This document discusses the anatomy, epidemiology, pathophysiology, clinical presentations, and classification of kidney stones. It notes that kidney stones are bilaterally paired organs measuring 10-12cm located in the retroperitoneal space. Risk factors include age, gender, geography, and certain occupations. Stones form when urine becomes supersaturated, and various substances can promote or inhibit crystal formation. Clinical presentations include flank pain, nausea, hematuria, and fever in cases of obstruction or infection.

2. REFFERENCES
 CAMPBELL-WALSH UROLOGY, 10TH ED.
 SMITH’S GENERAL UROLOGY,17TH ED.

3. ANATOMY
 The kidneys are bilaterally
paired reddish brown bean
shaped organs .
 150 g in the male and 135 g
in the female.
 Measure 10- 12 cmX 5 - 7
cmX 3 cm
 Because of compression by
the liver, the right kidney
tends to be somewhat
shorter and wider

4. INTERNAL STRUCTURE OF THE KIDNEY
 There are 5 to 14 minor calyces in
each kidney (mean of 8, with 70% of
kidneys having 7 to 9 minor calyces)
 If only one papilla drains into a
minor calyx, it is described as a
simple calyx.
 When there are two or more papillae
entering the calyx, it is termed a
compound calyx.
 There are three drainage zones:
the upper pole, the middle region,
and the lower pole.
 Compound calyces are the rule in the
upper pole, are common in the lower
pole, and are rare among the middle
calyces

5. NORMAL ROTATIONAL AXES OF THE KIDNEY

6. ORGANIZATION OF THE FAT AND FASCIA
SURROUNDING THE KIDNEY

7. EPIDEMIOLOGY
 Urinary calculi are the third most common affliction of the
urinary tract, exceeded only by urinary tract infections and
pathologic conditions of the prostate.
 The lifetime prevalence of kidney stone disease is estimated
at 1% to 15%.

8. EPIDEMIOLOGY CONT.
 GENDER:- men (2-3) >women
 RACE/ETHNICITY :- Whites,Hispanics, Asians,African
Americans
 AGE:-Uncommon before age 20, peak incidence in the 4th to
6th decade.
 GEOGRAPHY:- higher prevalence in hot, arid, or dry climates
such as the mountains, desert, or tropical areas.
 CLIMATE :- Seasonal variation is likely related to temperature
by way of fluid losses from perspiration thus more
in summer months.
 OCCUPATION:-Cooks, steel workers, workers at a glass plant.
 BODY MASS INDEX AND WEIGHT
 WATER

9. EPIDEMIOLOGY :KEY POINTS
 Upper urinary tract stones occur more commonly in men
than women, but there is evidence that the gender gap is
narrowing.
 Whites have the highest incidence of upper tract stones
compared with Asians, Hispanics, and African-Americans.
 Geographic variability, highest prevalence of stone disease
in the Southeast.
 Correlates with weight and BMI.

10. PHYSICOCHEMISTRY
 Stone formation is a complex cascade of events that
occurs as the glomerular filtrate traverses the nephron.
 It begins with urine that becomes supersaturated
with respect to stone-forming salts, such that
dissolved ions or molecules precipitate and form
crystals or nuclei.
 Once formed, crystals may flow out with the urine
or become retained in the kidney at anchoring
sites that promote growth and aggregation, ultimately
leading to stone formation.

11. INHIBITORS AND PROMOTERS
OF CRYSTAL FORMATION
 In urine, crystallization does not necessarily occur because of
the presence of inhibitors and other molecules.
Inhibits crystal Growth
 Citrate – complexes with Ca
 Magnesium – complexes with oxalates
 Pyrphosphate - complexes with Ca
 Zinc
Inhibits crystal Aggregation
 Glycosaminoglycans
 Urinary glycoproteins
-Nephrocalcin
-Tamm-Horsfall
-Uropontin/osteopontin
- Inter Alpha Trypsin

12. PROMOTERS
 Bacterial Infection
 Matrix –(non-crystalline component )
 Anatomic Abnormalities – PUJ Obst., MSK
 Altered Ca and oxalate transport
 Prolonged immobilisation.
 Increased uric acid levels i.e taking increased purine
subs– promotes crystalisation of Ca and oxalate .
 ?? Nanobacteria or Calcifying nanoparticles (CNPs )–
seen in 97% of renal stones

13. VARIOUS PROPOSED
MECHANISMS/THEORIES OF
STONE FORMATION
 FIXED PARTICLE GROWTH THEORY
-an anchoring site to which crystals bind
-oxalate induced injury
- mediated by free radicals
- prolonging the time the crystals are exposed to
supersaturated urine and
- facilitating crystal growth and aggregation.

