Kidney Infection (Pyelonephritis) Symptoms: Fever, Back Pain, Urinary Changes, and More

Classic Presentation

• Fever & chills (often >101°F / 38.3°C).
• Flank pain (CVA tenderness) — unilateral or bilateral.
• Urinary symptoms: Frequency, urgency, dysuria, hematuria.
• Urine changes: Cloudy, foul-smelling, dark.
• Systemic: Nausea, vomiting, fatigue, malaise.
• Less common: Diarrhea, confusion (elderly), weight loss (chronic).
• Rare: Seizures (severe sepsis, electrolyte disturbance).

Diagnosis & Urgency

• Urinalysis (WBC, bacteria, nitrite, leukocyte esterase).
• Urine culture & sensitivity.
• Blood cultures if febrile/toxic.
• Imaging (CT) if obstructing stone, abscess, no improvement 48–72 hrs.

Pyelonephritis requires prompt antibiotics (often IV initially) to prevent sepsis, scarring, abscess.