Differential Diagnosis 1 – Alzheimer’s Disease (AD)
Rationale:
Alzheimer’s Disease is also the most common form of dementia. Mrs. Heston exhibits cognitive or behavioral symptoms that interfere with the ability to function at usual activities, a decline in previous functioning levels not explained by delirium or a major psychiatric disorder, impaired ability to acquire and remember new information, impaired reasoning and handling of complex tasks, and changes in personality and behavior. She also demonstrates an insidious onset over within the last two years, a clear-cut history of worsening of cognition by family, an amnestic presentation, and a nonamnestic presentation including language, visuospatial, and executive dysfunction. She does not exhibit evidence of another concurrent, active neurological disease or comorbidity or use of medication that could have a substantial effect on cognition (McKhann et al, 2011).
While biomarkers and imaging aren’t used for routine diagnostic purposes, they may assist with diagnosis. The following molecular biomarkers are suggestive of AD:
Internationally established biomarkers in cerebral spinal fluid (CSF) used to diagnose Alzheimer’s disease (AD) (Humpel, 2011).
Differential Diagnosis 2 – Vascular Dementia (VaD)
Rationale:
The NINDS-AIREN criteria were used to rule out vascular dementia: cognitive impairment of two or more domains (orientation, attention, language, visuospatial functions, executive functions motor control, and praxis), presence of cerebrovascular disease AND a relationship between the previous two criteria (i.e. onset of dementia within 3 months following a recognized stroke and/or abrupt deterioration in cognitive functions; or fluctuating, stepwise progression of cognitive deficits). Mrs. Heston does not present with a history of cerebrovascular disease (CVD). Neurologic examination was negative for focal signs such as hemiparesis, lower facial weakness, Babinski sign, sensory deficit, hemianopia, and dysarthria. MRI results show no evidence of infarcts, white matter lacunes, or periventricular white matter lesions (Román et al, 1993).
Clinical characteristics of Alzheimer’s disease (AD) and vascular dementia (VaD) (Muangpaisan, 2007).
Differential Diagnosis 3 – Frontotemporal Degeneration (FTD)
Rationale:
A hallmark characteristic of FTD is a gradual, progressive decline in behavior and language (with memory usually relatively preserved). As the disease progresses, it becomes increasingly difficult for people to plan, organize activities, behave appropriately in social or work settings, interact with others, and care for oneself, resulting in increasing dependency on caregivers. Mrs. Heston does present with similar manifestations, like cognitive impairment, difficultly interacting appropriately with others, and increased dependency on others. However, stated recent agitation and mood swings may not be explained by FTD. Mrs. Heston also does not meet the age criteria, as typical age of onset of FTD often occurs in a person’s 50s and 60s, with roughly 60% of cases occurring in people 55-64 years old (Knopman, 2011).
Clinical features of frontotemporal dementia (FTD) and Alzheimer’s disease (AD) (Maungpaison, 2007).