Hyperoxaluria

What is hyperoxaluria?

Hyperoxaluria is a condition that occurs when there’s too much oxalate in your pee. Oxalate is a chemical your body makes naturally. It’s also in some foods. Your kidneys typically filter oxalate, and it comes out in your pee or poop. But for people with hyperoxaluria, oxalate builds up in their kidneys and mixes with calcium to form kidney stones and calcium oxalate crystals. Both can damage your kidneys and cause them not to work as well. Over time, this can cause kidney damage and kidney failure. Excess oxalate can prevent your body from absorbing other nutrients and lead to oxalate building up in other tissues and organs in your body.

Genetics, gastrointestinal (GI) conditions and eating foods high in oxalate can cause hyperoxaluria. Getting treatment for hyperoxaluria can help reduce the chances of long-term kidney damage.

Types of hyperoxaluria

There are three types of hyperoxaluria: primary hyperoxaluria, enteric hyperoxaluria and dietary hyperoxaluria.

• Primary hyperoxaluria (PH) is a rare genetic disorder (a condition that runs in biological families) of your liver. It occurs when your liver either doesn’t produce enough enzymes to prevent the overproduction of oxalate or the enzymes don’t work properly. There are three subtypes of primary hyperoxaluria, but all of them involve a genetic mutation that affects your liver.
• Enteric hyperoxaluria is when a gastrointestinal condition causes your body to absorb excess oxalate, which leads to having too much oxalate in your pee. Examples of intestinal conditions that can lead to hyperoxaluria are Crohn’s disease and inflammatory bowel disease. Conditions that prevent your small intestine from absorbing nutrients properly can also cause hyperoxaluria because oxalate isn’t absorbed and filtered properly. This can happen with gastric bypass surgery.
• Dietary hyperoxaluria happens when you eat foods high in oxalate. Some of these foods include spinach, beets, soy, almonds and potatoes.

What age does hyperoxaluria start?

Symptoms of hyperoxaluria can develop anytime from infancy to adulthood. The average age that symptoms appear is 5 years old.

People with primary hyperoxaluria tend to get recurring kidney stones as a child or teenager (usually before age 20). If infants develop primary hyperoxaluria, the condition tends to be severe. About 50% of these children will experience kidney failure by age 15. About 80% will experience kidney failure by age 30.

People with enteric and dietary hyperoxaluria tend to develop kidney stones and other symptoms in adulthood.

How common is hyperoxaluria?

Hyperoxaluria is rare, but healthcare providers can’t be entirely sure of how rare. Less than 1,000 people have primary hyperoxaluria in the United States. Enteric and dietary hyperoxaluria are less common.

What are the symptoms of hyperoxaluria?

Kidney stones are usually the first symptom. But not everyone with hyperoxaluria has kidney stones. Some other signs of hyperoxaluria could include:

• Blood in your pee.
• Recurrent urinary tract infections (UTIs).
• Failure to thrive as an infant.

Signs and symptoms of kidney stones include:

• Pain in your low back, side or lower abdomen. Pain can start as a dull ache that may come and go or become severe.
• Nausea and/or vomiting with the pain.
• Feeling the need to pee more often.
• Pain when peeing.
• Being unable to pee or peeing tiny amounts at a time.
• Fever/chills.
• Urine that smells bad or looks cloudy or bloody.

It’s important to report any kidney stones in your child to their pediatrician as this can often be a sign of hyperoxaluria.

What causes hyperoxaluria?

Hyperoxaluria occurs when you have excess oxalate in your pee. Oxalate can combine with calcium in your pee and cause kidney stones and crystals to form.

The three causes of hyperoxaluria are:

• A genetic mutation (primary hyperoxaluria). This means you get the condition from your biological parents.
• Intestinal disorders. Certain health conditions that affect your GI tract can cause you to have too much oxalate in your pee.
• Diet. People who eat large quantities of foods that are high in oxalate can have too much oxalate in their pee.

What are the risk factors for hyperoxaluria?

Having a biological parent with hyperoxaluria is the biggest risk factor for developing the condition yourself. Even people who don’t have symptoms can pass primary hyperoxaluria on to their children. Your healthcare provider may offer you genetic testing if your biological siblings have primary hyperoxaluria.

You may also be at greater risk if you:

• Have recurring kidney stones.
• Had kidney stones as a child (even one time).
• Have a family history of kidney stones.
• Have calcium deposits on your kidneys.

What are the complications of hyperoxaluria?

Kidney damage, which can lead to kidney failure, is the main complication of hyperoxaluria.

When kidney damage sets in, your kidneys can’t eliminate excess oxalate. This causes oxalate crystals to build up in other areas of your body like your blood, bones, muscles and heart. When oxalate builds up in your body’s tissues or organs, it’s called oxalosis.

Oxalosis can cause other health problems like:

• Bone disease.
• Anemia.
• Heart and eye problems.
• Growth and development problems in children.

How is hyperoxaluria diagnosed?

