Health Encyclopedia

Cystinuria

Definition

Cystinuria is a condition passed down through families in which stones form in the kidney, ureter, and bladder.

Alternative Names

Stones - cystine; Cystine stones

Causes, incidence, and risk factors

Cystinuria is an autosomal recessive disorder, so you must inherit the faulty gene from both parents in order to have symptoms.

Cystinuria is caused by too much of an amino acid called cystine in the urine. After entering the kidneys, most cystine normally dissolves and goes back into the bloodstream. But people with cystinuria have a genetic defect that interferes with this process. As a result, cystine builds up in the urine and forms crystals or stones, which may get stuck in the kidneys, ureters, or bladder.

About one in every 10,000 people have cystinuria. Cystine stones are most common in young adults under age 40. Less than 3% of urinary tract stones are cystine stones.

Symptoms

Blood in the urine
Flank pain or pain in the side or back
- Usually on one side; rarely felt on both sides
- Often severe
- May get increasingly worse over days
- Pain may also be felt in the pelvis, groin, genitals, or between the upper abdomen and the back.

Signs and tests

The disorder is usually diagnosed after an episode of kidney stones. Analysis of the stones shows they are made of cystine.

Tests that may be done to detect stones and diagnose this condition include:

Abdominal CT scan, MRI, or ultrasound
Intravenous pyelogram (IVP)
Urinalysis (may show cystine crystals)
24-hour urine collection (shows high levels of cystine)

Treatment

The goal of treatment is to relieve symptoms and prevent the development of more stones. A person with severe symptoms may need to be admitted to a hospital.

Treatment involves drinking plenty of fluids, particularly water, so that large amounts of urine are produced. The patient should drink at least 6-8 glasses per day.

In some cases, fluids may need to be given through a vein (by IV).

Medications may be prescribed to help dissolve the cystine crystals. Eating less salt can also decrease cystine excretion and stone formation.

Pain relievers may be needed to control pain in the kidney or bladder area associated with the passage of stones. The stones usually pass through the urine on their own. If they do not, surgery may be needed:

Percutaneous nephrostolithotomy or nephrolithotomy
Ureteroscopy, for stones in the lower urinary tract
Extracorporeal shock wavelithotripsy (ESWL). This procedure is not as successful for removal of cystine stones as it is for other types of stones)

Expectations (prognosis)

Cystinuria is a chronic, lifelong condition. Stones commonly return. However, the condition rarely results in kidney failure, and it does not affect other organs.

Complications

Bladder injury from stone
Ureteral obstruction
Kidney injury from stone
Kidney infection
Urinary tract infection

Calling your health care provider

Call your health care provider if you have symptoms of urinary tract stones.

Prevention

There is no known prevention for cystinuria. Any person with a known history of stones in the urinary tract should drink plenty of fluids to regularly produce a high amount of urine. This allows stones and crystals to leave the body before they become large enough to cause symptoms.

References

Rogers A, Kalakish S, Desai RA, Assimos DG. Management of cystinuria. Urol Clin North Am. 2007;34(3).

Review Date:8/30/2009
Reviewed By:Louis S. Liou, MD, PhD, Assistant Professor of Urology, Department of Surgery, Boston University School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional 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. © 1997-A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

The Agency for Health Care Administration (Agency) and this website do not claim the information on, or referred to by, this site is error free. This site may include links to websites of other government agencies or private groups. Our Agency and this website do not control such sites and are not responsible for their content. Reference to or links to any other group, product, service, or information does not mean our Agency or this website approves of that group, product, service, or information.

Additionally, while health information provided through this website may be a valuable resource for the public, it is not designed to offer medical advice. Talk with your doctor about medical care questions you may have.