Urolithiasis

Question 1

Define urolithiasis.

Answer 1

Calculi/urinary stones (urolithiasis) are masses of:
- crystals
- protein
- other substances

that are a common cause of urinary tract obstruction located in:
- kidneys
- ureters
- urinary bladder

Question 2

Who is most likely to develop kidney stones?

Answer 2

Men > Women
Whites > Non-whites

Note: 30% - 50% recurrence rate in 5 years

Question 3

List risk factors for urolithiasis.

Answer 3

• Age
• Gender
• Race
• Fluid intake
• Diet
• Genetic predisposition
• Other conditions:
  - UTI’s
  - HTN
  - Atherosclerosis
  - Metabolic syndrome
  - Obesity
  - Diabetes
  - Gout

Question 4

Urolithiasis is risk factor for which condition/s?

Answer 4

• CKD (risk)
• MI (increased risk)

Question 5

What are the most common types of kidney stones, including prevalence rates?

Answer 5

• Calcium oxalate or phosphate at 70% - 80%
• Struvite (magnesium ammonium, or phosphate) at 15%
• Uric acid at 7%
• Cystine = RARE at <1%

Question 6

Describe signs and symptoms of kidney stones.

Answer 6

• Usually unilateral
• Moderate to SEVERE flank pain with radiation to:
  - lateral flank
  - lower abdomen
  - groin
• Possible s/s:
  - N/V
  - urgency
  - frequent voiding
  - urge incontinence
  - gross or microscopic hematuria

Question 7

What tests might be ordered for a patient with suspected urolithiasis and why?

Answer 7

To diagnose urolithiasis and to identify type of stone:
- UA with pH
- 24-hour urine
- Collection of passed stones via urine straining

Imaging to identify size/location of stones:
- XRAY
- ultrasound
- CT or MRI
- possible intravenous pyelogram

Other PRN tests may be done to diagnose/treat underlying metabolic conditions (i.e., hyperparathyroidism)

Question 8

List the goals of treatment for urolithiasis.

Answer 8

• Manage pain
• Promote stone passage
• Reduce size of already-formed stones
• Prevent new stone formation

Question 9

List the components of treatment for urolithiasis.

Answer 9

• Pain medication
• Alpha blockers or calcium channel blockers to promote stone passage
• Increased fluid intake
• Removal of stones via:
  - percutaneous nephrolithotomy
  - ureteroscopy
  - ultrasound or laser lithotripsy

Question 10

What dietary recommendations should be given to patients who have developed kidney stones?

Answer 10

Recommendations should be made based on type of stone present

General recommendations:
- 2-3 quarts fluid/day
- 3 servings/day dairy with no calcium supplementation
- moderate protein intake
- low salt intake
- 60 mg/day vitamin C intake (< 1000 mg /day)
- Limit oxalate-containing foods:
- spinach
- nuts
- many berries
- chocolate
- wheat bran
- beets
- tea
- rhubarb