Nitrous oxide-induced myeloneuropathy: a case series

Area of Science:

• Neurology
• Toxicology
• Public Health

Background:

• Nitrous oxide (N₂O) is a prevalent recreational drug among young adults in the UK.
• Neurological adverse effects associated with N₂O use are increasingly recognized, yet data often comes from limited case reports.

Purpose of the Study:

• To summarize the clinical and investigative findings in the largest case series of N₂O-myeloneuropathy to date.
• To enhance awareness and facilitate early recognition and treatment of N₂O-induced neurological harm.

Main Methods:

• A retrospective analysis of 119 patients diagnosed with N₂O-myeloneuropathy.
• Data collected from NHS teaching hospitals in London, Birmingham, and Manchester.
• Clinical presentation, neurological examination, and MRI findings were reviewed.

Main Results:

• Paraesthesia, particularly in the lower limbs, was the most common presenting symptom (85%).
• Gait ataxia and bladder/bowel disturbances were frequent. MRI revealed cervical spinal cord involvement (C3-C5) in most cases.
• Weekly N₂O consumption correlated with elevated methylmalonic acid levels, indicating functional vitamin B₁₂ deficiency.

Conclusions:

• Neurological harm from recreational nitrous oxide abuse is a growing global concern.
• Increased availability of N₂O has contributed to a rise in myeloneuropathy cases in the UK.
• Understanding the diverse clinical manifestations is crucial for timely diagnosis and intervention.