Nephrocalcinosis in Tunisian children

Background: Nephrocalcinosis is rare in children. Its etiologies are multiple. The aim of this study was to analyze the etiology of nephrocalcinosis in Tunisian children

Methods: This retrospective study was conducted in the department of pediatrics in Charles Nicolle Hospital during a period of 10 years [2001-2010]

Results: There were 40 children. The mean age was 3.5 years. The most common signs and symptoms at presentation were growth retardation [42.5%] and hematuria [53.8%]. At presentation, renal failure was detected in 70% of patients. The diagnosis of nephrocalcinosis was performed by ultrasonography. The etiology of nephrocalcinosis included primary hyperoxaluria type 1 [65%] and distal renal tubular acidosis [20%]. A progression to renal insufficiency was observed in 18 cases

Conclusion: Primary oxaluria is the principal cause of nephrocalcinosis; early diagnosis and treatment are mandatory as they help limiting renal function deterioration

Primary hyperoxaluria type 1 in Tunisian children

Primary hyperoxaliuria type 1 is an autosomal-recessive disorder characterized by increasing urinary excretion of calcium oxalate, recurrent urolithiasis, nephrocalcinosis, and accumulation of insoluble oxalate throughout the body. This inborn error of metabolism appears to be a common cause of end stage renal disease in Tunisia. To review the clinical, biological and radiological futures of primary hyperoxaluria type 1 and to correlate these aspects with the development of end-stage renal disease. we retrospectively reviewed 44 children with Primary hyperoxaliuria type I who were treated in our department during a period of 15 years between 1995 and 2009. The diagnosis was established by quantitative urinary oxalate excretion. In patient with renal impairment, the diagnosis was made by infrared spectroscopy of stone or by renal biopsy. Male to female ratio was 1.2. The median age at diagnosis was 5.75 years. About 43% of those were diagnosed before the age of 5 years. Initial symptoms were dominated by uraemia. Four patients were asymptomatic and diagnosed by sibling screening of known patients. Nephrocalcinosis was present in all patients. It is cortical in 34%, medullary in 32% and global in 34%. At diagnosis, twelve children were in end-stage renal disease [27%]. Pyridoxine response, which is defined by a reduction in urine oxalate excretion of 60% or more, was found in 27%. In the majority of patients, the clinical expression of Primary hyperoxaliuria type 1 is characterized by nephrocalcinosis, urolithiasis and renal failure. Pyridoxine sensitivity is associated with better outcome