Membranous Nephropathy Overview

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Questions and Answers

What is a common marker of poor prognosis in adolescents presenting with MPGN?

Normal blood pressure

New-onset nephrotic syndrome (correct)

Severe hyponatremia

High serum C3 levels

Which type of MPGN is characterized by granular immune complex deposition in the mesangium capillary loops?

Type I MPGN (correct)

Type II MPGN

Type III MPGN

Secondary MPGN

What characterizes Type II MPGN concerning C3 nephritic factor?

Inhibition of alternative complement pathway

Mild reduction in serum C4 levels

Presence leads to continuous consumption of C3 (correct)

Elevated serum C3 levels

Which of the following findings is typically associated with Type III MPGN?

Electron-dense deposits in both sides of the basement membrane Signup and view all the answers

Which condition is NOT commonly associated with secondary MPGN?

Type I diabetes mellitus Signup and view all the answers

What usually characterizes the serum levels of C3 in Type II MPGN?

Mildly depressed Signup and view all the answers

What is the usual immunofluorescent staining pattern in Type I MPGN?

Granular staining for IgG, IgM, C1q, C4, and C3 Signup and view all the answers

In adolescents with MPGN, what condition is unusual despite most being hypertensive at presentation?

Severe hypertension Signup and view all the answers

What percentage of pediatric patients with idiopathic membranous nephropathy are typically nephrotic at presentation?

15% Signup and view all the answers

Which condition can be included in the differential diagnosis of glomerulonephritis in adolescents?

Membranous nephropathy Signup and view all the answers

What is a common urinary finding in children with Alport syndrome?

Large blood on dipstick Signup and view all the answers

Which ocular defect is most commonly associated with Alport syndrome?

Anterior lenticonus Signup and view all the answers

How is Alport syndrome often inherited in males from affected families?

X-linked dominant Signup and view all the answers

Which pathological finding is diagnostic for Alport syndrome?

Irregular thinned and thickened areas of the basement membrane Signup and view all the answers

What is a risk factor for individuals with Alport syndrome regarding progression to ESRD?

Males in X-linked pedigrees Signup and view all the answers

Which of the following symptoms might NOT be present in all individuals diagnosed with Alport syndrome?

Interstitial nephritis Signup and view all the answers

What is a common presenting symptom of glomerulonephritis?

Oliguria Signup and view all the answers

Which finding is highly sensitive for glomerular disease when greater than 30% is observed?

Dysmorphic red blood cells Signup and view all the answers

What is the typical protein-to-creatinine ratio indicating nephrotic range?

Greater than 2.0 Signup and view all the answers

Which of the following is NOT typically associated with glomerulonephritis?

Hepatomegaly Signup and view all the answers

What type of renal condition may present with normal physical examination findings?

Acute glomerulonephritis Signup and view all the answers

Which test is indicated to determine the precise diagnosis of glomerular disease?

Renal biopsy Signup and view all the answers

Which of the following conditions typically shows dysmorphic red blood cells in the urine?

Glomerulonephritis Signup and view all the answers

What condition is mainly characterized by significant depression of serum C3 concentration?

Poststreptococcal acute glomerulonephritis Signup and view all the answers

Study Notes

Renal Function and Glomerulonephritis (GN)

Renal function can be normal or impaired, influenced by acute conditions or chronic glomerular injury.
Patients may exhibit normal physical examination and blood pressure, but can also present with oliguria, hypertension, and edema.
Some GN types may show associated symptoms like vasculitic rash, arthritis, or pulmonary hemorrhage.

Hematuria and Urinalysis Findings

Hematuria can be either macroscopic (visible) or microscopic.
Urinary sediment typically reveals dysmorphic red blood cells (RBCs) and often RBC casts.
Dysmorphic RBCs are more effectively identified with phase contrast microscopy.
Over 30% of dysmorphic RBCs is a sensitive marker for glomerular disease.

Proteinuria Assessment

Proteinuria can range from normal (less than 4 mg/m²/h) to nephrotic range (greater than 40 mg/m²/h).
A random urine protein-to-creatinine ratio is comparable to a 24-hour collection, with normal < 0.2 and nephrotic range > 2.0.

Diagnosis and Referral

A renal biopsy is essential for accurate diagnosis and assessment except in uncomplicated cases like poststreptococcal acute glomerulonephritis (PSAGN).
Referral to a nephrologist is advised if GN is suspected beyond mild or typical cases of PSAGN.

Important Blood Tests

Baseline tests include complete blood count, creatinine levels, complement (C3 and C4), and streptococcal serology.
Significant decline in serum C3 is commonly seen in PSAGN, membranoproliferative glomerulonephritis (MPGN), systemic lupus erythematosus (SLE), and chronic bacteremia-related nephritis.

Membranous Nephropathy in Pediatrics

Most children with idiopathic membranous nephropathy present with nephrotic syndrome; only 15% were non-nephrotic in a study.
Non-nephrotic cases may display microscopic hematuria, warranting consideration of membranous GN in adolescents.

Alport Syndrome

Alport syndrome is a hereditary glomerular basement membrane defect leading to hematuria and potential progression to end-stage renal disease (ESRD).
Common initial presentation includes heavy microscopic hematuria, which may progress to proteinuria.
Associated symptoms include bilateral sensorineural deafness and ocular defects, with specific eye features like anterior lenticonus.
Inheritance patterns include X-linked dominant, with males usually more affected and progressing to ESRD in adulthood or adolescence.

Pathological Findings and Classification of MPGN

Type I MPGN exhibits granular immune complex deposition; electron microscopy shows sub-endothelial immune deposits containing IgG, IgM, and complement components.
Type II MPGN is characterized by presence of C3 nephritic factor (C3Nef) activating the alternative complement pathway, leading to consumption of C3.
Type III MPGN shows electron-dense deposits on both sides of the basement membrane and is associated with mutations linked to chromosome 1q31–32.
Secondary MPGN can be seen in conditions like chronic bacteremia and hepatitis infections.

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Description

This quiz explores the characteristics and presentation of membranous nephropathy in pediatric patients, particularly focusing on the occurrence of nephrotic syndrome. It also discusses the significance of considering this condition in differential diagnoses of glomerulonephritis in adolescents.