GUIDELINES ON UROLITHIASIS

(Limited update April 2014)

C. Türk (chair), T. Knoll (vice-chair), A. Petrik, K. Sarica, C. Seitz,

A. Skolarikos, M. Straub

Classification of stones
Urinary stones can be classified according to the following
aspects: stone size, stone location, X-ray characteristics
of stone, aetiology of stone formation, stone composition
(mineralogy), and risk group for recurrent stone formation
(Tables 1-3).

Table 1: X-ray characteristics

Radiopaque Poor radiopaque Radiolucent
Calcium oxalate Magnesium Uric acid
dihydrate ammonium phos-
phate
Calcium oxalate Apatite Ammonium urate
monohydrate
Calcium phos- Cystine Xanthine
phates
2,8-dihydroxyade-
nine
‘Drug-stones’

308 Urolithiasis
Table 2: Stones classified according to their aetiology
Non infection Infection Genetic Drug stones
stones stones stones
Calcium Magnesium Cystine e.g. indinavir
oxalates ammonium (see extended
phosphate document)
Calcium Carbonate Xanthine
phosphates apatite
Uric acid Ammonium 2,8-dihydroxy-
urate adenine

Table 3: Stones classified by their composition

Chemical composition Mineral
Calcium oxalate monohydrate whewellite
Calcium-oxalate-dihydrate wheddelite
Uric acid dihydrate uricite
Ammonium urate
Magnesium ammonium phosphate struvite
Carbonate apatite (phosphate) dahllite
Calcium hydrogenphosphate brushite
Cystine
Xanthine
2,8-dihydroxyadenine
‘Drug stones’

Risk groups for stone formation

The risk status of a stone former is of particular interest as it
defines both probability of recurrence or (re)growth of stones
and is imperative for pharmacological treatment.

Urolithiasis 309
 Table 4: High risk stone formers
General factors
Early onset of urolithiasis in life (especially children and
teenagers)
Familial stone formation
Brushite containing stones (calcium hydrogen phosphate;
CaHPO4.2H2O)
Uric acid and urate containing stones
Infection stones
Solitary kidney (The solitary kidney itself does not present
an increased risk of stone formation, but prevention of stone
recurrence is more important)
Diseases associated with stone formation
Hyperparathyroidism
Nephrocalcinosis
Gastrointestinal diseases or disorders (e.g. jejuno-ileal
bypass, intestinal resection, Crohn’s disease, malabsorptive
conditions, enteric hyperoxaluaria after urinary diversion and
bariatric surgery)
Sarcoidosis
Genetically determined stone formation
Cystinuria (type A, B, AB)
Primary hyperoxaluria (PH)
Renal tubular acidosis (RTA) type I
2,8-dihydroxyadenine
Xanthinuria
Lesch-Nyhan-Syndrome
Cystic fibrosis
Drugs associated with stone formation (see Chapter 11
extended text)

310 Urolithiasis
Anatomical abnormalities associated with stone formation
Medullary sponge kidney (tubular ectasia)
UPJ obstruction
Calyceal diverticulum, calyceal cyst
Ureteral stricture
Vesico-uretero-renal reflux
Horseshoe kidney
Ureterocele

DIAGNOSIS
Diagnostic imaging
Standard evaluation of a patient includes taking a detailed
medical history and physical examination. The clinical diagno-
sis should be supported by appropriate imaging.

Recommendation LE GR
With fever or solitary kidney, and when diagno- 4 A*
sis is doubtful, immediate imaging is indicated.
*Upgraded following panel consensus.

If available, ultrasonography should be used as the primary

diagnostic imaging tool although pain relief, or any other
emergency measures should not be delayed by imaging
assessments. KUB should not be performed if non-contrast
enhanced computed tomography (NCCT) is considered, but
KUB can differentiate between radiolucent and radiopaque
stones and serve for comparison during follow-up.

Evaluation of patients with acute flank pain

Recommendation LE GR
NCCT should be used to confirm stone diagno- 1a A
sis in patients with acute flank pain, because it
is superior to IVU.

Urolithiasis 311
 Some drug stones like indinavir stones are not detectable on
NCCT.

Recommendation LE GR
A renal contrast study (enhanced CT or IVU) 3 A*
is indicated when planning treatment for renal
stones.
*Upgraded following panel consensus.

Biochemical work-up
Each emergency patient with urolithiasis needs a succinct
biochemical work-up of urine and blood besides imaging
studies; no difference is made between high- and low-risk
patients.