14. RANDALL PLAQUE THEORY (1973)
 Randall (1937) first observed areas of damage associated with
subepithelial plaques on the renal papillae.
 Intracellular incorporation of these crystals could potentially
lead to cell death and deposition of crystals in the
interstitium, or transport of the crystals from the luminal to
the basement membrane side could promote cell damage and
subsequent erosion through to the papillary surface.
 Renal epithelial cells are more vulnerable to the toxic effects
of oxalate on their basolateral side compared with their
apical (luminal) side, implicating the interstitium as a
possible site of primary stone formation.

15. MECHANISMS/THEORIES CONT.
STOLLER AND COLLEAGUES (2004)
 Hypothesized that the inciting event in the pathogenesis of
stones may be vascular injury to the vasa recta near the
renal papilla. Repair of damaged vessel walls could involve an
atherosclerotic-like reaction that results in calcification of
the endothelial wall, followed by erosion into the papillary
interstitium and then into the collecting ducts, where it
could serve as a nidus for stone formation.

16. MECHANISMS/THEORIES CONT.
EVAN AND COLLEAGUES (2003)
 They localized the origin of the plaque to the basement
membrane of the thin limbs of the loops of Henle.
 Demonstrated that the plaque subsequently extends
through the medullary interstitium to a subepithelial
location.
 Once the plaque erodes through the urothelium, it is
thought to constitute a stable, anchored surface on which
calcium oxalate crystals can nucleate and grow as attached
stones.

17. MECHANISMS/THEORIES CONT.
MATLAGA AND COLLEAGUES (2006)
 Observed that in approximately half of a studied
cohort of calcium oxalate stone formers the stones
were observed to be attached to the renal papillae.
 Suggesting that formation of attached stones is an
early step in the process of stone formation.

19. UNCOMMON STONES
TRIAMTERENE
Anti-hypertensive used with hydroclorothiazide.
Mostly found as a nucleus in Ca oxalate or uric
acid calculus
Indinavir Stones ART (4 to13%)
Ephedrine or Guifenesin Radiolucent

20. Radiopaque stones Radiolucent stones(TUX)
 calcium oxalate
 calcium phosphate
 magnesium ammonium
phosphate (struvite)
 cystine
 uric acid
 xanthine
 Triamterene
 Guiphenesin/ephedrine

21. CALCIUM STONES
 Also called mulberry stone
 Covered with sharp projections
 Spiculated surface - haematuria
 Very hard
 radio – opaque
 Under microscope looks like Hourglass or Dumbbell shape if monohydrate and
Like an Envelope
if Dihydrate

22. PHOSPHATE STONE (BRUSHITE)
 Usually Calcium Phosphate
 Sometimes Calcium Magnesium Ammonium Phosphate Or
Triple Phosphate
 Smooth -Minimum Symptoms
 Dirty White
 Radio – Opaque
 Calcium Phosphate also called ‘Brushite’ appears like Needle
shape under microscope

23. CYSTINE STONE
 Autosomal recesive disorder
 Usually in young girls
 Due to cystinuria
 Cystine not absorbed by tubules
 Multiple
 Soft or hard
 Pink or yellow
 Radio-opaque
 Under microscope appears like hexagonal or benezene ring

24. URIC ACID & URATE STONE
 Hard & smooth
 Multiple
 Yellow or red-brown
 Radiolucent
 Under microscope appear like irregular plates or rosettes.

