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Results from glomerular mesangial deposition of immune complexes made up of aberrantly glycosylated immunoglobulin A (IgA) and immunoglobulin G (IgG) autoantibodies against these abnormal molecules
Can either be a primary (renal-limited) disease
Or can be secondary to
Most common primary glomerular disease worldwide, particularly in Asia
Usually occurs in children and young adults
Affects males 2–3 times more often than females
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Gross hematuria, frequently associated with a mucosal viral infection, often an upper respiratory tract infection (URI)
Urine becomes red or cola-colored 1–2 days after onset of URI
Can present clinically anywhere along the nephritic spectrum from asymptomatic microscopic hematuria to rapidly progressive glomerulonephritis
Rarely, a nephrotic syndrome can be present
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Proteinuria: minimal to nephrotic range
Glomerular hematuria: microscopic is common; macroscopic (gross) can occur after mucosal infection
Positive IgA staining on kidney biopsy
Serum complement levels usually normal
No serologic tests aid in diagnosis
Renal biopsy
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Patients at low risk for progression (no hypertension, normal glomerular filtration rate [GFR], minimal proteinuria) can be monitored expectantly
Angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB)
Recommended for patients at higher risk for progression (proteinuria > 1.0 g/d, decreased GFR, hypertension, or any combination of these)
Therapy should be titrated to reduce proteinuria to < 0.5 g/day and to control blood pressure to 120/70 mm Hg per practice guidelines
SGLT2-inhibitors may be added to standard care in proteinuric patients
Conflicting data regarding efficacy of corticosteroids for reducing proteinuria and slowing progression
Hydroxychloroquine
Cyclophosphamide and corticosteroid therapy should be considered for the rare patient with a rapidly progressive clinical course with diffuse crescent formation on biopsy
∼33% of patients experience spontaneous remission
Progression to end-stage kidney disease occurs in 20–40%
Proteinuria > 1 g/d is most unfavorable prognostic indicator; others include
Kidney transplantation
An excellent option for patients with end-stage kidney disease
However, recurrent disease develops in 30% of patients by 5–10 years posttransplant