Computed Tomography Imaging in Pyelonephritis and Its Complications

Abstract

BACKGROUND Acute pyelonephritis (APN) is a common disease which rarely evolves into abscesses. Urinary tract infections are the common urologic disease and the estimated annual incidence of pyelonephritis is 10.5 million to 25.9 million cases globally. In general, routine CT imaging is not required for diagnosis and treatment of uncomplicated cases in adult patients. It is of value in establishing the diagnosis in equivocal cases, in evaluating high-risk patients, and in determining the extent of disease and reveal complications such as abscess or obstruction. METHODSThis is a prospective study conducted over a period of 24 months from 2015 through 2017. We collected clinical, biochemical and radiological data of patients hospitalized with a diagnosis of APN. RESULTSWe identified the CT signs of acute pyelonephritis at different stages of the process. The typical CT-signs of AP were enlargement of the kidney with its thickened parenchyma and an impairment of corticomedullary differentiation. The highest incidence of acute pyelonephritis in our study was found in 41-50 years' age group accounting for 32% of cases and it was the least in the age group of 31-40 years constituting 0%. Out of total patients, 92% had unilateral pyelonephritis, while 8% had bilateral pyelonephritis, right kidney was involved in 48% of cases and left kidney was involved in 52% of cases. These finding correlated with previous studies wherein the left kidney involvement in pyelonephritis was marginally higher when compared to the right renal involvement. CONCLUSIONSCT is particularly useful for evaluating the complications of pyelonephritis such as abscesses and emphysematous pyelonephritis. It helps in defining the extent and severity of these complications. CT plays a critical role in the management of these complications, especially in critically ill patients and reducing the morbidity and mortality. Guided procedures are recommended for the drainage of collections or abscesses. KEY WORDSCT, Acute Pyelonephritis, Focal Nephritis, Renal Abscess, Urinary Tract Infection HOW TO CITE THIS ARTICLE: Belman M, Toka M, Hedau S. Computed tomography imaging in pyelonephritis and its complications. BACKGROUND Pyelonephritis is classically defined as an infection of the upper urinary tract involving the renal parenchyma and pelvis. It normally occurs as secondary to a bacterial infection in the lower urinary tract usually involving the bladder or urethra. This infection then ascends to involve the kidneys to cause acute pyelonephritis. (1) The natural flow of urine in the urinary tract is thought to prevent the build-up of pathogenic bacteria. Hence, any obstruction can cause stasis of urine and create conditions suitable for infection.