51 NEPHROLITHIASIS General Discussion The lifetime risk of passing a kidney stone is about 8–10% among North American males, with a peak incidence at age 30 years. Women have a risk about half that of men. Among patients who have passed one kidney stone, the lifetime recurrence rate is 60–80%. About 80% of kidney stones contain calcium, and the majority of these stones are composed of calcium oxalate. A minority contain calcium phosphate or admixtures of oxalate and phosphate salts. About 10% of stones are composed of uric acid. Another 10% are struvite stones which develop exclusively in patients with urinary tract infections caused by urease-producing organisms such as Proteus species. Cystine accounts for about 1% of all stones, but only occur in patients with cystinuria, an autosomal recessive disorder. Some controversy exists about the extent of investigation required after the passage of a single stone. Since the rate of recurrence is high, many experts favor a thorough evaluation for anyone who has passed a stone. A comprehensive urinary evaluation or referral is required for patients in whom multiple stones are detected clinically or radiographically, patients with anatomic abnormalities of the urinary tract, patients with a strong family history of nephrolithiasis, and patients with cystine or uric acid stones. Plain abdominal radiography, ultrasonography, intravenous pyelography (IVP), helical CT scanning, and MRI scanning can be used to demonstrate stones in the renal tract. IVP has been considered the gold standard for many years, but noncontrast helical CT scanning is now the preferred imaging modality in many centers because it is faster and more sensitive than IVP and does not require the use of intravenous contrast material. In addition, CT scanning may identify other causes of abdominal pain masquerading as renal colic. Medications Associated with Nephrolithiasis Acetazolamide Ascorbic acid Calcium supplementation Carbonic anhydrase inhibitors Corticosteroids Cytotoxic agents used for malignancies Indinavir Silicate Sulfonamides Triamterene Causes of Nephrolithiasis Hypercalciuria Hyperoxaluria Hyperuricosuria Hypocitraturia Idiopathic Infection (Proteus, Klebsiella, Serratia, and Mycoplasma urinary tract infection) Renal tubular acidosis type I Key Historical Features ✓ Patient age ✓ Frequency of stone formation ✓ Past medical history • Anatomic abnormalities of the renal system • Crohn’s disease Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: ARTHRITIS AND ARTHRALGIA HAIR LOSS HYPOTHYROIDISM SYNCOPE Stay updated, free articles. Join our Telegram channel Join Tags: Instant Work-ups A Clinical Guide to Medicine Aug 17, 2016 | Posted by admin in PEDIATRICS | Comments Off on NEPHROLITHIASIS Full access? Get Clinical Tree
51 NEPHROLITHIASIS General Discussion The lifetime risk of passing a kidney stone is about 8–10% among North American males, with a peak incidence at age 30 years. Women have a risk about half that of men. Among patients who have passed one kidney stone, the lifetime recurrence rate is 60–80%. About 80% of kidney stones contain calcium, and the majority of these stones are composed of calcium oxalate. A minority contain calcium phosphate or admixtures of oxalate and phosphate salts. About 10% of stones are composed of uric acid. Another 10% are struvite stones which develop exclusively in patients with urinary tract infections caused by urease-producing organisms such as Proteus species. Cystine accounts for about 1% of all stones, but only occur in patients with cystinuria, an autosomal recessive disorder. Some controversy exists about the extent of investigation required after the passage of a single stone. Since the rate of recurrence is high, many experts favor a thorough evaluation for anyone who has passed a stone. A comprehensive urinary evaluation or referral is required for patients in whom multiple stones are detected clinically or radiographically, patients with anatomic abnormalities of the urinary tract, patients with a strong family history of nephrolithiasis, and patients with cystine or uric acid stones. Plain abdominal radiography, ultrasonography, intravenous pyelography (IVP), helical CT scanning, and MRI scanning can be used to demonstrate stones in the renal tract. IVP has been considered the gold standard for many years, but noncontrast helical CT scanning is now the preferred imaging modality in many centers because it is faster and more sensitive than IVP and does not require the use of intravenous contrast material. In addition, CT scanning may identify other causes of abdominal pain masquerading as renal colic. Medications Associated with Nephrolithiasis Acetazolamide Ascorbic acid Calcium supplementation Carbonic anhydrase inhibitors Corticosteroids Cytotoxic agents used for malignancies Indinavir Silicate Sulfonamides Triamterene Causes of Nephrolithiasis Hypercalciuria Hyperoxaluria Hyperuricosuria Hypocitraturia Idiopathic Infection (Proteus, Klebsiella, Serratia, and Mycoplasma urinary tract infection) Renal tubular acidosis type I Key Historical Features ✓ Patient age ✓ Frequency of stone formation ✓ Past medical history • Anatomic abnormalities of the renal system • Crohn’s disease Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: ARTHRITIS AND ARTHRALGIA HAIR LOSS HYPOTHYROIDISM SYNCOPE Stay updated, free articles. Join our Telegram channel Join Tags: Instant Work-ups A Clinical Guide to Medicine Aug 17, 2016 | Posted by admin in PEDIATRICS | Comments Off on NEPHROLITHIASIS Full access? Get Clinical Tree
