Overview

Pyelonephritis is a type of urinary tract infection (UTI) that affects one or both kidneys. It occurs when bacteria, most commonly from the bladder or urethra, ascend into the kidneys, causing inflammation and infection. Pyelonephritis can be acute, developing suddenly and severely, or chronic, where repeated or persistent infections lead to kidney scarring. This condition is more common in women due to anatomical differences but can occur in both genders and at any age. If left untreated, pyelonephritis can lead to serious complications, including kidney damage, sepsis, or recurrent infections.

Causes

The primary cause of pyelonephritis is a bacterial infection that spreads to the kidneys, usually from the lower urinary tract. Common causes and risk factors include:

• Ascending bacterial infection: Most commonly caused by Escherichia coli (E. coli) bacteria from the gastrointestinal tract entering the urinary system.
• Urinary tract obstruction: Kidney stones, enlarged prostate, or structural abnormalities can block urine flow, increasing infection risk.
• Vesicoureteral reflux (VUR): A condition where urine flows backward from the bladder to the kidneys, common in children.
• Frequent urinary tract infections: Recurrent bladder infections can predispose individuals to kidney infections.
• Indwelling urinary catheters: Prolonged catheter use can introduce bacteria into the urinary tract.
• Weakened immune system: Conditions like diabetes, HIV/AIDS, or use of immunosuppressive drugs can increase susceptibility.

Symptoms

Symptoms of pyelonephritis can range from mild to severe and typically develop rapidly in acute cases. Common signs and symptoms include:

• Fever and chills: High fever, often accompanied by shaking chills.
• Flank pain: Pain in the back or side, below the ribs, on the affected side.
• Abdominal pain: May accompany the flank discomfort.
• Nausea and vomiting: Common systemic symptoms of infection.
• Urinary symptoms: Frequent urination, burning sensation during urination (dysuria), and urgency.
• Cloudy or foul-smelling urine: Indicating infection in the urinary tract.
• Hematuria: Presence of blood in the urine.
• Fatigue and general malaise: Feeling unwell and tired due to systemic infection.

Diagnosis

Diagnosing pyelonephritis involves a combination of medical history, physical examination, and laboratory tests:

• Medical history: Evaluation of symptoms and any prior history of UTIs.
• Physical examination: Checking for flank tenderness and signs of systemic infection.
• Urinalysis: Detects white blood cells, red blood cells, bacteria, and nitrites in urine, indicative of infection.
• Urine culture: Identifies the specific bacteria causing the infection and guides antibiotic selection.
• Blood tests: May show elevated white blood cell count and signs of systemic infection.
• Imaging studies: Ultrasound or CT scan may be used in severe, recurrent, or complicated cases to check for obstructions or abscesses.

Treatment

The primary treatment for pyelonephritis is antibiotic therapy to eliminate the infection:

• Oral antibiotics: Prescribed for mild to moderate cases; common options include ciprofloxacin, levofloxacin, or trimethoprim-sulfamethoxazole for 7-14 days.
• Intravenous (IV) antibiotics: Required for severe cases or hospitalized patients; medications may include ceftriaxone, gentamicin, or piperacillin-tazobactam.
• Pain management: Over-the-counter pain relievers like acetaminophen or ibuprofen can help manage fever and pain.
• Hydration: Increased fluid intake helps flush out bacteria from the urinary tract.
• Treatment of underlying cause: Addressing kidney stones, urinary blockages, or reflux to prevent recurrence.
• Hospitalization: Necessary for patients with severe symptoms, vomiting, pregnancy, or underlying health conditions.

Prognosis

With prompt and appropriate treatment, the prognosis for pyelonephritis is generally excellent:

• Rapid recovery: Most patients experience symptom improvement within 48 to 72 hours of starting antibiotics.
• Complete resolution: Full recovery typically occurs within 1 to 2 weeks in uncomplicated cases.
• Risk of complications: If untreated, pyelonephritis can lead to kidney abscesses, sepsis, chronic kidney disease, or recurrent infections.
• Chronic pyelonephritis: Repeated infections can cause permanent