Hyperoxaluria occurs when you have too much oxalate in your urine. Oxalate is a natural chemical in your body, and it's also found in certain types of food. But too much oxalate in your urine can cause serious problems.

Hyperoxaluria can be caused by inherited (genetic) disorders, an intestinal disease or eating too many oxalate-rich foods. Quick diagnosis and treatment of hyperoxaluria is important to the long-term health of your kidneys.

Oxalosis happens after the kidneys fail in people who have primary and intestinal causes of hyperoxaluria, and excess oxalate builds up in the blood. This can lead to oxalate deposits in blood vessels, bones and body organs.

  • Experience. Mayo Clinic is one of the most experienced medical centers in the world in caring for people who have genetic (primary) and intestinal forms of hyperoxaluria.
  • Special expertise and team approach. The Mayo Clinic Hyperoxaluria Center in Minnesota brings together doctors from many specialties to design a personalized treatment plan, based on the type and severity of hyperoxaluria and any related conditions. Mayo Clinic offers a range of services, from treatment to reduce oxalate in your urine, to minimally invasive procedures for kidney stone treatment and removal. Or, if needed for severe hyperoxaluria, Mayo's highly skilled surgeons can perform kidney or kidney-liver transplants.
  • Specialized testing. Mayo Clinic's laboratory has special capability to run specific tests for hyperoxaluria, such as measurement of oxalate in blood and urine and DNA testing, that aren't widely available.
  • Efficient care. Mayo Clinic coordinates your testing and doctor appointments to speed the process of diagnosis and treatment. A specialist in kidney diseases (nephrologist) usually manages your care.
  • Research. The Mayo Clinic Hyperoxaluria Center in Minnesota conducts research to understand the disease and find more effective treatments. When appropriate, you have the opportunity to participate in the Rare Kidney Stone Consortium primary hyperoxaluria registry and in clinical trials to test new diagnosis and treatment options.

Mayo Clinic in Rochester, Minn., ranks #1 for kidney disorders in the U.S. News & World Report Best Hospitals rankings. Mayo Clinic in Scottsdale, Ariz., is ranked among the Best Hospitals for kidney disorders, and Mayo Clinic in Jacksonville, Fla., is ranked high performing for kidney disorders by U.S. News & World Report.

About

There are several types of hyperoxaluria:

  • Primary hyperoxaluria. Primary hyperoxaluria is a rare inherited (genetic) condition present at birth. In this type, the liver doesn't create enough of a certain protein (enzyme) that prevents overproduction of oxalate, or the enzyme doesn't work properly. Excess oxalate is eliminated through your kidneys, in your urine. The extra oxalate can combine with calcium to create kidney stones and crystals, which can damage the kidneys and cause them to stop working (renal failure).

    Kidney stones form early and most often cause symptoms during childhood or adolescence. Because of the very large amounts of oxalate produced, most people's kidneys fail by early to middle adulthood, but renal failure can occur as early as infancy. To date, experts have identified three different genetic causes of primary hyperoxaluria.

  • Oxalosis. Oxalosis occurs if you have primary hyperoxaluria and your kidneys fail. Because your body can no longer eliminate the extra oxalate, it starts accumulating — first in your blood, then in your eyes, bones, skin, muscles, blood vessels, heart and other organs. This can cause multiple problems.
  • Enteric hyperoxaluria. Several intestinal diseases, including Crohn's disease and short bowel syndrome as a result of surgical procedures, increase the absorption of oxalate from foods, which can then increase the amount of oxalate excreted in the urine.
  • Hyperoxaluria related to consuming high-oxalate foods. Eating large amounts of foods high in oxalate can increase your risk of hyperoxaluria or kidney stones. Ask your doctor or dietitian for a list of high-oxalate foods. Avoiding high-oxalate foods is particularly important if you have enteric hyperoxaluria.

Resources

Below are some helpful Internet resources on this topic. Mayo Clinic does not own or control any of these sites and is not responsible for their content. Inclusion of these sites does not imply endorsement by Mayo Clinic.

