Differential Diagnosis for Delirium in a 100-Year-Old

Single Most Likely Diagnosis

• Urinary Tract Infection (UTI): Given the age of the patient, UTIs are common and can easily lead to delirium due to the body's systemic response to infection, including the release of cytokines that can affect brain function.

Other Likely Diagnoses

• Medication Side Effects: Elderly patients often take multiple medications, increasing the risk of drug interactions and side effects that can cause delirium.
• Dehydration: Common in the elderly, especially if they have difficulty accessing water or have conditions that increase fluid loss.
• Pain: Uncontrolled pain can lead to confusion and delirium, especially in patients who may not be able to communicate their discomfort effectively.
• Sleep Deprivation: Disruption in sleep patterns can contribute to delirium, and elderly patients may experience sleep disturbances due to various factors, including medical conditions or environmental changes.

Do Not Miss Diagnoses

• Sepsis: Although less likely than UTI, sepsis is a life-threatening condition that requires immediate attention. The elderly may not exhibit typical signs of sepsis, making it crucial not to miss.
• Stroke or Transient Ischemic Attack (TIA): Delirium can be a presenting symptom of stroke or TIA, especially in the elderly, where classic symptoms like hemiparesis may be absent.
• Hypoglycemia or Hyperglycemia: Both conditions can cause delirium and are critical to identify and treat promptly to prevent long-term damage.
• Subdural Hematoma: Falls are common in the elderly, and even minor trauma can lead to significant intracranial bleeding due to brain atrophy.

Rare Diagnoses

• Vitamin Deficiencies (e.g., Vitamin B12): While less common, deficiencies in certain vitamins can lead to neurological symptoms, including delirium.
• Endocrine Disorders (e.g., Thyrotoxicosis): Although rare, endocrine abnormalities can cause delirium and are important to consider, especially if other common causes have been ruled out.
• Autoimmune Encephalitis: A rare condition that can present with delirium, among other neurological symptoms, and requires specific treatment.
• Prion Diseases (e.g., Creutzfeldt-Jakob Disease): Extremely rare but fatal, these diseases can cause rapid cognitive decline and delirium, making them important to consider in the differential diagnosis of delirium in the elderly.