GLOMERULONEPHRITIS Flashcards
Which of the following is NOT a classic clinical feature of acute nephritic syndrome?
A. Hypertension
B. Hematuria
C. Nephrotic-range proteinuria
D. Red blood cell casts
C. Nephrotic-range proteinuria
Rationale: Acute nephritic syndrome is characterized by mild to moderate proteinuria, not nephrotic-range proteinuria (>3.5 g/day), which is seen in nephrotic syndrome.
What is the primary pathological process underlying acute nephritic syndrome?
A. Tubular atrophy
B. Glomerular inflammation
C. Vascular thrombosis
D. Obstruction of renal pelvis
B. Glomerular inflammation
Rationale: Acute nephritic syndrome results from extensive inflammatory damage to the glomeruli, which disrupts glomerular filtration and causes associated clinical features.
Which of the following findings in the urine sediment is pathognomonic for acute nephritic syndrome?
A. White blood cell casts
B. Red blood cell casts
C. Hyaline casts
D. Broad waxy casts
B. Red blood cell casts
Rationale: Red blood cell casts are a hallmark of glomerular inflammation and are diagnostic of acute nephritic syndrome.
A 7-year-old boy presents with facial swelling, hematuria, and hypertension. He had a sore throat two weeks ago that resolved without treatment. Physical examination reveals periorbital edema and blood pressure of 140/90 mmHg. Laboratory studies show the following:
Serum C3: Low
Serum C4: Normal
ASO titer: Elevated
Urinalysis: Hematuria, red blood cell casts, and mild proteinuria
What is the most likely diagnosis?
A. IgA nephropathy
B. Poststreptococcal glomerulonephritis
C. Membranous nephropathy
D. Minimal change disease
B. Poststreptococcal glomerulonephritis
Rationale: This patient presents with a classic nephritic syndrome following a recent streptococcal throat infection. The findings of low C3 with normal C4, elevated ASO titers, and RBC casts strongly support PSGN. IgA nephropathy is associated with synpharyngitic hematuria (hematuria occurring concurrently with the infection), whereas PSGN typically occurs 1–3 weeks after the infection.
Which of the following findings on renal biopsy is most characteristic of poststreptococcal glomerulonephritis?
A. Linear deposition of IgG along the glomerular basement membrane
B. Mesangial proliferation with IgA deposits
C. Subepithelial “humps” of immune complex deposits
D. Segmental sclerosis and podocyte effacement
C. Subepithelial “humps” of immune complex deposits
Rationale: PSGN is characterized by subepithelial immune complex deposits (“humps”) visible on electron microscopy. Linear IgG deposition (A) is seen in anti-GBM disease. Mesangial IgA deposits (B) are seen in IgA nephropathy, and segmental sclerosis with podocyte effacement (D) is associated with focal segmental glomerulosclerosis.
The renal biopsy in poststreptococcal glomerulonephritis demonstrates
hypercellularity of mesangial and endothelial cells; glomerular infiltrates of polymorphonuclear leukocytes; granular subendothelial immune deposits of IgG, IgM, C3, C4, and C5–9; and subepithelial deposits (which appear as “humps”)
A 12-year-old girl presents with hematuria and hypertension. She had impetigo 3 weeks ago. Her laboratory results show a low C3 level, a normal C4 level, and elevated anti-DNAse B titers. Which of the following is the primary mechanism of her kidney disease?
A. Autoantibodies against the glomerular basement membrane
B. Circulating immune complexes and complement activation
C. Direct bacterial invasion of the kidney
D. T-cell mediated podocyte injury
B. Circulating immune complexes and complement activation
Rationale: PSGN is an immune-mediated disease caused by nephritogenic streptococcal antigens, circulating immune complexes, and complement activation. The characteristic low C3 with normal C4 levels supports this mechanism. Autoantibodies against the GBM (A) cause Goodpasture syndrome. Direct bacterial invasion (C) is not typical of PSGN, and T-cell mediated podocyte injury (D) is associated with minimal change disease.
Which of the following is a common laboratory finding in poststreptococcal glomerulonephritis?
A. Elevated CH50 and normal C3
B. Positive rheumatoid factor and decreased C3
C. Low C3 and low C4
D. Normal C3 and elevated cryoglobulins
B. Positive rheumatoid factor and decreased C3
Rationale: PSGN is associated with low C3 and normal C4 levels, reflecting activation of the alternative complement pathway. Rheumatoid factor may be elevated in some cases. CH50 is typically low, and C4 levels remain normal.
A 55-year-old man with poorly controlled diabetes presents with hematuria, hypertension, and edema. He recently recovered from a streptococcal throat infection. Which of the following features would suggest the diagnosis of poststreptococcal glomerulonephritis?