Recommendations: Basic analysis emergency stone patient

Urine GR
Urinary sediment/dipstick test out of spot urine sam- A*
ple for: red cells / white cells / nitrite / urine pH level by
approximation.
Urine culture or microscopy. A
Blood
Serum blood sample creatinine / uric acid / ionized A*
calcium / sodium / potassium / CRP.
Blood cell count. A*
If intervention is likely or planned: Coagulation test A*
(PTT and INR).
*Upgraded following panel consensus.

Examination of sodium, potassium, CRP, and blood coagula-

tion time can be omitted in the non-emergency stone patient.

Patients at high risk for stone recurrences should undergo a

312 Urolithiasis
more specific analytical programme (see section on Metabolic
Evaluation below).

Analysis of stone composition should be performed in all first-

time stone formers (GR: A) and will need redoing if changes
are expected. The preferred analytical procedures are:
• X-ray diffraction (XRD)
• Infrared spectroscopy (IRS)
Wet chemistry is generally deemed to be obsolete.

Acute treatment of a patient with renal colic

Pain relief is the first therapeutic step in patients with an
acute stone episode.

Recommendations for pain relief during and LE GR

prevention of recurrent renal colic
First choice: start with an NSAID, e.g. 1b A
diclofenac*, indomethacin or ibuprofen.**
Second choice: hydromorphine, pentazocine 4 C
and tramadol.
Use a-blockers to reduce recurrent colic. 1a A
GFR = glomerular filtration rate; NSAID = non-steroidal anti-
inflammatory drug.
*Caution: Diclofenac sodium affects GFR in patients with
reduced renal function, but not in patients with normal renal
function (LE: 2a).
** Recommended to counteract recurrent pain after renal
colic (see extended document section 5.3).

If analgesia cannot be achieved medically, drainage, using

stenting or percutaneous nephrostomy, or stone removal,
should be performed.

Management of sepsis in the obstructed kidney

The obstructed, infected kidney is a urological emergency.

Urolithiasis 313
 Recommendations LE GR
For sepsis with obstructing stones, the collect- 1b A
ing system should be urgently decompressed,
using either percutaneous drainage or ureteral
stenting.
Definitive treatment of the stone should be 1b A
delayed until sepsis is resolved.

In exceptional cases, with severe sepsis and/or the formation

of abscesses, an emergency nephrectomy may become nec-
essary.

Recommendations - Further Measures GR

Collect urine for antibiogram following decompres- A*
sion.
Start antibiotics immediately thereafter (+ intensive
care if necessary).
Revisit antibiotic treatment regimen following antibio-
gram findings.
* Upgraded based on panel consensus.

Stone relief
When deciding between active stone removal and conserva-
tive treatment using MET, it is important to consider the
individual circumstances of a patient that may affect treat-
ment decisions.

314 Urolithiasis
Observation of ureteral stones
Recommendations LE GR
In patients with newly diagnosed ureteral 1a A
stones < 10 mm, and if active stone removal is
not indicated, observation with periodic evalua-
tion is optional initial treatment.
Such patients may be offered appropriate medi-
cal therapy to facilitate stone passage during
observation*.
*see also Section MET.

Observation of kidney stones

It is still debatable whether kidney stones should be treated,
or whether annual follow-up is sufficient for asymptomatic
caliceal stones that have remained stable for 6 months.

Recommendations GR
Kidney stones should be treated in case of growth, for- A
mation of de novo obstruction, associated infection,
and acute and/or chronic pain.
Comorbidity and patient preference need to be taken C
into consideration when making treatment decisions.
If kidney stones are not treated, periodic evaluation is A
needed.
* Upgraded following panel consensus.

Medical expulsive therapy (MET)

For patients with ureteral stones that are expected to pass
spontaneously, NSAID tablets or suppositories and α-blockers
may help to reduce inflammation and the risk of recurrent
pain.

Urolithiasis 315
 Recommendations for MET LE GR
For MET, a-blockers are recommended. A
Patients should be informed about the attend- A*
ant risks of MET, including associated drug side
effects, and should be informed that it is admin-
istered as ‘off-label’**.
Patients, who elect for an attempt at sponta- A
neous passage or MET, should have well-con-
trolled pain, no clinical evidence of sepsis, and
adequate renal functional reserve.
Patients should be followed to monitor stone 4 A*
position and to assess for hydronephrosis.
*Upgraded following panel consensus.
**MET using α-blockers in children and during pregnancy can-
not be recommended due to the limited data in this specific
population.

