About 50% of patients with IgA nephropathy present with recurrent episodes of visible hematuria after an upper respiratory tract infection or gastroenteritis; approximately one third of patients have invisible hematuria and mild proteinuria.
Less than 10% present with either nephrotic syndrome or rapidly progressive glomerulonephritis.
Acute or chronic kidney failure may develop.
Kidney biopsy is required for definitive diagnosis.
Light microscopy shows focal or diffuse mesangial proliferation and extracellular matrix expansion.
Immunofluorescence shows diffuse mesangial IgA deposition in a granular pattern.
Renin-angiotensin system inhibitors are widely used to reduce proteinuria, particularly if hypertension and/or proteinuria is present, and they have been shown to help preserve kidney function.
The value of immunosuppression in IgAN is widely debated. There is some evidence that early corticosteroid treatment may reduce the severity of proteinuria and delay kidney function deterioration in people with moderate proteinuria, but this may be associated with serious adverse effects.
IgA nephropathy (IgAN) is defined by the presence of dominant or co-dominant mesangial IgA immune deposits, often accompanied by C3 and IgG in association with a mesangial proliferative glomerulonephritis of varying severity. The etiology of this common glomerulonephritis remains unknown. Clinical presentation varies widely. Patients commonly present with recurrent episodes of visible hematuria (usually occurring after an upper respiratory tract infection or gastroenteritis) or asymptomatic invisible hematuria with or without proteinuria. Less commonly, patients may present with established chronic kidney disease, nephrotic syndrome, malignant hypertension, or a rapidly progressive glomerulonephritis.
History and exam
Key diagnostic factors
Other diagnostic factors
- family history of IgAN
- male sex
- age 20 to 30 years
- Asian/white/native American ancestry
- IgA vasculitis
- chronic liver disease
- HIV infection
1st investigations to order
- urine microscopy and culture
- basic biochemistry, including estimated glomerular filtration rate (GFR)
- C3 and C4 complement levels
- kidney ultrasound
- computed tomography (KUB)
- kidney biopsy
Investigations to consider
- flexible cystoscopy
- skin biopsy
low risk of progression
medium risk of progression
high risk of progression
acute kidney injury
- IgA vasculitis (previously known as Henoch-Schönlein purpura [HSP])
- Thin glomerular basement membrane disease
- Alport syndrome
- KDIGO 2021 clinical practice guidelines for the management of glomerular diseases
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