Kidney Infection (Pyelonephritis): Symptoms, Causes, Diagnosis, and Treatment

Pyelonephritis is a bacterial infection of the kidney, usually ascending from the bladder. Common pathogens: E. coli, Klebsiella, Proteus.

Acute vs. Chronic

• Acute: Sudden onset with high fever, chills, flank pain, nausea/vomiting, dysuria, cloudy/bloody urine.
• Chronic: Recurrent or persistent infection causing scarring, reduced function, potential kidney failure.

Diagnosis

• Urinalysis (WBC, bacteria, nitrites)
• Urine culture & sensitivity
• Blood tests (CBC, creatinine, electrolytes)
• Imaging (CT/US) if complicated, recurrent, or no improvement

Treatment

• Antibiotics: Empiric then targeted (7–14 days oral; IV if severe/sepsis).
• Supportive: Hydration, analgesics, antipyretics.
• Hospitalization: For sepsis, obstruction, pregnancy, immunocompromise, inability to tolerate oral meds.

Prevention

Hydration, prompt UTI treatment, good hygiene, post-coital voiding, managing structural abnormalities.