Statements LE
There is good evidence that MET accelerates sponta- 1
neous passage of ureteral stones and fragments gen-
erated with SWL limits pain.
No recommendation for the use of corticosteroids in 1b
combination with a-blockers in MET can be made, due
to limited data.
SWL = shock wave lithotripsy.

Chemolytic dissolution of stones

Oral or percutaneous irrigation chemolysis of stones can be
a useful first-line therapy or an adjunct to SWL, PNL, URS, or
open surgery to support elimination of residual fragments.
However, its use as first-line therapy may take weeks to be
effective.

316 Urolithiasis
Percutaneous irrigation chemolysis

Recommendations GR
In percutaneous chemolysis, at least two nephrosto- A
my catheters should be used to allow irrigation of the
renal collecting system, while preventing chemolytic
fluid draining into the bladder and reducing the risk of
increased intrarenal pressure*.
Pressure- and flow-controlled systems should be used
if available.
* Alternatively, one nephrostomy catheter with a JJ stent and
bladder catheter can serve as a through-flow system pre-
venting high pressure.

Methods of percutaneous irrigation chemolysis

Percutaneous irrigation chemolysis is rarely used; it may be
an option for infection stones (using 10% Hemiacidrin at a pH
of 3,5 -4) and for uric acid and cystine stones (using THAM
[Trihydroxymethylaminomethan], 0.3 or 0.6mol/L, pH 8.5-9.0).

For uric acid stones oral chemolysis is preferred.

Oral chemolysis
Oral chemolitholysis is efficient for uric acid calculi only. The
urine pH should be adjusted to between 6.5 and 7.2.

Recommendations GR
The dosage of alkalising medication must be modified A
by the patient according to the urine pH, which is a
direct consequence of the alkalising medication.
Dipstick monitoring of urine pH by the patient is A
required at regular intervals during the day. Morning
urine must be included.

Urolithiasis 317
 Careful monitoring of radiolucent stones during/after A
therapy is imperative.
The physician should clearly inform the patient of the A
significance of compliance.

SWL
The success rate for SWL will depend on the efficacy of the
lithotripter and on:
• size, location (ureteral, pelvic or calyceal), and composition
(hardness) of the stones;
• patient’s habitus;
• performance of SWL.

Contraindications of SWL
Contraindications to the use of SWL are few, but include:
• pregnancy;
• bleeding diatheses;
• uncontrolled urinary tract infections (UTIs);
• severe skeletal malformations and severe obesity, which
prevent targeting of the stone;
• arterial aneurism in the vicinity of the stone;
• anatomical obstruction distal of the stone.

Stenting prior to SWL

Kidney stones
A JJ stent reduces the risk of renal colic and obstruction, but
does not reduce formation of steinstrasse or infective compli-
cations.

Recommendation - stenting & SWL LE GR

Routine stenting is not recommended as part of 1b A
SWL treatment of ureteral stones.
SWL = shock wave lithotripsy.

318 Urolithiasis
Best clinical practice (best performance)
Pacemaker
Patients with a pacemaker can be treated with SWL, provided
that appropriate technical precautions are taken; patients
with implanted cardioverter defibrillators must be managed
with special care (firing mode temporarily reprogrammed
during SWL treatment). However, this might not be necessary
with new-generation lithotripters.

Recommendation - Shock wave rate LE GR

The optimal shock wave frequency is 1.0 1a A
(to 1.5) Hz.

Number of shock waves, energy setting and repeat treatment

sessions
• The number of shock waves that can be delivered at each
session depends on the type of lithotripter and shockwave
power.
• Starting SWL on a lower energy setting with step-wise
power (and SWL sequence) ramping prevents renal injury.
• Clinical experience has shown that repeat sessions are fea-
sible (within 1 day for ureteral stones).

Procedural control
Results of treatment are operator dependent. Careful imaging
control of localisation will contribute to outcome quality.

Pain control
Careful control of pain during treatment is necessary to limit
pain-induced movements and excessive respiratory excur-
sions.

Antibiotic prophylaxis
No standard prophylaxis prior to SWL is recommended.

Urolithiasis 319
 Recommendation LE GR
In case of infected stones or bacteriuria, 4 C
antibiotics should be given prior to SWL.
SWL = shock wave lithotripsy.

Medical expulsive therapy (MET) after SWL can expedite

expulsion and enhance stone-free rates.

