Patient handout

Acute Kidney Injury — Post-renal (Obstructive) Mechanism

PRODUCTION

1. Your condition

This handout is for acute kidney injury — post-renal (obstructive) mechanism. Your care team identified this based on: cr rise with anuria / oliguria / fluctuating output (kdigo 2012 aki).

Other reasons your team may use this plan: suprapubic fullness / distention + acute urinary retention (aua bph 2021 pmid 34384237); flank pain ± renal colic ± hematuria — obstructive uropathy (aua stone 2016 pmid 27238616); hydronephrosis on bedside us / ct (kdigo 2012 aki).

2. Your medications

Take these medications exactly as prescribed. Do not stop or change a dose without talking to your provider.

Medication	Starting dose	How	When	What it does
foley_catheter	—	—	—	AUA BPH 2021 PMID 34384237 — foley relieves outlet obstruction immediately; document residual volume drained
percutaneous_nephrostomy	—	—	—	AUA Stone 2016 PMID 27238616 — PCN preferred over stent for infected obstruction + emergent decompression
retrograde_ureteral_stent	—	—	—	AUA Stone 2016 — equivalent to PCN for non-infected ureteral obstruction; preferred in pregnancy

Plan: Post-renal AKI — STAT decompression → underlying treatment → post-obstructive diuresis management → recovery (KDIGO 2012 AKI; AUA Stone 2016; AUA BPH 2021)

3. When to call your provider

Contact your care team if any of the following happen:

Sustained eGFR <60 at 3 mo → neph.ckd.core.v1 (KDIGO 2024 CKD)
Recurrent obstruction → repeat imaging + intervention (AUA Stone 2016)
RPF imaging progression on steroids → mycophenolate / tamoxifen alternative

4. When to seek emergency care

Call 911 or go to the nearest emergency room right away if you have:

Bilateral ureteral obstruction OR obstruction of solitary kidney — STAT decompression with PCN or retrograde stent (KDIGO 2012 AKI; AUA Stone 2016 PMID 27238616)(life-threatening)
BPH-associated acute urinary retention — palpable suprapubic bladder + post-void residual >300 mL + recent anticholinergic/decongestant/opioid exposure (AUA BPH 2021 PMID 34384237)
Pelvic / retroperitoneal malignancy with progressive ureteral compression (cervical, prostate, colorectal, bladder, lymphoma, retroperitoneal sarcoma) (KDIGO 2012 AKI)
Retroperitoneal fibrosis (Ormond disease) — periaortic soft tissue encasing ureters; idiopathic or secondary (IgG4-related, drug-induced ergot, malignancy) (KDIGO 2012 AKI)
Obstructive urolithiasis — colic + hydronephrosis + stone on CT KUB; infected stone is surgical emergency (AUA Stone 2016 PMID 27238616)
Iatrogenic ureteral injury — post-hysterectomy, colectomy, pelvic radiation, ureteroscopy; new oliguria + flank pain + urinoma (KDIGO 2012 AKI)
Fungus ball obstruction (typically Candida) in immunocompromised / chronic catheterization — hydronephrosis + funguria + AKI (KDIGO 2012 AKI)
Post-obstructive diuresis — UOP >200 mL/h × 2-3h post-decompression with electrolyte wasting (Na, K, Mg, PO4); replace 50-75% UOP with 0.45% NaCl (KDIGO 2012 AKI)

5. Follow-up

Urology / nephrology / oncology follow-up by phenotype; permanent monitoring of solitary kidney + bilateral obstruction risk; stone metabolic workup; BPH med-rec; review anticholinergic burden (AUA Stone 2016; AUA BPH 2021; KDIGO 2024 CKD)

6. Sources

Guideline: KDIGO 2012 AKI Guideline + AUA Surgical Management of Stones 2016 + AUA LUTS/BPH 2021 + STARRT-AKI / AKIKI for RRT timing