Differential Diagnosis for an 87-year-old with Self-inflicted Injuries

The patient's presentation of frequently clutching himself with a strong grip, resulting in bruises on the arms and wrists, in the context of dementia and managed with quetiapine, lamotrigine, and citalopram, suggests a complex interplay of potential causes. Here is a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Serotonin Syndrome or Akathisia: Given the patient's medication regimen, which includes citalopram (an SSRI) and quetiapine (an atypical antipsychotic that can increase serotonin levels), serotonin syndrome or akathisia (a movement disorder characterized by a feeling of inner restlessness and a compelling need to be in constant motion) are plausible. These conditions could lead to the observed behavior of clutching due to discomfort or agitation.

• Other Likely Diagnoses

  • Dementia-related Behavioral Disturbances: Patients with dementia can exhibit a wide range of behavioral disturbances, including agitation, aggression, and self-injurious behaviors, which could be exacerbated by the patient's environment or underlying medical conditions.
  • Medication Side Effects (other than serotonin syndrome or akathisia): Quetiapine and lamotrigine can have side effects that might contribute to the patient's behavior, such as sedation, confusion, or, in the case of lamotrigine, rare but possible mood or behavioral changes.
  • Pain or Discomfort: Undiagnosed or undertreated pain could lead to agitation and self-injurious behavior in a patient with limited ability to communicate effectively due to dementia.

• Do Not Miss Diagnoses

  • Infection or Sepsis: Infections can present atypically in elderly patients, with confusion, agitation, or altered mental status being primary symptoms. It's crucial to rule out infections, as they can be life-threatening if not promptly treated.
  • Neuroleptic Malignant Syndrome (NMS): Although rare, NMS is a life-threatening side effect of neuroleptic medications (like quetiapine) characterized by fever, muscle rigidity, and altered mental status. Early recognition is critical.
  • Severe Hydration or Electrolyte Imbalance: Dehydration or significant electrolyte imbalances can cause or contribute to altered mental status and behavioral changes in elderly patients.

• Rare Diagnoses

  • Creutzfeldt-Jakob Disease: A rare, degenerative, fatal brain disorder that can cause dementia, behavioral changes, and myoclonus (sudden, involuntary jerking of a muscle or group of muscles), which might be mistaken for self-injurious behavior.
  • Other Neurodegenerative Diseases with Rapid Progression: Certain neurodegenerative diseases can present with rapid cognitive decline and behavioral disturbances, though these would be less likely given the patient's known history of dementia.

Each of these potential diagnoses requires careful consideration of the patient's full clinical picture, including a thorough review of medications, recent changes in condition, and a comprehensive physical and neurological examination.