The Problem of Occult Pyelonephritis: Acute Pyelonephritis in Patients Presenting Only with Lower Urinary Tract Symptoms.

Pyelonephritis is a prevalent diagnosis of emergency department visits. It commonly presents as flank pain and costovertebral tenderness with urinary symptoms. However, some cases occur without typical symptoms. Our study highlights the dubious presentation of pyelonephritis with lower urinary tract symptoms (LUTS) only. This study was conducted at a tertiary care hospital, where charts and files were reviewed from January 11, 2018 to February 28, 2019 for all the patients with a diagnosis of acute pyelonephritis from medical records. In our study, 521 patients were included and 492 (94%) of the participants were suffering from pyelonephritis. Approximately 22.8% of the patients showed the absence of both flank pain and costovertebral tenderness but were diagnosed with pyelonephritis based on computed tomography (CT) and magnetic resonance imaging (MRI). Moreover, 27% of the patients reported upper urinary tract symptoms only and were diagnosed by CT or MRI findings. Out of that only 24% and 16% of the patients reported flank pain and costovertebral tenderness, respectively. Insignificant associations with pyelonephritis were found for age, gender and other comorbidities. Our study showed a significant number of patients with pyelonephritis without any upper urinary tract symptoms. Patients with LUTS should be evaluated further by imaging if they belong to the high-risk population.