Differential Diagnosis of Cognitive Impairment in Bipolar Disorder: A Case Report

In old age bipolar disorder (BD) patients, cognitive complaints difficults an accurate differential diagnosis between cognitive deficits secondary to a primary affective disorder and neurocognitive disorders, such as dementia in Alzheimer’s disease (AD). This case report refers to a female 56-year-old patient with severe and treatment resistant BD type I that presented cognitive decline with loss in recent episodic memory and executive functions in the past year. The diagnosis of mild stage dementia associated to BD was suggested, however neuroimaging tests such as magnetic resonance imaging (MRI) and positron emission tomography with fluordeoxiglicose (PET - FDG) were not enough to exclude the differential diagnosis of AD. The CSF biomarkers (reduced levels of amyloid peptide Aâ1-42 and the elevation of total tau protein and phosphorylated tau levels) resources were decisive for exclusion of an etiological diagnosis of AD.