Hyperoxaluria and oxalosis
Hyperoxaluria occurs when you have too much oxalate in your urine. Oxalate is a natural chemical in your body, and it's also found in certain types of food. But too much oxalate in your urine can cause serious problems.Hyperoxaluria can be caused by inherited (genetic) disorders, an intestinal disease or eating too many oxalate-rich foods. Quick diagnosis and treatment of hyperoxaluria is important to the long-term health of your kidneys.Oxalosis happens after the kidneys fail in people who have primary and intestinal causes of hyperoxaluria, and excess oxalate builds up in the blood. This can lead to oxalate deposits in blood vessels, bones and body organs.
Commonly, kidney stones are the first sign of hyperoxaluria. Kidney stones are uncommon in childhood. Kidney stones that form in children and teenagers are likely to be caused by an underlying condition, such as hyperoxaluria. For this reason, all young people with kidney stones should have a thorough evaluation, including measurement of oxalate in the urine. Adults with recurrent kidney stones also should be evaluated for oxalate in the urine.Symptoms of a kidney stone can include the following:Severe or sudden abdominal or flank pain,Blood in the urine,Frequent urge to urinate,Pain when urinating,Fever and chills.Primary hyperoxaluria (PH) that goes untreated can eventually damage your kidneys. Over time your kidneys may stop working. For some people, this is the first sign of the disease.
Treatment will depend on the type, symptoms and severity of hyperoxaluria and how well you respond to treatment.Medications. Prescription doses of vitamin B-6 can be effective in reducing oxalate in the urine in some people with primary hyperoxaluria. Oral preparations of phosphates and citrate help prevent the formation of calcium oxalate crystals. Other medications, such as thiazide diuretics, also may be considered, depending on which other abnormalities are present in your urine.High fluid intake. If your kidneys are still functioning normally, your doctor will likely tell you to drink more water or other fluids. This flushes the kidneys, prevents oxalate crystal buildup and helps keep kidney stones from forming.Dietary changes. The effectiveness of diet will depend on the cause of increased levels of oxalate. Diet may include restricting foods high in oxalates, limiting salt, and decreasing animal protein and sugar (high fructose corn syrup). This may help to lower urinary oxalate in people with enteric hyperoxaluria or excess dietary intake. Dietary restrictions may not be as important for all people with primary hyperoxaluria. Follow the advice of your doctor.
The hallmark of type I and II PH is a strongly elevated urinary excretion of oxalate (>1 mmol/1.73 m2 BSA/day, normal <0.5). Urinary oxalate excretion in secondary hyperoxaluria is usually <1.0 mmol/1.73 m2 BSA/day. Urinary oxalate over creatinine ratios may be used for screening in children as long as age-specific normal values (for age <2 years, <300; for age 2–5 years, <130; for age 5–15 years, <70 and for age >16 years, <40 mmol/mol) are at hand. However, the ratios need to be confirmed by complete urine collection. Urinary glycolate excretion is elevated in most patients with PH I, whereas urinary l-glyceric acid excretion is increased in nearly all patients with PH II. Hence, isolated hyperoxaluria does not exclude with certainty either type of PH. On the other hand, hyperoxaluria plus elevated excretion of either glycolate or l-glyceric acid is a strong argument but no proof for this diagnosis (PH I or PH II).