The infected obstructed kidney
Flank pain, a fever, and a stone the urine can't get past. This is one of the few things on a urology service that can quietly kill a ward patient overnight — and antibiotics alone are not the treatment.
The one-liner
Obstruction + infection = decompress within hours. PCN and retrograde stent are equivalent (Pearle 1998) — the question is never whether to drain, only how. Stone clearance waits for a sterile, calm system.
A patient with a ureteral stone, a fever, and a rising white count is not a kidney-stone problem with an infection on top. It is an obstructed, infected upper tract — an abscess under pressure — and that combination is one of the two things on a urology service that can actually kill someone in front of you.
The frame
An infected collecting system that cannot drain is pus behind a dam. Antibiotics have to reach the bug, and a fully obstructed system limits delivery while bacteria build behind the blockage. Hypotension is a late sign here — the decompensation is fast and unforgiving once it begins. This is how a comfortable-looking stone patient slides into urosepsis overnight. The fix is mechanical: decompress the system within hours.
What everyone gets wrong
Reaching for stone treatment first. The instinct is to “treat the stone” — but lasering or operating on an actively infected, obstructed system can seed sepsis directly into the bloodstream. In the acute infected setting the goal is drainage and source control, not stone clearance. The stone is a problem for a different, calmer day.
The decision: not whether, but how
Two routes accomplish decompression, and the evidence calls them equivalent:
- Retrograde ureteral stent — placed cystoscopically, bypassing the obstruction from below.
- Percutaneous nephrostomy — a tube placed directly into the collecting system through the flank, often the better choice for a frankly septic patient or when retrograde access fails.
Pearle’s 1998 trial established that the two are equivalent for decompression — so the choice turns on the patient, the anatomy, the GA risk, and what your team can deliver fastest with the least physiologic insult. The principle that matters for a trainee: the question is never whether to decompress, only how.
The package around the drain
- Sepsis bundle: fluids, antibiotics within 1 hour of recognition, lactate, cultures (Surviving Sepsis 2021; 30 mL/kg crystalloid in shock).
- Decompress urgently — PCN or stent.
- 48–72 hours of targeted IV antibiotics after decompression, then complete the course.
- Definitive stone surgery later, on sterile urine. (If the stone is HU > 1000, you’re planning PCNL, not SWL — but that’s the next admission’s problem.)
If you remember one thing
When you hear “obstructing stone” and “fever” in the same sentence, your mind should go to a drain, not a laser. The stone can wait. The pressure cannot.