In addition to a physical exam, medical history and diet history, typical tests used to diagnose hyperoxaluria include:

• Urine tests to measure levels of oxalate and enzymes in your pee.
• Blood test to measure kidney function and the amount of oxalate in your blood.
• Imaging tests (X-rays, ultrasound and/or CT scan) of your kidneys and urinary tract to check for kidney stones or calcium oxalate crystals.

If you pass a kidney stone or have kidney stones surgically removed, a healthcare provider can analyze the stone to see what it consists of.

What tests will be done to diagnose hyperoxaluria?

Your provider may order other tests to determine if your other tissues contain oxalate. These tests include:

• Echocardiogram (echo) to look for oxalate deposits in your heart.
• Eye exam to check for oxalate deposits in your eye.
• Bone marrow biopsies to look for oxalate deposits in your bones.
• CT scan (computed tomography scan) to detect calcium or oxalate deposits in your bowel wall, muscles and arteries.

If your healthcare provider suspects primary hyperoxaluria, they may do genetic testing to determine if you have the gene mutation that causes it.

How is hyperoxaluria treated?

The goal of treatment is to lower the level of oxalate in your body and prevent calcium oxalate crystals from forming in your kidneys and other body tissues. Treatments could involve medication, lifestyle and dietary changes, and managing kidney stones. Your healthcare provider will recommend the best treatment based on the type of hyperoxaluria you have, your symptoms and how severe your condition is.

Medication

• For people with primary hyperoxaluria, medication options include a prescription dose of vitamin B6 (pyridoxine) to reduce oxalate levels. Thiazide diuretics are an option for people with a specific subtype of PH.
• For people with any type of hyperoxaluria, medication options include oral doses of potassium citrate or the combination of orthophosphate and magnesium to prevent calcium oxalate crystals from forming.
• For people with enteric hyperoxaluria, taking a calcium supplement with meals can also help. Calcium binds with oxalate, which may help oxalate leave your body through your pee and poop.

Lifestyle and diet

Drinking more fluids and making changes to your diet can help with high oxalate. It’s worth noting that diet changes don’t help manage primary hyperoxaluria since this type of hyperoxaluria is genetic. Lifestyle and diet treatments include:

• Increase your water intake to around 3 liters per day. Extra fluids help to flush oxalate from your kidneys, which prevent it from building up and creating stones or crystals. This should help all types of hyperoxaluria.
• Change your diet by limiting salt and sugar, eating less animal protein (meat, milk, eggs and fish) and avoiding foods high in oxalates. High-oxalate foods include spinach, rhubarb, beets, plums, chocolate, tea, nuts and nut butters.
• Adding calcium-rich foods to meals can help reduce oxalate levels. Calcium naturally binds to oxalate, so eating calcium-rich foods at meals helps with this.

Managing kidney stones

If you have kidney stones, the stones may pass on their own by drinking lots of water. If your kidney stones don’t pass, your healthcare provider may need to remove them. Not all kidney stones need to be removed. Your healthcare provider will discuss this option with you.

Dialysis or transplantation

If hyperoxaluria becomes severe, your kidneys may not work as well. If this happens, kidney dialysis can help. If you have primary hyperoxaluria, organ transplantation (kidney, liver or both) may be necessary. The type of transplant depends on the specific type of primary hyperoxaluria.

Can you prevent hyperoxaluria?

You can’t prevent primary hyperoxaluria because it’s in your genes. If someone in your family has primary hyperoxaluria, your healthcare provider can screen you for this gene mutation. If you receive a diagnosis of primary hyperoxaluria, treatment can begin before any symptoms or kidney damage occurs.

If you receive a diagnosis of enteric or dietary hyperoxaluria, you should follow your healthcare provider’s treatment plan to reduce complications from the condition.

What can I expect if I have hyperoxaluria?

Left untreated, hyperoxaluria can eventually lead to kidney damage and even kidney failure or death. Depending on its severity and the type, kidney dialysis and organ transplant may be necessary.

In addition, oxalate crystals can build up in other areas of your body and cause bone disease, anemia and other medical issues. Because of these complications, prompt diagnosis and early treatment are important.

There’s no cure for primary hyperoxaluria. The goal is to protect your kidneys by preventing kidney stones and calcium oxalate deposits in other body tissues. People with enteric and dietary hyperoxaluria can find relief with medication and lifestyle and dietary changes.

Your healthcare provider will talk with you about your type of hyperoxaluria and provide a treatment plan to best manage it. It’s critical for people living with hyperoxaluria to follow their provider’s treatment plan and have regular exams with their urologist or primary care provider.

When should I see my healthcare provider?

Contact your healthcare provider if you have signs of kidney stones, as this is often the first symptom of hyperoxaluria. Signs of kidney stones include:

• Pain in your lower back, sides, lower abdomen or groin area.
• Red, pink or brown in your pee.
• Changes in how often and how much you pee.
• Pain when you pee.

A note from Cleveland Clinic

Getting a hyperoxaluria diagnosis can make you feel overwhelmed and leave you with many questions. Lean on your healthcare team, family, friends and others for support as you navigate the best treatment options based on your symptoms. It’s crucial to follow the treatment plan your healthcare provider recommends. This can help prevent kidney damage and other systemic complications.