Urinary Tract Calculi Flashcards
Define Urinary Tract Calculi
Presence of crystalline stones (calculi) within the urinary system (kidneys and ureter)
(AKA Nephrolithiasis)
Aetiology of Urinary Tract Calculi and types
Urine supersaturation with stone-forming salts -> stone formation
Stones are crystalline mineral depositions that are from microscopic crystals in the loop of Henle, distal tubules or collecting duct.
- Response to elevated calcium, uric acid, oxalate, sodium
- Response to reduced citrate and magnesium
- Low urinary volume
Calcium oxolate (most common), uric acid, struvite, calcium phosphate, cystine, xanthine
Describe calcium oxalate stones (associated findings, urine pH, crystal appearancem radiopacity)
Most common
Associated with high calcium, oxolate and low citrate
Urine pH decreased
Biconcave dumbells or bipyramidal envelopes
Radiopaque
Describe uric acid stones (associated findings, urine pH, crystal appearancem radiopacity)
Associated with gout, hyperuricaemia, hyperuricosuria
Urine pH decreased
Rounded rhomboids or needle-shaped
Radiolucent
Describe struvite stones (associated findings, urine pH, crystal appearancem radiopacity)
Associated with UTI with urease-producing bacteria
Urine pH Increased
Rectangular prisms (coffin-lid appearance) STAG-HORN
Radiopaque
Describe cystine stones (associated findings, urine pH, crystal appearancem radiopacity)
associated with Cystinuria
urine pH decreased
Hexagon shaped
Weakly radiopaque
Describe calcium phosphate stones (associated findings, urine pH, crystal appearancem radiopacity)
Associated with Hyperparathyroidism
Urine pH Increased
Wedge shaped prism
Radiopaque
Symptoms of Urinary Tract Calculi
Loin to groin pain (sudden onset | sharp/dull ache | may radiate to scrotum/labium | constant/intermittent | 10/10)
Nausea and vomiting
Voiding symptoms (dribbling, hesitancy, intermittency, straining, dysuria)
Bladder stone/UTI: Dysuria | Frequency | Strangury | Penile tip pain
Ureter stone :Urinary retention
Fever
Signs of Urinary Tract Calculi on examination
Patient is restless and writhing/rolling in pain
Flank or loin tenderness
Sepsis: tachycardia, hypotension
Distended bladder (ureteric stones)
Investigations for Urinary Tract Calculi
Urgent non-contrast CT KUB: calcification seen, may see hydronephrosis
Pregnancy test: for those in child-bearing age
Urine dipstick and culture: leukocytes +, nitrates +, blood + | +ve for WBCs, RBCs or bacteria
U+Es: Hypercalcaemia suggests hyperparathyroidism | Hyperuricaemia suggests gout
FBC: may suggest infection e.g. pyelonephritis/UTI
CRP: raised
Coagulation panel: if PCI is planned
X-ray KUB: calcification seen
Renal USS: calcification seen + dilation (PREGNANT or CHILD)
Initial management for Urinary Tract Calculi
Symptomatic with
- Hydration
- Analgesia (NSAIDs, opiates)
- Anti-emetics (Diclofenac (esp. if renal colic)
Calculi <10mm -> reduce ureteric spasm:
CCB (nifedipine)
Alpha blocker (tamsulosin)
If no signs of infection and pain is not managed -> renal decompression
Post-care
Diet recommendations
Increase fluid intake, reduce salt and sugar intake
Management for Urinary Tract Calculi with signs and symptoms of infection
Immediate urologic consultation and renal decompression + empirical antibiotics
Management for Urinary tract stones that are not obstructing
- Hydration and analgesia (NSAID)
- Consider antibiotic therapy
<10mm - watchful waiting
>10mm - surgical intervention
Management for Urinary tract stones >10mm
- External shockwave lithotripsy (ESWL)
- Ureteroscopy if ESWL CI
- Percutaneous nephrolithotomy (PCNL) if above fails
Complications for Urinary Tract Calculi
Ureteric stricture
Acute or chronic pyelonephritis: potential of sepsis
Renal failure: obstruction and back pressure causing hydronephrosis and kidney damage
Intrarenal or perinephric abscess: complication of pyelonephritis, particularly if large “staghorn” stones are present
Xanthogranulomatous pyelonephritis
Urine extravasation into the pelvic cavity
