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Título

Vitamin B12 deficiency associated with atypical brain MRI findings

RESUMO

Case presentation: A 68-year-old woman was referred to our hospital complaining of progressive and symmetrical paraparesis, paresthesia, and gait imbalance over the last five months, currently confined to a wheelchair. She had no previous medical history or noteworthy dietary restrictions. On neurological examination, she had severe lower limb weakness, spasticity, and generalized brisk deep tendon reflexes with a bilateral Babinsky sign. The patient also had reduced light touch and vibration sense in both legs and upper limbs. Laboratory testing revealed reduced levels of B12 vitamin and on brain MRI it was noticed FLAIR and T2 hyperintensities in periventricular and centrum semiovale white matter, bilateral globus pallidus, cerebral and middle cerebellar peduncles, and in the brainstem. The described lesions had no diffusion restriction or contrast enhancement. These findings were therefore compatible with vitamin B12 deficiency and the patient was referred for further investigation in our outpatient clinic. Discussion: Vitamin B12 deficiency can be responsible for hematological, gastrointestinal, psychiatric, and neurological symptoms. The causes of depletion are numerous and include malabsorption due to GI tract abnormalities, autoimmune diseases, and dietary restrictions. The most common neurological manifestations are paresthesia, progressive symmetrical weakness and gait disturbances. The disease may progress to spastic paraplegia with cognitive and mood alterations. Spinal cord MRI often shows the altered signal in its lateral and posterior columns. Less commonly there are brain white matter and optic nerve involvement. Bilateral globus pallidus lesions are an even rarer presentation, described in the presented case. Treatment is based on vitamin B12 supplementation and neuropsychiatric improvement can be seen after months, however, some neurologic findings may be irreversible. Final comments: In this case there are classical neurological signs compatible with vitamin B12 deficiency such as combined subacute degeneration, hyperreflexia and peripheral neuropathy. Nevertheless, we present uncommon imaging finding poorly reported in the literature, more specifically bilateral hyperintensities in the globus pallidus.