Pulmonary embolism and deep vein thrombosis caused by nitrous oxide abuse: A case report

A recent surge of nitrous oxide misuse around London which merits a public health warning

BACKGROUND

Use of nitrous oxide (N2O) gas for recreational purposes by young people is increasingly recognized as a public health hazard in the UK.

METHODS

We looked at the hospital records of patients admitted over the last 4 years to a single neurological centre in Essex to determine the demographics, presentation, and management of patients presenting with symptoms of N2O toxicity from its recreational use.

RESULTS

Of the 17 patients (mean age = 22.9 ± 3 years) admitted between September 2018 and October 2022, 70% were admitted between January and October 2022. All patients reported limb paraesthesiae and 16/17 reported (95%) imbalance; 11/17 (65%) showed objective limb weakness. Serum B12 concentration was low in 9/17 (53%). Plasma methylmalonic acid (n = 7) and homocysteine (n = 8) levels were elevated in all patients tested. Spinal cord Magnetic Resonance Imaging (MRI) imaging was abnormal in 10/17 (59%) patients. Nerve conduction studies were abnormal in 10/13 (77%) patients, with evidence of a symmetric, length-dependent, large fibre neuropathy.

CONCLUSIONS

There has been a recent surge of cases with neurological complications of recreational N2O abuse in the UK, with a relatively greater rate in 2022. Greater awareness of this condition amongst clinicians and health regulators is urgently required to prevent harm from N2O misuse in young people.

Nitrous Oxide Inhalant Abuse: Preliminary Results from a Cross-Sectional Study on Knowledge, Attitudes, and Practices of Italian Physicians (2023)

Background and Objectives: Nitrous oxide (N2O) has recently emerged as a cheap alternative to other recreational substances. Although legally available, its chronic use is associated with severe neurological and hematological complications due to the irreversible inactivation of vitamin B12. While no reliable data on abuse of N2O in Italy have been provided to date, we assessed the knowledge, attitudes, and practices of Italian medical professionals on the management of N2O abuse cases. Materials and Methods: A cross-sectional study was performed as a web-based survey through a series of Facebook discussion groups (targeted medical professionals: 12,103), and participants were specifically asked about their previous understanding of N2O abuse and whether they had or not any previous experience in this topic. Results: A total 396 medical professionals participated in the survey. Overall, 115 participants had previous knowledge about N2O abuse (29.04%), with higher odds for professionals with a background in emergency medicine (adjusted odds ratio (aOR) 3.075; 95% confidence intervals (95%CI) 1.071 to 8.828) and lower for specialists in psychiatry (aOR 0.328; 95%CI 0.130 to 0.825). Knowledge status on N2O abuse was largely unsatisfying, as knowledge status, reported as a percent value, was estimated to 45.33% ± 24.71. Having previously managed a case of N2O abuse was associated with higher risk perception of the actual severity of this condition (aOR 5.070; 95%CI 1.520 to 16.980). Conclusions: Our study suggests that N2O poisoning cases are occurring in Italian settings but are not reasonably reported to national authorities. As substantial knowledge gaps of Italian medical workforces were identified, we cannot rule out that the actual abuse of N2O in the population may be far larger than currently suspected.

Nitrous oxide abuse leading to extreme homocysteine levels and thrombosis in young adults: a case series

BACKGROUND

Neurologic complications from recreational use of nitrous oxide (N₂O), which are attributed to vitamin B12 deficiency, have been well documented. With increasing dosages and frequency of N₂O use, an additional association with thromboembolisms is becoming apparent.

OBJECTIVES

To assess thrombotic complications of recreational N₂O use.

METHODS

All medical charts at the largest hospital in Amsterdam were searched for N₂O use and subsequent neurologic and/or thrombotic events. For patients with thrombotic events, we extracted data on the risk factors for arterial and venous thrombosis as well as serum vitamin B12 and homocysteine concentrations.

RESULTS

Between January 2015 and May 2021, 326 patients who reported recreational use of N₂O were identified; of these, 17 (5%) patients presented with severe thrombotic events associated with N₂O (71% men; median age, 26 years [range, 18-53 years]), 5 patients presented with arterial thrombosis (3 with acute coronary syndrome, 1 with femoral artery thrombosis, and 1 with middle cerebral artery thrombus), and 12 patients presented with venous thromboembolisms (10 with pulmonary embolisms, 1 with portal vein thrombosis and 1 with cerebral vein thrombosis). Additionally, homocysteine were concentrations severely increased (median, 125 μmol/L [range, 22-253 μmol/L]; reference, <15 μmol/L). Patients reported use of 400 to 6000 g (ie, 50-750 balloons) of N₂O in 1 day. Fifty percent of these patients had experienced neurologic symptoms before the thrombotic event.

