Infected obstructed kidney — the pyonephrosis viva

This is an infected obstructed system (pyonephrosis) — fever, sepsis physiology, pyuria and hydronephrosis — not uncomplicated renal colic. It is a urological emergency.^[1]

^[1]Immediate ED care

• ABCDE sepsis pathway; large-bore access; lactate, cultures (blood + urine), fluid resuscitation.
• Broad-spectrum IV antibiotics after cultures — e.g. ceftriaxone 2 g IV ± gentamicin, or piperacillin–tazobactam 4.5 g IV (local antibiogram).
• Analgesia: avoid NSAID in shock/AKI — use paracetamol 1 g IV and titrated opioid (e.g. morphine 2.5–5 mg IV).
• Imaging: non-contrast CT KUB (or CT with contrast/sepsis protocol per local practice) defines stone size/site and degree of obstruction; ultrasound already shows hydronephrosis.^[3]

Definitive therapy

• Urgent decompression within hours by ureteric stent or percutaneous nephrostomy — source control.^[1]
• Antibiotics are adjunctive: raised pressure prevents adequate antibiotic penetration into the collecting system; antibiotics alone will not cure pyonephrosis.
• Admit under urology ± HDU/ICU for septic shock; source control before delayed elective stone clearance.

^[4]Contrast with uncomplicated colic (afebrile, NSAID-first analgesia, CT KUB, selective MET, discharge) — discharging this patient as "colic" is the classic lethal Fellowship error.^[1]