MANAGING UROLITHIASIS
Dr Clarence Lei Chang Moh,
FRCS Urol, Consultant Urologist, Stone Centre, NMSC
clarencelei@gmail.com
Urinary stones affects 5-15% of populations, with a 50%
recurrence rate over 10 years. There is a slight world wide increase in stone
incidence. Managing urolithiasis is an important skill for all doctors. Diagnosis is usually with urinalysis, ultrasound,
plain Xray KUB & noncontrast low dose CT.
Prevention is as important as surgery. Ureteric colic is the most severe
pain
that men can ever experience and the usual analgesia is Diclofenac. However, if this is given
continuously for more than 48 hours, there is a nephrotoxic potential,
especially in patients who are dehydrated.
For small stones (< 6 mm) in the lower ureter, removal can be
facilitated by uroselective alpha-blockers (e.g. Tamsulosin, Alfuzosin). This
is now known as MET medical expulsive therapy! Stones <5mm by="" cause="" complicated="" do="" eventually="" intervention="" large="" not="" o:p="" require="" sepsis="" stones="" unless="" untreated="" urosepsis.="" usually="" whereas="">
The important medical treatment for urinary stones is that of water
therapy such that the patient produces 2 litres of urine per day. The fluid intake of the patient depends on his
environment. Ideally, such fluid should
be distributed throughout the day.
Uric acid stones can be effectively
dissolved by medical therapy by urinary
alkalinisation, keeping the urine pH at 7.0. Uric acid stones comprise about 20% stones
and are radiolucent on x-ray but readily seen on ultrasound and plain CT. Even
staghorn uric acid calculi can be dissolved over 6 months. However, the patient should have a good
renal function to avoid accumulation of the medications used e.g. potassium,
citrate, sodium (in Ural).
Potassium Citrate helps clear stones, eg post ESWL lower pole fragments. In one
study Potassium Citrate increased the stone-free rate to 45.5% from 12.5% in
control group, over a 12 month period.
The citrate in the urine reduces crystallization of calcium and uric
acid stones.
Stones associated with infection are called struvite
stones. Struvite stones are typically soft and faintly radiolucent. The
stone and infection should be cleared by surgery and vigorous antibiotic
therapy followed by prophylaxis at night for 6 months, including in children.
For patients who have underlying metabolic effects,
the benefit of the specific medications
may not justify the side effects and long term costs. The diet recommendations for patients with recurrent stone formation is
that of less salt, low oxalate, and normal calcium. Patients with uric acid
stones should take less uric acid in their diet e.g. red meat, nuts.
Open surgery for urinary stones now comprises <
5% of surgical treatment eg in large multiple bladder stones in boys, bulky
full staghorn kidney stones and giant ureteric stones. The later can also be removed by laparoscopic surgery. The
mainstay of stone surgery is endourology viz ureteroscopic lithotripsy, URS and
percutaneous nephrolithotripsy, PCNL.
URS has a successful outcome in >90% cases but can be hazardous in
the upper ureter. The main complications
of PCNL are bleeding & sepsis, occasionally fatal. Main energy sources for
lithotripsy include mechanical
(“Lithoclast”), ultrasonic and laser. In recent years equipments have become
smaller and better enabling miniPCNL, microPCNL and RIRS, retrograde
intrarenoscopy. ESWL, extra-corporeal
shockwave lithotripsy remains the most significant advance in stone treatment,
suitable for most upper urinary tract stones <20mm .="" achievable="" alara="" and="" as="" clearance.="" eg="" for="" in="" low="" management="" may="" must="" one="" radiation="" rather="" reasonably="" repeated="" require="" sessions="" some="" span="" stenting="" stones="" style="mso-spacerun: yes;" than="" the="" ultrasound="" ureteric="" use="" with=""> surgeon control of
fluoroscopy, protection for staff and patient.
Efficient and safe clearance of the stone, with followup preventive measures are needed for
proper management of urinary stones.
College of
Surgeons of Malaysia, Kuching, Annual Meeting, 25 May 2014, pages 45-46
