About 50% of patients with IgA nephropathy present with recurrent episodes of visible haematuria after an upper respiratory tract infection or gastroenteritis; approximately one third of patients have invisible haematuria 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 aetiology of this common glomerulonephritis remains unknown. Clinical presentation varies widely. Patients commonly present with recurrent episodes of visible haematuria (usually occurring after an upper respiratory tract infection or gastroenteritis) or asymptomatic invisible haematuria 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
Jonathan Barratt, PhD, FRCP
The Mayer Professor of Renal Medicine
Department of Cardiovascular Sciences
University of Leicester
Honorary Consultant Nephrologist
John Walls Renal Unit
Leicester General Hospital
JB has consultancies with Alnylam, argenx, Astellas, Calliditas, Chinook, Dimerix, Novartis, Omeros, Travere Therapeutics, Vera Therapeutics and Visterra. He is also an author of a number of references cited in this topic.
See Cheng Yeo, MBBS, M.Med (Int Med), FRCP (London), MD
Adjunct Assistant Professor
Head & Senior Consultant
Department of Renal Medicine
Tan Tock Seng Hospital
SCY is an author of a reference cited in this topic.
Professor Jonathan Barratt and Dr See Cheng Yeo would like to gratefully acknowledge Dr Hani Bleibel and Dr Chike Nzerue, previous contributors to this topic.
HB and CN declare that they have no competing interests.
Richard Lafayette, MD
Associate Professor of Medicine
Stanford University Medical Center
RL declares that he has no competing interests.
Alan Salama, MA, MBBS, PhD, FRCP
Professor of Nephrology
UCL Centre for Nephrology
Royal Free Hospital
AS declares that he has no competing interests.
- IgA vasculitis (previously known as Henoch-Schönlein purpura [HSP])
- Thin glomerular basement membrane disease
- Alport's syndrome
- KDIGO 2021 clinical practice guidelines for the management of glomerular diseases
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