Percutaneous nephrolitholapaxy (PNL)

Recommendations GR
Ultrasonic, ballistic and Ho:YAG devices are recom- A*
mended for intracorporeal lithotripsy using rigid
nephroscopes.
When using flexible instruments, the Ho:YAG laser is
currently the most effective device available.
* Upgraded following panel consensus.

Best clinical practice

Contraindications:
• all contraindications for general anaesthesia apply;
• untreated UTI;
• atypical bowel interposition;
• tumour in the presumptive access tract area;
• potential malignant kidney tumour;
• pregnancy.

Recommendation - Preoperative imaging GR

Preprocedural imaging, including contrast medium A*
where possible or retrograde study when starting the
procedure, is mandatory to assess stone comprehen-
siveness, view the anatomy of the collecting system,
and ensure safe access to the kidney stone.
* Upgraded based on panel consensus.

320 Urolithiasis
Positioning of the patient: prone or supine?
Traditionally, the patient is positioned prone for PNL, supine
position is also possible, showing advantages in shorter oper-
ating time, the possibility of simultaneous retrograde transure-
thral manipulation, and easier anaesthesia. Disadvantages
are limited manoeuvrability of instruments and the need of
appropriate equipment.

Nephrostomy and stents after PNL

Recommendation LE GR
In uncomplicated cases, tubeless (without 1b A
nephrostomy tube) or totally tubeless (without
nephrostomy tube and without ureteral stent)
PNL procedures provide a safe alternative.

Ureterorenoscopy (URS)
(including retrograde access to renal collecting system)

Best clinical practice in URS

Before the procedure, the following information should be
sought and actions taken (LE: 4):
• Patient history;
• physical examination (i.e. to detect anatomical and con-
genital abnormalities);
• thrombocyte aggregation inhibitors/anticoagulation (anti-
platelet drugs) treatment should be discontinued. However,
URS can be performed in patients with bleeding disorders,
with only a moderate increase in complications;
• imaging.

Recommendation GR
Short-term antibiotic prophylaxis should be adminis- A*
tered.

Urolithiasis 321
 Contraindications
Apart from general considerations, e.g. with general anaes-
thesia or untreated UTIs, URS can be performed in all patients
without any specific contraindications.

Access to the upper urinary tract

Most interventions are performed under general anaesthesia,
although local or spinal anaesthesia are possible. Intravenous
sedation with miniaturized instruments is especially suitable
for female patients with distal ureteral stones. Antegrade URS
is an option for large, impacted proximal ureteral calculi.

Safety aspects
Fluoroscopic equipment must be available in the operating
room. If ureteral access is not possible, the insertion of a
JJ stent followed by URS after a delay of 7-14 days offers an
appropriate alternative to dilatation.

Recommendation GR
Placement of a safety wire is recommended. A*
*Upgraded following panel consensus.

Ureteral access sheaths

Hydrophilic-coated ureteral access sheaths (UAS), can be
inserted via a guide wire, with the tip placed in the proximal
ureter. Ureteral access sheaths allow easy multiple access to
the upper urinary tract and therefore significantly facilitate
URS. The use of UAS improves vision by establishing a con-
tinuous outflow, decrease intrarenal pressure and potentially
reduce operating time.

Stone disintegration and extraction

The aim of endourological intervention is complete stone
removal. ‘Smash and go’ strategies should be limited to the
treatment of large renal stones. For flexible URS (RIRS) only

322 Urolithiasis
baskets made of Nitinol are suitable.

Recommendations LE GR
Stone extraction using a basket without endo- 4 A*
scopic visualisation of the stone (blind basket-
ing) should not be performed.
Ho:YAG laser lithotripsy is the preferred method 3 B
for (flexible) URS.
*Upgraded following panel consensus.

Stenting before and after URS

Pre-stenting facilitates ureteroscopic management of stones,
improves the stone-free rate, and reduces complications.
Following URS, stents should be inserted in patients who are
at increased risk of complications.

Recommendations LE GR
In uncomplicated URS, a stent need not be 1a A
inserted.
An α-blocker can reduce stent-related symp- 1a
toms

Open surgery
Most stones should be approached primarily with PNL, URS,
SWL, or a combination of these techniques. Open surgery may
be a valid primary treatment option in selected cases.

