Topic: Renal Stone Diseases Faculty: Medicine Course: BSc RDT - 2nd year - Nephrolithiasis - Risk factors - Types of stones - Clinical features, diagnosis - Treatment

1. Renal stone diseases
Dr. Salman Ansari
Kanachur Institute of Medical Sciences

2. Contents
● Nephrolithiasis
● Risk factors
● Types/classification
● Clinical features
● Diagnosis
● Treatment

3. Obstructive uropathy
Definition: obstruction in the urinary passage which leads to
impedance to urine flow and damage to renal function
- Can be acute or chronic
Causes: congenital defect, tumours, calculus, trauma
- In males: benign prostatic hypertrophy(BPH), prostate
cancer
- In females: cervical cancer, uterine cancer, ovarian cancer

4. Clinical features:
- Abdominal or flank pain
- Nocturia
- Dysuria
- Urinary urgency, frequency
- Decreased force of stream
Investigations: renal function tests(RFT), urinalysis,
USG abdomen, CT abdomen

5. Treatment:
- Correct electrolyte abnormalities
- Treat the cause of obstruction
- Catheterisation using Foley’s catheter
Complications:
- Acute or chronic renal failure

7. Nephrolithiasis
Other names: kidney stones, renal calculi
‘’Formation of aggregates of microscopic crystals into solid
stones’’

8. Risk factors for renal stones
Environmental factors Congenital disorders

9. Risk factors for renal stones
Environmental factors
- Low intake of fluid
- High protein/high sodium/low
calcium diet
- High excretion of sodium, oxalate
and urate
- Low excretion of citrate
- Hypercalcemia
Congenital disorders

10. Risk factors for renal stones
Environmental factors Congenital disorders
- Medullary sponge
kidney
- Familial
hypercalciuria
- Cystinuria
- Renal tubular
acidosis(RTA)

11. - Usually made of calcium or phosphate with small
amounts of proteins
- Size: varies from mm to cm
- Age: middle age usually
- Gender: M>F
- Risk of recurrence within 3 to 5 years

12. Risk factors for renal stones
● Normal urine contains inhibitors of crystal formation(e.g:
citrate, inorganic magnesium) that prevent formation of
calculi
● When the chemical concentration of urine is altered, the
calculus forming substances exceed maximum solubility
in water and favour crystal formation

13. Classification
Types of renal stones are as follows:
1. Calcium oxalate or calcium phosphate(80%)
2. Uric acid
3. Struvite(Magnesium, Ammonium, phosphate)
4. Cystine
5. Others

15. Calcium stones
- 80% of renal stones
- Calcium with oxalate or phosphate
- Radio opaque
Causes:
● Idiopathic hypercalciuria: Most common
● Hypercalciuria and hypercalcemia
● Hyperoxaluria: Enteric (oxalate-containing foods, salt, meat)
Vitamin C abuse
● Hyperuricosuria
● Idiopathic

16. Uric acid stones
- Commonly found in patients with hyperuricemia (e.g.
gout) and diseases involving rapid cell turnover (e.g.
leukemias)
- Uric acid is insoluble in acidic urine and urine pH below
5.5 is a risk factor for developing uric acid stones.
- They are radiolucent stones.
Causes:
● Associated with hyperuricemia
● Associated with hyperuricosuria
● Idiopathic

17. Uric acid stones

18. Struvite Stones - Magnesium, Ammonium, Phosphate
- Calcium phosphate with with magnesium and ammonium
phosphate - also called triple phosphate stones
- Also called ‘’Staghorn calculus’’
- develop after UTI by urea-splitting bacteria (e.g. Proteus) which
convert urea to ammonia → produces alkaline pH + slowing of
urine flow → precipitation of magnesium, ammonium,
phosphate (struvite), and calcium phosphate (apatite).

20. Cystine stones
- associated with a genetic condition called cystinuria,
which is due to genetic defects in the renal reabsorption
of cystine or other amino acids.
- Stones form at low urinary pH (acidic urine).
- Radiopaque stones
- Recur frequently in most affected individuals.
- Diagnosis is suggested by a positive urine nitroprusside
test and confirmed by analysis of the calculus.
- Urine sediment: characteristic hexagonal cystine
crystals

21. Cystine stones

23. Clinical features
- Renal colic: severe colicky pain in flank or
abdomen with hematuria
- Can be asymptomatic
- Nausea, vomiting
- Dysuria
- Frequency
- Urgency
- Fever: suggests UTI

24. Diagnosis
● CT-KUB(CT of kidney, ureter and bladder): gold
standard
● Abdominal USG
● Plain X-ray of abdomen
● Urine analysis: for blood, UTI
● Microscopic examination for crystals
● Other lab tests: RFT, electrolytes, calcium, magnesium,
phosphate and uric acid

25. Treatment of renal stones
● Acute management
● Chronic management

26. Acute management
- Powerful analgesic: e.g: oral or i.v diclofenac
- Increase water intake to maintain a daily urinary output of 2 L
- If not possible to take orally, i.v fluids should be given
- Small stones(<5 mm in diameter): may be passed
spontaneously
- Alpha blockers e.g: tamsulosin - help to expel stones

27. - Stone>1 cm - needs intervention such as
- Extracorporeal Shock Wave Lithotripsy(ESWL):
breaks the stone into smaller pieces
- Percutaneous nephrolithotomy(PCNL)
- Surgical removal: only in complicated cases

28. ESWL

31. Chronic management
- Increase fluid intake
- Avoid vitamin D and vitamin C supplements

32. For calcium-containing stones:
- Modify diet to reduce risk of stone formation
- Thiazide diuretics to reduce calcium excretion in urine
- Potassium citrate(60 mEq/day) to prevent recurrence
- Avoid food rich in oxalates. E.g: spinach, chocolate, potatoes

34. For uric acid stones:
- Allopurinol 100-200 mg/day
- Alkalinisation of urine to a pH of 7 or more to dissolve uric acid
crystals
- Potassium citrate
For cystine stones: alkalinise urine to a pH of 7.5 or above, using
Shohl’s solution(sodium citrate)

35. Questions:
LE: Define nephrolithiasis. Name various types of nephrolithiasis.
Explain causes, classification, diagnosis and management of
renal stone diseases.
SE: Explain obstructive uropathy
- Elaborate renal stone disease
- obstructive uropathy in males
- Obstructive uropathy in females
SA:

36. For notes, click here
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References:
● Archith Boloor, Ramadas Nayak - Exam
Preparatory Manual
Questions:
salman.s.ansari92@gmail.com
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