• Clinical science

IgA nephropathy (Berger disease)

Summary

IgA nephropathy (Berger disease) is the most common primary glomerulonephritis worldwide. It most frequently affects males in the second to third decades of life. Clinical manifestations are usually triggered by upper respiratory tract or gastrointestinal infections and include gross hematuria and flank pain. In some cases, it may present as rapidly progressive glomerulonephritis (RPGN). Urinalysis of asymptomatic patients often shows persistent microhematuria and minor proteinuria, while more severe cases may manifest with recurrent episodes of nephritic syndrome. A kidney biopsy is indicated in patients with signs of severe or progressive disease to make a definitive diagnosis. Treatment consists of measures to slow the progression of the disease (e.g., ACE inhibitors) as well as immunosuppressive therapy in more severe cases. Even with the appropriate treatment, up to 50% of patients progress to end-stage renal disease within 20–25 years.

Epidemiology

  • IgA nephropathy is the most common primary glomerulonephritis.
  • Peak incidence: second to third decades of life
  • Sex: > (2:1)
  • Ethnicity: more common in the Asian population (worldwide)

Epidemiological data refers to the US, unless otherwise specified.

Pathophysiology

  • The cause is still not entirely understood.
  • Most likely mechanism: an increased number of defective, circulating IgA antibodies are synthesized (often triggered by mucosal infections, i.e., upper respiratory tract and gastrointestinal infections) IgA antibodies form immune complexes that deposit in the kidney glomerulonephritis (type III hypersensitivity reaction)

Clinical features

The course of the disease is highly variable and can manifest in the following forms:

  • Asymptomatic
  • Recurring episodes of:
    • Gross hematuria
    • Flank pain
    • Low-grade fever
    • And/or nephritic syndrome (including hypertension)
    • Usually during or immediately following a respiratory or gastrointestinal infection
  • Can progress to RPGN and/or nephrotic syndrome (< 10% of patients)
  • Up to 50% of patients progress to end-stage renal disease within 20–25 years.
    • Risk factors associated with a worse prognosis: persistent gross hematuria, hypertension, proteinuria (> 1 g/24 h), males < 30 years of age, elevated serum creatinine, histopathologic signs of interstitial fibrosis

IgA nephropathy and Henoch-Schonlein purpura (HSP) are both IgA-mediated vasculitides triggered by a mucosal infection. HSP most commonly occurs in children < 10 years of age and affects multiple organ systems (palpable purpura, abdominal pain, arthralgia). IgA nephropathy is limited to the kidneys and typically affects adults.

Diagnostics

Diagnosis is based on clinical presentation and laboratory results. In some cases, renal biopsy may be indicated to confirm the diagnosis.

The renal manifestation of Henoch-Schönlein purpura is pathologically the same as IgA nephropathy.

Differential diagnoses

The differential diagnoses listed here are not exhaustive.

Treatment

last updated 06/04/2019
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