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Kidney Week

Abstract: PO1997

Systemic Oxalate Deposition in Patients with Primary Hyperoxaluria Type 3

Session Information

Category: Pediatric Nephrology

  • 1700 Pediatric Nephrology

Authors

  • Hoppe, Bernd, German Hyperoxaluria Center, Bonn, Germany
  • Birtel, Johannes, Oxford Eye Hospital, Oxford, Oxfordshire, United Kingdom
  • Herberg, Ulrike, Universitatsklinikum Bonn, Bonn, Nordrhein-Westfalen, Germany
  • Martin Higueras, Cristina, German Hyperoxaluria Center, Bonn, Germany
Background

In the contrary to previous reporting we now know, that patients with Primary Hyperoxaluria type 3 (PH3) remain symptomatic in adulthood with recurrent kidney stones. They also are on risk to develop chronic kidney disease (CKD). We therefore consider, that PH3 patients may also develop systemic oxalate deposition.

Methods

We are now examining PH3 patients regularly seen at the German Hyperoxaluria Center (GHC) for systemic depositions by eye exam (by fundus color photography and optical coherence tomography), hand x-rays, bone MRI (3 Tesla of the left knee and proximal tibia) and Speckle tracking echocardiography, which measures changes in global longitudinal strain (GLS), an index of left ventricular contractibility (normal GLS is ≤18%).

Results

At GHC we see 12 pediatric and 4 adult patients on a regular basis, at least twice a year. All 16 patients are in no less than CKD 2. So far the following examinations were performed: an eye exam was performed in 8 patients, it was normal in all. Speckle tracking echocardiography was done in 8 patients, it was abnormal in one (GLS – 17.3% and left ventricular hypertrophy) and borderline in another (GLS – 18.6%) in 2020. During 2021 GLS values returned to normal in both under increased treatment awareness (-23% and -21%, respectively). X-ray left hand was taken in 6 patients, one patient (multiple stone removal procedures, decline in GFR) had tiny sclerosing areas at caput MCP IV and the thumb. MRI of left knee and proximal tibia was performed in 6 patients, clearly visible textural changes as patchy areas of low signal intensity were found in one patient. Two patients had salivary stones in the parotid gland, found in a routine x-ray of the jaw before orthodontic treatment.

Conclusion

Although this is currently only data of a small cohort, systemic oxalate deposition may also occur in PH3. Of course, data in more patients are needed to elucidate the true risk of systemic oxalate deposition and we therefore recommend to screen all known PH3 patients.