Severe acute pyelonephritis: a review of clinical outcome and risk factors for mortality.

OBJECTIVE. To review demographics of patients with acute pyelonephritis, their outcomes of severe upper urinary tract infection, and to identify risk factors for long hospital stay and mortality. DESIGN. Case series. SETTING. A regional hospital in Hong Kong. PATIENTS. Patients admitted between June 2007 and June 2012 for acute pyelonephritis were identified. Those with the most severe outcomes were analysed of their mortality, need for care in the intensive care unit, or necessitation of urological intervention. RESULTS. Overall, 68 patients fulfilled our criteria for severe acute pyelonephritis. The female-to-male ratio was 7:3. Their mean age was 58 years. Overall, 57% of the patients had impaired renal function and 37% were diabetic; 47% developed shock after admission and 56% required further intensive care unit care; 75% of the patients demonstrated radiological evidence of urinary tract obstruction and required subsequent drainage procedures. Five patients died due to severe acute pyelonephritis. The prevalence of bacteraemia and bacteriuria was 57% and 74%, respectively. Escherichia coli accounted for the majority of causative organisms. Four risk factors-bacteraemia, shock, need for intensive care, and suppurative pyelonephritis-were associated with hospital stay of longer than 14 days. Old age (≥65 years), male sex, deranged renal function, and presence of disseminated intravascular coagulation were associated with mortality. CONCLUSION. There was high prevalence of bacteraemia and septic shock in patients with severe acute pyelonephritis. The factors of old age (≥65 years), male sex, deranged renal function, and presence of disseminated intravascular coagulation were associated with mortality. With the support of intensive care, early recognition of urinary tract obstruction and timely drainage, patients with severe acute pyelonephritis generally carry a good prognosis.