Category: Rare Neurometabolic Movement Disorders
Objective: To describe an uncommon case of choreoathetosis secondary to vitamin B12 deficiency, highlighting the importance of recognizing atypical movement disorders linked to metabolic causes.
Background: Vitamin B12 deficiency classically presents with sensory ataxia, myelopathy, and peripheral neuropathy due to subacute combined degeneration of the spinal cord. However, extrapyramidal and involuntary movements are rarely described and may lead to diagnostic confusion.
Method: We report the case of a man followed at the Department of Neurology, Mongi Ben Hamida National Institute of Neurology, for the exploration of a movement disorder. Clinical examination, laboratory tests, and magnetic resonance imaging (MRI) were performed.
Results: This 68-year-old patient presented with progressive distal paresthesia, gait imbalance, and involuntary upper limb movements evolving over several years. Neurological examination revealed cachexia, sensory ataxia, postural instability, loss of deep sensation, abolition of tendon reflexes, and bilateral choreoathetoid movements that worsened with eye closure and improved on a flat surface. Cranial nerves were normal. Laboratory tests showed megaloblastic anemia. Serum vitamin B12 level was markedly reduced at 90.33 pg/ml, and homocysteine was elevated at 106.7 umol/L, supporting the diagnosis of vitamin B12 deficiency. MRI of the spinal cord revealed a symmetric T2 hyperintensities of the posterior and lateral columns, concording with subacute combined degeneration. After parenteral vitamin b12 supplementation, no clear clinical improvement has been observed to date.
Conclusion: Choreoathetosis represents a rare manifestation of vitamin B12 deficiency, which may not always show rapid reversibility after supplementation, particularly in long‑standing disease. Early recognition of such atypical extrapyramidal presentations is therefore crucial.
To cite this abstract in AMA style:
O. Sakli, R. Zouari, A. Rachdi, Z. Saied, F. Nabli, D. Ben Mohamed, S. Ben Sassi. Choreoathetosis revealing vitamin B12 deficiency : an unusual manifestation of subacute combined degeneration [abstract]. Mov Disord. 2026; 41 (suppl 1). https://www.mdsabstracts.org/abstract/choreoathetosis-revealing-vitamin-b12-deficiency-an-unusual-manifestation-of-subacute-combined-degeneration/. Accessed October 1, 2026.« Back to 2026 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/choreoathetosis-revealing-vitamin-b12-deficiency-an-unusual-manifestation-of-subacute-combined-degeneration/