Understanding the Causes, Diagnosis, and Types of Hyperoxaluria
Kidney stones are common, but recurring stones may be a sign of an underlying condition called hyperoxaluria. Understanding the cause of elevated urine oxalate is an important step toward getting the right diagnosis and appropriate care.
Quick Summary
- Hyperoxaluria is a condition in which there is too much oxalate in the urine. It is an important cause of calcium oxalate kidney stones.
- Calcium oxalate stones are the most common type of kidney stone, accounting for up to 80% of all kidney stones.
- There are three main types of hyperoxaluria: dietary, enteric (gut-related), and primary (genetic). Each has different causes and may require different approaches to diagnosis and management.
- Identifying the type of hyperoxaluria is important because diagnosis and management differ for each type.
- Early diagnosis matters. In some people, untreated or poorly managed hyperoxaluria, particularly primary and enteric hyperoxaluria, can contribute to chronic kidney disease or kidney failure.
What Is Oxalate?
Oxalate is a natural substance made by your body and found in many healthy plant foods. Most people process oxalate without any problems.
Hyperoxaluria occurs when too much oxalate ends up in the urine. When oxalate combines with calcium, crystals can form and grow into calcium oxalate kidney stones.
Not everyone with elevated urine oxalate develops kidney stones. Many factors including genetics, digestive health, kidney function, hydration, and diet can influence a person’s risk.
The Three Types of Hyperoxaluria
Although the symptoms may be similar, the causes and management of hyperoxaluria differ depending on the type.
Dietary Hyperoxaluria
Dietary hyperoxaluria occurs when a person’s diet contributes to elevated urine oxalate levels. It is the most common cause of hyperoxaluria and is not a genetic disease.
Learn more about dietary hyperoxaluria.
Enteric Hyperoxaluria
Enteric hyperoxaluria develops when the digestive tract absorbs too much oxalate from food. This most often occurs when conditions that affect fat absorption allow the body to absorb more oxalate from food than normal. Conditions associated with enteric hyperoxaluria include:
- Crohn’s disease
- Inflammatory bowel disease (IBD)
- Celiac disease
- Short bowel syndrome
- Chronic pancreatitis
- Cystic fibrosis
- Bariatric surgery (including procedures such as Roux-en-Y gastric bypass)
- Other conditions that affect fat absorption
People with enteric hyperoxaluria may experience recurrent calcium oxalate kidney stones and, in some cases, progressive chronic kidney disease or kidney failure. Early recognition and appropriate management of fat malabsorption and enteric hyperoxaluria may help reduce complications.
Learn more about enteric hyperoxaluria.
Primary Hyperoxaluria
Primary hyperoxaluria (PH) is a rare inherited disease caused by genetic changes that cause the liver to produce excessive amounts of oxalate.
Most people with PH have one of three recognized forms (PH1, PH2, or PH3), although some people have an unclassified or as-yet unidentified genetic cause of the disease.
Without appropriate diagnosis and treatment, PH can lead to recurrent kidney stones, nephrocalcinosis, chronic kidney disease, and kidney failure.
Learn more about primary hyperoxaluria.
At a Glance
The Three Types of Hyperoxaluria
How Does Hyperoxaluria Cause Kidney Stones?
When urine contains high levels of oxalate, calcium oxalate crystals can form in the kidneys. Over time, these crystals may grow into kidney stones.
Other factors, such as low urine volume, low urinary citrate, and high urinary calcium, can also increase the likelihood of stone formation.
Kidney Stones by the Numbers
- Up to 80% of kidney stones are calcium oxalate stones.
- Kidney stones affect millions of people worldwide and are becoming more common in many countries.
- People who develop one kidney stone are at increased risk of developing another.
- Hyperoxaluria is an important but often overlooked cause of recurrent calcium oxalate kidney stones.
- Primary hyperoxaluria is a rare genetic disease that is frequently underdiagnosed, leading to delays in diagnosis and treatment.
When Should You Talk to Your Healthcare Provider?
If you have experienced any of the following, it may be appropriate to discuss additional testing with your healthcare provider:
- More than one kidney stone
- Kidney stones beginning during childhood or adolescence
- A family history of kidney stones or kidney failure
- Reduced kidney function
- A digestive disorder associated with fat malabsorption
- A history of bariatric surgery
Depending on your medical history, your healthcare provider may recommend additional testing to determine the cause of elevated urine oxalate.
How Is Hyperoxaluria Diagnosed?
Diagnosis may include one or more of the following:
- A 24-hour urine collection
- Blood tests to evaluate kidney function
- Kidney stone analysis
- Genetic testing when primary hyperoxaluria is suspected
Early diagnosis can help guide treatment, protect kidney health, and reduce the risk of long-term complications.
Managing Hyperoxaluria
Management depends on the type of hyperoxaluria and the underlying cause. Depending on your diagnosis, your healthcare provider may recommend dietary changes, medications, treatment of fat malabsorption, referral to a specialist, or disease-specific therapies for certain forms of hyperoxaluria.
Frequently Asked Questions
How do I know what type of hyperoxaluria I have?
The symptoms of dietary, enteric, and primary hyperoxaluria can be similar, but the causes are different. Your healthcare provider may recommend tests such as a 24-hour urine collection, blood tests, stone analysis, or genetic testing to determine the underlying cause and guide treatment.
Does everyone with kidney stones have hyperoxaluria?
No. Kidney stones can develop for many reasons. Hyperoxaluria is one possible cause, particularly in people with recurrent calcium oxalate kidney stones or certain risk factors.
Are high-oxalate foods bad for everyone?
No. Most people can eat foods containing oxalate as part of a healthy diet without developing kidney stones. However, for people with dietary or enteric hyperoxaluria, foods high in oxalate may contribute to elevated urine oxalate. Your healthcare provider can help determine whether dietary changes are appropriate based on your individual situation.
Can children develop hyperoxaluria?
Yes. Primary hyperoxaluria often begins in childhood and may even present during infancy. Any child with kidney stones should receive an appropriate medical evaluation to determine the underlying cause.
Can hyperoxaluria lead to kidney disease?
Yes. Some forms of hyperoxaluria, particularly primary and enteric hyperoxaluria, can contribute to chronic kidney disease or kidney failure if not recognized and appropriately managed.
When should I talk to my healthcare provider about hyperoxaluria?
If you have recurrent kidney stones, kidney stones that began at a young age (even just one), reduced kidney function, a family history of kidney stones or kidney failure, or certain digestive conditions, ask your healthcare provider whether additional evaluation for hyperoxaluria may be appropriate.
Learn More
Explore additional resources from the Oxalosis & Hyperoxaluria Foundation (OHF):
- About Hyperoxaluria
- Dietary Hyperoxaluria
- Enteric Hyperoxaluria
- Primary Hyperoxaluria
- Find Expert Care – OHF Care Center Network
- Patient Resources
This article is for informational purposes only and is not medical advice. Always consult a qualified healthcare provider with questions about your health or before making changes to your medical care.
Nephrologist & OHF Medical Advisor
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