Reversible nephrotic syndrome in a patient with amyloid A amyloidosis of the kidney following methicillin-resistant Staphylococcus aureus infection

A corn mon form of methicillin-resistant Staphylococcus aureus (MRSA) assoc iated glomerulonephritis is either an endocapillary proliferative glomerulo nephritis or a crescentic glomerulonephritis. This report describes the dev elopment of reversible nephrotic syndrome following MRSA infection in a pat ient with amyloid A amyloidosis. The patient had been diagnosed as having r heumatoid arthritis for 50 years. Suppurative arthritis due to MRSA became complicated 2 years prior to admission to our hospital. In the meantime, a nonnephrotic-range proteinuria developed. Two weeks before admission,nephro tic syndrome developed. The serum creatinine level remained unchanged throu ghout the course, but common features characteristic of MRSA-associated glo merulonephritis were observed in this patient, such as elevated serum IgG a nd IgA levels. A renal biopsy specimen showed glomerular amyloid A amyloido sis of a nodular type, infiltrated mononuclear cells in the mesangium, depo sition of IgG, IgA, and C3, and swelling of glomerular endothelial cells. T here were no crescentic glomeruli. Following surgical eradication of the MR SA focus in the right knee joint, nephrotic syndrome disappeared. Hence, it was highly possible that MRSA infection induced a reversible nephrotic syn drome by causing reversible injuries to glomerular endothelial cells. The d escription of this case serves to illustrate the range of MRSA infections t hat may cause various forms of glomerulonephritides. Copyright (C) 2001 S. Karger AG, Basel.