| Definition: |
Cystinuria is a disorder characterized by stones in the kidney, ureter, and bladder. It is caused by excessive excretion of certain amino acids (protein building blocks) because of genetic abnormality. (See also nephrolithiasis).
|
| Alternative Names: |
Stones - cystine; Cystine stones
|
| Causes, incidence, and risk factors: |
Cystinuria is an inherited autosomal recessive disorder. The kidneys do not adequately resorb certain amino acids during the filtering process, thus resulting in excess excretion of these amino acids. The amino acids may precipitate and form crystals or stones in the kidneys, ureters, or bladder.
The disorder is usually diagnosed after an episode of stones, where analysis of the composition of the stones indicates cystine. Less than 3% of known urinary tract stones are cystine stones.
Cystinuria affects approximately 1 out of 10,000 people. Cystine stones are most common in young adults under age 40. |
| Symptoms: |
- Flank pain or pain in the side
- On one side only (unilateral) or -- rarely, both sides
- Often severe
- May be progressive, getting increasingly worse over days
- May travel or radiate to lower flank, pelvis, groin, genitals
- Blood in the urine
|
| Treatment: |
Treatment goals include relief of symptoms and preventing the development of further stones. Hospitalization may be required if symptoms are severe.
Stones are usually passed spontaneously. The urine should be strained, and the stone saved for analysis of the type of stone. The patient should drink enough fluid to produce large amounts of urine. Water is encouraged, usually at least 6 to 8 glasses per day. Consistently high liquid intake is the mainstay of treatment. Intravenous fluids may be required.
Cystine is more soluble in alkaline solution, so sodium bicarbonate or sodium citrate (or similar medications) may be used to alkalinize the urine. Other medications (penicillamine) may be used to increase the solubility of cystine.
Analgesics may be needed to control renal or ureteric colic (pain associated with the passage of stones).
If the stone is not excreted spontaneously, surgical removal may be necessary.
Lithotripsy may be an alternative to surgery. In this procedure, ultrasonic waves or shock waves are used to break up stones so that they may be expelled in the urine (extracorporeal shock wave lithotripsy), or removed with an endoscope that is inserted into the kidney via a small flank incision (percutaneous nephrolithotomy). Lithotripsy is not as successful for removal of cystine stones as it is for other types of stones.
|
| Expectations (prognosis): |
| Cystinuria is a chronic and lifelong condition. The incidence of symptomatic stone formation is variable, but recurrence of stones is common. The disorder seldom results in kidney failure, and it does not affect other organs. |
| Calling your health care provider: |
| Call your health care provider if symptoms indicating urinary tract stones are present. |
| Prevention: |
| There is no known prevention for cystinuria. Any person with a known history of stones in the urinary tract should drink enough fluids to maintain a high urinary output by day and by night, allowing stones and crystals to be excreted before they become large enough to cause symptoms. Keeping the urine alkaline diminishes the risk of cystine stones. |
|
 |
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).
|
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2003 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
|
