Lower extremity numbness

A 38-year-old-male with a past medical history significant for acid reflux, pancreatitis, and substance abuse (alcohol and marijuana) presented to the emergency department with complaints of bilateral lower extremity numbness and difficulty with ambulation, as well as a tingling sensation from the umbilicus to his toes. The patient denied muscle weakness on admission; however, the patient did admit to recreational nitrous oxide use and stated a recent increase in the amount of use. In addition, he started suffering from a similar episode around 10 years ago. Regarding this episode, he reported symptoms began 1 week prior to admission while inhaling nitrous oxide. Neurological exam was significant for the following abnormalities, with all other neurological tests being normal: (a) strength was 4/5 in both lower extremities proximally and distally and (b) loss of sensation from the umbilicus down to feet.

Clinical workup included an MRI of the cervical and lumbar spine and lab work. MRI results showed mild degenerative disease in the thoracic spine. Lumbar spine changes were consistent with diffuse disc bulge at L5-S1 without significant foraminal stenosis. Moreover, cervical spine changes were also consistent with mild degenerative disease. MR of the brain showed no acute abnormalities, but changes were significant for mild cerebral atrophy. Dawsons' finger morphology was absent, with no periventricular lesions present. Labs on admission were significant for macrocytic anaemia with a haemoglobin of (9.5) and an MCV of (112.8). Low levels of B12 were also noted. Additionally, MCH was 36.8, MCHC was 32.6, and RDW was 73.2. Of note, glucose levels on admission were 116. The urine drug screen was positive for cannabinoids.