Approach to Ureteric Obstruction
A structured approach to ureteric obstruction sorts it along three axes — acute vs chronic, intrinsic vs extrinsic, unilateral vs bilateral — then asks whether the kidney/patient is threatened (infection, AKI, single kidney) to decide urgent drainage versus elective treatment of the cause.
The big picture
Ureteric obstruction blocks urine drainage and threatens the kidney behind it. Causes are intrinsic (stone, stricture, urothelial tumour, clot) or extrinsic (pelvic/retroperitoneal tumour, lymphadenopathy, retroperitoneal fibrosis, pregnancy, iatrogenic). It may be acute (sudden, painful) or chronic (insidious, often painless), and unilateral (the other kidney compensates) or bilateral/solitary (causes acute kidney injury).
Classify (acute/chronic, intrinsic/extrinsic, unilateral/bilateral), prove obstruction and function, and decompress urgently when infected/AKI/solitary — otherwise treat the cause electively.
Red flags
Emergency — urgent decompression (stent/nephrostomy) + antibiotics; treat the cause later.
Urgent drainage to protect/restore function; anticipate post-obstructive diuresis.
Easily missed — chronic obstruction can silently destroy function.
Symptom sorter
Tempo + symptoms.
Diagnostic algorithm
Each step answers one question. Tap to expand.
Treatment ladder
Relieve obstruction urgently when the kidney or patient is threatened; otherwise define and treat the underlying cause electively, protecting renal function.
Complications
- Renal impairment/loss, infection (pyonephrosis), urosepsis
- Stent/nephrostomy complications; post-obstructive diuresis
- Prove obstruction; decompress threatened systems promptly; treat cause
- Decompress emergencies; manage diuresis; treat the cause
Summary tables
Ureteric obstruction framework
| Axis / question | Implication |
|---|---|
| Acute vs chronic | Tempo and symptoms; chronic can be silent |
| Intrinsic vs extrinsic | Stone/stricture/tumour vs compression/fibrosis |
| Unilateral vs bilateral/solitary | Bilateral/solitary → AKI, urgent |
| Threatened (infection/AKI/solitary)? | Yes → decompress; No → treat cause electively |
Memory hooks
Classify: acute/chronic, intrinsic/extrinsic, unilateral/bilateral.
Prove obstruction + function (renogram).
Infected/AKI/solitary → decompress now.
Otherwise treat the cause electively.
Expect post-obstructive diuresis after relief.
Board traps
Infected obstruction → drain first, treat cause later.
Bilateral/solitary obstruction → AKI, urgent.
Unilateral obstruction can have normal renal function.
Clinical cases
A patient with an obstructing ureteric stone develops fever, rigors and hypotension; imaging shows hydronephrosis with pus.
What is the priority?
An asymptomatic patient is found to have bilateral hydronephrosis and a raised creatinine, with extrinsic compression of both ureters by a pelvic mass.
How is this approached?