Sensory ataxic polyneuropathy unmasking late-onset urea cycle defect

Clin Neurol Neurosurg. 2024 May:240:108260. doi: 10.1016/j.clineuro.2024.108260. Epub 2024 Mar 26.

Abstract

A 63-year-old man with type 2 diabetes mellitus, alcohol consumption in moderation, and three episodes of hepatic encephalopathy presented with symmetrical lower limb distal weakness, sensory ataxia, thickened palpable nerves, mood disturbances for seven years, and a family history of schizophreniform disorders. Nerve conduction studies showed demyelinating sensorimotor polyradiculoneuropathy. CSF analysis showed mild albumino-cytological dissociation. MRI brain and lumbosacral plexus showed thickened fifth cranial nerves and lumbosacral roots. He was treated with steroids for a provisional diagnosis of chronic inflammatory polyneuropathy and became encephalopathic. EEG showed triphasic waves. Serum ammonia was 201 micrograms/dL. Further evaluation suggested ornithine transcarbamylase (OTC) deficiency. The patient underwent hemodialysis with a low protein diet, rifaximin, and sodium benzoate, with subsequent recovery.

Keywords: Ammonia; Hemodialysis; Late-onset urea cycle defects; Ornithine transcarbamylase deficiency; Polyneuropathy.

Publication types

  • Case Reports

MeSH terms

  • Ataxia
  • Diabetes Mellitus, Type 2 / complications
  • Electroencephalography
  • Hepatic Encephalopathy / diagnosis
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Neural Conduction* / physiology
  • Ornithine Carbamoyltransferase Deficiency Disease* / complications
  • Ornithine Carbamoyltransferase Deficiency Disease* / diagnosis
  • Polyneuropathies / diagnosis
  • Renal Dialysis