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BY
JINU ALOYSIUS
2002 BATCH
HISTORICAL ….
• Renal stones has been detected in Egyptian
mummies dated to 4800BC.
• In 12th century BC Susruta performed
perineal lithotomy.
• The specialty of urologic surgery was
recognized even by Hippocrates (4th Century
BC) who wrote, in his famous oath for the
physician, “I will not cut, even for the stone,
but
leave
such
procedures
to
the
practitioners of the craft”.
EPIDEMIOLOGICAL ASPECTS
• Prevalence: 0.1-0.4% of the population every
year
• Life Time Incidence: Upto 12%
• Intrinsic Factors
– Peak Age: 20-50 yrs (Onset mostly in their
teens)
– Sex (M/F) : 3:1
– Race: Whites >Blacks
– Positive Family History: 25 fold higher
incidence
HEREDITARY
 Family renal tubular acidosis: Nephrolithiasis,
Nephrocalcinosis
 Cystinuria
 Xanthinuria
 Dihydroxyadeninuria
 X-linked hypercalciuric kidney stone
syndrome/DENT’s DISEASE
 X-linked recessive nephrolithiasis
 X-linked hypophosphatemic rickets
EXTRINSIC FACTORS
• Geography – Higher in mountainous, desert or tropical
areas
- High incidence: North India, Pakistan,
Britain, Mediterranean countries, North
Australia, Central Europe
- Low incidence: Central & South America,
Africa
• Climatic & Seasonal Factors – Higher in summer
months.
• Water Intake – Reduces stone formation (Hard water
may )
• Diet – High intake of Calcium, Phosphate, oxalates,
sodium, Vitamin A deficiency
• Occupation – Sedentary occupation, astronauts after
space flight
• Stress – due to emotional life events, marriage
problems.
RENAL STONE COMPOSITIONS
OXALATE – Calcium oxalate monohydrate,
Calcium oxalate dihydrate
PHOSPHATES – Hydroxy apatite, Carbonate
apatite, Calcium hydrogen phosphate dihydrate
(BRUSHITE), Tricalcium phosphate
(WHITLOCKITE), Ostacalcium phosphate,
Magnesium ammonium phosphate hexahydrate
(STRUVITE), Magnesium hydrogen phosphate
trihydrate (NEWBERYLITE)
• URIC ACIDS – Anhydrous uric acid, uric acid
dihydrate
• URATES – Ammonium acid urate, Sodium acid
urate monohydrate
• CYSTINES
• XANTHINES
PATHOPHYSIOLOGY OF STONE FORMATION
• NUCLEATION is a process, where by stone
formation is initiated by the presence of
a crystal or foreign body, which promotes
the growth of salt crystals only in
supersaturated urine.
• In HETEROGENOUS NUCLEATION, nidus
is composed of a substance other than
the stone crystal eg-crystallisation on
injured surface of renal tubular cells or
different solute.
• Transiently or intermittently
supersaturated urine is sufficient for
nucleation.
• Other factors – low concentration of
CRYSTALLISATION INHIBITORS –
Citrate, nephorcalcin, pyrophosphate,
acidic glycopeptides, uropontin,
magnesium
• Altered pH – Significant effect – on
solubility & crystallisation.
• Most crystals pass through the urinary
system unless they are adherent to
the renal collecting system or retained
by urinary stasis.
• In some instances, kidney stone can
be attached to Randall’s plaques or
sites of previous renal injury,
preventing distal passage.
• Anatomical factors such as distal
obstruction (i.e.ureteral structure) or
location in lower pole may lead to
stasis & subsequent stone formation.
