Urinary calculi are composed of substances normally found in urine that precipitate out of solution to form stones. The most common types of stones found are calcium oxalate, calcium phosphate, uric acid, and cystine. Risk factors for stone formation include dehydration, diet, medical conditions, and anatomical abnormalities. Management involves dietary changes to reduce stone-forming substances in urine, increased fluid intake, and surgical procedures like ESWL or ureteroscopy for stone removal.

1. M.Prasad Naidu
Msc Medical Biochemistry,
Ph.D. research scholar

2. Renal calculi:
The smooth epithileal tissue are formed the hardness by the
inorganic and organic substance like
kidney--------- stone ( calcium)
gall bladder---- stone ( cholesterol oxalates)
intestine ------- jejunum (hard substance)
Introduction:
Urinary calculi are mainly composed of substance normally in
urine and may be found in any part of the urinary tract.
Their size of an egg. These calculi can be divided into:

3. Simple calculi
Mixed calculi
Foreign body calculi
Formatin: The nucleus for stone can be obtained by the
presence of a small lesion. The crystals get deposited on the
nucleus and continue to grow. These can some times adhere
to the renal papillae.
Substances found in calculi : They are mainly uric acid,
urate , triple phosphate, calcium carbonate ,calcium
phosphate, calcium oxalates, cholesterol. Cystine calculi have
been reported but are extremly rare, and xanthin also form
stones ( xanthinuria)

4. COMPARATIVE INCIDENCES OF FORMS OF URINARY LITHIASIS
Stone analysis in Percentage
Form of Lithiasis India USA Japan UK
Pure Calcium Oxalate 86.1 33 17.4 39.4
Mixed Calcium Oxalate and 4.9 34 50.8 20.2
Phosphate
Magnesium Ammonium 2.7 15 17.4 15.4
Phosphate (Struvite )
Uric Acid 1.2 8.0 4.4 8.0
Cystine 0.4 3.0 1.0 2.8

5. Inhibitors & Promoters of Stone Formation in Urine
INHIBITORS
Inhibits crystal Growth -
 Citrate – complexes with Ca
 Magnesium – complexes
with oxalates
 Pyrphosphate - complexes
with Ca
 Zinc
Inhibits crystal Aggregation
 Glycosaminoglycans
 Tamm- Horsfall Protein
PROMOTERS
 Bacterial Infection
 Anatomic Abnormalities –
PUJ obst., MSK
 Altered Ca and oxalate
transport in renal epithelia
 Prolonged immobilisation
 Increased uric acid levels I.e
taking increased purine
subs– promotes
crystalisation of Ca and
oxalate

6. TYPES OF RENAL / URETER STONES
 Common stones:
 OXALATE (CALCIUM OXALATE)
 PHOSPHATE
 URIC ACID / URATE
 CYSTINE

7. Uncommon Stones
XANTHINE STONES
–(AutosomalRecessive.DefofXanthineOxidaseleadingtoXanthinuria)
DIHYDROXY ADENINE STONE
– ( Def. of enzyme adenine phospo ribosyl transferase )
SlLICATE STONES
– Rare in humans ( excess intake of Antacid with Mg Trisilicate. Mostly in cattle due to
ingestion of Sand )
MATRIX
- Infection by Proteus - Radiolucent (all calculi have some amt ( 3%) of matrix but
matrix calculus has 65% Matrix content in calculi)

8. Stones – BIO Chemical Constituents
Whewelite – Calcium Oxalate Monohydrate – CaC2
O4
-H2O
Weddelite - Calcium Oxalate dihydrate – CaC2
O4
-2H2O
Brushite – Calcium Hydrogen phosphate dihydrate – CaHPO4 2H2O
Whitlockite - TriCalcium Phosphate – Ca2(PO4)2
Struvite – Magnesium Ammonium hexahydrate – MgNH4PO4-6H2O

9. D/D of Radiolucent filling defect on IVU in Ureter or Kidney
Must Know
Uric Acid Calculus
Matrix Calculus
Sloughed Papilla
Blood Clots
TCC
Renal Cysts
Vascular Lesions
Know For Brownie Points
 Xanthine Calculus
 Hydroxy adenine Calculus
 Ephederine Calculus
 Infection due to gas forming Org.
 Fungal Ball
 Tuberculoma
 Malacoplakia
 Hyper trophied Papilla
 Renal pseudo-tumour

