A family member brought a senior to the clinic. The family member explained to the nurse that the patient suddenly from one day to the other, started with confusion, and agitation. The family states the patient used to be orientated and with very calm behavior. The nurse suspects that this patient is experiencing:

A. Delirium: Delirium is characterized by a sudden onset of confusion, agitation, and fluctuating levels of consciousness. It often develops over a short period, such as hours to days, and is typically associated with an underlying medical condition, medication, or infection. The patient's rapid change from being oriented and calm to confused and agitated suggests a sudden onset, which is indicative of delirium. B. Sundowning: Sundowning refers to a pattern of increased confusion and agitation that occurs in the late afternoon or evening, primarily in individuals with dementia. While it involves fluctuations in mental status, it does not usually present with a sudden onset of symptoms as described in this case. C. Alzheimer’s: Alzheimer’s disease is a form of chronic dementia characterized by gradual and progressive cognitive decline over months to years. The sudden onset of confusion and agitation does not align with the gradual progression typical of Alzheimer's disease. D. Dementia: Dementia is a general term for a decline in cognitive ability that affects daily life, usually developing gradually over time. Unlike delirium, dementia does not present with a sudden change in behavior or mental status, making it less likely in this scenario where the change was abrupt.