Oxalosis & Hyperoxaluria Foundation

Rare Diseases Clinical Research Network

Rare Kidney Stone Consortium

Mayo Clinic works with hundreds of insurance companies and is an in-network provider for millions of people. In most cases, Mayo Clinic doesn't require a physician referral. Some insurers require referrals or may have additional requirements for certain medical care. All appointments are prioritized on the basis of medical need.

At Mayo Clinic in Arizona, specialists in nephrology, urology and transplantation offer coordinated diagnosis and treatment of hyperoxaluria. Diagnosis and treatment are carried out in consultation with the Mayo Clinic Hyperoxaluria Center in Minnesota.

For appointments or more information, call the Central Appointment Office at 800-446-2279 (toll-free) 8 a.m. to 5 p.m. Mountain Standard Time, Monday through Friday or complete an online appointment request form.

At Mayo Clinic in Florida, specialists in nephrology, urology and transplantation offer coordinated care of hyperoxaluria. Diagnosis and treatment are carried out in consultation with the Mayo Clinic Hyperoxaluria Center at Mayo Clinic in Minnesota.

For appointments or more information, call the Central Appointment Office at 904-953-0853 8 a.m. to 5 p.m. Eastern time, Monday through Friday or complete an online appointment request form.

Mayo Clinic in Minnesota is one of the largest and most experienced medical centers in the world for treating hyperoxaluria. The Mayo Clinic Hyperoxaluria Center specializes in the care of both children and adults with hyperoxaluria. Mayo Clinic in Minnesota also has a Stone Clinic, specializing in the diagnosis and management of kidney stone disease, including rare types of stone disease. Mayo Clinic is the home of the Rare Kidney Stone Consortium, which is a member of the Rare Diseases Clinical Research Network of the National Institutes of Health.

Specialists in nephrology, urology, medical genetics and transplantation at Mayo Clinic in Minnesota work together to diagnose and treat adults and children who have hyperoxaluria.

For appointments or more information, call the Central Appointment Office at 507-538-3270 7 a.m. to 6 p.m. Central time, Monday through Friday or complete an online appointment request form.

At Mayo Clinic in Minnesota, pediatric specialists in nephrology and urology coordinate the diagnosis and treatment of hyperoxaluria in children. If inpatient care is needed, Mayo Eugenio Litta Children's Hospital offers the highest expertise in a family-friendly environment.

For appointments or more information, call the Central Appointment Office at 507-538-3270 7 a.m. to 6 p.m. Central time, Monday through Friday or complete an online appointment request form.

See information on patient services at the three Mayo Clinic locations, including transportation options and lodging.

Your doctor will conduct a thorough physical exam, including a medical history and discussion of your diet. Tests to diagnose hyperoxaluria may include those below.

  • Urine tests measure oxalate and other metabolite levels in the urine.
  • Blood tests show kidney function as well as oxalate levels in the blood.
  • Stone analysis determines the composition of kidney stones passed or surgically removed.
  • Kidney X-ray, ultrasound or computerized tomography (CT) scan shows any kidney stones or calcium oxalate deposits.

If these tests indicate that you may have primary hyperoxaluria, you'll likely need more tests to confirm the diagnosis and see how the disease has affected other parts of your body. These tests may include:

  • DNA testing to look for inherited causes (primary hyperoxaluria)
  • Kidney biopsy to look for oxalate deposits
  • Echocardiogram to check for oxalate deposits in the heart
  • Eye exam to check for oxalate deposits in the eyes
  • Bone marrow biopsy to check for oxalate deposits in the bones
  • Liver biopsy to look for enzyme deficiencies — only needed in rare cases where genetic testing does not reveal the cause of hyperoxaluria

If primary hyperoxaluria is suspected or confirmed, your siblings are at risk of the disease and should be tested as well. If your child has primary hyperoxaluria, you may want to consider genetic testing if you plan to have more biological children. Medical genetics counselors experienced in hyperoxaluria can help guide your decisions and testing.