CONCLUSION

We describe an alarming incidence of serious thrombotic events among young adults after excessive recreational use of N₂O, accompanied by extremely high homocysteine concentrations. The upward trend in the recreational use of N₂O warrants more awareness of its dangers among both users and medical professionals. Furthermore, these findings could reopen the discussion on possible associations between hyperhomocysteinemia and thrombosis mediated through N₂O.

Neurologic and Thrombotic Complications in the Setting of Chronic Nitrous Oxide Abuse

Nitrous oxide is a commonly used inhaled anesthetic for medical procedures, as well as a drug of abuse throughout the world. Excessive nitrous oxide inhalation has been shown to cause a functional vitamin B12 deficiency and hyperhomocysteinemia, which can lead to peripheral neuropathy and hypercoagulability, respectively. While the development of neurologic toxicity from chronic nitrous oxide abuse (i.e., encephalopathy, myelopathy, and neuropathy) has been previously described, the thrombotic potential of chronic nitrous oxide abuse is less known. The authors report two cases of nitrous oxide abuse leading to both neurologic and thrombotic complications.

Nitrous oxide: a unique official French addictovigilance national survey

Introduction

Nitrous oxide has become over the last few years a public health problem in many countries. France has a dedicated health monitoring system dedicated to the surveillance of the abuse, dependence and consequences associated with the use of psychoactive substances coordinated by the French National Agency for the Safety of Medicines and Health Products.We present the French national survey of nitrous oxide.

Materials and methods

We analyzed all the cases with nitrous oxide from 2012 to 2021: number of notifications, characteristics of the subjects and consumption, consequences reported and their evolutions over time. In addition, we have made a special focus on the four main complications reported.

Results

A total of 525 cases were received with an exponential increase since 2019. We observed changes in the characteristics of the notifications with an increase in the proportion of women [42.7% in 2021 vs. 30.8% in 2020 (p = 0.02)]; an increase in the quantities consumed (use of cylinders); a negative evolution of the contexts of use with a search for self-therapeutic effects and use in violent contexts; an increasing trend of the severity of cases [78.1% in 2021 vs. 70.0% in 2020 (p = 0.07)].The main effects were substance use disorders and/or associated criteria (82.5%), neurological disorders (75.4%), psychiatric symptoms (15.4%) and cardiovascular events (8.6%). In terms of evolution, we observed a significant increase in cases with a use disorder and an increase in neurological complications. Moreover, new serious effects, notably cardiovascular events were reported.

Discussion

The combination of high availability, varied effects from euphoria to relief of discomfort in a stressful global pandemic context and the development of dependence could explain the rapid growth of consumption and the seriousness of the cases.It must now be taken into account that (i) Substance use disorders are associated with nitrous oxide consumption; (ii) clinicians must consider "nitrous oxide" in young subjects presenting different types of manifestations; and (iii) stopping consumption is imperative and is the first treatment. In this context, an addictological assessment must also be carried out.

A Systematic Review of Recreational Nitrous Oxide Use: Implications for Policy, Service Delivery and Individuals

BACKGROUND

Nitrous oxide (N₂O) is a dissociative anaesthetic that is sometimes used recreationally. The prevalence of N₂O use is difficult to quantify but appears to be increasing. Research on N₂O harms and application of harm reduction strategies are limited. The aim of this mixed method systematic review was to collate and synthesise the disparate body of research on recreational nitrous oxide use to inform harm reduction approaches tailored for young people.

METHODS

To identify publications reporting the recreational use of N₂O, a search of public health, psychology and social science databases was conducted. Databases included PubMed, CIHNAL, PsycINFO, Scopus and Web of Science. Grey literature and Google advanced search were also used. Due to limited published literature on the recreational use of N₂O, no limit was placed on publication date or study type. A thematic synthesis extracted descriptive and analytical themes from the selected studies. Quality appraisal was conducted using the CASP Tool for Qualitative studies and the Joanna Briggs Institute case report assessment tool.

RESULTS

The search retrieved 407 reports. Thirty-four were included in the final analysis, including sixteen case reports. The included studies were primarily concerned with raising awareness of the apparently increasing use and subsequently increasing harms of recreational N₂O use. There was limited reference to policy or legislative responses in any published studies, no suggestions for harm reduction strategies or application of service level responses. In general, individuals lack awareness of N₂O-related harms.