10. OXALATE (CALCIUM OXALATE)
 ALSO CALLED MULBERRY STONE
 COVERED WITH SHARP PROJECTIONS
 SHARP → MAKES KIDNEY BLEED (HAEMATURIA)
 VERY HARD
 RADIO - OPAQUE
Under microscope looks like Hourglass or Dumbbell shape if monohydrate and
Like an Envelope if Dihydrate

11. Bio chemical test for oxalate stone
Procedure:
 Make fine powder
Add 2 to 3 drops of 10% Hcl
Cool it and add pinch Mn O2- do not mix
Result: fomation of gas bubbles form bottom

12. PHOSPHATE STONE
 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

13. Bio chemical test for phosphate stone
Procedure:
Make fine powder
Add o.5ml of ammonium molybdate warm over a gas flame
Results: formation of yellow precipitate.

14. PHOSPHATE STONES
 IN ALKALINE URINE
↓
ENLARGES RAPIDLY
↓
TAKE SHAPE OF CALYCES
↓
STAGHORN →

15. CALCIUM PHOSPHATE STONES
Hyperparathyroidism Ca P
Renal Tubular Acidosis K CO2
Medullary Sponge Kidney -
PTH Hormone Promotes renal production of 1-25-dihyroxycholecalciferol – active Vit.D and also
increases absorption of Calcium and decreases Phosphorus absorption from Kidneys

16. URIC ACID & URATE STONE
 HARD & SMOOTH
 MULTIPLE
 YELLOW OR RED-BROWN
 RADIO - LUCENT (USE ULTRASOUND)
pKa of uric acid 5.75 at this pH 50% of uric acid insoluble.
If pH falls further - uric acid more insoluble

17. Bio chemical test for urate stone
Murexide test
Procedure:
Make fine powder of the stone by using mortor
Take a pinch of the powder in a test tube
Add 1 drop of 20g/dl Na2 Co3.
Add 2drops of phopho tungstic acid reagent
Results : formation of deep blue color.
Clinical significance: gout

18. CYSTINE STONE AUTOSOMAL RECESIVE DISORDER
 USUALLY IN YOUNG GIRLS
 DUE TO CYSTINURIA -
 CYSTINE NOT ABSORBED BY TUBULES
 MULTIPLE
 SOFT OR HARD – can form stag-horns
 PINK OR YELLOW
 RADIO-OPAQUE
Under microscope appears like hexagonal or benezene
ring – ask for first morning sample

19. CYSTINE STONE - Management
High Fluid Intake and Alkalanise Urine – dissolve most of the
smaller cystine stones
D-Pencillamine or MPG (Mercaptopropionylglycine) binds to
cystine that is soluble in urine
Side effects of Pencillamine restricts it use – Allergic rashes, GI
problems- Nausea, Vomiting, Diarrhoea
MPG better tolerated
Large obstructive stones – Surgery required first
Cyanide Nitroprusside Calorimeteric Test for detecting Cystinuria. If positive do
amino acid chromatography

20. Bio chemical test for cystine stone
Procedure:
Make fine powder
Add 1 drop of ammonium hydrooxide reagent and one drop
of
Na Cl reagent, wait for 5 min
add 2-3 drops of sodium nitroprusside reagent
Result: beet red color changes to orange is standing
Clinical significance: cystinuria

21. Cause of Stone Disease
 Supersaturation of urine is the key to stone formation
 Intermittent supersaturation - Dehydration
 Crystal aggregation
 Anatomic Abnormailities – PUJ , MSK
 Bacterial Infection
 Defects in transport of Calcium and Oxalate by Renal
epithelia
E.Coli infection increases matrix content in urine . Proteus makes urine alkaline

22. Surgical Conditions and Stone Disease
Regional ileitis and Ileal Bypass Surgery for eg
Obesity can lead to increase oxalate absorption
and stone ds
ileostomies - In Chr. Diarrhoea with– Bicabonate
loss – systemic acidosis and acidic urine –
increases risk of Uric Acid stones

