Purpose Acute pyelonephritis (APN) generally involves a single kidney, but it can be bilateral. The aim of the present study was to evaluate differences in clinical presentation, progress and outcome for bilateral APN compared with unilateral APN.
Study design The medical records of all patients over 19 years of age, hospitalised for APN and who underwent abdominal enhanced CT at Samsung Changwon Hospital between January 2009 and August 2012 were retrospectively reviewed. Patients were divided into two groups according to whether unilateral or bilateral lesions were identified on the CT scan.
Results Of the 296 patients, 99 had bilateral APN. Only 64/86 (74.4%) patients with clear tenderness in the bilateral APN group had bilateral tenderness. Patients with bilateral APN had more severe abnormalities, based on the results of laboratory tests. Leukocytosis, thrombocytopenia, bacteraemia, acute kidney injury, shock and death occurred more frequently in bilateral than in unilateral APN. In the bilateral APN group, broad spectrum antibiotics were used more frequently as an initial antibiotic treatment. A history of stroke or diabetes mellitus, and duration of symptoms before admission, were independent risk factors associated with bilateral APN.
Conclusions Patients with bilateral APN experienced more severe clinical and laboratory manifestations and had a poorer outcome than those with unilateral APN. Early imaging tests can be considered to discriminate unilateral from bilateral APN, especially in those with a history of stroke or diabetes and with a longer duration of symptoms. Moreover, initial use of broader spectrum antibiotics can be considered in patients with bilateral APN.