CONCLUSION

The review found three key areas that deserve further consideration including: (1) policy, (2) service delivery, and (3) harm associated with N₂O use. We recommend a top-down (policy) and bottom-up (services delivery/services users) approach to harm reduction for N₂O use which also includes further consultation and research with both groups. Future research could explore young people's experience of N₂O use including benefits and problems to inform contextually relevant harm reduction strategies.

Thromboembolic complications of recreational nitrous oxide (ab)use: a systematic review

The recreatinal use of nitrous oxide has become more common in recent years, especially in adolescents and young adults. It has been mainly associated with medical conditions like megaloblastic anemia and (myelo)neuropathy. We report on the thromboembolic complications, a less known side effect, associated with recreational inhalation of nitrous oxide. An extensive literature search was performed for publications reporting on the thromboembolic complications associated with recreational nitrous oxide abuse. Data about sex, age, location of thrombosis, laboratory findings, therapy and outcome were collected. A total of 13 case reports or case series were identified comprising a total of 14 patients. The reported thromboembolic side effects included deep venous thrombosis, pulmonary embolism, mesenterial-, portal and splenic vein thrombosis, cerebral sinus thrombosis, cortical vein thrombosis, stroke, acute myocardial infarction and peripheral artery thromboembolism. These side effects are possibly mediated by the interaction of nitrous oxide with vitamin B12, a cofactor of the methionine synthase complex, which eventually results in elevation of plasma levels of homocysteine. Despite being a known risk factor for cardiovascular disease, the exact pathophysiological mechanism remains unclear. Cessation of nitrous oxide inhalation is necessary to prevent recurrent thrombosis. Nitrous oxide abuse may thus result in a wide spectrum of thromboembolic complications. One should be aware of this etiology, especially in a young person with no obvious risk factors for cardiovascular disease. Spreading awareness is important to inform people about the potentially serious side effects associated with nitrous oxide inhalation.

Neurological and Psychological Characteristics of Young Nitrous Oxide Abusers and Its Underlying Causes During the COVID-19 Lockdown

Background

The COVID-19 pandemic has a serious impact on the mental health of the public due to its economic and social impact. And psychological effects have led to drug and alcohol abuse. After the city lifted the lockdown, we consecutively encountered several young nitrous oxide abusers admitted to hospital for neurological treatment.

Purpose

To inform physician decisions and social intervention, this observational study aimed at investigating the neurological and psychological characteristics of nitrous oxide abusers and its underlying causes during the COVID-19 lockdown.

Methods

The nitrous oxide abusers who sought neurological treatment at our hospital between May 2020 and June 2020 were enrolled. Clinical data including socio-demographic, physical examination, laboratory examination, electromyography and neuroimaging were collected. Their motivations for inhaling nitrous oxide, knowledge about the nitrous oxide abuse and the accompanying of family were investigated face to face. Psychological status was assessed by the Symptom Checklist 90 (SCL-90) psychological evaluation.

Results

Six nitrous oxide abusers were enrolled and the age was 22 ± 4.3. Clinical presentations included varying degrees of limb numbness and an ataxic gait. Laboratory examination revealed that all the patients did not have pernicious anemia, 4 patients had decreased vitamin B12 while 3 patients exhibited elevated homocysteine levels. MR of the spinal cord revealed that 4 patients had abnormal signals in the cervical spinal cord of high symmetry with splayed or inverted V sign after T2WI. Electromyogram (EMG) test showed 5 patients had peripheral nerve damage. The SCL-90 psychological evaluation results indicated that all patients had severe anxiety, depression and psychosis and they had severer psychological problems than ordinary citizens. Their motives for inhaling nitrous oxide are to relieve boredom, curiosity and buddy pressure. Their family spent <1 day per week to stay with them during city lockdown.

Conclusion

The enrolled patients caused by abuse of nitrous oxide presented with symptoms of subacute combined with spinal degeneration. They had more serious psychological problems related to the COVID-19 pandemic. These cases make us value the psychological problems of young people under the outbreak and take multi-layered measures from families, schools (companies), hospitals, and governments to address it.

Pulmonary embolus associated with a rare provoking factor: recreational nitrous oxide use

Pulmonary embolism (PE) is a common acute presentation which may be provoked by multiple factors. We present the unique case of a young man with no underlying health conditions who was diagnosed with bilateral PE which we believe was provoked by chronic use of nitrous oxide (NO), a potentially under-recognised risk factor for PE. NO is a substance that is commonly used recreationally, particularly among young adults in the UK. It has been shown to increase serum homocysteine levels which may create a prothrombotic state.Our patient had raised serum homocysteine levels on admission. He was anticoagulated and discharged with advice to stop nitrous oxide use. We recommend asking patients about recreational drug use when screening for provoking factors for PE so as to offer appropriate treatment and counselling.

