A case of brain metastases masquerading as cognitive decline

ABSTRACT

Introduction: Cognitive decline in the elderly is a diagnostic challenge - one that must consider numerous differential diagnoses, including dementia. Given the profound impact of one's cognition on functional status and quality of life, early recognition of reversible and treatable causes of cognitive decline, especially when it occurs at a rate faster than expected, is critical. Case Presentation An 86-year-old female was admitted from long-term care for a 2-week history of cognitive decline, hypoxia, and vomiting that began after receiving the second dose of the COVID vaccine. Her past medical history was significant for dementia, right middle cerebral artery stroke, benign left parietal neoplasm under surveillance, and pulmonary emboli. Investigations for her hypoxia were unremarkable;thus, it was thought to be due to aspiration from emesis. Initially, the patient's cognitive decline was presumed to be secondary to her dementia, which has been progressive for the past 5 years, leading to her eventual admission to long-term care. However, it was highlighted that the patient's cognition rapidly declined in a period of weeks. Despite her dementia, at baseline, the patient could engage in full conversations. However, over the past few weeks, the patient could only communicate with a few words and became newly dependent with ADLs. The patient was not delirious, given the non-fluctuating cognitive decline with normal attention and level of consciousness. Laboratory studies, including TSH and vitamin B12, were normal. CT Brain was completed given patient's history of parietal neoplasm, demonstrating a new left occipital lobe lesion with vasogenic edema. The patient was started on dexamethasone given the size of the lesion and edema. With this, her cognition significantly improved over days, allowing the patient to be involved in the decision-making of her care. Unfortunately, the patient had an aspiration event during her admission. As per her wishes, she was discharged to long-term care with symptom-focused, comfort care. Discussion: In this case, we discuss our approach to cognitive decline and highlight the importance of maintaining a broad differential, even in the face of known dementia. Finding reversible causes of cognitive decline can not only improve quality of life, but as seen in our patient, it can allow individuals to participate in meaningful decisions regarding their goals of care.