23. HISTORY
A. IS PATIENT DRINKING ENOUGH ?
B. PROFESSION
C. ENQUIRE ABOUT UTI → STONES
D. FAMILY HISTORY
E. LONG ILLNESS → BEDRIDDEN → STONES

24. MANAGEMENT OF STONES
HISTORY :
A. FIND OUT IF DRINKING ENOUGH LIQUIDS
(NOT DRINKING ENOUGH IMPORTANT CAUSE OF
STONE FORMATION & GROWTH)

25. HISTORY (Cont...)
B. ASK ABOUT THEIR PROFESSION
DEHYDRATION → STONES CAN FORM e.g.
 MARATHON
 WORK NEAR A FURNACE,
 BRICK - LAYER, LABOURERS & WEAVERS
 TRUCK & BUS DRIVERS

26. CLINICAL FEATURES
1. PAIN IN 75 % OF THE CASES
“RENAL COLIC” IF SEVERE AND ACUTE
A) KIDNEY STONE
FIXED PAIN IN THE LOIN
B) URETERIC STONE
PAIN RADIATES → LOIN TO GROIN

27. CLINICAL FEATURES (Contd....)
2) HAEMATURIA
 CAN BE FRANK
 OR ONLY FOUND ON DIP - STICK OR LAB.
3) PYURIA - IF INFECTION CAN HAVE PUS IN URINE

28. Clinical Features
acute obstruction of
ureter---severe colic
flank pain referred to
genitalia
 nausea, vomiting may
mislead and look like
gi problem
microhematuria likely
chronic stone dis.
tends to be associated
with large or multiple
stones
can be little or no pain
may have impaired
renal function, anemia,
weight loss etc.
concomitant infection
more likely

29. Clinical Risk Factors
occupation
family history
diet
hydration
small bowel disease (i.b.d.)
medical conditions causing hypercalcuria
medical conditions causing aciduria

30. ON EXAMINATION
1. ACUTE PRESENTATION
 ABDOMEN TENSE AND RIGID
 TENDERNESS PRESENT IN THE LOIN
2.ASSYMPTOMATIC PRESENTATION
 NO TENDERNESS, FINDINGS IN ABDOMEN

31. INVESTIGATIONS
1. FULL BLOOD COUNT TO CHECK FOR
(ANAEMIA IF GOING FOR SURGERY)
2. SERUM ELECTROLYTES / UREA / CREATININE / CALCIUM / URIC ACID / PHOSPHATE/
BICARBONATES
3. 24-HOURS URINE FOR ELECTROLYTES
(Only if recurrent stone former)
CALCIUM / OXALATE / URIC ACID /
CYSTINE / CITRATE/ URATES

32. INVESTIGATIONS (Cont...)
4. PLAIN KUB X-RAY OF ABDOMEN (Mandatory)
5. IVU OR IVP (INTRA VENOUS UROGRAM)
 Not Mandatory
 Useful for radio-lucent stones & to detect Congenital Anomalies in Urinary
tracts
6. ULTRASOUND (Mandatory)
7. CT – TO LOOK AT UNUSUAL ANATOMY OF THE KIDNEY (To
differentiate cause of acute colic – stone or anuria Suspected due to stone

33. Bilateral Ureteric Calculus in a patient presenting with AnuriaBilateral Ureteric Calculus in a patient presenting with Anuria
Helical or Spiral CT provides 3D reconstruction. Helical refers to path the X ray follows on
Gantry. These are rapidly performed and do not require contrast agents for reconstruction.

34. MANAGEMENT OF UROLITHIASIS
Non-invasive approach to urinary calculas-HALLMARK of
last 20 yrs.
Lithotripters –
1.Extra Corporeal Shock wave
2.Intra Corporeal
Better fiber optics – Mini turisation of Telescopes
Accessories - Innovative variety

35. Modern Management of Urolithiasis
 ESWL
 Ureterorenoscopy
 Percutaneous Nephrolithotomy
 Laparoscopic Approach to stones
Open Ureterolithotomy, Pyelolithotomy or Nephropyelolithotomy is required in less
than 1 to 2% of modern stone management

36. EXTRA - CORPOREAL SHOCK WAVE LITHOTRIPSY
(ESWL)
SHOCK WAVES GENERATED UNDER WATER CAN TRAVEL
THROUGH BODY WITHOUT ANY APPRECIABLE LOSS OF
ENERGY. WHEN THEY ENCOUNTER STONES THE
CHANGES IN DENSITY CAUSES ENERGY TO BE ABSORBED
AND REFLECTED BY THE STONE & THIS RESULTS IN
FRAGMENTATION OF THE STONES.

