2. Introduction
• A kidney stone is a solid piece of material that
forms in a kidney when substances that are
normally found in the urine become highly
concentrated
• Kidney stones are one of the most common
disorders of the urinary tract
• One in every 20 people develop kidney stones
at some point in their life
3. Symptoms
• Intermittent colicky flank pain – radiation to
lower abdomen or groin
• Nausea and vomiting
• Dysuria
• Urinary urgency
• Restlessness
• Hematuria
4. Risk factors
• Family history
• Hypercalciuria
• Cystic kidney disease
• Hyperparathyroidism
• Renal tubular acidosis
• Dehydration from low fluid intake
• High dietary intake of animal protein
• Crohn’s disease
5. Diagnosis
• Detailed medical and dietary history
– Medical conditions
– Nutritional factors in diet
– Medications (probenecid, some protease inhibitors, lipase inhibitors,
triamterene, chemotherapy, vitamin C, vitamin D)
• Serum chemistries
– electrolytes (sodium, potassium, chloride, bicarbonate), calcium, creatinine
and uric acid
• Urinanalysis
– Dipstick and microscopic evaluation
• Review of imaging studies
– Plain radiography
– Ultrasonogrphy
– CT
• 24 hour urine profile
• Stone analysis
7. Diet therapy
• Fluid intake that will achieve a urine volume of at least 2.5
liters daily
• Calcium stones and relatively high urinary calcium – limit
sodium intake and consume 1,000-1,200 mg per day of
dietary calcium
• Calcium oxalate stones and relatively high urinary oxalate
- limit intake of oxalate-rich foods and maintain normal
calcium consumption
• Calcium stones and relatively low urinary citrate - increase
intake of fruits and vegetables and limit non-dairy animal
protein
• Uric acid stones / calcium stones and relatively high
urinary uric acid - limit intake of non-dairy animal protein
• Cystine stones - limit sodium and protein intake
8. Pharmacologic therapy
• Thiazide diuretics - high or relatively high urine calcium and recurrent
calcium stones
• Potassium citrate - recurrent calcium stones and low or relatively low
urinary citrate
• Allopurinol - recurrent calcium oxalate stones who have hyperuricosuria
and normal urinary calcium
• Thiazide diuretics and/or potassium citrate - recurrent calcium stones in
whom other metabolic abnormalities are absent or have been
appropriately addressed and stone formation persists
• Potassium citrate - uric acid and cystine stones to raise urinary pH to an
optimal level
• Cystine-binding thiol drugs (tiopronin) - cystine stones who are
unresponsive to dietary modifications and urinary alkalinization, or have
large recurrent stone burdens
• Acetohydroxamic acid (AHA) - residual or recurrent struvite stones only
after surgical options have been exhausted
• Should not routinely offer allopurinol as first-line therapy to patients with
uric acid stones
10. Follow up
• Should obtain a single 24-hour urine specimen
for stone risk factors within six months of the initiation
of treatment to assess response to dietary and/or
medical therapy
• After the initial follow-up, should obtain a single 24-
hour urine specimen annually or with greater
frequency, depending on stone activity, to assess
patient adherence and metabolic response
• Obtain periodic blood testing to assess for adverse
effects in patients on pharmacological therapy
• Obtain a repeat stone analysis, when available,
especially in patients not responding to treatment
11. • Monitor patients with struvite stones for
reinfection with urease-producing organisms
and utilize strategies to prevent such
occurrences
• Periodically obtain follow-up imaging studies
to assess for stone growth or
new stone formation based on stone activity
