Progressive polyradiculoneuropathy due to intraneural oxalate deposition in type 1 primary hyperoxaluria.
[primary hyperoxaluria type 1]
Introduction: A 24 year old man with primary hyperoxaluria type 1 (PH1) presented with a rapidly progressive axonal and demyelinating sensorimotor polyradiculoneuropathy shortly after the onset of end stage renal disease. His plasma oxalate level was markedly elevated at 107 µmol/L (normal: <1.8 µmol/L). Methods: A sural nerve biopsy was performed. Teased fiber, paraffin and epoxy sections, and morphometric procedures were performed on this sample and on an archived sample from a 22 year old man as an age- and gender-matched control. Embedded teased fiber electron microscopy was also performed. Results: The biopsy revealed secondary demyelination and axonal degeneration. Under polarizing light, multiple bright hexagonal, rectangular, and starburst inclusions typical of calcium oxalate monohydrate crystals were seen(1,2,3) . Discussion: Proposed mechanisms of nerve damage include disruption of axonal transport due to crystal deposition, toxic effect of oxalate, or nerve ischemia related to vessel occlusion from oxalate crystal deposition. © 2014 Wiley Periodicals, Inc.
