From the Guidelines
Pyelonephritis is a severe urinary tract infection that involves inflammation of the renal pelvis and kidney, potentially leading to sepsis, shock, and death, and is typically characterized by symptoms such as fever, flank pain, and urinary frequency. The condition often presents with signs and symptoms of both systemic inflammation and bladder inflammation, and can range from mild flank pain with low-grade or no fever to septic shock 1.
Key Characteristics
- Inflammation of the renal pelvis and kidney
- Potential to cause sepsis, shock, and death
- Symptoms include fever, flank pain, and urinary frequency
- Can range from mild to severe presentations
Diagnosis and Treatment
The diagnosis of pyelonephritis is typically based on clinical presentation, urinalysis, and urine culture, with fluoroquinolones and cephalosporins being the recommended antimicrobial agents for oral empiric treatment of uncomplicated pyelonephritis 1.
- Urinalysis and urine culture are essential for diagnosis
- Fluoroquinolones and cephalosporins are recommended for treatment
- Uncomplicated cases can often be treated as outpatients, while severe cases may require hospitalization for intravenous antibiotics
Complications and Prevention
If left untreated, pyelonephritis can lead to serious complications including kidney damage, sepsis, or abscess formation, and recurrent episodes may indicate underlying anatomical abnormalities or other predisposing factors that require further investigation 1.
- Untreated pyelonephritis can lead to serious complications
- Recurrent episodes may indicate underlying abnormalities
- Further investigation is necessary to identify and address underlying factors
From the Research
Definition of Pyelonephritis
Pyelonephritis is a bacterial infection of the kidney and renal pelvis, which can be suspected in patients with flank pain and laboratory evidence of urinary tract infection 2.
Causes and Risk Factors
The most common cause of pyelonephritis is infection with Escherichia coli (E. coli), accounting for 70-90% of infections 3, 4. Other organisms, such as Enterococci, Klebsiella, Pseudomonas, Proteus, and Staphylococci, can also cause pyelonephritis 4. Risk factors for uncomplicated acute pyelonephritis include recent sexual intercourse, acute cystitis, stress incontinence, and diabetes, while risk factors for complicated acute pyelonephritis include pregnancy, diabetes, anatomical abnormalities of the urinary tract, and renal calculi 4.
Symptoms and Diagnosis
Symptoms of pyelonephritis may include flank pain, fever, frequency, urgency, and dysuria 5, 2. Laboratory evidence of urinary tract infection, such as a positive urine culture, is essential for diagnosis 2. Imaging studies, blood cultures, and measurement of serum inflammatory markers may not be necessary in uncomplicated cases 2.
Treatment and Management
Treatment of pyelonephritis typically involves antibiotic therapy, with fluoroquinolones and trimethoprim/sulfamethoxazole being effective oral antibiotics in most cases 3, 2. However, increasing resistance to these antibiotics makes empiric use problematic 2. Parenteral antibiotic therapy may be necessary in patients with sepsis or risk of infection with a multidrug-resistant organism 2. Outpatient management is appropriate in patients with uncomplicated disease who can tolerate oral therapy 2.
Complications
Pyelonephritis can have serious complications, including acute kidney injury, papillary necrosis, renal or perinephric abscess, and emphysematous pyelonephritis 4. Pregnant patients with pyelonephritis are at significantly elevated risk of severe complications and should be admitted and treated initially with parenteral therapy 2.