Clinical and electrodiagnostic characteristics of nitrous oxide-induced neuropathy in Taiwan. Issue 10 (October 2016)

• Record Type: Journal Article
• Authors: Li, Han-Tao; Chu, Chun-Che; Chang, Kuo-Hsuan; Liao, Ming-Feng; Chang, Hong-Shiu; Kuo, Hung-Chou; Lyu, Rong-Kuo
• Is Part Of: Clinical neurophysiology. Volume 127:Issue 10(2016:Oct.)
• Page Start: 3288
• Page End: 3293
• Publication Date: 2016-10
• Subjects: N2O nitrous oxide -- NCS nerve conduction study -- CMAP compound motor action potential -- SNAP sensory nerve action potential -- LLN lower limit of normal -- ULN upper limit of normal -- CIPN chemotherapy-induced peripheral neuropathy -- MRI magnetic resonance imaging -- MCV mean corpuscular volume -- CV conduction velocity -- Hcy homocysteine -- BMI body mass index; Nitrous oxide-induced neuropathy -- N2O neuropathy -- Toxic neuropathy -- Electrodiagnosis -- Nerve conduction study -- Homocysteine; Neurophysiology -- Periodicals; Electroencephalography -- Periodicals; Electromyography -- Periodicals; Neurology -- Periodicals; 612.8
• DOI: 10.1016/j.clinph.2016.08.005
• Languages: English
• ISSNs: 1388-2457

Abstract

Highlights: Detailed clinical and electrodiagnostic features of N2 O neuropathy are described. 36% of patients exhibited mixed axonal and demyelinating neuropathy, being the most common subtypes. Severe lower limbs' CMAP or SNAP impairments were associated with higher homocysteine levels. Abstract: Objective: Nitrous oxide-induced neuropathy is toxic neuropathy occasionally encountered in Taiwanese neurological clinics. Only several case reports described their electrodiagnostic features. We used a case-control design to investigate the detailed electrodiagnostic characteristics and possible factors relating to severe nerve injury. Methods: We retrospectively reviewed 33 patients with nitrous oxide-induced neuropathy over a 10-year period and reported their demographic data, spinal cord MRI, laboratory examinations and nerve conduction studies. 56 healthy controls' nerve conduction studies were collected for comparison analysis. Results: We noted significant motor and sensory amplitudes reduction, conduction velocities slowing, and latencies prolongation in most tested nerves compared to the controls. Similar nerve conduction study characteristics with prominent lower limbs' motor and sensory amplitudes reduction was observed in patient groups with or without abnormal vitamin B12 and/or homocysteine levels. Among those with lower limbs' motor or sensory amplitudes reduction <20% of the lower limit of normal, higher homocysteine levels were detected. Conclusions: Severe impairments of the lower limbs' sensory and motor amplitudes were frequently noted in patients with nitrous oxide exposure. Nitrous oxide exposure itself is an important factor for the development of neuropathy. Significance: Our study contributes to the understanding of electrodiagnostic features underlying the nitrous oxide-induced neuropathy.