IgA Acute Glomerulonephritis Associated with S. Aureus



IgA Acute Glomerulonephritis Associated with S. Aureus


Robert B. Colvin, MD










Glomerulitis may be mild in cases of IgA positive acute glomerulitis associated with Staphylococcus aureus infection. Many mononuclear and a few polymorphonuclear leukocytes are present image.






Acute glomerulonephritis associated with Staphylococcal aureus infection typically has prominent mesangial IgA deposits, which resemble IgA nephropathy or HSP.


TERMINOLOGY


Definitions



  • Acute glomerulonephritis (GN) associated with Staphylococcus aureus infection with predominance of IgA deposition


ETIOLOGY/PATHOGENESIS


Infectious Agents



  • S. aureus, coagulase positive, often methicillin resistant (MRSA)



    • Osteomyelitis, pneumonia, septic arthritis, discitis, soft tissue abscess, empyema, sinusitis, endocarditis


    • Septicemia


    • Not usually postinfectious GN but occurs during chronic infection



      • Average duration of infection is 5 weeks


Host Factors



  • Diabetes mellitus, neoplasia, old age, alcoholism


Immune Response



  • IgA antibodies to S. aureus cell membrane antigen (GenBank BAB41819.1)


  • S. aureus enterotoxins may act as superantigens, stimulating T cells and leading to polyclonal B-cell activation


  • 1 superantigen-like protein (SSL7) binds to Fc of IgA, blocking FcR activity


CLINICAL ISSUES


Presentation



  • Persistent infection, septicemia


  • Acute renal failure


  • Hematuria


  • Proteinuria, nephrotic range (20-80%)


  • Hypertension


  • Hypocomplementemia (minority)


  • Purpura


Treatment



  • Antibiotics and renal support


  • Anecdotal reports of steroids/immunosuppression


Prognosis



  • Data limited



    • Range of outcomes from complete recovery to ESRD


    • Recovery possible if infection successfully treated


  • Underlying disease and age are important factors


Prevalence



  • ˜ 25% of renal biopsies with acute postinfectious glomerulonephritis


MICROSCOPIC PATHOLOGY

Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on IgA Acute Glomerulonephritis Associated with S. Aureus
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