Clinical and electrodiagnostic characteristics of nitrous oxide-induced neuropathy in Taiwan

Li, Han-Tao; Chu, Chun‐Che; Chang, Kuo‐Hsuan; Liao, Ming‐Feng; Chang, Hong‐Shiu; Kuo, Hung‐Chou; Lyu, Rong‐Kuo

doi:10.1016/j.clinph.2016.08.005

Cited by 47 publications

(71 citation statements)

References 26 publications

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“…N 2 O abuse could induce sensory-motor neuropathy with axonal and myelin damage (decreased CMAP and SNAP, slowing of MCV and SCV as well as prolongation of DL), and with predominant lower-limb involvement. 20 These findings were corroborated in our present study. Besides that, we also found electrophysiological abnormalities of 3 patients who came to our hospital for memory loss or vision decline without symptoms of peripheral neuropathy.…”

Section: Mri Findingssupporting

confidence: 92%

<p>Clinical, Electrophysiological and Radiological Features of Nitrous Oxide-Induced Neurological Disorders</p>

Bao¹,

Li²,

Li³

et al. 2020

NDT

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These authors contributed equally to this workPurpose: We summarized the clinical manifestations, laboratory and electrodiagnostic characteristics and magnetic resonance imaging (MRI) findings of nitrous oxide (N 2 O) abuse-induced neurological disorders. Patients and Methods: We retrospectively reviewed 33 patients with N 2 O abuse-induced neurological disorders and reported their demographic data, clinical manifestations, laboratory examinations, nerve conduction studies, together with spinal and brain MRI. Results: The most frequent clinical manifestations included numbness and weakness in the extremities and unspecified gait disturbance. Low serum vitamin B 12 levels were found in 9 patients, and high homocysteine levels were noted in 27 patients. Nerve conduction studies showed a sensory-motor neuropathy. Sixteen patients showed bilateral high-intensity T2 signal within the posterior column on spinal MRI, and four patients showed cerebral white matter lesions on brain MRI. Conclusion: N 2 O abuse has become a significant public health problem because of the severe neurological disorders related to chronic abuse. Clinical physicians should be aware of the toxic effects of N 2 O.

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Section: Mri Findingssupporting

confidence: 92%

<p>Clinical, Electrophysiological and Radiological Features of Nitrous Oxide-Induced Neurological Disorders</p>

Bao¹,

Li²,

Li³

et al. 2020

NDT

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“…Lower rates have been reported by other authors, such as Patel et al 12 and Li et al . 13 , who reported rates of 67% and 64%, respectively. Decreased or lost tendon reflexes were also common symptoms in our study, which was similar to the report by Li et al 13 Our results were comparable with those reported by previous studies, which indicated that Romberg’s sign was also a very common symptom.…”

Section: Discussionmentioning

confidence: 99%

“… 13 , who reported rates of 67% and 64%, respectively. Decreased or lost tendon reflexes were also common symptoms in our study, which was similar to the report by Li et al 13 Our results were comparable with those reported by previous studies, which indicated that Romberg’s sign was also a very common symptom. 11 , 14 , 15 Lhermitte’s sign was found in 21 patients in our study (44.7%), which was higher than the occurrences reported in the studies by Oussalah et al 14 (15%) and Wang et al 11 (30%).…”

Section: Discussionmentioning

confidence: 99%

The clinical and subclinical features of spinal cord injury on magnetic resonance imaging of patients with N2O intoxication

