Myeloradiculoneuropathy due to vitamin B12 deficiency: an unusual clinical and radiological presentation.

A 42-year-old man from rural India presented with asymmetric progressive paraparesis mimicking compressive dorsal myelopathy, followed by distal upper limb, truncal and neck-flexor weakness, further complicated by acute urinary retention. His sensory deficits were marked by loss of joint position sense (JPS) and graded loss of vibration sense, along with a definite sensory level. Deep tendon jerks were hypo-to-areflexic, plantar was bilaterally extensor. He had become less attentive and occasionally failed to keep track with conversations. A syndromic diagnosis of myeloradiculoneuropathy with cognitive impairments was made. Further tailored investigations revealed vitamin B12 deficiency with positive anti-parietal cell antibody. Diagnosis of subacute combined cord degeneration (SACD) was confirmed. Neuro-imaging revealed intramedullary intensity changes only along lateral aspect of spinal cord instead of characteristic posterior involvement. Following parenteral vitamin B12 supplementation, patient started showing improvement in motor power and subjective sensory symptoms. His bladder symptoms persisted initially, however recovered finally after 6 months.

Subacute Combined Degeneration of the Spinal Cord Caused by Autoimmune Gastritis.

A 68-year-old woman presented with a 2-year history of worsening unsteady gait. Her neurological examination revealed peripheral neuropathy with lower limb sensory dominance. T2-weighted imaging revealed a disorder of the posterior cervical cord. Blood test findings revealed vitamin B12 deficiency, and gastroscopy revealed typical findings of autoimmune gastritis. She received vitamin B12 supplementation, but some peripheral neuropathy symptoms persisted due to longstanding vitamin B12 deficiency. Asymptomatic patients should undergo gastroscopy to detect autoimmune gastritis, as chronic vitamin B12 deficiency causes irreversible peripheral neuropathy.

Recreational nitrous oxide abuse related subacute combined degeneration of the spinal cord in adolescents - A case series and literature review.

BACKGROUND: Nitrous oxide (N2O) is a commonly used inhaled anesthetic in outpatient dental procedures. However, the increasing recreational use of N2O may result in vitamin B12 deficiency-related neurologic and psychiatric symptoms. The aim of this study was to demonstrate the clinical features of chronic N2O abuse in pediatric patients. METHODS: Patients under 20 years of age who were diagnosed with N2O-induced subacute combined degeneration of the spinal cord from 2012 to 2018 were enrolled in this study. Clinical presentations, laboratory, imaging, ancillary studies, treatments and outcomes were analyzed. RESULTS: Nine patients were included, all of whom presented with symptoms of myeloneuropathy including limb numbness, limb weakness or unsteady gait. Six patients had low or low-normal vitamin B12 (cyanocobalamin) levels. Eight patients had evidence of subacute combined degeneration of the spinal cord via neuroimaging studies. All of the patients received vitamin B12 supplementation as treatment. All had full recovery of muscle power within 2 months. Five patients had persistent sensory deficits. CONCLUSION: Chronic N2O abuse can cause permanent neurological damage if not treated promptly. Clinical staff should be aware of the various presentations of neurotoxicity related to N2O abuse.

Pitfalls in the diagnostic evaluation of subacute combined degeneration.

We report a case of a 43-year-old man presenting with a 2-week history of painless ascending sensory disturbances, suspected to be suffering from acute inflammatory polyneuropathy. On clinical examination, deep tendon reflexes were preserved and muscle strength was 5/5 everywhere. Gait was ataxic with positive Romberg test. Lumbar puncture was normal and electroneurography demonstrated demyelination. With spinal cord involvement centred on the posterior tracts on MRI, differential diagnosis focused on cobalamin deficiency. Initial laboratory work up showed nearly normal holotranscobalamin (43 pmol/L, normal>50) suggesting no vitamin B12 deficiency. Surprisingly, further testing including methylmalonic acid (3732 nmol/L, normal<271) and homocysteine (48.5 µmol/L, normal<10) showed an impairment of vitamin B12-dependent metabolism leading to the diagnosis of subacute combined degeneration. Only after repeated history taking did the patient remember having taken tablets containing cobalamin for 3 days before hospitalisation. In case of B12 deficiency, holotranscobalamin can rapidly normalise during supplementation, whereas methylmalonic acid and homocysteine might help to detect B12 deficiency in patients who recently started supplementation.