Renal Pathology Practice Questions

Q: Azotemia occurs when:

Glomerular filtration rate is 20% - 50% of normal.. **Explanation:** **Azotemia** is a biochemical abnormality characterized by elevation of blood urea nitrogen (BUN) and serum creatinine levels [1]. It is primarily a reflection of a decreased **Glomerular Filtration Rate (GFR)**. 1. **Why Option C is correct:** The kidneys possess a significant "renal reserve." In the early stages of renal impairment, the remaining functional nephrons undergo compensatory hypertrophy to maintain filtration. Consequently, serum markers like BUN and creatinine do not rise significantly until the GFR falls below **50% of its normal value**. Therefore, azotemia typically manifests when the GFR is in the range of **20% to 50%**. At this stage, patients are often asymptomatic but have measurable biochemical abnormalities [1]. 2. **Why other options are incorrect:** * **Option A & B (50% - 80%):** At these levels, the condition is often termed "diminished renal reserve." The GFR is reduced, but the compensatory mechanisms are sufficient to keep BUN and creatinine within the normal reference range. * **Option D (25%):** While azotemia is certainly present at 25%, this option is too narrow. The biochemical onset begins earlier (at the 50% threshold), making the range of 20-50% the more accurate clinical definition for the onset of azotemia. **NEET-PG High-Yield Pearls:** * **Azotemia vs. Uremia:** Azotemia is a purely biochemical finding [1]. **Uremia** occurs when azotemia is accompanied by clinical signs and symptoms (e.g., asterixis, pericarditis, encephalopathy) and systemic metabolic alterations [2]. * **Prerenal Azotemia:** Characterized by a **BUN:Creatinine ratio >20:1** and a Fractional Excretion of Sodium (**FeNa) <1%**, usually due to hypoperfusion. * **Renal Failure:** Defined when the GFR drops below **20%** of normal; **End-Stage Renal Disease (ESRD)** occurs when GFR is **<5%** of normal [1].

Q: A 50-year-old male presented with blurring of vision. Urine examination showed proteinuria. Fundus examination showed dot-and-blot hemorrhages, microaneurysms, and cotton wool spots. What is the most probable diagnosis based on the provided histopathology?

Kimmelstiel-Wilson lesions. ***Kimmelstiel-Wilson lesions*** - These are **nodular glomerulosclerosis** lesions pathognomonic of **diabetic nephropathy**, correlating with the clinical picture of **diabetic retinopathy** (dot-and-blot hemorrhages, microaneurysms) and **proteinuria**. - The combination of **retinal changes** and **renal involvement** strongly indicates **diabetes mellitus** with end-organ damage, making Kimmelstiel-Wilson lesions the characteristic histopathological finding. *Crescents* - These are found in **rapidly progressive glomerulonephritis (RPGN)** and represent **epithelial cell proliferation** in Bowman's capsule. - Associated with **acute renal failure** and **hematuria**, not the chronic diabetic complications seen in this case. *Amyloid* - **Amyloid deposits** appear as **Congo red-positive** material with **apple-green birefringence** under polarized light. - Typically associated with **systemic amyloidosis** or **multiple myeloma**, not the diabetic retinopathy pattern described. *Segmental sclerosis* - This refers to **focal segmental glomerulosclerosis (FSGS)**, characterized by **sclerosis of glomerular segments**. - Commonly presents with **nephrotic syndrome** in younger patients without the characteristic **diabetic retinopathy** findings.

Question 1

A 20-year-old primigravid woman in her third trimester reports minimal fetal movement. Ultrasound reveals bilaterally enlarged echogenic kidneys and a markedly decreased amniotic fluid index. The patient delivers a stillborn male fetus at 33 weeks' gestation. Autopsy shows deformations consistent with marked oligohydramnios, including flattened facies, varus deformities of the feet, and severe pulmonary hypoplasia. Microscopic examination of the liver reveals multiple epithelium-lined cysts and bile duct proliferation. What is the most likely renal disease in this fetus?

Accepted Answer

Autosomal recessive polycystic kidney disease

Answer

Autosomal dominant polycystic kidney disease

Answer

Medullary sponge kidney

Answer

Multi-cystic renal dysplasia

Question 2

A person with radiologically confirmed reflux nephropathy develops nephrotic range proteinuria. Which of the following would be the most likely histological finding in this patient?

Accepted Answer

Focal segmental glomerulosclerosis

Answer

Nodular glomerulosclerosis

Answer

Membranous glomerulopathy

Answer

Proliferative glomerulonephritis with crescents

Question 3

Rapidly progressive glomerulonephritis is characterized by which of the following?

Accepted Answer

Crescents

Answer

Splitting of the basement membrane

Answer

Neutrophil infiltration of the mesangium

Answer

Glomerulosclerosis

Question 4

All of the following conditions can cause interstitial nephritis except?

Accepted Answer

Hepatorenal syndrome

Answer

Infections

Answer

Lymphoma

Answer

Sarcoidosis

Question 5

Which of the following markers is NOT characteristically positive in Wilms tumor?

Accepted Answer

TTF-1

Answer

Desmin

Answer

Vimentin

Answer

Cytokeratin

Question 6

What is the most common pathological feature in diabetes mellitus?

Accepted Answer

Diffuse glomerulosclerosis

Answer

Papillary necrosis

Answer

Renal atherosclerosis

Answer

Chronic pyelonephritis

Question 7

Azotemia occurs when:

Accepted Answer

Glomerular filtration rate is 20% - 50% of normal.

Answer

Glomerular filtration rate is 50% of normal.

Answer

Glomerular filtration rate is 80% of normal.

Answer

Glomerular filtration rate is 25% of normal.

Question 8

A 50-year-old male presented with blurring of vision. Urine examination showed proteinuria. Fundus examination showed dot-and-blot hemorrhages, microaneurysms, and cotton wool spots. What is the most probable diagnosis based on the provided histopathology?

Accepted Answer

Kimmelstiel-Wilson lesions

Answer

Crescents

Answer

Amyloid

Answer

Segmental sclerosis

Question 9

An elderly male patient presented with blurring of vision. Fundus examination revealed cotton wool spots on retina and systemic examination showed decreased peripheral sensations and increased urine output. What finding is shown on renal biopsy?

Accepted Answer

Kimmelstiel-Wilson lesion

Answer

Amyloid deposits

Answer

Crescents

Answer

Hyaline atherosclerosis

Question 10

Renal pathology in SLE includes all EXCEPT?

Accepted Answer

Lipoid nephrosis

Answer

Focal glomerulonephritis

Answer

Diffuse glomerulonephritis

Answer

Membranous glomerulonephritis

Renal Pathology — MCQs

Renal Pathology — MCQs

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