Tuấn

Duc

et al. 2020

Neurol Int

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Nitrous oxide (N2O) is a weak anesthetic gas that was first used in 1844 in the field of dental anesthesia. However, currently, N2O is being abused for entertainment purposes in the form of N2O-filled balloons, called funky balls, which can cause many adverse effects, especially nervous system injury. This study aimed to investigate the detailed clinical and subclinical features associated with N2O intoxication. We retrospectively reviewed 47 patients diagnosed with N2O intoxication, from May 2018 to July 2019, and collected demographic data, clinical and laboratory tests, and spinal cord magnetic resonance imaging (MRI) findings. The mean time of funky ball use was 8.8 months, with a mean use of 36.3 balls per day. All patients presented with superficial sensory disorders. Reductions in muscle strength, decreased vibration sensation, and decreased or lost tendon reflexes were the most common clinical signs of N2O intoxication. Romberg sign and Lhermitte sign were observed in 39 patients (83%) and 21 patients (44.7%), respectively. Spinal cord lesions on MRI were observed in 32 patients (68.1%), which mostly presented with an inverted V sign. The total duration of N2O use, the number of days of using N2O per week, and the presence of Lhermitte sign (P<0.05) were significantly different between patients with and without spinal cord lesions on MRI. Serum levels of homocysteine and vitamin B12 were significantly different between the time of admission and discharge (P<0.05). Our study indicated that the days of using N2O per week was significantly associated with Spinal Cord Injuries (SCI) on MRI. According to the Receiver Operating Characteristic (ROC) curve analysis, a cutoff days of using per week value of 2.5 days could predict SCI with a sensitivity of 81.3%, a specificity of 73.3%, and an area under the ROC curve (AUC) of 0.813. Changes in the serum levels of homocysteine and vitamin B12 were effective markers for the evaluation of treatment response.

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“…Recreational use of nitrous oxide (N 2 O) is escalating in many countries, including the United States, the United Kingdom, and Taiwan (1, 2). With an unusually high lifetime prevalence in developed countries (38.6% in the UK and 29.4% in the US), N 2 O consistently ranked the seventh most popular drug in the world in the Global Drug Survey (GDS) from 2016 to 2018 (3–5).…”

Section: Introductionmentioning

confidence: 99%

Elucidating Unique Axonal Dysfunction Between Nitrous Oxide Abuse and Vitamin B12 Deficiency

et al. 2019

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Introduction: Abuse of nitrous oxide (N 2 O) has an unusually high lifetime prevalence in developed countries and represents a serious concern worldwide. Myeloneuropathy following the inhalant abuse is commonly attributed to the disturbance of vitamin B12 metabolism, with severe motor deficits are often noted. The present study aims to elucidate its underlying pathophysiology. Methods: Eighteen patients with N 2 O abuse or vitamin B12 deficiency were recruited. Comprehensive central and peripheral neuro-diagnostic tests were performed, including whole spine MRI, and thermal quantitative sensory testing (QST). Specifically, paired motor and sensory nerve excitability tests were performed in order to obtain a complete picture of the sensorimotor axonal damage. Results: The mean duration of N 2 O exposure for the N 2 O abuse patients was 17.13 ± 7.23 months. MRI revealed T2 hyperintensity in 87.5% of the N 2 O abuse patients and 50% of the vitamin B12 deficiency patients. In N 2 O abuse patients, the motor nerve excitability test showed decreased in peak response (7.08 ± 0.87 mV, P = 0.05), increased latency (7.09 ± 0.28 ms, P < 0.01), increased superexcitability (−32.95 ± 1.74%, P < 0.05), and decreased accommodation to depolarizing current [TEd (40–60 ms) 56.53 ± 0.70%, P < 0.05]; the sensory test showed only decreased peak response (30.54 ± 5.98 μV, P < 0.05). Meanwhile, motor test in vitamin B12 deficiency patients showed only decreased accommodation to depolarizing current [TEd (40–60 ms) 55.72 ± 1.60%, P < 0.01]; the sensory test showed decreased peak response (25.86 ± 3.44 μV, P < 0.05) increased superexcitability (−28.58 ± 3.71%, P < 0.001), increased subexcitability (8.31 ± 1.64%, P < 0.05), and decreased accommodation to depolarizing current [TEd (peak) 67.31 ± 3.35%, P < 0.001]. Conclusion: Compared to vitamin B12 deficiency, N 2 O abuse patients showed prominent motor superexcitability changes and less prominent sensory superexcitability changes, hinting a unique pathological process different from that of vitamin B12 deficiency. N 2 O abuse might cause axonal dysfunction not only by blocking methionine metabolism but also by toxicity affecting the paranodal region.

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Clinical and electrodiagnostic characteristics of nitrous oxide-induced neuropathy in Taiwan

Cited by 47 publications

References 26 publications

<p>Clinical, Electrophysiological and Radiological Features of Nitrous Oxide-Induced Neurological Disorders</p>

<p>Clinical, Electrophysiological and Radiological Features of Nitrous Oxide-Induced Neurological Disorders</p>

The clinical and subclinical features of spinal cord injury on magnetic resonance imaging of patients with N2O intoxication

Elucidating Unique Axonal Dysfunction Between Nitrous Oxide Abuse and Vitamin B12 Deficiency

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