Indications for open surgery:

• Complex stone burden
• Treatment failure of SWL and/or PNL, or URS
• Intrarenal anatomical abnormalities: infundibular steno-
sis, stone in the calyceal diverticulum (particularly in an
anterior calyx), obstruction of the ureteropelvic junction,
stricture if endourologic procedures have failed or are not
promising

Urolithiasis 323
 • Morbid obesity
• Skeletal deformity, contractures and fixed deformities of
hips and legs
• Comorbidity
• Concomitant open surgery
• Non-functioning lower pole (partial nephrectomy), non-
functioning kidney (nephrectomy)
• Patient choice following failed minimally invasive proce-
dures; the patient may prefer a single procedure and avoid
the risk of needing more than one PNL procedure
• Stone in an ectopic kidney where percutaneous access
and SWL may be difficult or impossible
• For the paediatric population, the same considerations
apply as for adults.

Laparoscopic surgery
Indications for laparoscopic kidney-stone surgery include:
• complex stone burden;
• failed previous SWL and/or endourological procedures;
• anatomical abnormalities;
• morbid obesity;
• nephrectomy in case of non-functioning kidney.

Indications for laparoscopic ureteral stone surgery include:

• large, impacted stones;
• multiple ureteral stones;
• in cases of concurrent conditions requiring surgery;
• when other non-invasive or low-invasive procedures have
failed.

If indicated, for upper ureteral calculi, laparoscopic urolithomy

has the highest stone-free rate compared to URS and SWL
(LE: 1a).

324 Urolithiasis
Recommendations LE GR
Laparoscopic or open surgical stone removal 3 C
may be considered in rare cases where SWL,
URS, and percutaneous URS fail or are unlikely
to be successful.
When expertise is available, laparoscopic sur- 3 C
gery should be the preferred option before pro-
ceeding to open surgery. An exception is com-
plex renal stone burden and/or stone location.
For ureterolithotomy, laparoscopy is recom- 2 B
mended for large impact stones or when endo-
scopic lithotripsy or SWL have failed.

Indication for active stone removal and selection of

procedure
Ureter:
• stones with a low likelihood of spontaneous passage;
• persistent pain despite adequate pain medication;
• persistent obstruction;
• renal insufficiency (renal failure, bilateral obstruction, sin-
gle kidney).
Kidney:
• stone growth;
• stones in high-risk patients for stone formation;
• obstruction caused by stones;
• infection;
• symptomatic stones (e.g. pain, haematuria);
• stones > 15 mm;
• stones < 15 mm if observation is not the option of choice;
• patient preference (medical and social situation);
• comorbidity;
• choice of treatment.
The suspected stone composition might influence the choice
of treatment modality.

Urolithiasis 325
 Recommendations GR
For asymptomatic caliceal stones in general, active C
surveillance with an annual follow-up of symptoms
and stone status (KUB, ultrasonography [US], NCCT)
is an option for 2-3 years, whereas intervention should
be considered after this period provided patients are
adequately informed.
Observation might be associated with a greater risk of
necessitating more invasive procedures.

STONE REMOVAL

Recommendations GR
Urine culture or urinary microscopy is mandatory A*
before any treatment is planned and urinary infection
should be treated ahead of stone removal.
In patient at high risk for complications (due to anti- B
thrombotic therapy) in the presence of an asympto-
matic caliceal stone, active surveillance should be
offered.
Temporary discontinuation, or bridging of antithrom- B
botic therapy in high-risk patients, should be decided
in consultation with the internist.
Antithrombotic therapy should be stopped before B
stone removal after weighting the thrombotic risk.
If stone removal is essential and antithrombotic A*
therapy cannot be discontinued,  retrograde (flexible)
ureterorenoscopy is the preferred approach since it is
associated with less morbidity.
*Upgraded based on panel consensus.

Radiolucent uric acid stones, but not sodium urate or ammo-

nium urate stones, can be dissolved by oral chemolysis.

326 Urolithiasis
Selection of procedure for active removal of renal
stones**

Fig. 1: Treatment algorithm for renal calculi

Kidney stone
(all but lower pole stone 10-20 mm)

> 20 mm 1. PNL
2. RIRS or SWL

10-20 mm SWL or Endourology*

1. SWL or RIRS
< 10 mm 2. PNL

Lower pole stone

> 20 mm and < 10 mm: like above

SWL or Endourology
Yes
Favourable
10-20 mm factors for
SWL***
No 1. Endourology
2. SWL

* Flexible URS is used less as first-line therapy for renal stones

> 1.5 cm.
** The ranking of the recommendations reflects a panel
majority vote.
*** see Table 19 extended document.
Urolithiasis 327
 Selection of procedure for active stone removal of
ureteral stones (GR: A*)
Stone location and size First choice Second choice
Proximal ureter < 10 mm SWL URS
Proximal ureter > 10 mm URS (retrograde or antegrade)
or SWL
Distal ureter < 10 mm URS or SWL
Distal ureter > 10 mm URS SWL
*Upgraded following panel consensus.

