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The case report by Hirvioja et al. raises some interesting points [1]. Unfortunately, the title is somewhat misleading because it suggests that it was nitrous oxide alone that caused the death and ignores the likelihood, from the data presented, that the death was probably due to the other substances found in the patient's blood as well as the nitrous oxide [1]. As far as I am aware, there is no case in the literature where nitrous oxide alone has caused sudden death during misuse, except when the subject has been asphyxiated because of oxygen lack [2]. I would like to congratulate the authors for not confusing abuse with use, something not always done with enough precision [3]. Indeed, some authors have given the impression that recreational use automatically means abuse [4]. Their paper also highlights the point that pure nitrous oxide abuse is extremely rare and that those who do abuse it do so as part of their polydrug abuse [1, 4]. It is also important to note that although the recreational use of nitrous oxide seems currently to be an increase, the history of the use of nitrous oxide since the late 17th century has been punctuated by cycles of increased and decreased popularity. Furthermore, and in all this time, it has never yet caused the severe problem as found with other drugs such as morphine, heroin, cocaine or the benzodiazepines [4]. However, the statement that ‘Nitrous oxide… is used as an anaesthetic…. during small dental procedures and labour’ is simply wrong. For these indications, nitrous oxide is used at concentrations well below those that could produce unconsciousness and anaesthesia and while the patient is conscious and fully responsive and definitely not anaesthetized [5].
9Vitamin B12 inactivation may not be the only cause of acquired peripheral neuropathy in chronic nitrous oxide users.
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25Does vitamin B12 deficiency explain psychiatric symptoms in recreational nitrous oxide users? A narrative review
Background Recreational use of nitrous oxide (N2O) is associated with many side effects, of which neurological complications are most common. Nitrous oxide abuse is also associated with psychiatric symptoms, but these have received less attention so far. Vitamin B12 deficiency may play a role in the development of these psychiatric symptoms. Aims To explore the relationship among the occurrence of recreational nitrous oxide-induced psychiatric symptoms, accompanying neurological symptoms, vitamin B12 status and choice of treatment. Methods A retrospective search for case reports was conducted across multiple databases (Pubmed, Embase, Web of Science, PsycINFO and CINAHL). Keywords included variants of “nitrous oxide”, “case report” and “abuse”. No restrictions to language or publication date were applied. Results The search retrieved 372 articles. A total of 25 case reports were included, representing 31 patients with psychiatric complications following nitrous oxide abuse. The most often reported symptoms were: hallucinations (n = 16), delusions (n = 11), and paranoia (n = 11). When neurological symptoms were present, patients were treated more frequently with vitamin B12 supplementation. Conclusions This review highlights the need to recognize that psychiatric symptoms may appear in association with nitrous oxide use. Approximately half of the cases that presented with nitrous oxide-induced psychiatric complaints did not show neurological symptoms, and their vitamin B12 concentration was often within the hospital's reference range. Psychiatrists and emergency physicians should be aware of isolated psychiatric symptoms caused by recreational nitrous oxide abuse. We suggest asking all patients with new psychiatric symptoms about nitrous oxide use and protocolizing the management of nitrous oxide-induced psychiatric symptoms.
Read more26Nitrous oxide abuse leading to extreme homocysteine levels and thrombosis in young adults: a case series
Nitrous oxide abuse leading to extreme homocysteine levels and thrombosis in young adults: a case series
2Vision Threatening Raised Intracranial Pressure Associated with Recreational Nitrous Oxide Use
Nitrous oxide is used as an anaesthetic and analgesic agent in the medical setting and is known to cause raised intracranial pressure. The use of nitrous oxide recreationally for the drug’s euphoric and relaxant properties has been linked to multiple neurological and psychiatric sequelae including neuropathy, myelopathy, and psychosis. We describe a case of a young person who declared heavy nitrous oxide use resulting in vision-threatening papilloedema secondary to raised intracranial pressure. He underwent emergency lumbar drainage alongside high-dose acetazolamide and parenteral vitamin B12 injections. To our knowledge, there have yet to be other reports of cases where heavy nitrous oxide use has caused secondary pseudotumor cerebri syndrome.
Read more16Acute ST-Elevation Myocardial Infarction, a Unique Complication of Recreational Nitrous Oxide Use.
Acute ST-Elevation Myocardial Infarction, a Unique Complication of Recreational Nitrous Oxide Use.
4Subacute Combined Degeneration of the Spinal Cord: A Consequence of Recreational Nitrous Oxide Use
A 21-year-old female presented to the hospital with worsening bilateral lower extremity weakness and sensory changes in the distal extremities following chronic nitrous oxide (N2O) abuse. Laboratory and radiographic results were suggestive of subacute combined degeneration of the upper cervical and thoracic spinal cord in the setting of a normal vitamin B12 level of 374 pg/mL with an elevation in methylmalonic acid to 1.14 mcmol/L. She was diagnosed with a relative B12 deficiency and treated with supplemental vitamin B12, resulting in an improvement in symptoms. This case highlights the importance of considering relative vitamin B12 deficiency as a diagnosis in the setting of nitrous oxide use, regardless of measured vitamin B12 level.
Read more3Recreational nitrous oxide abuse causing B12 deficiency with subacute combined degeneration of the spinal cord: A case report.