25. STRUVITE(INFECTION STONES)
 Struvite (magnesium ammonium
phosphate-MAP)
 Presents as Stag Horn Calculus
 Associated with recurrent UTI
 Progress at a rapid rate.
 Microscopic appearance-coffin
lid appearence

26. STRUVITE(INFECTION STONES) CONT.
 Struvite precipitates in alkaline urine, forming stones.
 Struvite stones are potentiated by bacterial infection
that hydrolyzes urea to ammonium and raises urine
pH to neutral or alkaline values.
 The mostcommon urease-producing pathogens are
Proteus, Klebsiella, Pseudomonas, and Staphylococcus
species.
 Association with urinary tract infections, thus
women >men (2 : 1)

27. Drugs that promote calcium
stone formation:
 Loop diuretics
 Antacids
 Acetazolamide
 Glucocorticoids
 Theophylline
 Vitamins D and C

28. Drugs that promote uric acid
stone formation:
 Thiazides
 Salicylates
 Probenecid

29. CLINICAL PRESENTATIONS
PAIN- 2 types of pain
 Colic
 Non-colicky
 Urinary obstruction is the main mechanism responsible for renal
colic.
 Renal colic does not always wax and wane or come in waves like
intestinal or biliary colic but may be relatively constant.
 Patients with renal calculi have pain primarily due to urinary
obstruction.
 Local mechanisms such as inflammation, edema, hyperperistalsis,
and mucosal irritation may contribute to the perception of pain in
patients with renal calculi.

30. REFFERED PAIN

31. PAIN CONT.
 In the ureter, local pain is referred to the distribution of the
ilioinguinal nerve and the genital branch of the
genitofemoral nerve.
 Pain from obstruction is referred to the same areas as for
collecting system calculi (flank and costovertebral angle),
thereby allowing discrimination.
 The severity and location of the pain can vary from patient to
patient due to stone size, stone location, degree of
obstruction, acuity of obstruction, and variation in
individual anatomy (eg, intrarenal versus extrarenal pelvis).

32. PAIN CONT.
 The stone burden does not correlate with the severity of the
symptoms.
 Small ureteral stones frequently present with severe pain, while
large staghorn calculi may present with a dull ache or flank
discomfort.
 The symptoms of acute renal colic depend on the location of the
calculus;
-renalcalyx,
-renal pelvis,
-upper and midureter,
-distal ureter

33. NAUSEA AND VOMITING
 Upper-tract obstruction is frequently associated with nausea
and vomiting.
 Both stomach and kidney are supplied by celiac
ganglion.Thus, renal pain results in nausea and vomiting.
 Intravenous fluids are required to restore a euvolemic state.

34. CLINICAL PRESENTATIONS CONT.
HEMATURIA
 Intermittent gross hematuria or occasional tea-colored
urine.
 Most patients will have at least microhematuria.
 Rarely (in 10–15% of cases), complete ureteral obstruction
presents without microhematuria.

35. CLINICAL PRESENTATIONS CONT.
FEVER
 The association of urinary stones with fever is a relative
surgical emergency.
 Costovertebral angle tenderness
 Mass may be palpable  a grossly hydronephrotic kidney.
 Fever associated with urinary tract obstruction requires
prompt decompression.
 If retrograde manipulations are unsuccessful, insertion of a
percutaneous nephrostomy tube is required.

36. CLINICAL PRESENTATIONS CONT.
INFECTION
 Magnesium ammonium phosphate (struvite) stones are
synonymous with infection stones.
 They are commonly associated with Proteus, Pseudomonas,
Providencia, Klebsiella, and Staphylococcus infections.
 Calcium phosphate stones are the second variety of stones
associated with infections.
 All stones, however, may be associated with infections
secondary to obstruction and stasis proximal to the offending
calculus.
 Culture-directed antibiotics should be administered before
elective intervention.

37. INFECTION CONT.
PYONEPHROSIS
 Implies gross pus in an obstructed collecting system.
 An extreme form of infected hydronephrosis.
 Presentation is variable
-asymptomatic bacteriuria to
-florid urosepsis
 May develop into a renocutaneous fistula.

