Renal stone disease Flashcards
Magnesium ammonium phosphate
Struvite stones
Form staghorn stones
Infection with urease producing bacteria
Clinical features of patients with calculi- Renal
Pain (loin)
Haematuria (microscopic, or, rarely, macroscopic)
Recurrent UTI (struvite stones)
Malaise, weakness, loss of appetite
Clinical features of patients with calculi- Ureteric
Ureteric colic- loin to groin pain
Haematuria (microscopic usually)
Fever (suspect infection proximal to stone)
Clinical features of patients with calculi- Bladder
Suprapubic pain Haematuria Urgency + urge incontinence Recurrent UTI LUTS
CT-KUB
Diagnosis gold standard
99% diagnosed
Not operator dependent
Can give idea of hardness –> what treatments work
Detects= calcium phosphate>calcium oxalate>struvite>cysteine
Doesn’t detect uric acid
X ray KUB
Done after CT KUB to assess position
Renal ultrasound
Relatively sensitive (75%) for renal calculi and good if radiolucent (e.g. oxalate)
Operator dependent
Imaging modality of choice in pregnant + children
Intravenous Urogram
If done well can give size and position
Not used anymore
Small risk death contrast allergy
Tests for underlying conditions that increase stone risk
Type 1 RTA- Fasting morning urine=>5.5
Primary hyperparathyroidism= high PTH, adenoma/carcinoma/hyperplasia of thyroid gland
Cysteinuria= cyanide-nitroprusside spot test
Fluid intake
Increase fluid intake
–> decreases urine conc of solutes –> moves conc further from formation product
Oxalate
Lower oxalate intake
Avoid- rhubarb, spinach, swiss chard, beetroot
Moderate- berries, nuts, seeds, cocoa, choc, soy
Allow- carrots, apples, sprouts, leeks, broccoli, green beans
Meat- high oxalate but also high Ca so cancel each other out
Vitamin C
No more than 1 tablet a day
Urate
Lower intake
Avoid- meat, shellfish, beer, red wine
Calcium
Take calcium with high animal protein meals
Citrate
Increase
High fruit diet
Preventative drugs
Thiazides (reduce calciumuria) Potassium citrate Sodium bicarb Allopurinol Penicillamine
Drug treatments
Analgesics- NSAIDs- IM 75mg diclofenac
Fluids (if necessary)
Medical expulsive therapy- alpha blockers (Tamsulosin)- relax ureter, but may cause hypotension
Dissolution therapy:
–> urate stones- hydration, urine alkalisation, allopurinol, diet
–> cysteine stones= hydration, urine alkalisation, conversion cysteine to more soluble products
Extracorporeal shock wave lithotripsy
External application high frequency sound waves to stone
Breaks it up
Most effective stones <2cm + upper pole stones
Don’t do in- pregnancy, lower ureter stones, lower pole stones
Semi-rigid ureteroscopy (URS)
Telescope passed into ureter
Helps break up stone by laser fragmentation
Good for ureteric stones that don’t respond to ESWL
1st line for ureteric stones in pregnant women
Flexible ureterenoscopy
Telescope passed into ureter
Helps break up stone by laser fragmentation
Often used when EWSL not successful- large stones, lower pole stones, poor anatomical location of stone
Better than URS for stones higher in ureter as scope more flexible
Lower risk than PCNL
Percutaneous nephrolithotomy (PCNL)
Incision made in skin where straight telescope can be inserted into urological tract where stone can be broken + fragments removed
Recommended stones >3cm and those that have failed ESWL, FURS + laser
First line staghorn calculi
Lower ureteric stone
Medial expulsion therapy
If this fails, ESWL or utereroscopy
Middle ureteric stone
Medial expulsion therapy
ESWL impossible
If problematic, consider ureteroscopy
High ureteric stone
Medial expulsion therapy low in effectiveness as few alpha receptors
Lithotripsy
Can also consider ureteroscopy, FURS or PCNL
Renal stone
Small (<5mm) and asymptomatic stones can be observed
Lithotripsy if favourable location in kidney (upper pole) and small size (<2cm)
FURS, PCNL
URS no
Acidic urine
Urate stone will form
Diseases associated with Ca phosphate
Hyperparathyroidism
Type 1 RTA
Medullary sponge kidney
Causes for underlying predisposition to renal calculi
Hypercalcaemia Hyperoxaluria Hypocitraturia Hyperuricaemia Tamm-Horsfall protein mutation
