Are hyperoxaluria and oxalate toxicity dangerous?

Hyperoxaluria is a condition in which there is too much oxalate in the urine. This very condition can have many negative consequences, including damage to impaired kidney function. What causes increased oxalateuria? Let's find out with SignsSymptomsList.

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• 1. An overview of hyperoxaluria and oxalate toxicity
• 2. What are the symptoms of hyperoxaluria?
• 3. When should you see a doctor?
• 4. What causes this oxalate increase?
• 5. Complications of increased urinary oxalate
• 6. Diagnosis of hyperoxaluria
• 7. Treatment of primary hyperoxalate

1. An overview of hyperoxaluria and oxalate toxicity

Hyperoxaluria occurs when you have too much oxalate in your urine. Oxalate is actually a substance that occurs naturally in the body. It is also present in some foods. However, too much oxalate buildup in the urine can lead to a host of health problems.

Increased oxalateuria can be caused by certain genetic conditions, gastrointestinal problems, or simply by eating too many oxalate-rich foods. Timely detection and treatment of the disease will help reduce the extent of kidney damage.

Oxalate poisoning occurs when the kidneys lose the ability to excrete excess oxalate from eating too many oxalate-rich foods or due to intestinal disease. The consequence of oxalate poisoning is the accumulation of this substance in many organs. Includes vessel walls, bones and internal organs.

2. What are the symptoms of hyperoxaluria?

Usually, the first symptom is the appearance of kidney stones. Some of the signs below that suggest you have kidney stones include:

• Sudden, severe pain in the back.
• Pain is located just below the ribs and does not subside.
• Bloody urine.
• Urinary urgency (urinating a lot).
• Painful urination.
• Mild to high fever.

People with increased urinary oxalate may have symptoms of flank pain due to kidney stones.

3. When should you see a doctor?

Kidney stones in young children are very rare. If a child or teen has a kidney stone, it is likely that the child has another underlying medical condition, such as increased oxalateuria.

All young people with kidney stones should see a doctor to help assess the level of oxalate in the urine. Adults with recurrent kidney stones should also have a urine oxalate test. Refer to the article:  Kidney stones: What you should know.

All young people with kidney stones should see a doctor to help assess the level of oxalate in the urine.

4. What causes this oxalate increase?

Hyperoxaluria is caused by excessive self-accumulation of a substance called oxalate in the urine. There are many levels of urinary oxalate elevation, including:

4.1. Primary hyperoxaluria

This is an inherited disease, present from birth. At this time, the liver cannot make enough of an enzyme (essentially a protein) that inhibits overproduction of oxalate, or the enzyme does not work properly. Excess oxalate is eliminated through the kidneys and out of the body in the urine. It is the oxalate in the urine that binds with calcium to form urinary tract stones and small crystals, causing kidney damage and even kidney failure.

Increased urinary oxalate can cause kidney stones.

Because of the overproduction of oxalate, people with this condition have a very early decline in kidney function. People with hyperoxaluria may have impaired kidney function from a very young age, but there are also people with no impairment of kidney function. Now, experts have discovered three different genes that can cause this disease.

Learn more at:  Systemic fibrosis of renal origin: Causes, symptoms, treatment

4.2. Oxalate poisoning

This condition is caused by an excessive increase in oxalate urine and the inability of the kidneys to eliminate excess oxalate from the body. Because of this, oxalate accumulates in the blood, and then to the eyes, bones, skin, muscles, blood vessels, heart, and other organs. Therefore, they lead to many different diseases.

4.3. Increased urinary oxalate due to gastrointestinal causes

There are many gastrointestinal diseases, for example Cohn's syndrome or short bowel syndrome (caused by surgical resection of the bowel) that lead to excessive absorption of oxalate from food, increasing the amount of oxalate excreted in the urine.

4.4. Increased oxalateuria due to eating foods rich in oxalate

Eating large amounts of foods high in oxalate increases the risk of increased oxalateuria and kidney stones. You should consult with your doctor or dietitian to find out which foods are rich in oxalates. Avoid these foods if you have the gastrointestinal disease mentioned above.

