IgA nephropathy

Last reviewed: September 2018

Last updated: May 2018

Summary

About 50% 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 acute rapidly progressive glomerulonephritis.

Acute or chronic renal failure may develop.

Renal 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.

ACE inhibitors are widely used to reduce proteinuria, particularly if hypertension and/or proteinuria is present, and they have been shown to help preserve renal 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 renal deterioration in people with moderate proteinuria, but this may be associated with serious adverse effects.

Definition

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. [1]

History and exam

Key diagnostic factors

hematuria

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Other diagnostic factors

proteinuria
hypertension
edema

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Risk factors

family history of IgAN
male sex
age 20 to 30 years
Asian/white/native American ancestry
IgA vasculitis
chronic liver disease
HIV infection

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Diagnostic investigations

1st investigations to order

urinalysis
urine microscopy and culture
basic biochemistry, including estimated glomerular filtration rate (GFR)
C3 and C4 complement levels
renal ultrasound
computed tomography (KUB)
renal biopsy

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Investigations to consider

flexible cystoscopy
skin biopsy

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Treatment algorithm

ONGOING

low risk of progression

medium risk of progression

high risk of progression

acute kidney injury

Contributors

Authors VIEW ALL 

Jonathan Barratt, PhD, FRCP

The Mayer Professor of Renal Medicine

Department of Infection, Immunity & Inflammation

University of Leicester

Honorary Consultant Nephrologist

John Walls Renal Unit

Leicester General Hospital

Head of the Postgraduate Specialty School of Clinical Academic Training

Health Education East Midlands

Disclosures

JB has consultancies with Kancera AB, AduroBiotech, Anthera Pharmaceuticals, Calliditas, Novartis, Omeros, and EMD Serono. He is also an author of a number of references cited in this monograph.

See Cheng Yeo, MBBS, MRCP (UK), M.Med (Int Med)

Adjunct Assistant Professor

Deputy Head & Consultant

Department of Renal Medicine

Tan Tock Seng Hospital

Singapore

Disclosures

SCY is an author of a reference cited in this monograph.

Acknowledgements

Dr Jonathan Barratt and Dr See Cheng Yeo would like to gratefully acknowledge Dr Hani Bleibel and Dr Chike Nzerue, previous contributors to this monograph. HB and CN declare that they have no competing interests.

Peer reviewers VIEW ALL 

Richard Lafayette, MD

Associate Professor of Medicine

Nephrology Division

Stanford University Medical Center

Stanford

Disclosures

RL declares that he has no competing interests.

Alan Salama, MA, MBBS, PhD, FRCP

Professor of Nephrology

UCL Centre for Nephrology

Royal Free Hospital

London

Disclosures

AS declares that he has no competing interests.

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IgA nephropathy

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Treatment algorithm

low risk of progression

medium risk of progression

high risk of progression

acute kidney injury

Contributors

Authors VIEW ALL 

Jonathan Barratt, PhD, FRCP

Disclosures

See Cheng Yeo, MBBS, MRCP (UK), M.Med (Int Med)

Disclosures

Acknowledgements

Peer reviewers VIEW ALL 

Richard Lafayette, MD

Disclosures

Alan Salama, MA, MBBS, PhD, FRCP

Disclosures

Differentials

Guidelines

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