A. Subepithelial immune complex deposits on renal biopsy
B. Deposition of IgA in the mesangium
C. Rapid progression to end-stage kidney disease within weeks
D. Persistent proteinuria with normal complement levels
A. Subepithelial immune complex deposits on renal biopsy
Rationale: The hallmark of PSGN on biopsy is subepithelial immune complex deposits (“humps”). Mesangial IgA deposits (B) suggest IgA nephropathy. Rapid progression to ESRD (C) suggests RPGN, and normal complement levels (D) are not typical of PSGN.
Which of the following is the mainstay of treatment for poststreptococcal glomerulonephritis?
A. High-dose corticosteroids
B. Antibiotics to treat cohabitants with active streptococcal infection
C. Long-term immunosuppressive therapy
D. Supportive care including hypertension and edema control
D. Supportive care including hypertension and edema control
Rationale: The primary treatment for PSGN is supportive care aimed at controlling hypertension, managing edema, and providing dialysis if needed. Antibiotics are only indicated for active streptococcal infections, not for the glomerulonephritis itself. Immunosuppressive therapy, including corticosteroids, has no role in PSGN, even in the presence of crescents.
What is the typical prognosis of poststreptococcal glomerulonephritis in children?
A. ESRD occurs in 50% of cases
B. Most children recover fully within 3–6 weeks
C. Persistent hematuria and proteinuria are common and progressive
D. High mortality is observed due to hypertension-related complications
B. Most children recover fully within 3–6 weeks
Rationale: The majority of children with PSGN experience complete resolution of azotemia, hematuria, and proteinuria within 3–6 weeks. Persistent microscopic hematuria or nonnephrotic proteinuria occurs in a small percentage of cases but is usually not progressive. ESRD is rare in children.
What is the primary mechanism leading to renal damage in lupus nephritis?
A. Bacterial infection of the renal parenchyma
B. Deposition of circulating immune complexes and complement activation
C. Autoantibodies targeting renal tubules
D. Direct cytotoxic effects of T cells on renal glomeruli
B. Deposition of circulating immune complexes and complement activation
Rationale: Lupus nephritis results from the deposition of circulating immune complexes, primarily DNA and anti-DNA, which activate the complement cascade. This leads to complement-mediated damage, leukocyte infiltration, and cytokine release.
What laboratory findings are most strongly associated with lupus nephritis?
A. Low levels of C-reactive protein (CRP)
B. Elevated anti-dsDNA antibodies and hypocomplementemia
C. Increased serum albumin and normal complement levels
D. Positive rheumatoid factor
B. Elevated anti-dsDNA antibodies and hypocomplementemia
Rationale: Anti-dsDNA antibodies that fix complement correlate best with renal involvement in SLE. Hypocomplementemia (low C3 and C4 levels) is common during active lupus nephritis and may precede a flare.
A kidney biopsy is essential in lupus nephritis primarily to:
A. Confirm the diagnosis of systemic lupus erythematosus.
B. Establish the histologic class, which guides therapy.
C. Evaluate for bacterial or fungal infection.
D. Determine the need for immediate dialysis.
B. Establish the histologic class, which guides therapy.
Rationale: The histologic classification of lupus nephritis (e.g., Class I–VI) provides critical information for determining the severity and type of renal involvement, which directly influences treatment decisions.
Which of the following best describes the histologic findings in Class I lupus nephritis?
A. Mesangial immune complexes with mesangial proliferation
B. Normal glomerular histology on light microscopy with minimal mesangial deposits
C. Subendothelial immune deposits with diffuse glomerular proliferation
D. Thickened glomerular basement membrane with subepithelial deposits
B. Normal glomerular histology on light microscopy with minimal mesangial deposits
Rationale: Class I lupus nephritis is characterized by normal glomerular appearance on light microscopy but with minimal mesangial immune deposits detected by immunofluorescence or electron microscopy.
Which statement is true regarding Class II lupus nephritis?
A. It is associated with severe renal manifestations and poor prognosis.
B. It features mesangial immune complex deposition with mesangial proliferation.
C. It often progresses to Class V lupus nephritis.
D. It requires aggressive immunosuppressive therapy.
B. It features mesangial immune complex deposition with mesangial proliferation.
Rationale: Class II lupus nephritis involves mesangial immune deposits accompanied by mesangial proliferation, typically with minimal clinical renal manifestations and a favorable prognosis.
Patients with lupus nephritis limited to the renal mesangium (Class I and II) typically present with:
A. Nephrotic syndrome and acute kidney injury
B. Hypertension and hematuria
C. Minimal renal manifestations and normal renal function
D. Rapidly progressive glomerulonephritis
C. Minimal renal manifestations and normal renal function
Rationale: Lesions limited to the mesangium (Class I and II) are usually associated with minimal renal symptoms and normal renal function. Nephrotic syndrome is rare in these classes.
