Differential Diagnosis

The patient's presentation with altered mental status, bizarre behavior, and neurological findings suggests a complex and multifactorial etiology. The following differential diagnosis is organized into categories:

• Single most likely diagnosis
  • Wernicke-Korsakoff syndrome: This diagnosis is likely due to the patient's history of alcohol use disorder, subacute onset of altered mental status, and neurological findings such as apraxia, aphasia, and selective mutism. The patient's episode of lethargy after opioid use and subsequent return to baseline may have been a precursor to the development of Wernicke's encephalopathy, which can progress to Korsakoff syndrome if left untreated.
• Other Likely diagnoses
  • Traumatic brain injury (TBI): The patient's fall and head injury could have contributed to her altered mental status and neurological findings. The presence of a headache after the fall and subsequent bizarre behavior suggests a possible TBI.
  • Opioid-induced neurotoxicity: The patient's recreational use of opioids, including morphine, oxycodone, and heroin, could have led to neurotoxicity, which may have contributed to her altered mental status and neurological findings.
  • Alcohol withdrawal: The patient's history of alcohol use disorder and recent cessation could have led to withdrawal symptoms, including altered mental status and neurological findings.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Subdural hematoma: The patient's fall and head injury increase the risk of a subdural hematoma, which can be life-threatening if left untreated.
  • Meningitis or encephalitis: The patient's altered mental status and neurological findings could be indicative of an infectious process, such as meningitis or encephalitis, which requires prompt treatment.
  • Status epilepticus: The patient's bizarre behavior and altered mental status could be indicative of status epilepticus, which is a life-threatening condition that requires immediate treatment.
• Rare diagnoses
  • Hashimoto's encephalopathy: This rare condition is characterized by altered mental status, neurological findings, and elevated anti-thyroid antibodies. While unlikely, it should be considered in the differential diagnosis.
  • Creutzfeldt-Jakob disease: This rare prion disease is characterized by rapidly progressive dementia, neurological findings, and myoclonus. While unlikely, it should be considered in the differential diagnosis due to the patient's rapid decline in cognitive function.

Next steps would include:

• Laboratory tests: Complete blood count, basic metabolic panel, liver function tests, thyroid function tests, and toxicology screen.
• Imaging studies: Computed tomography (CT) or magnetic resonance imaging (MRI) of the brain to evaluate for structural abnormalities, such as subdural hematoma or TBI.
• Lumbar puncture: To evaluate for infectious processes, such as meningitis or encephalitis.
• Electroencephalogram (EEG): To evaluate for seizure activity or status epilepticus.
• Neuropsychological evaluation: To assess the patient's cognitive function and guide further management.