CAUSES FOR STONE FORMATION
•
CALCIUM OXALATE STONE
- Hypercalciuria
– Absorptive hypercalciuria
- Renal hypercalciuria
- Resorptive hypercalciuria
- Idiopathic hypercalciuria
- Hypercalcemia
– Primary hyperparathyroidism
- Malignancy associated
hypercalcaemia
- Sarciodosis and other granulomatous diseases
- Glucocorticoid – induced
hypercalcemia
- Pheochromocytoma
- Familal hypocalciuric hypercalcemia
- Immobilisation
- Iatrogenic hypercalcemia
– Thiazide, lithium, tamoxifen
Excess vit D, Milk-alkali
syndrome
• Hyperoxaluria
- Increased oxalate production:
: Primary hyper oxalauria
: Increased hepatic conversion
- Increased oxalate absorption
: Enteric hyperoxaluria
- Hyperoxaluria in idiopathic calcium
oxalate stone disease
• Sexhormones – testosterone increase urine
oxalate excretion
• Hypocitraturia – since uric acid can complex
with calcium
• Hypomagnesemia
CALCIUM PHOSPHATE STONES
• Hypercalciuria
• Hypercalcemia
• Nanobacteria – produces carbonate aptite at
physiological pH.
• Renal tubular acidosis.
• URIC ACID STONES
• Hyperuricosuria – Excess dietary purine intake
• Excessively acidic urine
• Secondary uric acid stones in Gout
• Diminished urinary volume
STRUVITE STONES (TRIPLE PHOSPHATE/
INFECTION STONES)
• Accounts for majority of staghorn calculi
• Urea splitting organisms includes gram
negative, gram positive bacteria,
mycoplasma and yeasts. Eg: Proteus
mirabilis (most common), Klebsiella,
Psudomonas, Ureoplasma ureolyticum
• Urine pH > 7.2 and ammonia in Urine.
• CYSTINE STONES
– Cystnuria – Autosomal
recessive disorder
• DIHYDROXYADENINE STONES
– Deficiency of enzyme adenine
phsophoribosyl transferase
• XANTHINE STONES
– Xanthinuria – deficiency of enzyme
xanthine oxidaseLesch – Nyhan syndrome
• IATROGENIC STONES
– Proteinaceus material and fungus balls in patients
with prolonged courses of antibiotic therapy
• SILICATE CALCULI
– Intake of large amounts of antacids containing
silicates
• MATRIX CALCULI
– Stone composed of coagulated mucoids in
infection by urease producing organisms.
– Usually associated with alkaline UTI.
• AMMONIUM ACID URATE CALCULI
– Ureolytic infection in excess uricosuria
– Urinary phosphate deficiency
– Low fluid intake
• DRUG INDUCED STONES
– Antitussives containing ephedrine or
guaiphenesin
– Triamterene, a potassium sparing diuretic
– Indinavir, a protease inhibitor for HIV
• SPURIOUS CALCULI
– Factitious, patients mimicking of having colic
eg. Munchausen syndrome.
• CLINICAL PRESENTATION
• ASYMPTOMATIC in 25% cases, may be discovered
only incidently
• PAIN – Classical ureteral colic is a sudden onset
excruciating pain which is intermittent and radiates
from loin to groin.
• Severity of pain is not related to amount of distension
but due to the rapidity with which it develops.
• HAMATURIA – microscopie/gross (may be negative in
5% of cases)
• PYURIA – limited and usually sterile
• NAUSEA & VOMITING – due to stimulation of
coeliac plexus
• FEVER – uncommon unless there is
concomitant infection
• STRANGURY – (painful passage of a few drops
of urine) in intramural ureteric stones.
• URINARY FREQUENCY & URGENCY – when
stones are near bladder
• COSTOVERTEBRAL ANGLE TENDERNESS is
frequently observed
RELATIONSHIP OF STONE LOCATION
TO SYMPTOMS
STONE LOCATION
COMMON SYMPTOMS
• KIDNEY
• Vague flank pain,
haematuria
• PROXIMAL URETER
• Renal colic, Flank pain
Upper abdominal pain
•MIDDLE SECTION OF
URETER
• Renal colic, anterior
abdominal pain, flank
pain
• DISTAL URETERA
• Renal colic, dysuria,
urinary frequency,
anterior abdominal pain
flank pain
• D/D – All other causes of acute
abdominal pain should be ruled out.
• COMMON LOCATIONS WHERE
STONES GET IMPACTED.
1. Calyces
2. Ureteropelvic junction
3. At or near pelvic brim, where ureter begins to
arch over the iliac vessels posteriorly into the
true pelvis.
4. Posterior pelvis, especially in females where
ureter is crossed anteriorly by the broad
ligament.