Symptoms

Typically, the first sign of hyperoxaluria is a kidney stone. Symptoms of a kidney stone can include:

  • Severe or sudden back pain or pain over the area below the ribs on the back (flank) that doesn't go away
  • Blood in the urine
  • Frequent urge to urinate
  • Pain when urinating
  • Chills or fever

Kidney stones in childhood are uncommon. Kidney stones that form in children and teenagers are likely to be caused by an underlying condition, such as hyperoxaluria. For this reason, all young people with kidney stones should have a thorough evaluation, including measurement of oxalate in the urine. Adults with recurrent kidney stones also should be evaluated for oxalate in the urine.

Untreated primary hyperoxaluria can eventually damage your kidneys. Over time your kidneys may stop working. For some people, this is the first sign of the disease. Signs and symptoms of kidney failure include:

  • Decrease in urine output or no urine output at all
  • Feeling generally ill and tired
  • Loss of appetite, nausea and vomiting
  • Pale skin color related to anemia
  • Swelling of hands and feet

Oxalosis in its late stages can cause a variety of complications outside the kidney, including bone disease, anemia, skin ulcers, heart and eye problems, and in children, a failure to develop and grow normally.

Treatment will depend on the type, symptoms and severity of hyperoxaluria and how well you respond to treatment.

Reducing oxalate

To reduce the amount of calcium oxalate crystal formation in your kidneys, your Mayo Clinic medical team may recommend one or more of these treatments:

  • Medications. Prescription doses of vitamin B-6 can be effective in reducing oxalate in the urine in some people with primary hyperoxaluria. Oral preparations of phosphates and citrate help prevent the formation of calcium oxalate crystals. Other medications, such as thiazide diuretics, also may be considered, depending on which other abnormalities are present in your urine.
  • High fluid intake. If your kidneys are still functioning normally, your doctor will likely tell you to drink more water or other fluids. This flushes the kidneys, prevents oxalate crystal buildup and helps keep kidney stones from forming.
  • Dietary changes. The effectiveness of diet will depend on the cause of increased levels of oxalate. Diet may include restricting foods high in oxalates, limiting salt, and decreasing animal protein and sugar (high fructose corn syrup). This may help to lower urinary oxalate in people with enteric hyperoxaluria or excess dietary intake. Dietary restrictions may not be as important for all people with primary hyperoxaluria. Follow the advice of your doctor.

Kidney stone management

Kidney stones are common in people with hyperoxaluria, but they don't always need to be treated. If large kidney stones are causing pain or blocking urine flow, you may need to have them removed or broken up so they can pass in the urine. Mayo Clinic is experienced in kidney stone treatment and removal and offers several minimally invasive procedures.

Dialysis and transplant

Depending on the severity of your hyperoxaluria, you may eventually lose kidney function. Kidney dialysis may help temporarily, but it doesn't keep up with the amount of oxalate produced. A kidney transplant or kidney and liver transplant can cure certain inherited types of hyperoxaluria (primary hyperoxaluria). Mayo Clinic provides outstanding transplant teams, led by highly skilled surgeons and medical transplant teams experienced in the care of patients with primary hyperoxaluria.

Mayo Clinic is active in several areas of research on hyperoxaluria, coordinated through the Mayo Clinic Hyperoxaluria Center and the Rare Kidney Stone Consortium in Rochester, Minn. The center maintains an international registry of data on people with hyperoxaluria, compiles statistics on outcomes, and maintains a bank of urine, plasma, blood and liver samples for investigation and collaborative research.

The center offers people the opportunity to participate in clinical trials, testing new diagnosis and treatment approaches.

Ongoing research projects include:

  • Genetic mutations in primary hyperoxaluria and correlation with disease outcomes
  • New technology for measuring calcium content and stones in the kidneys
  • Evaluation of new treatments for hyperoxaluria, including use of the oxalate-degrading bacteria Oxalobacter formigenes
  • Evaluation of the effect of diet on urine oxalate levels
  • Effect of hydroxyproline on urine oxalate levels in people with primary hyperoxaluria
  • Quality of life in patients with primary hyperoxaluria and other people who develop kidney stones

Publications

See a list of publications by Mayo Clinic doctors on hyperoxaluria on PubMed, a service of the National Library of Medicine.

Apr. 01, 2013