Differential Diagnosis for a 70-year-old Male Patient with Behavioral Changes and Memory Loss

• Single most likely diagnosis:
  • A. Frontotemporal dementia: This condition is characterized by significant changes in personality, behavior, and social conduct, often accompanied by memory loss. The patient's new behavior of fighting with everyone in the street suggests a profound change in social behavior, which is a hallmark of frontotemporal dementia.
• Other Likely diagnoses:
  • B. Dementia of Lewy body: This condition can present with fluctuations in cognitive function, visual hallucinations, and changes in behavior, which might include aggression. However, the primary symptoms described do not directly point to the core features of Lewy body dementia.
  • D. Alzheimer disease: While Alzheimer's disease is the most common cause of dementia and can lead to behavioral changes and memory loss, the prominent early feature of significant behavioral change (such as fighting) is less typical for Alzheimer's, where memory loss is usually the predominant early symptom.
• Do Not Miss diagnoses:
  • Vascular dementia: Although not listed among the options, vascular dementia (due to the patient's history of hypertension) could lead to cognitive decline and behavioral changes. It's crucial to consider this diagnosis because managing vascular risk factors can potentially slow disease progression.
  • Delirium: Not listed among the options but critical to consider, especially in an elderly patient with acute changes in behavior and cognition. Delirium can be caused by various factors, including infections, medications, or other medical conditions, and is a medical emergency.
• Rare diagnoses:
  • C. Parkinson disease: While Parkinson's disease can lead to dementia (Parkinson's disease dementia), the primary symptoms described (behavioral changes and memory loss without mention of motor symptoms like tremors, rigidity, or bradykinesia) make this a less likely initial diagnosis for the presentation described.
  • Other rare causes of dementia: Such as Creutzfeldt-Jakob disease, which presents with rapid cognitive decline, but the described symptoms do not specifically suggest this diagnosis.

Each of these diagnoses requires careful consideration of the patient's full clinical picture, including history, physical examination, laboratory tests, and possibly imaging studies, to determine the most accurate diagnosis and appropriate management plan.