What Is Hyperoxaluria?
Hyperoxaluria is a rare condition characterized by excess oxalate production, excreted as a urine waste product. This leads to abnormally high levels of oxalate in the urine. During the time of its excretion, oxalate combines with calcium to form calcium oxalate. It is the main constituent of calcium oxalate stones in the bladder and the kidney. Deposits of calcium oxalate are harmful to the kidney and other organs. They can cause symptoms like blood in the urine, urinary tract infections, end-stage renal disease, injury to other organs, and kidney damage. In addition, kidney function impairment occurs due to calcium oxalate substances in the kidneys. As a result, oxalate levels rise in the blood and get deposited in various tissues throughout the body, causing systemic oxalosis. The deposition generally occurs in the bones and walls of blood vessels. Oxalosis of bones can cause fractures.
What Are the Types of Hyperoxaluria?
There are two types of hyperoxaluria - primary and secondary.
1. Primary Hyperoxaluria - It is a rare condition characterized by overproduction of oxalate as the enzyme production by the liver is low or the enzymes do not work properly. It is also associated with recurrent renal infections and bladder stones. The condition results in end-stage kidney disease, renal failure, and kidney impairment. It is a life-threatening condition that prevents the kidney from performing normal functions like filtering fluids and waste products in the body. Three types of primary hyperoxaluria differ in genetic cause and severity. The three types include:
- Type 1 - The appearance of kidney stones occurs anytime from childhood to early adulthood, and end-stage renal disease can develop at any age of life.
- Type 2 - Primary hyperoxaluria with the appearance of kidney stones that occur anytime from childhood to adulthood, but the end-stage renal disease can develop at later stages in life.
- Type 3 - The appearance of kidney stones occurs in early childhood. A few cases of this type have been known to describe additional symptoms.
2. Secondary Hyperoxaluria - A condition with excess oxalate absorption from the gastrointestinal tract and then excretion in the urine is secondary hyperoxaluria. The reason behind increased absorption can be due to consuming foods containing high levels of oxalate or suffering from medical conditions that can cause the gastrointestinal tract to absorb more oxalate. The medical conditions include inflammatory bowel disease, gastric bypass, and Crohn's disease.
What Are the Symptoms of Hyperoxaluria?
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Kidney Stones - Symptoms generally develop from infancy to later adulthood. The initial symptom of hyperoxaluria is kidney stones.
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Hematuria - It is the presence of blood in urine and generally occurs with hyperoxaluria.
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Kidney Failure - In some patients, the initial symptoms are mild to moderate and do not cause much discomfort. The diagnosis is made after kidney failure, which can then be considered the first symptom.
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Flank Pain - Pain in the lower back or side of the body, which is dull and can be moderate to severe.
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Problems With Urination - Pain while urinating or a condition where the patient cannot urinate is related to hyperoxaluria. Urine with a bad odor and a cloudy appearance can be seen.
Other symptoms, like nausea and vomiting with pain, fevers, and chills, can be present.
How Is Hyperoxaluria Diagnosed?
Diagnosis starts with a physical examination, medical history, diet history, and routine lab tests. These tests include:
1. Urine Tests - Urine analysis measures the level of oxalate and other specific enzymes. It is checked for the presence of crystals. It also determines the presence of blood in the urine.
2. Blood Tests - Blood analysis measures the amount of oxalate in blood.
3. Imaging Tests - X-rays, computed tomography (CT) scans, and ultrasound of the kidneys and urinary tract are done to rule out the presence of kidney stones or calcium oxalate stones. If kidney stones or calcium oxalate stones are found, they are removed surgically or passed without surgery.
4. Other Tests - Tests to determine the presence of oxalate deposits in other organs and tissues include:
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Kidney and bone marrow biopsy to check for oxalate deposits in the bones.
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An echocardiogram is done to look for oxalate deposits in the heart's tissues.
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Eye tests to rule out oxalate deposits in the retina and eye.
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A computed tomography scan is done to detect the presence of calcium or oxalate in the bowel wall, arteries, and muscle.
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In the case of primary hyperoxaluria, genetic screening must be done to determine the presence of any genetic mutations.
How to Treat Hyperoxaluria?
The treatment modality depends on absolute lowering mechanisms. The treatment plan includes the following:
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Medications - In the case of primary hyperoxaluria, drugs include vitamin B-6 to reduce oxalate levels. Thiazide diuretics are also used for a specific subtype of primary hyperoxaluria. Further treatment with either primary or secondary hyperoxaluria includes oral doses of potassium citrate. Also, the combination of orthophosphate and magnesium can be taken to prevent the formation of calcium oxalate crystals.
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Dietary Changes - Increase in daily water intake, about 2.5 to 3 liters per day, will help the kidneys flush out oxalate and prevent buildup in the body. Limiting salt intake, decreasing sugar intake, limiting the animal protein intake, and limiting foods high in oxalate levels such as plums, beets, chocolate, strawberries, tofu, almonds, french fries, nuts, potato chips, and spinach can impair the health of the kidney.
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To Treat Kidney Stone - If calcium oxalate stones are present in the kidney or urinary bladder, then an excessive amount of water can be recommended to pass it on its own. If that does not happen, procedures like shockwave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy can be performed.
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To Treat Kidney Failure - In severe cases of hyperoxaluria, kidneys can stop working. In such cases, dialysis or kidney transplantation can be needed.
Conclusion:
Hyperoxaluria is a rare condition associated with an increased level of oxalate in the body. It can be either due to the overproduction of the substance, more absorption by the gastrointestinal tract, or less excretion by the kidneys. The symptoms can be associated with kidney stone formation, hematuria, or kidney failure. The treatment depends upon the factors that can decrease the oxalate in the blood. In case of severe symptoms and kidney failure, dialysis and kidney transplantation may be required.
