A 62-year-old woman is brought to the physician by her son due to progressive forgetfulness over the last year. She has been less active than normal and is having some difficulty walking. The patient has no urinary incontinence. Her past medical history is significant for exertional angina and hypertension. She has recently been depending on her son to manage her medications, which include metoprolol, amlodipine, and aspirin. She does not smoke or consume alcohol. Her father had hypertension and stroke, and her mother had Alzheimer disease. The patient is oriented to person and place, but not time. She has difficulty with 3-word recall. Her gait is slightly unstable and she has problems balancing when she closes her eyes. Examination of the lower extremities show decreased vibratory sensation, spastic paresis, and hyperreflexia bilaterally.
What is the most likely cause of this patient's condition?

Question

A 62-year-old woman is brought to the physician by her son due to progressive forgetfulness over the last year.  She has been less active than normal and is having some difficulty walking.  The patient has no urinary incontinence.  Her past medical history is significant for exertional angina and hypertension.  She has recently been depending on her son to manage her medications, which include metoprolol, amlodipine, and aspirin.  She does not smoke or consume alcohol.  Her father had hypertension and stroke, and her mother had Alzheimer disease.  The patient is oriented to person and place, but not time.  She has difficulty with 3-word recall.  Her gait is slightly unstable and she has problems balancing when she closes her eyes.  Examination of the lower extremities show decreased vibratory sensation, spastic paresis, and hyperreflexia bilaterally. 
What is the most likely cause of this patient's condition?

Quizplus · Accepted Answer

Explanation: Vitamin B12 deficiency is relatively common in older adults and can present with dementia and subacute combined degeneration (SCD). This patient's dementia is represented by progressive memory impairment that is interfering with her daily activities (eg, medication management). She also has signs of dorsal spinal column dysfunction (eg, impaired vibration, positive Romberg sign) and lateral corticospinal tract abnormalities (eg, spastic paresis, hyperreflexia), which are fairly specific for SCD. Vitamin B12 levels should be checked in all patients with suspected dementia and/or SCD as these conditions are reversible with vitamin supplementation in the majority of cases. (Choice A) Alzheimer dementia can present with impaired cognition and diffuse cortical atrophy on neuroimaging. However, motor abnormalities are normally a late manifestation of the disease, and signs of dorsal spinal column dysfunction are not typical. (Choice B) Normal-pressure hydrocephalus is associated with ventriculomegaly and typically presents with gait abnormalities, cognitive dysfunction, and urinary incontinence. This patient's signs of dorsal spinal column dysfunction and lack of urinary incontinence make the diagnosis less likely. (Choice C) Wilson disease can result in copper accumulation in the brain and present with cognitive and gait dysfunction. However, the majority of cases are diagnosed at age 5-35, and the most common neurologic symptom is dysarthria. (Choice D) Although this patient has risk factors for stroke, her bilateral neurologic findings are consistent with myelopathy due to subacute combined degeneration. Educational objective: Dementia and subacute combined degeneration are potential complications of vitamin B12 deficiency that are reversible with vitamin supplementation in the majority of cases. References: Cobalamin deficiency: clinical picture and radiological findings. (http://www.ncbi.nlm.nih.gov/pubmed/24248213) Vitamin B(12) deficiency with bilateral globus pallidus abnormalities. (http://www.ncbi.nlm.nih.gov/pubmed/22332180)

A 62-Year-Old Woman Is Brought to the Physician by Her