Flashcards in Renal Stones Deck (39):
Epidemiology of stone disease?
Peak incidence 30-50y
Risk of recurrence of renal stones at 1/5/lifetime?
10% recurrence at 1 year; 50% recurrence at 5 years; 60-80% lifetime risk.
Hereditary RFx for renal stones?
RTA, G6PD, cytinuria, xanthinuria, oxaluria.
Lifestyle RFx for renal stones?
minimal fluid intake; excess vitamin c, oxalate, purines, calcium, animal protein ++
Medications RFx for renal stones?
Loop diuretics (frusemide); acetzolamide, topiramate, zonisamide.
Medical conditions RFx for renal stones?
UTI (with urea-splitting organisms); myeloproliferative disorders, IBD, gout, DM, hypercalcaemia disorders, sarcoidosis, obesity (>30).
What causes pain in renal stones?
Urinary obstruction -> upstream distension -> pain.
-Flank pain from renal capsular distension (non-colicky)
-Severe waxing and waning pain radiating from flank to groin/testis/tip of penis due to stretching or collecting system or ureter (ureteral colic).
CFx of renal stones?
Storage and voiding LUTS; terminal haematuria; suprapubic pain.
-+/- trigonal irritation (F, U)
GU Ddx of renal colic?
-Ureteral obstruction of other cause (UPJ obstruction, clot colic 2" to gross haematuria)
-Gynaec: ectopic pregnancy, ovarian cyst torsion/rupture, PID.
Abdominal Ddx of renal colic?
-Other acute abdomen
Neurological Ddx of renal colic?
-Radiculitis (L1): herpes zoster, nerve root compression.
What are the narrow points for upper tract stones?
-Under Vas deferens/ broad ligament
Outline the features in pathogenesis of renal stones.
-Supersaturation of stone constituents
-Stasis, low flow and low volume (dehydration)
-Crystal formation and stone nidus
-Loss of inhibitory factors
Which factors inhibit stone formation?
-Citrate (forms soluble complex with calcium)
-Magnesium (forms soluble compound with oxalate)
Indications for hospital admission in renal stones?
-Intractable pain / vomiting
-Compromisesd renal fxn (single kidney, bilateral obstruction)
How should septic patients with stones be managed?
Urgent decompression via ureteric stent or percutaneous nephrostomy.
Delay definitive Rx until clearance of infection.
Ix in renal stones?
-Serum calcium and uric acid
-CT KUB (or CT IVP)
Acute medical management of renal stones?
-Analgesis +/- antiemetic
-Medical explulsion therapy
-IV fluids (if vomiting)
Why are NSAIDs used in renal stones in acute medical management?
Help lower intra-ureteral pressure
What is medical expulsion therapy?
-alpha blockers (increase rate of spontaneous passage in distal ureteral stones)
Indications for interventional management of renal stones?
-Infection / sepsis
-Inability to control Sx
-Spontaneous passage unlikely
Interventional options for management of renal stones?
-JJ stent and delayed management
-Ureteroscopy and lithotripsy
-Shock wave lithotripsy
What is first line treatment for ureteral stones >10mm?
Extracorporeal shock wave lithotripsy (ESWL)
Dietary modifications for prevention of renal stones?
-Increased fluid (>2L/day), K+ intake
-reduce animal protein, oxalate, Na+, sucrose, fructose intake
-avoid high dose vitamin C supplements
Medication alterations for prevention of renal stones?
-Thiazide diuretics for hypercalciuria
-Allopurinol for hyperuricosuria
-Potassium citrate for hypocitraturia, hypyeruricosuria
Features of calcium stones?
-Radioopaque on KUB
-Reducing dietary Ca2+ NOT an effective prevention method
Treatment of calcium stones
-Increase fluids >2L/d
Calcium stones: Cellulose phosphate, orthophosphate for absorptive causes
Calcium oxalate: thiazides, +/- potassium citrate +/- allopurinol.
Calcium struvite: ABx (must remove stone)
Aetiology of uric acid stones?
Uric acid precipitates in low volume, acidic urine with a high uric acid concentration.
Key features of uric acid stones on imaging?
-Radiolucent on KUB
-Radioopaque on CT
Treatment of uric acid stones?
-Increased fluid intake
-Akalinisation of urine to pH 6.5-7 (bicarb, potassium citrate)
-+/- allopurinol (if serum uric acid levels elevated)
Aetiology of struvite stones?
-Infection with urea splitting organisms (e.g. proteus, pseudomonas)
-Produces alkaline urinary pH and precipitation of struvite (magnesium ammonium phosphate)
Hx features to elicit in renal colic?
-?Previous episodes and outcomes
-Complicating factors: pregnancy, renal impairment
What proportion of renal stones are radiopaque?
Common cause of obstructive pylonephrosis?
Usually GNB (E.Coli)
Management of obstructive pyelonephrosis?
-IV Abx (G-ve and enterococcus coverage)
-Urgent decompression (nephrostomy, JJ stent)
-Supportive (fluids, monitoring, +/- ICU/HDU)
What does spontaneous passage of renal stone depend on?
-Max size in transverse plane
-PHx of stone passage
Explain physiology of medical expulsive therapy?
-Ureter wall contain a1 R that mediating SM contraction
-a-blockers relax ureteric wall
-stone pass inc by 30%
Medical expulsive therapy dose?
Tamsulosin 0.4mg OD x 2/52