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Difficulty: HardNephrology

The following vignettes describe patients presenting with various glomerular diseases. Match each patient's clinical presentation with the most characteristic renal biopsy finding (immunofluorescence or electron microscopy) associated with their underlying condition.

  • A 58-year-old man with a history of chronic hepatitis C presenting with lower extremity edema, palpable purpura, and a significantly decreased serum C4 level.Subendothelial immune complex deposits with interposition of mesangial cell processes
  • A 62-year-old man with a recent diagnosis of lung adenocarcinoma presenting with severe lower extremity edema, frothy urine, and 5.5 g/day of proteinuria.Subepithelial immune complex deposits with adjacent basement membrane projections
  • A 9-year-old boy presenting with hypertension, periorbital edema, and tea-colored urine 3 weeks after recovering from an episode of impetigo.Large, irregular, subepithelial electron-dense humps
  • A 24-year-old man presenting with an episode of macroscopic hematuria that began 24 hours after the onset of a sore throat and low-grade fever.Granular mesangial immune complex deposition
  • A 33-year-old man presenting with acute kidney injury, dysmorphic red blood cells in the urine, hemoptysis, and normal serum complement levels.Linear deposition of IgG along the glomerular basement membrane

Answer

The correct matches correlate each clinical presentation to its pathognomonic renal biopsy finding: Hepatitis C to MPGN Type I (subendothelial deposits), solid tumor to Membranous Nephropathy (subepithelial with projections), post-impetigo to PSGN (subepithelial humps), synpharyngitic hematuria to IgA Nephropathy (mesangial deposits), and pulmonary-renal syndrome to Anti-GBM disease (linear IgG).
Each vignette represents a specific glomerular disease. Identifying the disease from the clinical context (timeline, associated conditions, and symptoms) accurately predicts the highly stereotyped histopathological findings on renal biopsy.

Step-by-Step Solution

1
Analyze the systemic associations and timelines in each clinical vignette to diagnose the underlying glomerular disease.
The vignettes describe MPGN Type I, Membranous Nephropathy, Post-streptococcal Glomerulonephritis, IgA Nephropathy, and Anti-GBM disease, respectively.
Accurate clinical diagnosis is a prerequisite for predicting histopathological findings.
2
Pair each diagnosed disease with its characteristic immunofluorescence or electron microscopy pattern.
MPGN has subendothelial deposits; Membranous has subepithelial deposits with basement membrane projections; PSGN has subepithelial humps; IgA has mesangial deposits; Anti-GBM has linear IgG deposition.
These biopsy findings are pathognomonic and define the pathophysiologic mechanism of each glomerulopathy.

Key Concept

Clinical associations and pathognomonic renal biopsy findings of primary and secondary glomerulopathies
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Topics

Nephrology

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