5. Uretero vesical junction- most common site of
impaction.
INVESTIGATIONS
LABORATORY STUDIES
•URINALYSIS
Haematuria
 Pyuria  Usually mild
Significant pyuria with fever
Urine culture for UTI
 Urine pH  pH> 7 suggests presence of urea splitting
organisms and possible struvite stones
 pH<5.5 associated with uric acid stones
 Presence of crystals
 Blood  Complete blood count
-Mild leucocytosis common
 WBC>15,000/mm3 in obstructive
/nonobstructive pyelonephritis
 Serum electrolytes to identify acidosis,
alkalosis or hypokalemia
 RFT (Blood urea and serum creatinine )
RADIOGRAPHIC EXAMINATION
PLAIN ABDOMINAL FILMS of kidneys, ureters and
bladder (KUB)
Advantages
 Readily available
 Most useful in the follow-up of stones
 Reasonably accurate in detection of
radioopaque stones
LIMITATIONS
 Radio lucent calculi cannot be visualized
 Frequently observed by bowel gas
 Ureteral stones overlying the bony pelvis or
transverse process of vertebrae difficult to identify
 Nonurologic radioopacities such as calcified
mesenteric lymphnodes, gall stones, stool and
phlebolith may be misinterpreted as stones
 Inability to display renal anatomy and functions
 Sensitivity and specificity of KUB is poor
(Sensitivity-45-59%; specificity-71-77%)
STONE COMPOSITION IN DECREASING
ORDER OF RADIOOPACITY
Stone composition
Radio opacity
Calcium hydrogen phosphate
dihydrate (brushite)
Densely opaque
Calcium oxalate
monohydrate
Densely opaque
Calcium phosphate (apatite)
Densely opaque
Calcium oxalate dihydrate
Moderately opaque
Magnesium ammonium
phosphate (struvite)
Moderately opaque
Cystine
Faint to moderately
opaque
Uric acid
Radiolucent
INTRAVENOUS UROGRAPHY
• IVU has been the mainstay for renal stones because
the study has high sensitivity (64-87%) and
specificity (92-94%) for diagnosis of stones
Advantages
 Information about the stone (size, location,
radio density) and its environment (calyceal
anatomy, degree of obstruction) as well as the
contralateral renal unit function, anomalies
like medullary spongy kidney, ureteral stricture
ureteral duplication or calyceal diverticulum
 Ureteral calculi can be easily distinguished
from nonurologic radioopacities by this method
LIMITATIONS
 An unprepared study (without a prior
mechanical bowel preparation) in the
emergency department caused poor
visualisation of retroperitoneal structures
 Failure to visualize radiolucent stones but may
demonstrate a filling defect.
 Risks of contrast reaction and nephrotoxicity
 Prolonged examination time , especially with a
high grade obstructing stone – even prolonged
reimaging at 12to 24 hrs may not demonstrate
the level of obstruction because of inadequate
concentration of the contrast medium.
• PRECAUTIONS: although a creatine level
greater than 1.5 per dL (130mol per L ) is
not an absolute contraindication, the risks
and benefits of using contrast media must be
carefully weighed, particularly in patients
with DM, cardiovascular diseases or multiple
myeloma.
• These risks may be minimized by adequately
hydrating the patient, minimizing the
amount of contrast material that is infused,
and maximizing the time interval between
consecutive contrast studies.
• It is prudent to avoid the use of contrast
media when an alterative imaging modality
can provide equivalent information.
• ROLE OF NONIONIC CONTRAST MEDIA : may
decrease reactions such as nausea , flushing
and bradycardia, but there is no apparent
reduction of anaphylactic reactions or
nephrotoxicity
• A new concern has emerged because of
reports of fatal metabolic acidosis after
radiological procedures using I.V. contrast
media in patients with DM with preexisting
renal failure and who are taking metformin
• The basic mechanism of interaction involves
impairment of renal metformin excretion by
contrast media induced nephrotoxicity that
results in elevated serum metformin levels
• Therefore discontinue metformin at the time
of or before a procedure using contrast
material and to withhold the drug for 48
hours after the procedure. Metformin therapy
is reinstituted only after renal function is
reevaluated and found to be normal.
