IgA Nephropathy

 

An 18-year-old Asian female with no past medical history presents with runny nose, cough, and gross hematuria.

 

Epidemiology:  

  • Worldwide IgA nephropathy is the most common glomerulonephritis
    • It is most common in Asians and Caucasians
    • Low incidence in African-Americans
  • In the US it makes up 5-10% of primary glomerular diseases
  • Male: female ratio anywhere from 2:1 to 6:1
  • Most common in 20s and 30s, uncommon under 10 years of age

 

Presentation:

  • Anywhere from asymptomatic to acute renal failure
  • Patients may present with low grade fever
  • The most typical presentaiton is asymptomatic microscopic urinary abnormalities with an episode of gross hematuria
  • The presentation of recurrent painless hematuria associated with viral URI is common in children
  • Can be associated with proteinuria, hypertension, edema, reduced renal clearance function

 

Physical exam:

  • Unlikely to demonstrate abnormalities but can be associated with edema

 

Labs:

  • Urinalysis: look for hematuria, proteinuria, white blood cells, red blood cell casts
  • Electrolytes: look for early abnormalities
  • Measure BUN and Creatinine to estimate renal function
  • Rule out other causes of IgA deposition with CBC, 24 hour creatinine clearance, urine calcium to creatinine, C3 (should be normal)
    • IgA deposition can be due to a variety of diseases including Henoch Schonlein Purpura, celiac disease, IBD, CF, cancers, and many others
  • Definitive diagnosis with a percutaneous renal biopsy (biopsy is only performed if the disease is progressing)
  • Imaging studies are not sensitive or specific for IgA nephropathy
  • Renal ultrasound may be used to rule out structural abnormalities

 

Treatment:

  • There is no clear and proven approach to treatment
  • Much of the treatment revolves around managing sequelae: blood pressure control, ACE-inhibitors or Angiotensin II Receptor Blockers for proteinuria, statins
    • Some studies suggest fish oil may be helpful
  • Patients with only hematuria are not usually treated, but they are monitored every 6-12 months for disease progression
  • Immunosuppressive therapy is sometimes used in severe disease and includes glucocorticoids, cyclophosphamide, mycophenolate mofetil
  • Tonsillectomy in combination with immunosuppressive therapy has shown some benefit for renal outcomes in limited studies
    • The role of tonsillectomy is not entirely clear however
    • It is possible that the tonsils are a source of abnormal IgA
  • Transplant is necessary for patients who progress to end stage renal disease, although histologic recurrence is common

 

Prognosis:

  • 35-53% go into clinical remission
  • Kidney survival at 10 years for kids is >90%
  • Mortality is usually secondary to renal failure and its associated complications:
    • Hypertension leading to stroke
    • Renal insufficiency leading to growth failure
    • Medication reactions
  • Morbidity is associated with hypertension, electrolyte abnormalities, problems associated with renal dysfunction

 

References

 

  1. Alamartine E, Sabatier JC, Berthoux FC. Comparison of pathological lesions on repeated renal biopsies in 73 patients with primary IgA glomerulonephritis: value of quantitative scoring and approach to final prognosis. Clin Nephrol. Aug 1990;34(2):45-51.
  2. Béné MC, Faure GC, Hurault de Ligny B, de March AK. Clinical involvement of the tonsillar immune system in IgA nephropathyActa Otolaryngol Suppl. Dec 2004;10-4.
  3. Cattran DC, Coppo R, Cook HT, et al. The Oxford classification of IgA nephropathy: rationale, clinicopathological correlations, and classification.  Kidney Int. Sep 2009;76(5): 534-45.
  4. D’Amico G. Natural history of idiopathic IgA nephropathy and factors predictive of disease outcome. Semin Nephrol. May 2004;24(3): 179-96
  5. Donadio JV, Grande JP.  IgA Nephropathy. New England Journal of Medicine. Sep 2002;347(10):738-48.
  6. Ilyas M, Langman C. Medscape Reference: IgA Nephropathy.  Updated September 6, 2012.