tram-track" appearance; it is not a sequela of reflux. * **MGN (Option C):** A common cause of nephrotic syndrome in adults caused by subepithelial deposits (e.g., PLA2R antibodies), unrelated to mechanical reflux or scarring [4]. **Clinical Pearls for NEET-PG:** * **Secondary FSGS** is a common pathway for any condition causing "Nephron Mass Reduction" (e.g., unilateral renal agenesis, morbid obesity, or chronic pyelonephritis). * **Vesicoureteral Reflux (VUR)** is most commonly diagnosed via **Voiding Cystourethrogram (VCUG)**. * Reflux nephropathy typically causes **polar scarring** (at the upper and lower poles of the kidney) due to the anatomy of compound papillae [1][2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, p. 939. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 543-544. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 530-531. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 531-532.

Practice by Chapter

Congenital Anomalies of the Kidney

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Glomerular Diseases

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Tubular and Interstitial Diseases

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Vascular Diseases of the Kidney

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Cystic Diseases of the Kidney

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Urinary Tract Obstruction and Stones

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Renal Tumors

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Kidney in Systemic Diseases

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Renal Transplantation Pathology

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Urinary Tract Infections

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