Chronic liver disease and hepatic calcium-oxalate deposition in patients with primary hyperoxaluria type I.

Patients with primary hyperoxaluria type I (PH I) are prone to develop early kidney failure. Systemic deposition of calcium-oxalate (CaOx) crystals starts, when renal function declines and plasma oxalate increases. All tissue, but especially bone, heart and eyes are affected. However, liver involvement, as CaOx deposition or chronic hepatitis/fibrosis has never been reported. We examined liver specimen from 19 PH I patients (aged 1.5 to 52 years at sample collection), obtained by diagnostic biopsy (1), at autopsy (1), or transplantation (17). With polarization microscopy, birefringent CaOx crystals located in small arteries, but not within hepatocytes were found in 3/19 patients. Cirrhosis was seen in one, fibrosis in 10/19 patients, with porto-portal and nodular fibrosis (n = 1), with limitation to the portal field in 8 and/or to central areas in 5 patients. Unspecific hepatitis features were observed in 7 patients. Fiber proliferations were detectable in 10 cases and in one sample transformed Ito-cells (myofibroblasts) were found. Iron deposition, but also megakaryocytes as sign of extramedullary erythropoiesis were found in 9, or 3 patients, respectively. Overall, liver involvement in patients with PH I was more pronounced, as previously described. However, CaOx deposition was negligible in liver, although the oxalate concentration there must be highest.

Nephrocalcinosis and urolithiasis in children.

The incidence of adult urolithiasis has increased significantly in industrialized countries over the past decades. Sound incidence rates are not available for children, nor are they known for nephrocalcinosis, which can appear as a single entity or together with urolithiasis. In contrast to the adult kidney stone patient, where environmental factors are the main cause, genetic and/or metabolic disorders are the main reason for childhood nephrocalcinosis and urolithiasis. While hypercalciuria is considered to be the most frequent risk factor, several other metabolic disorders such as hypocitraturia or hyperoxaluria, as well as a variety of renal tubular diseases, e.g., Dent's disease or renal tubular acidosis, have to be ruled out by urine and/or blood analysis. Associated symptoms such as growth retardation, intestinal absorption, or bone demineralization should be evaluated for diagnostic and therapeutic purposes. Preterm infants are a special risk population with a high incidence of nephrocalcinosis arising from immature kidney, medication, and hypocitraturia. In children, concise evaluation will reveal an underlying pathomechanism in >75% of patients. Early treatment reducing urinary saturation of the soluble by increasing fluid intake and by providing crystallization inhibitors, as well as disease-specific medication, are mandatory to prevent recurrent kidney stones and/or progressive nephrocalcinosis, and consequently deterioration of renal function.