Первичная гипероксалурия: диагностика, лечение, исходы

Abstract

Primary hyperoxaluria (PH) is a rare autosomal recessive disease caused by defects in liver glyoxylate metabolism and leading to overproduction of oxalates. Of the three types of PH, type I is the most common and severe form of the disease, which is caused by deficiency or loss of the liver-specific, vitamin B6-dependent, peroxisomal enzyme alanine-glyoxylateaminotransferase (AGT). In all types of PH, urinary excretion of oxalate is strongly elevated (> 1 mmol /1,73 m2/24 h), which results in recurrent urolithiasis and/or progressive nephrocalcinosis and subsequently, with a decrease in glomerular filtration rate (GFR), to the deposition of oxalates in the tissues of the body and the development of systemic oxalosis. PH type I is diagnosed late, in > 30% of patients already at the terminal stage of renal disease (ESRD). Every fourth patient with PH type II achieves ESRD, but cases of ESRD in type III are extremely rare. The diagnosis of PH is based on clinical and imaging (ultrasound, X-ray, CT scan) findings, urine oxalate assessment, genetic analysis. Early initiation of conservative treatment (high fluid intake, sodium citrate, etc.) is aimed at preserving renal function. Pyridoxine treatment can be effective in about 30% of patients with PH type I. Time on dialysis in anticipation of transplantation should be short to avoid overt systemic oxalosis. Transplantation methods depend on the type of PH and on the degree of GFR reduction, but combined liver and kidney transplantation is the method of choice in patients with primary hyperoxaluria type I. High index of clinical suspicion of PH must be in patients with nephrocalcinosis and/or recurrent urolithiasis, especially if urinary stones are predominantly whewellite (calcium oxalate monohydrate) in order to start early conservative treatment and preserve kidney function.