Primary hyperoxaluria: The Baragwanath experience

Background. Primary hyperoxaluria (PH) is a rare autosomal recessive condition characterised by defects in the metabolism of glyoxylate which leads to excess oxalate production. It is an important disease to diagnose as it can progress to kidney failure (KF). Objective. To describe the characteristics, diagnosis and management of PH in South Africa and to identify any determinants of KF and death. Method. A retrospective study of all children younger than 16 years of age, diagnosed with PH at the Paediatric Renal Unit, Chris Hani Baragwanath Academic Hospital, from 1984 - 2017. Results. A total of 24 patients were identified, of which 20 records were available for complete analysis. The median age of presentation was 6.0 years. The common clinical presentations were urolithiasis (90%), KF (85%), nephrocalcinosis (75%), urinary tract infections (55%) and haematuria (30%). Nephrocalcinosis was better detected on abdominal radiograph compared with ultrasonography. Both nephrocalcinosis (p=0.009) and haematuria (p=0.018) were significantly associated with KF. Five patients had A112D genetic mutation in the AGXT. Fourteen received dialysis and four were transplanted. The mortality rate in this study was 58.3%. Conclusion. Clinicians should have a high index of suspicion for PH in patients presenting with haematuria, urolithiasis and KF. This study supports the measurement of urine oxalate levels and abdominal radiographs in screening for PH in children presenting in KF.