What is the most appropriate management for a patient with Class I or II lupus nephritis and no significant renal manifestations?
A. High-dose corticosteroids and cyclophosphamide
B. Supportive care without specific therapy for lupus nephritis
C. Plasmapheresis and intravenous immunoglobulin (IVIG)
D. Renal transplantation
B. Supportive care without specific therapy for lupus nephritis
Rationale: Class I and II lupus nephritis have an excellent prognosis and usually do not require specific treatment beyond general supportive care for systemic lupus erythematosus (SLE).
Which of the following findings is most characteristic of Class III lupus nephritis?
A. Proliferative lesions involving >50% of glomeruli
B. Focal lesions involving <50% of glomeruli with segmental proliferation or scarring
C. Nephrotic syndrome without hematuria
D. Normal glomerular histology with minimal mesangial deposits
B. Focal lesions involving <50% of glomeruli with segmental proliferation or scarring
Rationale: Class III lupus nephritis is characterized by focal involvement of <50% of glomeruli, often with segmental proliferation or scarring. The clinical course can vary widely depending on the severity of the lesions.
What is the primary difference between Class IV-S and Class IV-G lupus nephritis?
A. Presence of mesangial proliferation in IV-S but not in IV-G
B. Degree of proteinuria, which is higher in IV-S than in IV-G
C. Extent of glomerular tuft involvement in diffuse lesions
D. Response to treatment, with IV-G having a better prognosis
C. Extent of glomerular tuft involvement in diffuse lesions
Rationale: In Class IV lupus nephritis, segmental lesions (IV-S) involve <50% of the glomerular tuft, while global lesions (IV-G) involve >50%. Both are diffuse, affecting >50% of the glomeruli.
Which of the following is most associated with a poor prognosis in Class IV lupus nephritis?
A. Low serum complement levels and high anti-dsDNA antibody titers
B. Hematuria and mild proteinuria
C. Mesangial immune deposits without crescents
D. Normal renal function at presentation
A. Low serum complement levels and high anti-dsDNA antibody titers
Rationale: Class IV lupus nephritis commonly involves aggressive disease with immune complex deposition, low complement levels, high anti-dsDNA antibody titers, and crescents on biopsy, all associated with a poor prognosis if untreated.
What is the recommended initial treatment for severe Class IV lupus nephritis?
A. Supportive care only, as the prognosis is poor regardless of treatment
B. High-dose corticosteroids with cyclophosphamide or mycophenolate mofetil for induction
C. Low-dose corticosteroids and azathioprine for maintenance
D. Antihypertensive therapy to control blood pressure and prevent further progression
B. High-dose corticosteroids with cyclophosphamide or mycophenolate mofetil for induction
Rationale: The standard treatment for severe Class IV lupus nephritis involves an induction phase with high-dose corticosteroids and either cyclophosphamide or mycophenolate mofetil to achieve remission, followed by maintenance therapy.
Which of the following best describes the histopathological findings in Class V lupus nephritis?
A. Mesangial immune deposits with proliferation
B. Subepithelial immune deposits producing a membranous pattern
C. Focal proliferative lesions involving <50% of glomeruli
D. Diffuse proliferative lesions involving >50% of glomeruli
B. Subepithelial immune deposits producing a membranous pattern
Rationale: Class V lupus nephritis is characterized by subepithelial immune deposits that create a membranous pattern, similar to idiopathic membranous nephropathy.
Which condition predisposes patients with Class V lupus nephritis to renal vein thrombosis?
A. Nephrotic syndrome
B. Elevated complement levels
C. Lack of proteinuria
D. Hypertension
A. Nephrotic syndrome
Rationale: Nephrotic syndrome in Class V lupus nephritis is associated with hypercoagulability, predisposing patients to renal vein thrombosis and other thrombotic complications.
Class VI lupus nephritis is defined by which of the following?
A. Subepithelial immune deposits
B. >90% sclerotic glomeruli and interstitial fibrosis
C. Diffuse proliferative endocapillary lesions
D. Focal proliferative lesions with crescents
B. >90% sclerotic glomeruli and interstitial fibrosis
Rationale: Class VI lupus nephritis represents advanced chronic kidney disease with >90% sclerotic glomeruli, extensive interstitial fibrosis, and is typically associated with end-stage renal disease (ESRD).
Which of the following is recommended for lupus patients with ESRD due to Class VI lupus nephritis?
A. Immediate renal transplantation without waiting for disease inactivity
B. Renal transplantation after ~6 months of inactive disease
C. High-dose corticosteroids to reverse ESRD
D. Conservative management without transplantation
B. Renal transplantation after ~6 months of inactive disease
Rationale: Patients with ESRD due to lupus nephritis often undergo renal transplantation after ~6 months of inactive disease, which provides comparable allograft survival rates to other causes of ESRD.
