Differential Diagnosis

The patient's presentation of progressively strange behavior, impulsivity, distractibility, and changes in personal hygiene, along with mild memory problems and the presence of grasp and snout reflexes, suggests a neurodegenerative or psychiatric condition. Here is a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Frontotemporal Dementia (FTD): This condition is characterized by changes in personality, behavior, and language due to degeneration of the frontal and temporal lobes of the brain. The patient's impulsivity, distractibility, rudeness, and lack of concern for personal hygiene are classic symptoms of the behavioral variant of FTD. The presence of grasp and snout reflexes, which are primitive reflexes, also supports this diagnosis, as they can be indicative of frontal lobe dysfunction.

• Other Likely Diagnoses

  • Alzheimer's Disease: While memory problems are more prominent in Alzheimer's, some patients can present with significant behavioral changes and impulsivity, especially in early stages or in atypical forms.
  • Dementia with Lewy Bodies: Characterized by fluctuations in cognitive function, visual hallucinations, and parkinsonian motor symptoms, which are not explicitly mentioned but could be considered given the broad differential for dementia.
  • Vascular Dementia: Given the patient's history of hypertension, vascular dementia could be a consideration, especially if there were evidence of stepwise decline or focal neurologic signs, which are not present in this case.

• Do Not Miss Diagnoses

  • Chronic Subdural Hematoma: Although less likely given the gradual onset and lack of reported trauma, a chronic subdural hematoma could cause changes in behavior and cognition, and is important to rule out due to its potential for treatment and significant morbidity if missed.
  • Normal Pressure Hydrocephalus (NPH): Presents with the triad of gait disturbance, dementia, and urinary incontinence. While not all symptoms are present here, NPH is a treatable condition and thus should be considered.
  • Neurosyphilis: A classic cause of dementia and behavioral changes, which can be treated with antibiotics, making it a crucial diagnosis not to miss.

• Rare Diagnoses

  • Creutzfeldt-Jakob Disease: A rare, rapidly progressive dementia that could present with behavioral changes, myoclonus, and other neurologic signs. The rapid progression and presence of myoclonus or other specific signs would make this a consideration.
  • Huntington's Disease: Characterized by chorea, psychiatric symptoms, and cognitive decline. The absence of chorea or a family history makes this less likely but still a consideration in a broad differential for dementia and behavioral changes.
  • Wilson's Disease: A genetic disorder leading to copper accumulation in the brain, which can cause psychiatric symptoms, cognitive decline, and movement disorders. Typically presents at a younger age, but late-onset cases can occur.