Norberto Escobales, MD
Resident
Department of Physical Medicine & Rehabilitation Temple University Hospital
Philadelphia, Pennsylvania, United States
Gabriel Howard, DO
Resident Physician
Temple University Hospital
Pipersville, Pennsylvania, United States
Sandeep Singh, MD
CMO
Good Shepherd Rehabilitation Network
Allentown, Pennsylvania, United States
An account of the functional progression of a 58-year-old male who developed subacute combined degeneration (SCAD) of the spinal cord in the setting of nitrous oxide use.
Case Description:
A 58-year-old male without significant past medical history presented for evaluation of two months of neurocognitive deficits, unsteady balance, and weight loss. On acute care admission he was tachypneic, with evidence of an acute pulmonary embolism on CT imaging. Additionally he exhibited bilateral lower extremity ataxia with a wide-based steppage gait. MRI of the cervical and thoracic spine found abnormalities of the posterior spinal cord at levels C3-C5 and C7-T1 concerning SCAD of the spinal cord. Further work-up revealed vitamin b12 deficiency, elevated methylmalonic acid, homocysteine and history of recreational nitrous oxide which were thought to contribute to the neurodegenerative and hypercoagulable processes experienced by the patient. On admission to acute inpatient rehabilitation, the patient was max assist for transfers and required assistance for short-distance ambulation with rolling walking due to severe ataxia.
Discussions:
Whilst admitted his ataxia persisted, rehabilitation interventions were focused on the optimization of wheelchair mobility and muscular endurance. Functionally he progressed to close supervision with transfers and ambulation with a rolling walker to 300ft on rehabilitation discharge.
Conclusions:
SCAD is a degenerative condition that can result in demyelination of the lateral and posterior columns of the spinal cord. It can be induced by nitrous oxide use via the oxidation of vitamin B12 with subsequent impacts on DNA synthesis and manifestations of hypercoagulability. The case described is a rare case of nitrous oxide induced SCAD of the spinal cord with concomitant hypercoagulability and a functional deficit of persistent ataxia. Ataxia is a persistent rehabilitation challenge, as proprioceptive feedback is impaired however emphasizing ambulation safety can optimize functional independence.
