The document discusses kidney stones, which are solid, crystalline concretions that can cause pain and obstruction, with an increasing prevalence in the industrialized world. It outlines the various types, risk factors, and diagnostic approaches for kidney stones, as well as treatment options that include hydration, pain management, and potential surgical intervention. Key factors influencing stone composition, clinical presentation, and indicators for hospitalization and referral to a urologist are also addressed.

1. M. N. Jalalian
Faculty of Medicine
Tehran University of Medical
Sciences

2. Definition
 Presence of calculi (stones) in the kidney or
collecting system
 Usually small (2-12 mm), solid, crystalline
concretions
 Calcium salts, uric acid, cystine, or struvite
 Stones < 0.5 cm without symptoms
 Larger calculi cause pain and obstruction
 Staghorn calculi (struvite, cystine, and uric
acid) can grow as large as renal pelvis

4. Epidemiology
 3rd common problem of urinary tract
 In the U.S., ~13% of men and 7% of women
during their lifetime
 Prevalence is increasing throughout the industrialized world.
 Sex
 Calcium and uric acid More common in men
○ Calcium stones
 Male-to-female ratio, 2-3:1
 Onset in the third to fourth decades of life
 Struvite stones are more common in women
○ Male-to-female ratio, 1:3

5. Risk Factors
 Family history: calcium and uric stones
 UTI with urease-producing bacteria
 Diet high in oxalate, purine, and calcium
 Poor fluid intake
 Gout
 Chronic bladder catheterization: struvite
stones
 Prior stone formation
 50% of people who form a single calcium stone form
another within the subsequent decade

6. Etiology
 Types of Stones
 Calcium stones
○ Calcium oxalate and calcium phosphate
stones
 Uric acid stones
 Struvite stones
 Cystine stones
 Other types
○ Xanthine, Indinavir, etc.

7. Etiology
Calcium stones
 75-85% of renal stones
 Major causes
 Hypercalciuria
○ Absorptive
 Type I: relatively unresponsive to dietary modifications (15%)
- Treatment: Cellulose phosphate, thiazide diuretics (limited)
 Type II: responds to moderate dietary calcium restriction.
 Type III: renal phosphate leak (5%)
- Hypophosphatemia  ↑ activation of vitamin D-3  ↑
intestinal absorption  ↑ urinary excretion
- Treatment: orthophosphate

8.  Hypercalciuria…
○ Resorptive hypercalciuria
(hyperparathyroidism)
 5-10%
 Resection of parathyroid adenoma
○ Renal leak hypercalciuria
 Defect in kidney
 Mild hypocalcemia and secondary
hyperparathyroidism
 Treatment: thiazide diuretics (long-term)

9. Etiology
Calcium stones
 Hyperuricosuria (20%)
 secondary to dietary excesses or uric
acid metabolic defects
 pH > 5.5
 Treatment
○ Limited purine in diet
○ Allopurinol

10.  Hyperoxaluria (20%)
 Small-bowel disease
○ Causing fat malabsorption
 Dramatic effect
 Treatment
○ Oxalate binders (Ca, Mg, other cations)
○ dietary oxalate restriction
 Hypocitraturia (20-40%)
 Can be primary or secondary

11. Etiology
Struvite stones
 5-10%
 Magnesium-ammonium-phosphate (MAP)
 Common in women with recurrent UTI
 urease-producing bacteria
○ Proteus, Pseudomonas, or Providencia species
 pH > 7.2 (Nl = 5.85)

12. Etiology
Uric acid stones
 5-10%
 Hyperuricosuria
 Gout
 Myeloproliferative syndromes
 Chemotherapy
 high purine intake
 pH < 5.5
 Treatment: alkali therapy,, allopurinol

13. Etiology
 Cystine stones
 1-3%
 Cystinuria
○ autosomal recessive disorder
○ defective proximal tubular and jejunal transport of
cystine, lysine, arginine, and ornithine
○ Clinical disease due to insolubility of cystine
 Drug-induced stone disease
 Indinavir
 tazanavir; triamterene; silicate

14. Clinical Presentation
 Pain
 Usually very severe
 Sudden onset
 Localized to the flank, with radiation to the groin
 Colicky
 Hematuria
 Infection
 Fever
 Nausea and vomiting
 Patient constantly moving

15. Differential Diagnosis
 Pyelonephritis
 Acute abdomen
 Gynecologic problems
 Diverticulitis
 Abdominal aortic aneurysm
 Aortic dissection
 Appendicitis
 Biliary colic
 Perforating duodenal ulcer
 Viral gastroenteritis
 Acute pancreatitis
 Urinary tract infection

16. Diagnostic Approach
 Clinical suspicion
 Rapid imaging
 Ultrasonography
 Noncontrast spiral CT scanning
 likelihood of passing spontaneously
 < 4 mm: 80%
 4-6 mm: 60%
 >6 mm: 20%
 U/A

17. Imaging
 Plain abdominal radiography
 KUB radiography
 size, shape, and location of urinary calculi
 Radiopaque
○ Calcium-containing stones,
○ Cystine
○ struvite stones are
 Radiolucent
○ pure uric acid

19.  Spiral CT without contrast
 Preferred tool when KUB is nondiagnostic
 Advantages
○ More sensitive
○ Identify other pathology
 Disadvantages
○ More costly than intravenous pyelography

20.  Ultrasonography
 Advantages
○ Detects uric acid or cystine stones (not in KUB)
○ Inexpensive
○ Readily available
 Disadvantages
○ Ureteral calculi, especially in the distal ureter,
and stones < 5 mm not easily observed

21.  Intravenous pyelography
 Formerly the standard (for size and location)
 Advantages
○ Both anatomic and functional
○ Stones vs calcification
 Disadvantages
○ Intensive and time consuming if severe
obstruction
○ Requires bowel preparation for optimal results
○ Allergic and nephrotoxic contrast material

22. Treatment Approach
 Goal : Remove existing stones and prevent
stone recurrence
 Treatment depends on:
 Location of the stone
 Nature of the stone
 Extent of obstruction
 Function of affected and unaffected kidney
 Presence or absence of urinary tract infection
 Progress of stone passage
 Risk of operation or anesthesia

23.  Stones already present
 Combined medical and surgical approach
 Oral α1-adrenergic blockers
○ Relax ureteral muscle
○ Reduce time to stone passage
○ Reduce need for surgical removal of small
stones

24. Indications for stone removal
 A stone, usually >5mm, that does not
pass spontaneously
 Severe obstruction
 Infection
 Intractable pain
 Serious bleeding

25. Management of renal colic
 Hydration
 Pain control
 Parenteral: morphine sulfate and/or
intravenous NSAID (e.g.,ketorolac)
 Oral: narcotic (codeine, oxycodone,
hydrocodone) plus acetaminophen together
with an NSAID, such as ibuprofen
 Antiemetic agents
(e.g.,metoclopramide orprochlorperazi
ne)

26.  Strain urine
 Antibiotics, if infection is suspected
 Agents to relax the ureters
 α1-blockers (e.g.,tamsulosin 0.4 mg PO daily
30 minutes after a meal)
○ Faster and fewer hospitalization
 Calcium-channel blockers

27. When to hospitalize
 Intractable pain requiring parenteral
medications
 Persistent vomiting
 Obstruction with infection
 Solitary kidney with obstruction

28. When to refer to urologist
 Obstruction
 Stone size > 6 mm
 Infection
 Failure to progress
 Solitary kidney
 Pregnancy
 Severe renal disease

29. Thank you for your
attention