The primary hyperoxalurias

Abstract

The primary hyperoxalurias (PHs) are rare disorders of glyoxylate metabolism in which specific hepatic enzyme deficiencies result in overproduction of oxalate. Due to the resulting severe hyperoxaluria, recurrent urolithiasis or progressive nephrocalcinosis are principal manifestations. End stage renal failure frequently occurs and is followed by systemic oxalate deposition along with its devastating effects. Due to the lack of familiarity with PHs and their heterogeneous clinical expressions, the diagnosis is often delayed until there is advanced disease. In recent years, improvements in medical management have been associated with better patient outcomes. Although there are several therapeutic options that can help prevent early kidney failure, the only curative treatment to date is combined liver-kidney transplantation in patients with type I PH. Promising areas of investigation are being identified. Knowledge of the spectrum of disease expression, early diagnosis, and initiation of treatment before renal failure are essential to realize a benefit for patients.

Figure 1

a) Typical sonographical and x-ray findings of severe urolithiasis in patients with primary hyperoxaluria type 1 aged 5, 9 and 39 years of age and still normal or only slightly impaired renal function. b) Low enhanced CT scan showing a Staghorn calculus and 5 further smaller stones in the left kidney of a 16 year old patient with primary hyperoxaluria, uncompliant with regard to medication and fluid intake.

Figure 2

Severe systemic oxalosis – calcium oxalate depositions in the bone (osteolytic lesions, epiphyseolysis), skin (crystal deposition at finger tip, livedo reticularis like picture) and retina in different patients with primary hyperoxaluria type 1.