SU29.4-5 | Hydronephrosis and Renal Calculi — Summary & Reflection

KEY TAKEAWAYS

Hydronephrosis is dilatation of the renal pelvis and calyces from obstruction to urine flow; classify it by level — unilateral (ureteric: PUJ obstruction, calculus, stricture, tumour, retroperitoneal fibrosis) versus bilateral (outlet: BPH, urethral stricture, posterior urethral valves), with pregnancy a physiological cause. It may be silent or cause a loin ache or mass, and unrelieved obstruction thins the cortex and destroys function. Renal calculi are classified by composition: calcium oxalate is commonest (~70-80%, radiopaque); struvite is the infection/staghorn stone (urease-producing Proteus, alkaline urine); uric acid is radiolucent and dissolvable by alkalinisation; cystine is rare and inherited. Ureteric colic is severe colicky loin-to-groin pain in a restless patient with haematuria. Investigate with urinalysis and renal function, USG first-line, NCCT KUB as the gold standard for stones, and diuretic MAG3 renography to confirm true obstruction and split function. Management principles are relieve obstruction, treat the cause, preserve function: stones are managed by size — <5 mm pass with conservative care + medical expulsive therapy (tamsulosin), ESWL for smaller stones, URS+laser for ureteric stones, PCNL for >2 cm/staghorn/lower-pole — while hydronephrosis is treated by correcting its cause (e.g. pyeloplasty). The overriding rule: an obstructed, infected kidney is an emergency needing urgent decompression (nephrostomy/stent) + antibiotics before any definitive stone surgery.

REFLECT

Recall a patient you have seen with loin pain, or imagine clerking one on your next on-call. Did you establish the tempo and character of the pain — the restless, colicky loin-to-groin pain of a stone versus the dull dragging ache of a chronically obstructed kidney — and did you actively look for the red flags of an obstructed, infected system (fever, rigors, a toxic patient) that change everything? Consider the work-up: would you have chosen ultrasound first, reached for an NCCT KUB to find even a radiolucent stone, and known when a MAG3 renogram is needed to prove true obstruction and split function? And consider the decision that most often goes wrong under pressure: faced with an obstructed, septic patient, would you decompress and treat the infection before thinking about removing the stone? Reflect on how classifying obstruction by level and stones by composition turns a frightening presentation into an orderly plan.