5. Complications of increased urinary oxalate

Untreated primary hyperoxaluria can damage the kidneys. Over time, the kidneys can fail to function completely. In some people, this may be the first symptom of the disease.

Signs suggestive of impaired renal function:

• Decreased urine output or anuria.
• Feeling tired and lethargic often.
• Loss of appetite, nausea and vomiting.
• Pale skin due to anemia.
• Swollen feet and hands.

Symptoms of kidney failure are fatigue, loss of appetite, pale skin…

Late-stage oxalate toxicity can cause a variety of extrarenal complications, including bone disease, anemia, skin ulcers, heart and eye disease, and, in children, abnormal growth.

6. Diagnosis of hyperoxaluria

Your doctor will likely do a physical exam, take your medical history, and discuss your diet. Your doctor may recommend additional tests:

• Urinalysis helps assess the concentration of substances (including oxalates) in the urine.
• Blood tests , which suggest decreased kidney function as well as increased blood oxalate levels.
• Analysis of urolithiasis, to determine the composition of kidney stones (required in the urine or surgically).
• Renal X-ray, ultrasound, and CT-scan , to evaluate for kidney stones or calcium oxalate buildup in the urinary tract.

After the initial tests mentioned above, your doctor may recommend some more tests

The purpose of the tests is to diagnose and evaluate the extent of damage to organs in the body due to increased oxalate urine.

• Genetic testing helps to assess whether you are carrying the gene that causes primary hyperoxaluria.
• A kidney biopsy helps to assess whether there is an accumulation of oxalate here.
• Echocardiography helps to assess the absence of myocardial oxalte accumulation.
• Eye examination.
• Bone biopsies.
• Biopsy of the liver for impairment of enzymes involved in oxalate metabolism. Usually done only when genetic testing does not suggest a cause for the elevation of oxalate.

If you've been diagnosed with primary hyperoxaluria, it's possible that your siblings are also at risk. You should take your loved one to the doctor. If your child has primary hyperoxalate, you should see a doctor and have genetic testing.

7. Treatment of primary hyperoxalate

Treatment will depend on the degree of urinary oxalate elevation, the symptoms and severity of the hyperoxalate, and how well the treatment responds.

7.1. Reduce urinary oxalate

To reduce the risk of calcium oxalate crystals forming in your kidneys, your doctor will give you some instructions:

• Drugs . Vitamin B6 administered in appropriate doses reduces renal oxalate deposition in patients with primary hyperoxalate disease. Additionally, phosphate and citrate tablets can help reduce calcium oxalate crystal formation. Other medications, such as thiazide diuretics, may be used, depending on the individual case.
• Use lots of fruit . If kidney function remains normal, your doctor will recommend drinking plenty of water or juice. They will help the kidneys increase excretion, thereby preventing the deposition of oxalate crystals and avoiding the formation of kidney stones.

Changing your diet helps reduce oxalates in your body.

• Change your diet . In general, dietary modification plays a very important role in the treatment of oxalate disease caused by eating or by gastrointestinal disease. Your doctor will advise you to limit your intake of foods rich in oxalte, limit salt and reduce animal protein and sugar (especially high-fructose corn syrup). Dietary changes will help reduce the amount of oxalate excreted in the urine. But such a special diet may not help everyone with primary oxalate disease.

7.2. How to control kidney stone disease?

Kidney stones are a common condition in people with increased oxalateuria. However, treatment is not always required. If the stones are large enough, causing pain or preventing the kidneys from passing urine, the doctor may remove the stones surgically or break them up (to make them smaller and easier to pass).

7.3. Dialysis and kidney transplant

Depending on the severity of your hyperoxaluria, your kidneys may lose function completely. Dialysis is a temporary solution, but does not help reduce the oxalate produced by the body. Kidney and liver transplants can help treat the disease.

In summary, hyperoxaluria and oxalate toxicity have many causes, including genetic and other acquired causes. Kidney stones are a common complication of hyperoxaluria. In addition, increased urinary oxalate may impair renal function. Therefore, when you suspect that you have hyperoxaluria, you should see your doctor immediately.

Doctor Vu Thanh Do