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Primary renal disease results from glomerular mesangial deposition of immune complexes made up of aberrantly glycosylated IgA and IgG autoantibodies against these abnormal molecules
Can be a primary (renal-limited) disease
Can be secondary to
Most common primary glomerular disease worldwide, particularly in Asia
Usually occurs in children and young adults
Males affected 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 smoky-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 as well
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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 with low risk for progression (no hypertension, normal glomerular filtration rate [GFR], minimal proteinuria) can be monitored annually
Angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB)
Recommended for patients at higher risk for progression (proteinuria > 1.0 g/day, decreased GFR, and/or hypertension)
Therapy should be titrated to reduce proteinuria to < 1 g/day and to reduce blood pressure to between 125/75 mm Hg and 130/80 mm Hg
SGLT2-inhibitors may be added to standard care in the well-selected patient
Conflicting data regarding efficacy of corticosteroids for reducing proteinuria and slowing progression
Mycophenolate mofetil
Cyclophosphamide and corticosteroid therapy should be considered for the rare patient with a rapidly progressive clinical course with crescent formation on biopsy
~33% of patients experience spontaneous remission
Progression to end-stage kidney disease occurs in 20–40%
Proteinuria > 1 g/day is most unfavorable prognostic indicator; others include
Kidney transplantation
An excellent option for patients with end-stage kidney disease
However, recurrent disease has been documented in 30% of patients by 5–10 years posttransplant