 ULTRASONOGRAPHY
• Ultrasound is a noninvasive method which is
highly sensitive for renal calculi greater than
5 mm and for detecting consequent
hydronephrosis
ADVANTAGES
• Non invasive quickly performed readily available in both
hospital and outpatient setting
• No radiation risk: has become the procedure of choice in
pregnant women and pediatric population
• Detects stones in the kidney and ureterovesical function
with reasonable accuracy and gives some anatomical
information such as presence of hydronephrosis
• Useful in assessing renal parenchymal processes, which may
mimic renal colic
SHORTCOMINGS
• It is virtually blind to upper and middle ureteral
stones (sensitivity :19%) which are far more
likely to be symptomatic than renal calculi.
Distal ureteric calculi occasionally visualized
though window of a fluid filled bladder. However,
if a ureteral stone is visualized by ultrasound, is
reliable (Specificity: 97%)
• Frequent limitation in defining the level and
nature of obstruction
• Lack of functional information
• Limited visualization of renal anatomy
RETROGRADE PYELOGRAPHY
• Indicated for patients in whom
administration of intravenous contrast
material is contraindicated or when
the IVU or renal sonogram is inconclusive
• Ureteral calculi typically produce a filling
defect in the ureter and cause a discrepancy in
the caliber of the ureter above and below the
defect (dilated above, narrow below)
CT SCAN
Advantages
• Non contrast enhanced helical CT is fast and
accurate and it readily identifies all stone types
in all locations
• Quick, does not require intravenous contrast or
bowel preparation
• Its sensitivity (95-100%) and specificity (94-96%)
suggests that it may definitely exclude stones in
patients with colicky abdominal pain.
• New signs such as renal enlargement, perinephric
or periureteral inflammation or “stranding” and
distension of the collecting system or ureter are
sensitive indicators of degree of ureteral
obstruction .
• Hounsfield density of calculi may be
used to distinguish cystine and uric
acid stones from calcium bearing
stones and is capable of further
subtyping calcium stones into
calcium phosphate, calcium oxalate
monohydrate and calcium oxalate
dihydrate stones.
• It is also useful in diagnosing non
urolgic causes of abdominal pain,
such as abdominal aortic aneurysms
and cholelithiasis.
LIMITATIONS
• More expensive
• Lack of functional information
• Does not accurately delineate the
anatomy of ureter and renal
collecting system (detection of
anomalies such as calyceal
diverticulum or ureteral duplication
is critical for proper preoperative
planning).
• Follow up of stone disease is usually
done using plain films. In many
instances, comparison of plain films
with spiral CT is difficult in
assessing stone movement or
passage.
MRI
• MRI specifically used to visualise the urinary
tract has been termed magnetic resonance (MR)
urography.
• MR sequencing using both half-fourier
acquisition single-shot turbo spin-echo (HASTE)
imaging and ultra-fast breath-hold sequences are
technically adequate.
ADVANTAGES OVER CT:
• Effective in demonstrating urinary tract dilation
and level of obstruction in 96% of cases.
• Ability to identify perirenal fluid is of value in
differentiating acute from chronic obstruction.
DISADVANTAGES:
• Unable to visualise most stones clinically.
• Not useful for characterising the composition of the
stones.
• Expensive.
COMPLICATIONS OF UROLITHIASIS
• Renal failure
• Ureteral structure
• Infection
• Sepsis
• Urine extravasation
• Perinephric abscess
• Xanthogranulomatous pyelonephritis
HOW LONG CAN ONE WAIT BEFORE TREATING THE
STONE?
• In the absence of infection and with complete
obstruction, detectable renal damage does not occur in
previously normal kidneys until complete obstruction has
been present for 4 weeks, so one can give the patient upto
4 weeks to pass the stone spontaneously.
