I had a patient last night who has a history of kidney stones who came in with another episode. To try to pass the stone, he drank 3 gallons of cranberry juice. Here’s the low down:
Kidney Stones
Introduction
Kidney stones (nephrolithiasis) are relatively common with up to 12% of men and 5% of women having a stone in their lifetimes. The annual incidence of urinary tract stones in the industrialized world is estimated to be 0.2%.
Pathophysiology
Kidney stones are caused by crystal aggregations formed in the kidneys from dissolved urinary materials. Kidney stones are mainly made of calcium oxylate crystals or uric acid (~75%). Nearly 15% are caused by magnesium-ammonium-struvite (phosphate) which is usually the result of recurrent UTIs.
Treatment
Nearly 90% of stones 4mm or less will pass spontaneously and 99% of stones greater than 6mm will require some sort of intervention.
When a patient comes to the emergency department with a kidney stone the standard treatment is:
- Pain control with an opiate (morphine, dilaudid) and/or anti-inflamatory (toradol)
- Anti-nausea medication
- Antibiotics, if evidence of infection
- Intravenous hydration is recommended but using fluids to flush out stones is not shown to be beneficial.
Kidney Stones and Cranberry Juice
Apple and cranberry juice contain oxalates, and both have been associated with a higher risk for risk for calcium oxalate stones. Cranberry juice has properties that may increase the risk for both calcium oxalate and uric acid stones. On the other hand, cranberry juice helps prevent urinary tract infections and so may be helpful for reducing the risk for struvite and brushite stones. (These stones are far less common, however.) For many years it was believe cranberry juice could be used as a home remedy to help prevent kidney stones. After the latest research results were concluded it is now believed cranberries may very well be the causes of kidney stones.
References:
UptoDate.com
About.com
Emedicine
Newton CR, Khare R, “Emergency Medicine”