The Clinical Presentations of Nitrous Oxide Users in an Emergency Department

Today, the concomitant abuse of nitrous oxide (N₂O) and illicit drugs is evident and problematic. However, there are few reports regarding the clinical manifestations of N₂O users when they present to the emergency department (ED). The purpose of this study was to describe the clinical presentations, the associated illicit substances used in combination, and the outcomes in N₂O users visiting the ED. This was a retrospective observational cohort study. All N₂O adult users admitted to the ED at Linkou Chang Gung Memorial Hospital between 2012 and 2020 were included. Demographic variables, clinical symptoms, and examination results were collected from medical records. Univariate comparisons were conducted between pure N₂O users and combined illicit drug users. A total of 40 patients were included, 24 of which were pure N₂O users. Limb weakness and numbness accounted for the majority of chief complaints. Neurologic symptoms were the most common clinical manifestations (90%). A more severe ED triage level, faster heart rate, greater agitation, and cardiovascular symptoms were significantly noted in combined illicit drug users. In ED, limb numbness/weakness should arouse physicians’ awareness of patients using N₂O. Combined use of N₂O and illicit drugs can cause great harm to health.

Extensive Cerebral Venous Thrombosis Secondary to Recreational Nitrous Oxide Abuse

Nitrous oxide, colloquially known as "whippets," is a commonly abused inhalant by adolescents and young adults. There are limited data describing the adverse effects of this abuse. We present a 16-year-old girl with no medical history who presented to the emergency department for confusion, hallucinations, weakness, and headaches. Imaging revealed extensive cerebral thrombosis. She had no prior history of venous or arterial thrombosis. Hypercoagulability workup demonstrated an elevated homocysteine level. She was treated with effective anticoagulation and vitamin B12 folate supplementation. To our knowledge, there are a very few cases in the medical literature of cerebral venous thrombosis following the use of nitrous oxide. The pathophysiology of the disorder appears to be linked to the metabolism of vitamin B12 inducing hyperhomocysteinemia and a procoagulant state.

Cerebral venous sinus thrombosis: a complication of nitrous oxide abuse

Nitrous oxide (NO) is an inhalant that has become increasingly popular as a recreational drug. While it is presumed to be harmless, a number of adverse effects of NO have been described. We discuss the case of a 24-year-old man with no medical history, who initially presented to the emergency department with progressive polyneuropathy caused by vitamin B12 deficiency after NO abuse. Two days after being discharged with hydroxocobalamin supplementation, the patient returned with a severe headache, blurry vision and slurred speech. Imaging revealed cerebral venous sinus thrombosis. Hypercoagulability workup showed slightly elevated homocysteine and normalised vitamin B12 after supplementation. Genetic testing showed a heterozygous prothrombin G20210A mutation. He was treated with low-molecular-weight heparin followed by dabigatran. We hypothesise that NO use may increase the risk of developing cerebral venous thrombosis, especially in patients with multiple risk factors and elevated homocysteine levels.

A 19-Year-Old Man with a History of Recreational Inhalation of Nitrous Oxide with Severe Peripheral Neuropathy and Central Pulmonary Embolism

Patient: Male, 19-year-old

Final Diagnosis: Peripheral neuropathy • pulmonary embolism • vitamin B₁₂ deficiency

Symptoms: Balance problems • muscle weakness • sensorial deficit • thoracic pain

Medication:—

Clinical Procedure: —

Specialty: Cardiology • Laboratory Diagnostics • Neurology

Activation of NLR family, domain of pyrin containing 3 inflammasome by nitrous oxide through thioredoxin-interacting protein to induce nerve cell injury

Nitrous Oxide (N₂O) has been shown to be neurotoxic, but its specific mechanism is still unclear. The purpose of this work is to probe into the impact of N₂O on nerve cell injury through regulating thioredoxin-interacting protein (TXNIP)/the NOD-like receptor domain of pyrin containing 3 (NLRP3) pathway. The results indicated that, N₂O exposure elevated TXNIP/NLRP3 expression in vivo and in vitro, led to declined learning and memory capabilities in mice, reduced apoptosis rate in hippocampal neuron and Nissl bodies, elevated inflammatory factors TNF-α, IL-1β and IL-6 levels, as well as cleaved caspase-3 and Bax expressions, and reduced Bcl-2 expression. Overexpressing TXNIP or NLRP3 further aggravated these injuries, but knocking down TXNIP or NLRP3 improved them. CO-IP indicated that TXNIP and NLRP3 can be combined, with interaction relationship. All in all, the results manifested that N₂O is available to promote nerve cell inflammation and apoptosis through activating the TXNIP/NLRP3 pathway that can be used as a potential target for N₂O-induced nerve damage in the future.

