Mycoplasma pneumoniae-associated acute tubulointerstitial nephritis with gross hematuria and transient renal dysfunction

Abstract

Mycoplasma pneumoniae infection is responsible for both respiratory and extra respiratory symptoms, but renal involvement is rare. We here report a 15-year-old girl with gross hematuria appeared 5 days after the onset of low-grade fever and cough. Because of her proteinuria and moderate renal dysfunction, she was referred to our hospital. She was diagnosed as Mycoplasma pneumoniae pneumonia. But hypertension, oliguria and hypocomplementemia were absent, which are often seen in case of acute nephritis. Because her proteinuria and hematuria persisted even after her pneumonia improved, and tubular dysfunction was detected, a percutaneous renal biopsy was performed. The main histopathological finding was acute interstitial nephritis associated with mild IgA nephropathy. Her renal dysfunction was self-limiting, and subsequently she made a full recovery, except for microscopic hematuria. We conclude that Mycoplasma pneumoniae infection had an influence on the development of acute interstitial nephritis.