The recreational use of nitrous oxide (N2O) is a growing public health concern. Increasing numbers of young individuals are presenting to accident emergency departments complaining of adverse neurological symptoms as a result of N2O induced vitamin B12 deficiency. Despite its increasing popularity, many are still not aware of its devastating potential to cause a myriad of severe longstanding neurological impairment. Herein we present a case that highlights the effects of N2O abuse and the best way to investigate and manage such patients.
Read moreMonitoring use of nitrous oxide in hospitals
In their editorial, Acharya and colleagues say that recreational use of nitrous oxide is an emerging public health problem.1 In hospital, nitrous oxide is generally used as an analgesic for...
Read more3Peripheral Neuropathy Due to Recreational Use of Nitrous Oxide Presenting After an Ankle Sprain With Foot Drop.
A 22-year-old man was referred for orthopedic follow-up after an ankle injury. Initial evaluation in urgent care included radiographs with negative findings. After a delayed presentation, a course of functional treatment was recommended. Subsequently, he developed a deep venous thrombosis and pulmonary emboli. He was found to be factor V Leiden deficient and was fully anticoagulated on warfarin. Later reevaluation revealed a steppage gait and foot drop. Electrodiagnostic studies (ie, electromyography and nerve conduction studies) revealed a severe peripheral polyneuropathy. The patient admitted to engaging in high-volume recreational use of nitrous oxide. Neurological evaluation confirmed vitamin B12 deficiency consistent with the toxic effects of nitrous oxide. The patient's condition improved with vitamin B supplementation, bracing, and avoidance of nitrous oxide and similar neurotoxins. He participated in a 3-month physical rehabilitation program, and he displayed partial recovery at most recent follow-up. [Orthopedics. 2018; 41(3):e432-e433.].
Read moreDeux cents ans d’histoire des usages et mésusages du protoxyde d’azote
Deux cents ans d’histoire des usages et mésusages du protoxyde d’azote
16Nitrous oxide abuse direct measurement for diagnosis and follow-up: update on kinetics and impact on metabolic pathways.
Recreational use of nitrous oxide (N2O) has become a major health issue worldwide, with a high number of clinical events, especially in neurology and cardiology. It is essential to be able to detect and monitor N2O abuse to provide effective care and follow-up to these patients. Current recommendations for detecting N2O in cases of recreational misuse and consumption markers are lacking. We aimed to update current knowledge through a review of the literature on N2O measurement and kinetics. We reviewed the outcomes of experiments, whether in preclinical models (in vitro or in vivo), or in humans, with the aim to identify biomarkers of intoxication as well as biomarkers of clinical severity, for laboratory use. Because N2O is eliminated 5 min after inhalation, measuring it in exhaled air is of no value. Many studies have found that urine and blood matrices concentrations are connected to ambient concentrations, but there is no similar data for direct exposure. There have been no studies on N2O measurement in direct consumers. Currently, patients actively abusing N2O are monitored using effect biomarkers (biomarkers related to the effects of N2O on metabolism), such as vitamin B12, homocysteine and methylmalonic acid.
Read more11Lessons of the month: Nitrous oxide-induced functional vitamin B12 deficiency causing subacute combined degeneration of the spinal cord
Lessons of the month: Nitrous oxide-induced functional vitamin B12 deficiency causing subacute combined degeneration of the spinal cord
Read moreReview of: "Exploring the Experiences and Perceptions of Young People’s Recreational Nitrous Oxide Use"
Review of: "Exploring the Experiences and Perceptions of Young People’s Recreational Nitrous Oxide Use"
56Severe Myeloneuropathy from Acute High-Dose Nitrous Oxide (N 2O) Abuse
Severe Myeloneuropathy from Acute High-Dose Nitrous Oxide (N 2O) Abuse
1A Case Report of Nitrous Oxide-induced Myelopathy: An Unusual Cause of Weakness in an Emergency Department.
Weakness is a common symptom that within itself does not indicate a specific diagnosis. Recreational inhalant use such as nitrous oxide (NO) may not often be disclosed. Additionally, professional or occupational history, such as being a dentist or dental assistant, should be determined because of higher reported rates of NO misuse. Nitrous oxide can cause vitamin B12 deficiency and resulting neuropathy. Nitrous oxide toxicity can have a wide variation of presentations with or without laboratory abnormalities or remarkable imaging findings, which can further complicate a diagnosis of weakness secondary to NO use. A 33-year-old female presented to the emergency department with progressive bilateral leg numbness and objective weakness after repeated recreational NO use. After an extensive workup, she was found to have vitamin B12 deficiency and an electromyography study consistent with myeloneuropathy, despite normal imaging. She was prescribed high-dose vitamin B12 therapy and stopped using NO. One year after diagnosis, our patient maintained NO sobriety and had near-complete resolution of prior neurologic deficits. The use of recreational inhalant and the patient's occupation should be considered when a patient presents with weakness. Obtaining vitamin B12 and methylmalonic acid levels should be considered for diagnosis. However, NO-induced neuropathy can be seen in patients with normal vitamin B12 and methylmalonic levels and patients do not always have abnormal imaging findings. The healthcare team should consider the varied presentations and findings of substance-induced conditions such as NO toxicity.
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