Abstract

Introduction

There are approximately 250,000 cases of acute pyelonephritis each year, resulting in more than 100,000 hospitalizations¹. Acute pyelonephritis is an infection of the upper urinary tract, specifically the renal parenchyma and renal pelvis.

It is considered uncomplicated if the infection is caused by a typical pathogen in an immunocompetent patient who has normal urinary tract anatomy and renal function. It is critical to determine whether the patient has an uncomplicated or complicated UTI because significant abnormalities have been found in 16% of patients with acute pyelonephritis². Misdiagnosis can lead to sepsis, renal abscesses, and chronic pyelonephritis that may cause secondary hypertension and renal failure³.

The clinical spectrum ranges from gram negative sepsis to cystitis with mild flank. Abrupt onset of chills, fever (100.3° F or greater), and unilateral or bilateral flank or costovertebral angle pain and/or tenderness³.  These so-called upper tract signs are often accompanied by dysuria, increased urinary frequency, and urgency.

Most renal parenchymal infections occur secondary to bacterial ascent through the urethra and urinary bladder. In men, prostatitis and prostatic hypertrophy causing urethral obstruction predispose to bacteriuria.

Hematogenous acute pyelonephritis occurs most often in debilitated, chronically ill patients and those receiving immunosuppressive therapy.