Diagnostic Challenges of Late-Onset Mania versus Dementia with Behavioral Disturbances: A Case Report

Introduction Late-onset mania presents as a diagnostic challenge given the interplay between psychiatry and neurology. Neurocognitive disorders, especially the behavioral subtype of Frontotemporal Dementia (FTD), are among one of the differential diagnoses in patients presenting later in life with manic-like symptoms. Here we discuss a case of new-onset manic symptoms in an elderly patient with no prior history of bipolar disorder and conduct a comprehensive literature review to assist with the diagnostic challenges of late-onset mania and dementia with behavioral disturbances. Case Mrs. X is a 67-year-old female with bipolar disorder diagnosed 2 months prior to admission who presented to the hospital after a mechanical fall and witnessed seizure-like activity thought to be due to benzodiazepine withdrawal. She was found to have new atrial fibrillation that was stabilized, and clonazepam was resumed. Psychiatry was consulted to assist with manic behaviors. On initial evaluation, Mrs. X presented as anxious, distractible, tangential with pressured speech, increased psychomotor activity, and paranoid towards her husband. She was treated for a urinary tract infection but otherwise workup was unremarkable. Head imaging demonstrated gray matter volume loss that appeared more prominent in the temporal and frontal lobes. Once transferred to the inpatient psychiatry unit, she presented with elevated mood, excessive jocularity, disinhibition, and poor insight. SLUMS of 18 noted poor attention, processing, and short-term recall. She was started on divalproex sodium titrated to 1500 mg daily (VPA level 108 mcg/mL) and olanzapine 25 mg daily. Observations throughout this time included minimal change in affect, elevated mood, memory deficits and social disinhibition. She did have less aggression, minimal paranoia towards her husband and circumstantial thought process although noted with confabulation. Methods We completed a comprehensive literature review utilizing PubMed and Google Scholar. Search terms included combinations of “late-onset”, “bipolar disorder”, “mania”, “neurocognitive disorder”, “dementia”, “frontotemporal”, “behavioral disturbances”. Discussion Once Mrs. X’s initial delirium resolved, she remained with manic-like symptoms. Collateral, brain imaging of reduced gray matter volume in the frontal and temporal lobes, and lack of response to high doses of a mood stabilizer and antipsychotic favor a probable neurocognitive disorder with behavioral disturbances. Literature reviewed helped to narrow down the differential diagnosis for Mrs. X and allowed for a more comprehensive treatment plan. Conclusion Diagnostic elucidation of late-onset mania relies on a comprehensive investigation into psychiatric and non-psychiatric etiologies, a detailed collateral history, and a neuropsychiatric lens. Neurocognitive disorders remain an important differential diagnosis. Funding No Funding