Recommendation GR
Percutaneous antegrade removal of proximal ureteral A
stones is an alternative when SWL is not indicated
or has failed, and when the upper urinary tract is not
amenable to retrograde URS.
SWL = shock wave lithotripsy; URS =ureterorenoscopy.

Steinstrasse
Steinstrasse occurs in 4% to 7% of cases after SWL, the major
factor in steinstrasse formation is stone size.

Recommendations LE GR
Medical expulsion therapy increases the stone 1b A
expulsion rate of steinstrasse.
PCN is indicated for steinstrasse associated 4 C
with UTI/fever.
SWL is indicated for steinstrasse when large 4 C
stone fragments are present.
Ureteroscopy is indicated for symptomatic 4 C
steinstrasse and treatment failure.

328 Urolithiasis
Residual stones

Recommendations LE GR
Identification of biochemical risk factors and 1b A
appropriate stone prevention is particularly
indicated in patients with residual fragments or
stones.
Patients with residual fragments or stones 4 C
should be followed up regularly to monitor dis-
ease course.
After SWL and URS, MET is recommended using 1a A
an a-blocker to improve fragment clearance.
For well-disintegrated stone material in the 1a B
lower calix, an inversion therapy with simultane-
ous mechanical percussion manoeuvre under
enforced diuresis may facilitate stone clearance.
SWL = shock wave lithotripsy; URS = ureterorenoscopy; MET =
medical expulsion therapy.

The indication for active stone removal and selection of the

procedure is based on the same criteria as for primary stone
treatment and also includes repeat SWL.

Management of urinary stones and related problems

during pregnancy

Recommendations LE GR
US is the method of choice for practical and 1a A
safe evaluation of pregnant women.
Conservative management should be the first- A
line treatment for all non-complicated cases
of urolithiasis in pregnancy (except those that
have clinical indications for intervention).

Urolithiasis 329
 If intervention becomes necessary, placement 3
of an internal stent, percutaneous nephrostomy,
or ureteroscopy are treatment options.
URS is a reasonable alternative to avoid long- 2a
term stenting/drainage.
Regular follow-up until final stone removal is
necessary due to higher encrustation tendency
of stents during pregnancy.
URS = ureterorenoscopy; US = ultrasound.

Pregnancy remains an absolute contraindication for SWL.

Management of stone problems in children

Spontaneous passage of a stone and of fragments after SWL
is more likely to occur in children than in adults (LE: 4). For
paediatric patients, the indications for SWL and PNL are
similar to those in adults, however they pass fragments more
easily. Children with renal stones with a diameter up to 20 mm
(~300 mm2) are ideal candidates for SWL.

Recommendations GR
Ultrasound evaluation is the first choice for imaging in A*
children and should include the kidney, filled bladder
and adjoining portions of the ureter.
If US does not provide the required information, KUB B
radiography (or NCCT) should be performed.
In all paediatric patients all efforts should be made to A
collect stone material for analysis, followed by
complete metabolic evaluation.
*Upgraded from B following panel consensus.
KUB = kidney ureter bladder; NCCT = non-contrast enhanced
computed tomography; US = ultrasound.

330 Urolithiasis
Table 5: Stones in exceptional situations

Caliceal diverticulum SWL, PNL (if possible) or RIRS

stones (retrograde intrarenal surgery via
flexible ureteroscopy).
Can also be removed using
laparoscopic retroperitoneal
surgery.
Patients may become asympto-
matic due to stone disintegra-
tion (SWL) whilst well-disinte-
grated stone material remains in
the original position.
Horseshoe kidneys Can be treated in line with
the stone treatment options
described above.
Passage of fragments after SWL
might be poor.
Stones in pelvic kidneys SWL, RIRS or laparoscopic sur-
gery
For obese patients, the options
are SWL, PNL, RIRS or open
surgery
Stones in transplanted PNL, (flexible) URS, SWL.
kidneys Metabolic evaluation based on
stone analysis
Stones formed in urinary Individual management
division necessary.
For smaller stones SWL is
effective.
PNL and antegrade flexible URS
frequently used .

