Hyperoxaluria – Symptoms and Causes
Overview
Hyperoxaluria happens when a person has too much oxalate in their urine. Oxalate is a waste product that should leave the body through urine. When oxalate levels get too high, it can join with calcium to form kidney stones or damage the kidneys.
Three main types of hyperoxaluria exist: primary, secondary, and enteric. Understanding the differences and identifying signs early is important for protecting kidney health and overall well-being.
Symptoms
Primary hyperoxaluria often shows no symptoms until kidney or bladder stones form. When symptoms do occur, they can vary by severity and age of onset.
Early signs might include:
- Pain in the side, back, or lower belly
- Pain when urinating
- Strong need to urinate often
- Blood in the urine
- Cloudy or smelly urine
- Fever or chills (if infection is present)
As the condition worsens, oxalate can build up in other parts of the body. This can cause:
- Bone pain
- Joint pain
- Skin changes
- Vision problems
In children, hyperoxaluria may affect growth and development. Some kids have their first stone during childhood, while others might not have symptoms until adulthood.
Symptoms become more serious as kidney function declines. People may feel tired, have a poor appetite, or notice swelling in their hands and feet.
When to See a Doctor
Contact your doctor if you notice any symptoms that might suggest hyperoxaluria. Blood in the urine, severe pain in your back or side, frequent urinary tract infections, or passing kidney stones are important warning signs that require medical attention.
If you have a family history of kidney stones or hyperoxaluria, talk to your healthcare provider about screening options.
Seek immediate medical care if you experience:
- Severe, sudden pain in your back or side
- Blood in your urine
- Fever and chills with urinary symptoms
- Inability to urinate
- Nausea and vomiting prevent keeping fluids down
Make sure to bring a list of all symptoms you’re experiencing to your appointment. Your doctor may recommend urine and blood tests to check oxalate levels and kidney function.
What Leads to Hyperoxaluria
Hyperoxaluria develops when there’s too much oxalate in urine. This happens through several different pathways.
| Type | Main Causes |
|---|---|
| Primary | Genetic mutations affecting liver enzymes |
| Secondary | Diets high in oxalate-rich foods |
| Enteric | Digestive disorders, bowel surgeries |
Primary hyperoxaluria is caused by inherited gene mutations that affect liver enzymes responsible for breaking down glyoxylate, a compound that can be converted to oxalate. The most commonly involved genes are AGXT, GRHPR, and HOGA1.
Enteric hyperoxaluria develops when certain gastrointestinal conditions increase oxalate absorption in the intestines. This can happen in people with:
- Weight-loss surgeries
- Inflammatory bowel disease
- Short bowel syndrome
- Chronic diarrhea
Secondary hyperoxaluria occurs from eating too many foods high in oxalate. Foods high in oxalate include:
| High-Oxalate Foods | Oxalate Content |
|---|---|
| Spinach | Very high |
| Rhubarb | Very high |
| Almonds | High |
| Chocolate | Moderate to high |
| Beets | Moderate |
Medication use can sometimes trigger hyperoxaluria. Some vitamin C supplements, when taken in large amounts (over 1,000 mg daily), convert to oxalate in the body.
Dehydration worsens the condition by concentrating oxalate in urine. Not drinking enough water means less dilution of these crystals.
Complications
Hyperoxaluria can lead to several serious health issues if not treated properly. When oxalate builds up in the body, it combines with calcium to form calcium oxalate crystals that can damage various organs.
Kidney stones are the most common complication. These painful mineral deposits form when calcium oxalate crystals cluster together in the kidneys. Some patients may develop recurring kidney stones, which can cause severe pain and potential kidney damage over time.
Kidney damage may occur as calcium oxalate crystals deposit in kidney tissue. This can lead to:
- Reduced kidney function
- Inflammation
- Scarring of kidney tissue
Chronic kidney disease may develop in severe cases. As kidney function worsens, waste products build up in the blood, potentially leading to the need for dialysis or kidney transplantation.
In advanced cases, a condition called oxalosis can develop. This happens when the kidneys can no longer filter out enough oxalate, causing oxalate deposits to form in other body parts including:
- Bones
- Eyes
- Heart
- Blood vessels
- Skin
Children with severe forms of primary hyperoxaluria may experience delayed growth and bone deformities due to oxalate interference with normal bone development.
