Deficiency of vitamin B12 produces protean effects on the nervous system, most commonly neuropathy, myelopathy, cognitive and behavioural symptoms, and optic atrophy. Involuntary movements comprise a relatively rare manifestation of this readily treatable disorder. Both adults and infants deficient in vitamin B12 may present with chorea, tremor, myoclonus, Parkinsonism, dystonia, or a combination of these, which may precede diagnosis or become apparent only a few days after parenteral replacement therapy has begun. The pathogenesis of these movement disorders shows interesting parallels to certain neurodegenerative conditions. The clinical syndrome responds well to vitamin B12 supplementation in most cases, and an early diagnosis is essential to reverse the haematological and neurological dysfunction characteristic of this disorder. In this article, we elucidate the association of vitamin B12 deficiency with movement disorders in adults and in infants, discuss the pathogenesis of this association, review previously reported cases, and present a young adult male with severe generalized chorea that showed a salutary response to vitamin B12 supplementation.

The emergence of the coronavirus 2019 (COVID-19) pandemic has presented an unprecedented global challenge. Vaccines against COVID have been developed to date. Covid-19 has been linked with the development of Guillain-Barre Syndrome (GBS), a rare immune-mediated demyelinating neuropathy. We report three cases of Guillain-Barre Syndrome and one case of Chronic Inflammatory Demyelinating Polyneuropathy (CIDP), presenting to a Tasmanian hospital, and review 15 other reported cases and discuss likely immunopathology. Nearly all reported cases of post-COVID-19 vacciation inflammatory demyelinating polyneuropathy are linked to AstraZeneca vaccination and a variant with bifacial weakness is the most reported form of GBS globally.

No abstract