MANAGEMENT OF RENAL STONES
Initial management of radiology confirmed stone
CONFIRMED STONE
RULE OUT EMERGENCY
Urosepsis, anuria, rental failure
Yes
No
URGENT
UROLOGIC
CONSULTATION
CONSIDER HOSPITAL ADMISSION
Refractory pain, refractory nausea
Extremes of age, debilitated condition
No
SYMPTOMS AMENABLE TO MEDICAL MANAGEMENT
Ureteral stone
Renal stone or ureteral stone > 5mm
<5mm
TRIAL OF CONSERVATIVE MANAGEMENT
WEEKLY KUB RADIOGRAPHS
Stone passes Stone fails to pass within 2 - 4 weeks
REFERRED TO UROLOGIC
CLINIC
EMERGENCY SITUATIONS
• SEPSIS in conjunction with an obstructing stone –
adequate drainage of the system must be established
with all possible speed by means of percutaneous
nephrostomy or retrograde ureteral stent insertion.
• ANURIA & ACUTE RENAL FAILURE secondary to
bilateral obstruction, or unilateral obstruction in a
patient with a solitary functioning kidney – should be
treated urgently.
• Patients with REFRACTORY SYMPTOMS – should be
treated by placing a retrograde ureteral stent or
percutaneous nephrostomy tube as a temporizing
measure.
AMBULATORY MANAGEMENT
• The corner stones of ambulatory management are
adequate analgesia, timely urologic consultation and
close follow-up.
• Narcotics such as codeine, morphine, meperidine are
effective in suppressing pain, but have side effects of
dependence and disorientation.
• NSAIDs such as Ketorolac, aspirin, diclofenac (Voveran)
and ibuprofen are effective in managing pain of renal
colic due to their combined anti inflammatory and
spasmolytic effects.
ANALGESIA
• Unfortunately, the antiplatelet effects of
NSAIDS are a contraindication to the use of
ESWL, because of the increased risk of
perinephric bleeding.
• An effective approach to outpatient
management is to use both an oral narcotic
drug and an oral NSAID.
• Patients are instructed not to take NSAIDs
for 3 days before anticipated ESWL; also told
to avoid aspirin for 7 days before the
procedure.
TREATMENT OPTIONS
•
•
CONSERVATIVE MANAGEMENT
The safest management of ureteral stones is spontaneous
passage, provided there are no complicating factors.
• The two major prognostic factors are stone size and
location.
PROBABILITY OF STONE PASSAGE
Stone location & size
• Proximal ureter
>5mm
5mm
< 5mm
• Middle section of
ureter
>5mm
5mm
<5mm
•Distal ureter
>5mm
5mm
< 5mm
Probability of
passage
0%
57%
53%
0%
20%
38%
25%
45%
74%
• Referral to urologist is appropriate for patients with a
ureteral stone >5mm in greatest diameter or a stone
that has not passed after 2-4 weeks.
TREATMENT MODALITIES FOR RENAL & URETERAL CALCULI
• EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY (ESWL) – is
an image guided therapy where by shock waves are generated
and focused on target stone which is pulverized into small
fragments that can easily pass through the UT.
Treatment
•Indications
•Advantages
•Limitations
•Complications
•ESWL
•Radiolucent
calculi
•Renal stones
>2cm
•Ureteral
stones >1cm
•Minimally
invasive
•Outpatient
procedure
•Requires
spontaneous
passage of
fragments
•Less effective in
patients with
morbid obesity or
hard stones
•Ecchymosis
•Perinephric
hematoma
•Ureteral obstruction
by stone fragment
•Ureteric colic after
procedure
•Sepsis
•
URETERORENOSCOPY – ureteroscope is a
long endoscope that can be passed
transurethrally across the bladder in a
retrograde fashion – larger stones can be
fragmented using intracorporeal lithotripsy
and smaller stones can be grasped and
removed under direct vision – Available
lithotripsy devices include holmium and
pulsed – dye lasers and electrohydraulic,
electromechanical and ultrasonic devices.
Treatment
Indications
Advantages
Limitations
Complications
Ureterorenoscopy
Ureteral stones
Renal stones>2cm
Definitive
outpatient
procedure
Difficult to
clearfragments .
Commonly
requires
postoperative
uretral stent
Uretreal injury
Stricture
Sepsis
•
PERCUTANEOUS NEPHROLITHOTOMY- Involves
establishment of a nephrostomy tract directly
into the renal collecting system from the flank,
through which large- diameter instruments are
passed, resulting in the ability to remove large
amounts of stone from the kidney and upper
ureter efficiently.