38. INFECTION CONT.
Xanthogranulomatous pyelonephritis
 Is associated with upper-tract obstruction and infection.
 One-third of patients present with calculi;
 Two-thirds present with flank pain, fever, and chills.
 50% present with persistent bacteriuria.
 Urinalysis usually shows numerous red and white cells.
 It usually presents in a unilateral fashion.

39. DIAGNOSTIC EVALUATION OF
NEPHROLITHIASIS
Computed tomography
 CT has a sensitivity of 97%, specificity of 96%, and overall
accuracy of 97%.
 CT is the most accurate radiologic study for the diagnosis of
ureteral calculi.
 Noncontrast spiral CT scans are now the imaging modality
of choice in patients presenting with acute renal colic.

40. COMPUTED TOMOGRAPHY CONT.
Advantages
 It is rapid and reproducible.
 Can be done in derranged renal functions and in
contraindicated intravenous contrasts.
 Gives most of anatomical details.
 Can detect clinically occult stones or radio-lucent
stones(uric acid, xanthine, dihydroxyadenine, and many
drug-induced stones).
 It images other peritoneal and retroperitoneal structures
and helps when the diagnosis is uncertain.
 Ability to detect other pathologic entities.
 Preferred investigation in Chronic obstructive uropathy.

41. COMPUTED TOMOGRAPHY CONT.
Disadvantages
 Calculi composed of protease inhibitors
(Indinavir), are not visualized by NCCT.
 Do not give anatomic details as seen on an IVP ( a bifid
collecting system).

42. DIAGNOSTIC EVALUATION CONT.
Ultrasonography
 Mainstay in the evaluation of suspected urinary tract
obstruction.
 Primarily an anatomic study, Doppler modifications may
add a functional component.
 No associated ionizing radiation, and it is thus considered
safe in pediatric and pregnant patients.
 Can be used in those with azotemia or contrast allergy.

43. DIAGNOSTIC EVALUATION CONT.
Intravenous pyelography
It is to investigate
 Suspected or known congenital anomaly of urinary tract.
 Ureteral obstruction
 Upper Tract mucosal neoplasm
 Patient with obstructing renal or uretral calculus
 Hematuria

44. IVP CONT.
PLAIN X-RAY KUB OR SCOUT FILM
Provides information about
 Stone
 Size and position of stone
 Position of kidney
 Size of the kidney
 Renal parenchyma
 Axial skeleton
 Abnormal calcifications
 Visceral Enlargement
 Soft tissue mass
 Bowel gas patterens
 Important For subsequent interpretation of IVP

48. IVP CONT.
Nephrogram Phase
 After a bolus dose of contrast medium,
 A cortical nephrogram can be seen after 60-90 sec
 It represents contrast material with in the tubules.
INFORMATION
 Cortical functions
 Position of the kidney

49. IVP CONT.
Excretory Urography
 Films are taken at 3-5min, at 10 min, at 15 min
 Delayed films at 25 min.
 Post micturation film.
 In infants and children at 3,5, 8 and 12 min.

50.  Provides both anatomic and functional information.
 Acute urinary obstruction may be inferred from the
functional abnormality of a delayed nephrogram and
pyelogram on the affected side or sides.
 Delayed images may then ultimately reveal the
anatomic level of obstruction and cause.
 Ureteral filling with contrast beging at about the same
time and peak opacification occurs in 5-10 min.

51. TREATMENT OPTIONS
1. Conservative Observation
2. Dietary Recommendations
3. Expectant Treatment
4. Extracorporeal Shock Wave Lithotripsy (ESWL)
5. Ureteroscopic Stone Extraction
6. Percutaneous Nephrolitotomy (PCNL)
7. Open Surgery

52. CONSERVATIVE MEDICAL
MANAGEMENT
Fluid Recommendations
 Volume
Mainstay Daily urine outputof 2 L .
Increased urine output may have two effects.
- The mechanical diuresis prevent
urinary stagnation and the formation of
symptomatic calculi.
-Creation of dilute urine prevents supersaturation.

