What is the Difference Between IgA Nephropathy and Post Streptococcal Glomerulonephritis?

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IgA Nephropathy and Post-Streptococcal Glomerulonephritis (PSGN) are both relatively common causes of glomerulonephritis, which is an inflammation of the glomeruli in the kidneys. However, there are key differences between the two conditions:

  1. Cause: IgA Nephropathy occurs due to the accumulation of antibodies called IgA in glomeruli. PSGN, on the other hand, occurs after 10 to 14 days of throat or skin infection by Streptococcus bacteria.
  2. Latency Period: IgA Nephropathy typically occurs within days after the onset of an inciting illness, while PSGN has a latent period of 10 to 14 days between the infection and the onset of glomerulonephritis.
  3. Symptoms: IgA Nephropathy may present with so-called "synpharyngitic glomerulonephritis," where pharyngitis and glomerulonephritis coincide. In contrast, PSGN classically presents with hypocomplementemia, which is a decrease in the activity of the complement system, a part of the immune response.
  4. Serologic Values: IgA Nephropathy shows normal serologic values, although IgA levels may be elevated in about a third of cases. In contrast, PSGN presents with abnormal serologic values.
  5. Histopathology: In PSGN, the presence of immune complexes leads to the activation of the alternative complement pathway, causing proliferation of the mesangial cells in the glomerulus and impairing capillary perfusion. This can result in a reduction in Glomerular Filtration Rate (GFR) and lead to renal failure. In IgA Nephropathy, the predominant finding is muddy brown casts, which are indicative of acute tubular necrosis.

In summary, IgA Nephropathy and PSGN are both causes of glomerulonephritis, but they differ in their causes, latency periods, symptoms, serologic values, and histopathology.

Comparative Table: IgA Nephropathy vs Post Streptococcal Glomerulonephritis

IgA Nephropathy and Post-Streptococcal Glomerulonephritis are two kidney diseases that affect the glomeruli, the tiny blood vessels in the kidneys that filter waste from the blood. Both conditions are due to the immune system attacking the glomeruli, causing inflammation and filtration problems. However, there are key differences between the two:

Feature IgA Nephropathy Post-Streptococcal Glomerulonephritis
Cause Accumulation of IgA antibodies in glomeruli Immune response to streptococcal infection, typically occurring 10-14 days after throat or skin infection
Presentation May present with "synpharyngitic glomerulonephritis" (pharyngitis and glomerulonephritis occurring together) Typically does not set in until several weeks after the initial infection
Serology Normal serologic values (though IgA levels may be elevated in about a third of cases) Hypocomplementemia, an immune complex-mediated process
Diagnosis Renal biopsy, blood tests, urine tests Renal biopsy, blood tests, urine tests

Both conditions can lead to proteinuria (elevated protein levels in the urine) and can be diagnosed through blood tests and urine tests.