Diagnosing Delirium in Elderly Patients
Establishing Diagnostic Features
- The American Academy of Neurology recommends determining the patient's baseline cognitive function, behavior, and functional abilities before this episode, and documenting the exact timeline of when the confusion started, to establish acute onset and fluctuating course 1, 2
- The American Geriatrics Society suggests asking specifically about fluctuations in confusion, such as worsening at night, and identifying potential precipitants like new medications or recent infections 1, 2
- The Society of Critical Care Medicine recommends testing attention directly by asking the patient to recite months of the year backwards or perform serial 7s, and assessing level of consciousness and disorganized thinking 5, 6
Critical Pitfalls and Underlying Causes
- The American College of Physicians states that hypoactive delirium is the most commonly missed subtype, especially in elderly patients presenting with nighttime confusion, and carries higher mortality risk than hyperactive delirium 1, 2
- The Infectious Diseases Society of America recommends immediately evaluating for precipitants such as point-of-care glucose, vital signs including oxygen saturation, and medication review focusing on recent additions or dose changes 3, 4
Differentiating from Dementia
- The American Academy of Neurology notes that the time course distinguishes delirium from dementia, with delirium having a hours to days onset and fluctuating throughout the day, whereas dementia has a months to years onset and is stable throughout the day 1, 2
- The Alzheimer's Association recommends not attributing acute confusion to known dementia without investigating for reversible causes 2, 3