53. FLUID RECOMMENDATIONS CONT.
Not the type of fluid but the absolute
amount of fluid is important.
So fluid intake should be at least 3000
mL/day to maintain a urine output >2500
mL/24 hours.

54. Dietary Recommendations
Protein Restriction
 Epidemiologic studies  increased animal protein
intake  increased incidence of renal stones.
 Cause : increased urinary calcium, oxalate, and uric
acid excretion, thus increases risk of stone formation.

55. DIETARY RECOMMENDATIONS CONT.
Sodium Restriction
 High-sodium diet increased propensity for the
crystallization of calcium salts in urine.
 When combined with animal protein restriction and
moderate calcium ingestion, a reduced-sodium diet will
decrease stone episodes by roughly 50%.

56. DIETARY RECOMMENDATIONS CONT.
Role of Dietary Calcium
 Older recommendations Restrict calcium intake likely
lead to an increase in available intestinal oxalate. As a result,
this limitation in dietary calcium increase oxalate
absorption, thereby raising the supersaturation of calcium
oxalate in urine.
 Thus, the maintenance of a moderate calcium intake is
recommended.
 Calcium citrate more “stone-friendly” calcium
supplement due to the additional inhibitor action of citrate.
 Dietary calcium restriction actually increases stone
risk.

57. DIETARY RECOMMENDATIONS CONT.
Oxalate Avoidance
 Avoiding foods rich in oxalate such as spinach, beets,
chocolate, nuts, and tea.
 Vitamin C in large doses may increase the risk of stone
recurrence. Doses should probably be limited to 2 g/day.

58. EXPECTANT TREATMENT IN URETRIC
STONES
INDICATIONS CONTRA-INDICATIONS
 Size
 Location of stone
 Stone load
 Surface
 Infection
 Symptoms
 Renal function
 Pt. Compliance and follow
up.
 Solitary kidney with large
stone
 B/L Stones with Deranged
RFT
 Obstructed Pyelonephritis
 Occupational Considerations

59. TERMINATION OF EXPECTANT
TREATMENT
 Duration
 Position of stone
 Size
 Recurrent UTI
 Renal Function
 Symptomatic

60. Extracorporeal Shockwave
Lithotripsy
PRINCIPLES OF SWL
 Shockwaves are generated by an external source.
 Then propagated into the body and focused on kidney stone.
 Waves are relatively weak, on generation and they build to
sufficient strength only at the target.
 Enough force is thus generated to fragment a stone.

61. PRINCIPLES OF SWL CONT.
On collision of “ shock waves” with calculi-
 On front surface – compressive forces
 On back surface of the stone-
Reflection of compression pulse creates negative or
tensile wave that travel back ward through calculi
 Once tensile force exceeds “ cohesive strength” of
calculi fragmentation occurs

62. ESWL CONT.
Generator Type
Electrohydraulic (spark gap)
Electromagnetic

63. ESWL
Absolute Contra-indication Relative Contra-Indications
Pregnancy  Renal Colic
 Urinary obstruction
 Infection
 Altered Renal Function
 Hematuria

64. ESWL COMPLICATIONS
 Haematuria – is quite
common ( short term
antibiotics Recommended )
 Incomplete stone
Fragmentation &
Obstruction
 “Stienstrasse” ( stone street)
usually due to a large “
Leading fragment”
 So, Stents Recommended
prior to ESWL for Calculi >
1.5 cm

65. ROLE OF URETERAL STENTS
 Drain obstructed kidney thereby alleviating pain
 Facilitate passage of stone
 Facilitate performance of SWL and ureteroscopic procedures
 Avoid problems from “steinstrasse” in the post treatment
period.

66. PCNL

67. ABSOLUTE CONTRAINDICATIONS
 Uncorrected coagulopathy
 An active or untreated UTI

68. COMPLICATIONS OF PNL
 Hemorrhage
 Sepsis (0.3% to 2.5%)
 Adjacent organ injury (<0.5%)
 Perforation of renal pelvis and ureter (<2%)
 Supracostal puncture the risk of pneumothorax or pleural
effusion requiring drainage is 4% to 12%
 Failure of equipment is an often-ignored but significant potential
complication

69. URETEROSCOPIC STONE EXTRACTION
 Lower ureteral calculi
 Uses a small small caliber ureteroscope with balloon dilation.
 Calculi less than 8mm are frequently removed intact.
 Complications - ureteral injuries range from perforations to
complete avulsion of ureter.