Urolithiasis 331
 Stones formed in a conti- Present a varied and often dif-
nent reservoir ficult problem.
Each stone problem must be
considered and treated individu-
ally.
Stones in patients with All methods apply based on indi-
neurogenic bladder dis- vidual situation.
order Careful patient follow up and
preventive strategies are impor-
tant.
In myelomeningocele-patients,
latex allergy is common, appro-
priate measures needed.
Patients with obstruc- PNL followed by percutaneous
tion of the ureteropelvic endopyelotomy or open/laparo-
junction which needs cor- scopic surgery, or URS together
rection endopyelothomy with Ho:YAG.
Incision with an Acucise balloon
catheter might be considered,
provided the stones can be
prevented from falling into the
pelvo-ureteral incision.

332 Urolithiasis
Metabolic evaluation and recurrence prevention
Stone prevention is based on a reliable stone analysis and
basic analysis as mentioned above. Every patient should be
assigned to the low- or high risk group for stone formation. For
both groups general preventive measures apply:

Fluid intake (drinking Fluid amount: 2.5-3.0 L/day

advice) Circadian drinking
Neutral pH beverages
Diuresis: 2.0-2.5 L/day
Specific weight of urine: < 1010
Nutritional advice for Balanced diet*
a balanced diet Rich in vegetable and fibre
Normal calcium content: 1-1.2 g/day
Limited NaCl content: 4-5 g/day
Limited animal protein content: 0.8-
1.0 g/kg/day
Lifestyle advice to BMI: 18-25 kg/m2 (adults)
normalise general Stress limitation measures
risk factors Adequate physical activity
Balancing of excessive fluid loss

For patients assigned to the high risk group of stone formers

specific laboratory analysis of blood and urine including two
consecutive 24-hour urine samples are necessary. For the
specific metabolic work-up, the patient should stay on a self-
determined diet under normal daily conditions and should ide-
ally be stone free for at least 20 days, better 3 months. These
findings are the basis for further recommendations:

Urolithiasis 333
 Recommendations for a specific diet LE GR
Hyperoxaluria Oxalate restriction 2b B
High sodium excretion Restricted intake of 1b A
salt
Small urine volume Increased fluid intake 1b A
Urea level indicating a Avoid excessive intake 1b A
high intake of animal of animal protein
protein

Recommendations for specific pharmacological treatment

Urinary risk factor Suggested treatment LE GR
Hypercalciuria Thiazide + potassium 1a A
citrate
Hyperoxaluria Oxalate restriction 2b A
Enteric hyperoxaluria Potassium citrate 3-4 C
Calcium supplement 2 B
Oxalate absorption 3 B
Hypocitraturia Potassium citrate 1b A
Sodium bicarbonate 1b A
when intolerance to
potassium citrate
Hyperuricosuria Allopurinol 1b A

Calcium oxalate stones

(Hyperparathyreoidism excluded by blood examination)

334 Urolithiasis
 Calcium oxalate stone

Basic evaluation

24 h urine collection

Hypercalcuria Hypercitraturia Hyperoxaluria Hyperuricosuria Hypomagnesuria

oxalate stones

Hyperuricosuria and
5-8 mmol/d2 > 8 mmol/d < 2.5 mmol/d > 5 mmol/d > 1 mmol/d > 4 mmol/d < 3 mmol/d
Hyperuricemia > 380 µmol

Hydrochlorothiazide Alcaline Calcium > 500 Pyridoxine Alkaline Citrate Magnesium

Alcaline Citrate Alkaline Citrate 200-400 mg/d3
Initially 25 mg/d Citrate mg/d1 Initial 5 mg/kg/d 9-12 g/d
9-12 g/d 9-12 g/d
Up to 50 mg/d 9-12 g/d 200-400 mg/d Up to 20 mg/kg/d PLUS
or or
Sodium Allopurinol
Sodium
Bicarbonate 100-300 mg/d4
Bicarbonate
1.5 g tid2,4 1.5 g tid2
PLUS
Allopurinol
100 mg/d
Fig. 2: Diagnostic and therapeutic algorithm for calcium

Urolithiasis 335
 Calcium phosphate
stones

336 Urolithiasis
Carbonate apatite
Brushite stones
stones
phosphate stones

Basic evaluation Basic evaluation

Calcium phosphate stones

Hypercalciuria Elevated calcium

Urinary pH > 5.8 Exclude HPT Exclude RTA
> 8 mmol/d exclude HPT

Hydrochlorothiazide
Hypercalciuria
initially 25 mg/d Exclude RTA Exclude UTI
> 8 mmol/d
up to 50 mg/d

Adjust urinary pH Hydrochlorothiazide

initially 25 mg/d
Fig. 3: Diagnostic and therapeutic algorithm for calcium

between 5.8 and 6.2 with

L-methionine up to 50 mg/d
200-500 mg 3 times daily
Hyperparathyroidism
Elevated levels of ionized calcium in serum (or total calcium
and albumin) require assessment of intact parathyroid hor-
mone (PTH) to confirm or exclude suspected hyperparathy-
roidism (HPT). Primary HTP can only be cured by surgery.

