Differential Diagnosis for 89 year old male with MMSE score 14 and increased confusion and evening agitation

• Single most likely diagnosis
  • Alzheimer's disease: Given the patient's age and MMSE score of 14, indicating significant cognitive impairment, Alzheimer's disease is a leading consideration. The symptoms of increased confusion and evening agitation (sundowning) are common in advanced stages of the disease.
• Other Likely diagnoses
  • Dementia with Lewy bodies: This condition often presents with fluctuations in cognitive function, visual hallucinations, and Parkinsonian motor symptoms, which could explain the confusion and agitation.
  • Vascular dementia: A history of vascular risk factors or evidence of cerebrovascular disease could support this diagnosis, as it can cause cognitive decline and behavioral changes.
  • Mixed dementia: Many patients have a combination of Alzheimer's disease and vascular dementia, which could contribute to the patient's symptoms.
  • Delirium: An acute or subacute change in mental status, especially with increased confusion and agitation, suggests delirium, which can be superimposed on dementia.
• Do Not Miss diagnoses
  • Infections (e.g., UTI, pneumonia): In elderly patients, especially those with dementia, infections can present atypically with confusion, agitation, or altered mental status rather than typical symptoms like fever or pain.
  • Medication side effects or interactions: Many medications can cause or exacerbate confusion and agitation in elderly patients, making it crucial to review the patient's medication list.
  • Dehydration or electrolyte imbalances: These conditions can lead to delirium and are easily missed but critical to identify and treat.
  • Subdural hematoma: Especially in the context of a fall or trauma, which might not always be reported or recognized, a subdural hematoma can cause sudden changes in mental status.
• Rare diagnoses
  • Creutzfeldt-Jakob disease: A rare, rapidly progressive dementia that can cause significant cognitive decline, myoclonus, and other neurological symptoms.
  • Normal pressure hydrocephalus (NPH): Characterized by the triad of gait disturbance, dementia, and urinary incontinence, NPH is a rare but treatable condition.
  • Neurosyphilis: In the appropriate clinical context, particularly if there's a history of syphilis or risk factors for sexually transmitted infections, neurosyphilis can cause a range of neurological symptoms including dementia and personality changes.