Nitrous Oxide Abuse

There is a toxicity linked to the chronic use of nitrous oxide, leading to neurological disorders such as combined sclerosis of the spinal cord. One thus frequently observes patients presenting disorders of walking or paresthesias, of more or less resolving evolution being able to go until the need for using a wheelchair and more recently cases of thrombosis were reported Serum or urine N2O assays are rarely performed routinely, because they do not allow to ensure a real exposure due to the very short half-life of this gas in the body. Thus, other biological monitoring markers are mentioned in the literature, such as vitamin B12 or homocysteine. Unfortunately, there are still no recommendations for biological monitoring of nitrous oxide consumption. Moreover, underlying mechanisms leading to clinical outcomes remains misunderstood.

Nitrous oxide has become an increasingly popular recreational drug amongst young people, particularly at festivals, nightclubs and parties. Considering the drug is not illegal to possess, has low cost in the form of 'whippets' and can be easily purchased online, it has become the second most commonly used recreational drug amongst people aged 16-24 in the UK. However, nitrous oxide is known to irreversibly inactivate the functioning of vitamin B12, a vitamin required for the maintenance and proper functioning of nerves in the spinal cord. Neurological symptoms in this population have been reported in around 3.4% of nitrous oxide users, although the true incidence is expected to be higher as the cases being reported by UK hospitals continues to rise. Patients may present with adverse neurological symptoms like tingling, weakness, coordination and mobility problems. Currently, studies reviewing the functional recovery of these patients have been limited by a retrospective study design, short follow up duration and being limited to small cohort sizes. This is in part linked to patient non-compliance and non-attendance at follow-up appointments. The investigators will therefore prospectively recruit all patients presenting with these symptoms and continue to collect data relating to their neurological recovery for 12 months. Data collection will be remote to ensure it is of low burden to the participants. This will allow the investigating team and others to fully appraise the severity of these toxic neuropathies and understand how best to manage their follow up.