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)
Immunofluorescence and electron microscopy:
IgA deposits
H&E: mesangial proliferation
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
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.