Differential Diagnosis for 66 yo Female with Hallucinations and Found Down

Single Most Likely Diagnosis

• Delirium: Given the patient's history of being found down and presenting with hallucinations, delirium is a strong consideration. It can be caused by various factors including infections, medications, or metabolic disturbances, which are common in elderly patients, especially those with a history of surgery like Roux-en-Y.

Other Likely Diagnoses

• Psychotic Episode due to Bipolar Disorder (BPD): The patient's history of BPD increases the likelihood of a psychotic episode, which could manifest as hallucinations.
• Major Depressive Disorder with Psychotic Features (MDD): Given the patient's history of MDD, it's possible that she is experiencing a depressive episode with psychotic features, including hallucinations.
• Generalized Anxiety Disorder (GAD) Exacerbation: While less directly linked to hallucinations, severe anxiety can contribute to or exacerbate psychotic symptoms in vulnerable individuals.
• Malnutrition or Electrolyte Imbalance Post-Roux-en-Y: The Roux-en-Y surgery can lead to malabsorption of essential nutrients and electrolytes, potentially causing neurological symptoms including hallucinations.

Do Not Miss Diagnoses

• Hypoglycemia: A potentially life-threatening condition that can cause hallucinations and altered mental status. Given the patient's history of Roux-en-Y, she is at risk for hypoglycemia due to malabsorption or other metabolic changes.
• Infection (e.g., UTI, Pneumonia): Infections are common in elderly patients and can cause delirium or hallucinations. Early detection is crucial for effective treatment.
• Medication-Induced Psychosis: Certain medications can induce psychotic symptoms. Given the patient's psychiatric history, she may be on medications that could contribute to hallucinations.
• Neuroendocrine Disorders (e.g., Hyperthyroidism, Cushing's Syndrome): These conditions can cause a range of psychiatric symptoms, including hallucinations, and are critical to identify due to their significant impact on health.

Rare Diagnoses

• Wernicke's Encephalopathy: A rare but serious condition caused by thiamine deficiency, which can occur post-Roux-en-Y surgery due to malabsorption. It presents with confusion, ataxia, and ophthalmoplegia, and can include hallucinations.
• Hashimoto's Encephalopathy: A rare condition associated with Hashimoto's thyroiditis, characterized by cognitive impairment, seizures, and psychiatric symptoms, including hallucinations.
• Paraneoplastic Syndromes: Rare neurological disorders caused by the immune response to a cancer, which can present with a wide range of neurological and psychiatric symptoms, including hallucinations.