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
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
14.
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
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).
19.
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
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
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
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
33.
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
or scan:
References:
● Archith Boloor, Ramadas Nayak - Exam
Preparatory Manual
Questions:
salman.s.ansari92@gmail.com
For PPT, scan: