Kidney Stones Facts and Myths

MYTH: Kidney stones are common in adults.

FACT: Although kidney stones (renal calculi) are a common cause of urinary tract obstruction in adults, only about 1% of Americans will develop one.

MYTH: Uric acid stones are the most common type.

FACT: Calcium oxalate accounts for 75% to 80% of all kidney stones; uric acid, only 7%. Other substances include struvite (magnesium, ammonium, and phosphate) stones, accounting for 15%, and cystine, accounting for less than 1%.

MYTH: Anxiety is usually the key symptom of an acute kidney stone episode.

FACT: Pain is the hallmark symptom of an acute episode. The pain's location and severity vary with the site of the stone. For example, a stone obstructing the ureter causes a colicky pain as the ureter contracts rhythmically to advance the stone.

MYTH: Patients prone to kidney stones should drink at least I liter of fluid per day.

FACT: Teach your patient that drinking at least 2.5 liters a day (unless contraindicated) helps prevent urinary stasis that can lead both to stone formation and urinary tract infection. Water is the best fluid to drink.

MYTH: More than half of kidney stones are associated with urinary tract infection.

FACT: More than half of kidney stones are idiopathic, although urinary tract infection is a major predisposing factor. Other factors associated with stone development include long-term use of antacids that contain calcium, hyperparathyroidism, and high uric acid levels.

MYTH: Less than half of kidney stones are passed spontaneously.

FACT: Up to 85% of kidney stones are passed spontaneously. Whether intervention is needed depends on the stone's position and related factors. In the absence of infection and obstruction, and with adequate pain control, a stone may be left to pass on its own.

Last updated Dec 12/06