Encrusted Urinary Tract Infections Due to Corynebacteria Species

INTRODUCTION: Encrusted pyelitis and cystitis are peculiar disorders characterized by the calcification of the vesical, the pyelic, and/or the ureteral walls. These calcifications are composed of struvite and calcium carbonate‒apatite due to the presence of Corynebacterium urealyticum. METHODS: We have identified the clinical features and outcomes of 17 patients with encrusted pyelitis (n = 15) or encrusted cystitis (n = 2). Diagnosis was based on computed tomography scan and sonography including thickening and calcified lesions of the urinary tract. RESULTS: The main clinical presentation was suggestive of subacute urinary tract infection with fever and urologic symptoms, mostly gross hematuria. Biologic features were characterized by the presence of struvite crystals and alkaline urine. Acute kidney injury was reported in 70.6% of cases. Predisposing factors were mostly due to urologic background (82.4%) with a history of urologic procedure (71%) and prior exposure to antibiotics (59%). All patients received appropriate antibiotherapy and 15 were treated with topical urinary acidification. A significant reduction of encrusted calcifications was observed in 88% of cases. Renal function improved in 71% of the patients. Nevertheless, poor tolerance of the treatment and side effects were common, affecting 71% of patients, with Gram-negative bacilli urinary tract infections (53%) being the most frequent. At last follow-up, 4 patients (23.5%) progressed to end-stage renal disease and only 1 had a clinical relapse. CONCLUSIONS: Encrusted urinary tract infections are rare, characterized by a severe renal and overall prognosis in the absence of appropriate treatment. Topical urinary acidification and appropriate antibiotherapy are efficient but may be burdened by significant adverse events.