70. INTRACORPOREAL LITHOTRIPTERS
TECHNIQUES :-
 Ultrasonic lithotripsy
 Ballistic lithotripsy
 Laser lithotripsy

71. ULTRASONIC LITHOTRIPSY
PRINCILPE

72. ULTRASONIC LITHOTRIPSY CONT.
 First modality used for stone fragmentation during PNL.
 Efficient combination of stone fragmentation and
simultaneous fragment removal.
 Rigid nature limit their use in uretric stones

73. LASER LITHOTRIPSY
PULSED-DYE LASERS
The pulsed laser causes release of electrons and formation of
a “plasma” bubble .
Collapse of the plasma bubble generates a shockwave stone
fragmentation.
HOLMIUM:YAG LASER
Photothermal mechanism that causes stone vaporization

74. LASER LITHOTRIPSY CONT.
ADVANTAGES
 The safest and most effective
 Fragment all stones regardless of composition
 Weak shockwavereduces the likelihood of retropulsion of
the stone.
 Can be used to treat patients with benign prostatic
hyperplasia and urothelial tumors
MAJOR DISADVANTAGE
High cost of the device and laser fibers.

75. BALLISTIC LITHOTRIPSY
PRINCIPLE

76. BALLISTIC LITHOTRIPSY CONT.
ADVANTAGES
 Successful fragmentation  73% to 100%.
 Success rate similar to that of EHL
 Risk of perforation < 1%.
 No thermal injury to the urothelium as no heat is produced.
DISADVANTAGES
 Relatively high rate of stone retropulsion

77. SUMMARY
 Adequate fluid intake should be advised so as to maintain
urine output of around 2.5 ltr/day.
 Patients on conservative management should be in regular
follow up.
 Obstructed kidney with infection and deranged renal
functions is an emergency.

78. SUMMARY
 Dietary advise is important.
 The primary goal of surgical stone management is to achieve
maximal stone clearance with minimal morbidity to the
patient.
 Eswl is cosidered in stones upto 2 cm.
 Surgical removal is indicated in larger stones.

79. STONES IN PREGNANCY
 Symptomatic stones during pregnancy -1 in 250(Lewis et al,
2003) to 1 in 3000 (Butler et al, 2000).
 Renal colic is the most common non-obstetric cause of
acute abdominal pain during pregnancy.
 Majority of symptomatic stones occur in the 2nd and 3rd
Trimesters.
 Up to 28% of women are misdiagnosed with appendicitis,
diverticulitis, or placental abruption.

80. STONES IN PREGNANCY CONT.
 USG can miss up to 40% of stones.
 Most stones pass spontaneously and complications are rare.
 Physiologic hydronephrosis occurs in up to 90% of
pregnant women and persists up to 4 to 6 weeks postpartum.

81. STONES IN PREGNANCY CONT.
 Physiologic dilatation  crystallization due to urinary stasis,
and the increased renal pelvic pressure increase the
likelihood of stone movement and symptoms.
 Pregnant women have been shown to excrete increased
amounts of inhibitors such as citrate, magnesium, and
glycoproteins.
 Thus, the overall risk of stone formation has been reported
to be similar in gravid and nongravid women.

82. STONES IN PREGNANCY CONT.
 Treatment of stones at any location in the collecting system :-
ureteroscopic access
 Ionizing radiation exposure is minimized by use of
- a below-table x-ray source
- shield the fetus with a lead apron placed below
the patient

83. RENAL TRANSPLANTATION
 Stones associated with renal transplantation are rare.
 Peri-renal nerves are severed at the time of renal harvesting.
Thus, Classic renal colic is not found in these patients.
 The patients usually are admitted with the presumptive
diagnosis of graft rejection.
 Only after appropriate radiographic and ultrasonic
evaluation the correct diagnosis is made.

84. THANK YOU