From the Guidelines
For elderly patients presenting with confusion, I recommend a comprehensive workup starting with basic laboratory tests including complete blood count, comprehensive metabolic panel, urinalysis, thyroid function tests, vitamin B12 and folate levels, as well as imaging studies such as a head CT or MRI to rule out stroke, hemorrhage, or mass lesions, as supported by the most recent guidelines 1.
When evaluating elderly patients with confusion, it is essential to consider the broad range of potential causes, including infection, intoxication, metabolic disorders, and neurologic causes such as stroke, traumatic brain injury, or central nervous system infection 1. The yield of neuroimaging studies in patients with altered mental status (AMS) is relatively low, with one meta-analysis showing relevant abnormal findings in only 11% of patients 1. However, neuroimaging with CT or MRI is usually appropriate if the clinical suspicion for an acute neurological cause is high, where the cause of symptoms is not found on initial assessment, and for patients whose symptoms do not respond appropriately to management 1.
The workup should be tailored to the clinical presentation, with attention to recent medication changes, as polypharmacy is a common cause of confusion in this population 1. Additional important tests include:
- Blood glucose
- Arterial blood gases
- Toxicology screen
- Blood cultures if infection is suspected
- Electrocardiogram and chest X-ray to identify cardiac or pulmonary causes
- Lumbar puncture if meningitis or encephalitis is suspected
- Specific medication levels if the patient is on drugs with narrow therapeutic windows like digoxin, lithium, or anticonvulsants
Early identification of the underlying cause is crucial for appropriate management and preventing further cognitive decline, as delirium and agitation can have significant consequences, including increased mortality, morbidity, and extended hospital length of stay 1. A comprehensive evaluation, including routine cognitive screening and documentation, can lead to directed interventions that can positively affect the duration of the patient’s hospitalization 1.
From the Research
Diagnostic Approach
To diagnose the cause of confusion in elderly patients, the following steps can be taken:
- A complete history, including onset of symptoms, corresponding illness, medication use, and time of day that the confusion occurs, should be taken 2
- A physical examination, mental status evaluation, and laboratory evaluation should be performed to identify potential causes of delirium or dementia 3
- The patient's cognitive, affective, and social factors should be carefully evaluated to clarify diagnosis and management 4
Potential Causes
The potential causes of confusion in elderly patients include:
- Metabolic disorders, infections, and medications, which can cause delirium 3
- Thyroid dysfunction, vitamin deficiencies, and normal-pressure hydrocephalus, which are potentially reversible causes of dementia 3
- Alzheimer's disease, central nervous system damage, and human immunodeficiency virus infection, which are major irreversible causes of dementia 3
- Dehydration and polypharmacy, which are particularly strongly associated with delirium in the elderly 5
Laboratory Tests
The following laboratory tests may be ordered to help diagnose the cause of confusion in elderly patients:
- Thyroid function tests to rule out thyroid dysfunction 3
- Vitamin level tests to rule out vitamin deficiencies 3
- Complete blood count and blood chemistry tests to rule out metabolic disorders and infections 3
- Urinalysis to rule out urinary tract infections 3
- Imaging studies, such as CT or MRI scans, to rule out structural brain abnormalities 3
Treatment
Treatment of confusion in elderly patients depends on the underlying cause:
- Delirium can be treated by addressing the underlying cause, such as stopping medications that may be contributing to the delirium or treating underlying infections 3, 5
- Non-pharmacological treatments, such as creating a calm and patient-centered environment and involving relatives, can be effective in managing delirium 5
- Neuroleptics and benzodiazepines may be used to treat hyperactive delirium, but should be used with caution and under close monitoring 5