Abstract
Vitamin deficiency is common in the geriatric population and is responsible for majorly imbalanced hematological, neurological, and neuropsychiatric functioning. Methylcobalamin deficiency or vitamin B(12) deficiency can be underestimated in some cases and be misdiagnosed as other illnesses, such as thalamic syndrome. Timely diagnosis of this deficiency is essential, especially in the geriatric population, as it might cause irreversible structural brain damage. This is also presented as elevated levels of homocysteine and methylmalonic acid. Clinically, it presents with the following symptoms: lower sensitivity levels to touch and light, psychosis, paresthesia, anemia, imbalance, fatigue, cognitive disturbances, difficulty remembering, and confusion. Symptoms are usually progressive and worsen over a period of time. In this case report, we present the case of a 62-year-old male with clinical symptoms of numbness and tingling in the right side of the body. The neurological presentations resembled left thalamic infarct, but the underlying reason was methylcobalamin deficiency.