37. ESWL – For Urinary Tract CalculusESWL – For Urinary Tract Calculus

38. ESWL
Absolute Contra-indication-
Pregnancy
Relative Contra-Indications for ESWL –
 Renal Colic
 Urinary obstruction
 Infection
 Declining Renal Function
 Significant Hematuria

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

40. Renal Lithiasis Blood Pressure Study
(Patients treated 1984-1986 Dallus Study)
First Follow Up Second Follow Up
1988 1990
No.Pts Annualized Rate No. Pts Annualized Rate
of Hypertension of Hypertension
 ESWL 771 2.5% 590 2.1%
 non-ESWL 195 3.8% 155 1.6%
 Total 966 745

41. Diet & Fluid Advice
High Fluid Intake
Restrict Salt (Na)
Oxalate Restrict
Avoid high intake of Purine food
Increased citrus fruits may help
If hypercalciuria restrict Ca intake
Role of Potassium Citrate in preventing Cal Oxalate stone ds – KCit lowers
urinary calcium whereas Na Citrate does not lower Calcium due to Sodium load

42. Moderate Amounts : High Amounts :
Apple Juice Cocoa
Beer Fresh Tea
Coffee
Cola
FOODS :
Almonds, Asparagus, Cashew Nuts, Currants, Greens,
Plums, Raspberries, Spinach

43. Clinical significance of Renal Stones
all urinary stones are composed of 98% crystalline material
and 2% mucoprotein
the crystalline component(s) may be found “pure” or in
combination with each other.
the common characteristic that all crystalline components
share, is that they have a very limited solubility in urine
99% of renal stones (in western hemisphere) are composed
of:
calcium oxalate 75% (mono or di hydrate)
calcium hydroxyl phosphate (15%)(apatite)
magnesium ammonium phosphate 10% (struvite)
uric acid 5%

44. investigations show that the formation of a stone is similar
to the development of a crystalline mass in vitro
given that stone formation is an example of crystallization
one could predict:
the necessity for a supersaturated state in urine
the occurrence of spontaneous crystallization
the need for the earliest polycrystalline state to be arrested in
the u.t. allowing time for growth

45. Spontaneous Crystallization
normal urine has crystals (at times)
normal urine is extremely effective in maintaining a stable
supersaturated state
there are certain components of urine that
enhance ability to maintain ss state
inhibit development of crystals

46. Principles of Stone Prevention
prevent supersaturation
water! water and more water enough to make 2L of urine per
day
prevent solute overload by low oxalate and moderate Ca intake
and treatment of hypercalcuria
replace “solubilizers” i.e... citrate
manipulate pH in case of uric acid and cystine
flush! forced water intake after any dehydration

47. Treatment Renal Stones
> 2cm or multiple stones, percutaneous ultrasonic lithotripsy
(pul)
large branched stones “staghorn” may require pul and eswl.
cystine stones pul or open nephrolithotomy
MAJORITY : 80 TO 85 % of all stones can be treated by -
EXTRA - CORPOREAL SHOCK WAVE LITHOTRIPSY (ESWL)
MINORITY : 15 TO 20 % SHOULD NEED MINIMALLY INVASIVE SURGERY
(PCNL / URETEROSCOPY)
(LESS THAN 1 % SHOULD NEED OPEN SURGERY)

48. Treatment:
small ureteral stones
with good chance of
passage (<7 mms)
allow time to pass (2-
4 weeks)
lower ureter-
ureteroscopic stone
removal
mid-upper ureter eswl
large ureteral stones
(>7mms)
eswl
ureteroscopic stone
fragmentation
open surgery