Treatment
Indications
Advantages Limitations
Precutaneous
Nephrolithot
omy
•Renal stones >2
cm
•Proximal
urethral stones >
1cm
Definitive
treatment
• More
invasive
•Higher
morbidity
Complications
•Bleeding
•Injury to
collecting system
•Injury to
adjacent
structures
OPEN SURGERY OR LAPAROSCOPY
•
Rarely required
INDICATIONS
• Larger staghorn calculi
• Stones refractory to conventional , minimally invasive
options
• Patients with anatomic limitations preventing a minimally
invasive procedure
ADVANTAGES
• Stone removal can be done concomitantly with repair of an
anatomic defect such as ureteropelvic junction obstruction
LOCATION SPECIFIC TREATMENT OPTIONS
RENAL CALCULI
Condition
•Size <2 cm
Treatment Option
ESWL
•Staghorn calculus
•Lower pole location
•Cystine composition
Percutaneous
nephrolithotomy
•Patients who have failed
SWL therapy and not good
candidates for percutaneous
nephrolithotomy
Ureteroscopy
PROXIMAL AND MIDURETERAL CALCULI
• ESWL and ureteroscopy are acceptable
options
• ESWL has low success rates
• Ureteroscopic approach can be technically
difficult
• Antegrade ureteroscopy through an
established nephrostomy tract is an
alternative
• Open surgery is reserved as a salvage
procedure.
DISTAL URETERAL CALCULUS
• Choice depends largely on patient and
urologist preference
• ESWL has less morbidity than ureteroscopy
but has some what lower success rates
because of difficulty in stone localization
• Ureteroscopy is technically straight forward
using rigid or semi-rigid endoscopes and has
success rates over 95% with minimal
complications.
EVALUATION OF THE STONE
FORMING PATIENT
Gather the stone for analysis
History
• Including family history of urolithiasis, bone/GI disease,
gout, chronic UTI, nephrocalcinosis, previous bowel
surgery, fluid intake, diet
Complete physical examination and Base line laboratory
evaluation
• Consisting of urinalysis , urine culture, serum
electrolytes, blood urea, creatinine, uric acid and
calcium
• Screening test for cystinuria if stone not collected.
UNCOMPLICATED CALCIUM STONE DISEASE
• Presence of normocalcemia and
normouricemia + absence of UTI, bowel
disease or marked hyperoxaluria
• For the first time uncomplicated calcium
stone former, no further evaluation is
warranted
• Patient is counselled on a low-oxalate diet,
enough fluid intake to produce more than
2L of urine per day
• Follow up on regular basis for evaluation of
stone recurrence .
METABOLICALLY ACTIVE STONE DISEASE
Characterized by
– Formation of new stones
– Enlargement of an old some
– Passage of gravel
• For patients with non calcium or metabolically active
stone disease, a complete evaluation is indicated
• Evaluation is directed at identifying specific factors
that influence the crystallization of stone-forming
salts which include 24 hr urine analysis, complete
serum panels, further evaluation of risk factors.
PREVENTION OF RENAL STONES
• Drink plenty of fluid, especially in
summer
• Calcium stones: Calcium Intake (dairy
products avoid Vit D supplements)
• Oxalate stones:  Oxalate intake (less tea,
chocolate, nuts, spinach, beans, beetroot
etc.)
• Triple phosphate stones : antibiotics
• Uric acid stones : Urine alkalinization,
allopurinol.
• Cystine stones: Vigorous hydration,
D-penicillamine, urine alkalinization.
SUMMARY
Renal calculi consists mainly of crystal aggregates,
formed in the collecting duets and may be
deposited anywhere from renal pelvis to urethra.
The initial management is based on 3 key
concepts.
The recognition of urgent and emergency
requirements for urologic consultation.
The provision of effective pain control using a
combination of narcotics and NSAIDs in
appropriate patients.
An understanding of the impact of stone
location and size on natural history and
definitive urologic management.
 Since without preventive treatment, the
incidence of recurrence is as high as 50%
with in 5 years of the first stone event, proper
evaluation of the patient should be done to
find the exact etiology and proper preventive
measures should be taken.