Uric acid and ammonium urate stones

Fig 4: Diagnostic and therapeutic algorithm for uric acid and

ammonium urate stones.

Urate containing stones

Urid acid stone Ammonium urate stone

Basic evaluation Basic evaluation

Urine
“Uric acid arrest” Hyperuricosuria pH > 6.5
Urine pH < 6
L-methionine
UTI 200-500 mg tid
> 4.0 mmol/d > 4.0 mmol/d
Alcaline citrate Target urine-pH
and 5.8-6.2
9-12 g/d2
Hyperuricemia
Or Antibiotics
Allopurinol > 380 µmol
Sodium Correction of
bicarbonate 100 mg/d factors
1.5 g tid predisposing
amm.urate stone
Allopurinol
formation
100-300 mg/d
Dose depends on
targeted urine pH

Prevention Chemolytholisis
urine pH 6.2-6.8 urine pH 6.5-7.2

Urolithiasis 337
 Fig 5: Metabolic management of cystine stones.

Cystine stones

Basic evaluation

Appropriate hydration
with > 3.5 L/d in adults and
1.5 L/m2 body surface in
children
AND
Adjust urine pH
between 7.5. and 8.5
with
alkaline citrates or
sodium bicarbonate

Cystine excretion Cystine excretion

< 3 mmol/d > 3 mmol/d

possible add. treatment Additional treatment with

with Tiopronin Tiopronin 250 mg/d up to
(depending on recurrence) 2000 mg/d max. dos

338 Urolithiasis
Struvite and infection stones

Recommendations Therapeutic measure LE GR

Surgical removal of the stone material as com- 3,4 A*
pletely as possible.
Short-term antibiotic course. 3 B
Long-term antibiotic course. 3 B
Urinary acidification: ammonium chloride; 3 B
1 g, 2 - 3 x daily.
Urinary acidification: methionine; 3 B
200-500 mg, 1 - 3 x daily.
Urease inhibition. 1b A

Cystine stones

Therapeutic measures LE GR
Urine dilution 3 B
High fluid intake recommended so that 24-h urine
volume exceeds 3 L.
Intake should be ≥ 150 mL/h.
Alkalinisation 3 B
For cystine excretion < 3 mmol/day: potassium
citrate 3–10 mmol 2 or 3 times daily, to achieve
pH > 7.5.
Complex formation with cystine 3 B
For patients with cystine excretion > 3 mmol/day,
or when other measures are insufficient:
tiopronin, 250–2000 mg/day.
Captopril, 75–150 mg/day, remains a second-line
option if tiopronin is not feasible or unsuccessful.

Urolithiasis 339
 2,8-dihydroyadenine stones and xanthine stones
Both stone types are rare. In principle, diagnosis and specific
prevention is similar to that of uric acid stones.

Drug stones
Drug stones are induced by pharmacological treatment. Two
types exist:
• stones formed by crystallised compounds of the drug;
• stones formed due to unfavourable changes in urine com-
position under drug therapy.
Treatment includes general preventive measures and the
avoidance of the respective drugs

Investigating a patient with stones of unknown composition

Investigation Rationale for investigation

Medical history − Stone history (former stone events,
family history)
− Dietary habits
− Medication chart
Diagnostic imaging − Ultrasound in case of a suspected
stone
− Unenhanced helical CT
(Determination of the Houndsfield
unit provides information about the
possible stone composition)
Blood analysis − Creatinine
− Calcium (ionized calcium or total
calcium + albumin)
− Uric acid

340 Urolithiasis
Urinalysis − Urine pH profile (measurement
after each voiding, minimum 4
daily)
− Dipstick test: leucocytes, eryth-
rocytes, nitrite, protein, urine pH,
specific weight
− Urine culture
− Microscopy of urinary sediment
(morning urine)
− Cyanide nitroprusside test (cystine
exclusion)

Further examinations depend on the results of the investiga-

tions listed above.

This short booklet text is based on the more comprehensive EAU

guidelines (ISBN 978-90-79754-65-6) available to all members of the
European Association of Urology at their website,
http://www.uroweb.org.

Urolithiasis 341