From the Guidelines
Pyelonephritis is a severe urinary tract infection that involves inflammation of the renal pelvis and kidney, often presenting with signs and symptoms of both systemic inflammation and bladder inflammation, and is typically diagnosed clinically with a urinalysis showing pyuria and/or bacteriuria, and confirmed by urine cultures yielding >10,000 colony-forming units of a uropathogen per milliliter of urine 1. The condition can range from mild flank pain with low-grade or no fever to septic shock, and up to 20% of patients lack bladder symptoms.
- Key characteristics of pyelonephritis include:
- Inflammation of the renal pelvis and kidney
- Systemic inflammation symptoms such as fever, chills, and fatigue
- Bladder inflammation symptoms such as urgency, dysuria, and urinary frequency
- Urinalysis showing pyuria and/or bacteriuria
- Urine cultures yielding >10,000 colony-forming units of a uropathogen per milliliter of urine
- The most common cause of pyelonephritis is Escherichia coli, particularly in young healthy women, but other organisms such as gram-negative bacilli, gram-positive organisms, and candida can also be responsible, especially in men, elderly women, and urologically compromised and institutionalized patients 1.
- Risk factors for pyelonephritis include sexual activity, new sexual partner, spermicide exposure, personal or maternal history of UTIs, genetic predisposition, and diabetes mellitus, as well as factors that disrupt urinary flow such as vesicoureteral reflux, congenital urinary tract anomalies, altered bladder function, pregnancy, renal calculi, or mechanical obstruction 1.
From the Research
Definition of Pyelonephritis
Pyelonephritis is an infection of the upper urinary tract, specifically the kidneys, which can be caused by various organisms, with Escherichia coli being the most frequent cause 2.
Key Characteristics
- The pathogenesis of acute pyelonephritis involves the adhesion of urothelial cells by P-fimbriae of E. coli and other virulence factors such as hemolysin and aerobactin 2.
- Renal damage can occur due to the release of toxic oxygen radicals during ischemic episodes and the respiratory burst of phagocytosis 2.
- Effective antibacterial treatment is crucial to prevent complications and promote recovery 2, 3, 4.
Risk Factors and Complications
- Complicated infections are often associated with diabetes mellitus, instrumentation, stone, and immunosuppression 2.
- The scarring of chronic pyelonephritis can lead to the loss of renal tissue and function, potentially progressing to end-stage renal disease 2.
- Delayed or ineffective treatment can result in increased morbidity and mortality 2, 3, 4.
Treatment and Management
- Antibacterial agents such as trimethoprim/sulfamethoxazole or fluoroquinolones may be used as outpatient therapy for uncomplicated pyelonephritis 2, 3.
- Parenteral antibiotics such as ceftriaxone and gentamycin may be necessary for severe or complicated infections 2.
- The choice of antibiotic should be guided by local resistance patterns and susceptibility testing 3, 5, 6.