Recreational Nitrous Oxide Abuse: Prevalence, Neurotoxicity, and Treatment

Nitrous oxide (N₂O), also known as "laughing gas," is a colorless, nonirritating gas. Clinically, it is widely used as an inhaled anesthetic, analgesic, and anxiolytic. In recent years, recreational abuse of N₂O has become increasingly common, especially among young adults and adolescents, but many of them lack awareness of the possible side effects associated with this drug. N₂O abuse can damage multiple systems, especially the nervous system, but the exact mechanism of N₂O toxicity remains controversial. At present, an increasing number of cases of nervous system damage caused by N₂O abuse have been reported both at home and abroad. Discontinuation of N₂O use and timely supplementation with vitamin B12 are essential for a good prognosis. Long-term abuse without timely treatment will eventually lead to irreversible neurological damage. In this article, we discuss the epidemiology of N₂O abuse, neurotoxicity mechanisms, clinical manifestations, relevant auxiliary examinations, treatments, and prognosis to improve social awareness of N₂O exposure risk, especially among users and clinicians.

Case report of an acute myocardial infarction after high-dose recreational nitrous oxide use: a consequence of hyperhomocysteinaemia?

Background

Nitrous oxide (N₂O, laughing gas) is increasingly used as a recreational drug and is presumed relatively safe and innocent. It is often being used in combination with other substances, such as cannabis.

Case summary

A young adult attended the emergency room because of chest pain after recreational use of very high-dose nitrous oxide in combination with cannabis. Electrocardiography demonstrated ST-elevation in the anterior leads. Coronary angiography showed thrombus in the proximal and thrombotic occlusion of the distal left anterior descending coronary artery for which primary percutaneous coronary intervention was attempted. Thrombus aspiration was unsuccessful and the patient was further treated with a glycoprotein IIb/IIIa in addition to dual platelet therapy. Blood results showed low vitamin B12 and folic acid status with concomitant hyperhomocysteinaemia, a known cause of hypercoagulation. Transthoracic echocardiogram showed a moderately reduced left ventricular ejection fraction (LVEF). Three months later, an improvement in LVEF and no recurrent angina or symptoms of heart failure were noticed.

Discussion

We report a case of acute myocardial infarction secondary to very high-dose nitrous oxide abuse in combination with cannabis and possible hypoxia. We propose that severe hyperhomocysteinaemia secondary to nitrous oxide-induced vitamin B12 deficiency together with the vasoconstrictive effects of cannabis might pose a seriously increased risk for intracoronary, among others, thrombus formation. In conclusion, we contest the safety and innocence of recreational nitrous oxide (ab)use, notably in the context of other factors increasing the risk of coagulation.

Isolated cortical vein thrombosis after nitrous oxide use in a young woman: a case report

Background

Nitrous oxide has become a popular inhalant as abused substance by young Chinese people in recent years. It has been mainly associated with medical conditions including megaloblastic anemia and myeloneuropathy.

Case presentation

We report a case of a 25-year-old high school graduate who had been abusing nitrous oxide for twenty months. She had a history of peripheral neuropathy and subacute combined degeneration in between. The young woman presented with headache, motor aphasia and right arm paralysis of eight hours after intermittently consuming nitrous oxide for one week. D-dimer was increased (1.1 mg/ml). Blood vitamin B12, folate, homocysteine and beta-HCG levels were normal. Head CT showed hemorrhagic infarction and subarachnoid hemorrhage. MR angiography and venography were normal. Head MRI identified left frontal isolated cortical vein thrombosis. Her muscle strength and verbal fluency significantly improved after initiation of Low Molecular Weight Heparin and serial head MRI showed continuous reduction in the size of thrombus.

Conclusions

For the first time nitrous oxide use is found to be related to isolated cortical vein thrombosis. Public education regarding the potential consequences of abusing nitrous oxide especially in high-risk individuals is urgently needed.

Nitrous oxide inhalant abuse and massive pulmonary embolism in COVID-19

A patient presented to the emergency department with altered mental status and lower extremity weakness in the setting of nitrous oxide inhalant abuse and Coronavirus Disease-2019 (COVID-19) infection. He subsequently developed hypotension and severe hypoxia, found to have a saddle pulmonary embolus (PE) with right heart strain requiring alteplase (tPA).