Delirium Older persons are particularly vulnerable to developing delirium. Common causes include urinary tract infection, bowel impaction, heart failure, endocrinopathies, and drug toxicity caused by prescribed or over-the-counter drugs. CNS conditions such as subdural hematoma, cerebrovascular accident, slow-growing intracranial tumors, and encephalitis can be associated with the development of hallucinations and delusions without clouding consciousness.
While an agitated, hallucinating patient with clearly evident fluctuations in the sensorium may be readily diagnosed with a delirium, patients who are quiet, withdrawn, and apathetic may be less easy to recognize. Clinicians should therefore be vigilant for both the hyperkinetic and hypokinetic presentations of delirium when assessing older patients.
Work-up
When psychotic symptoms present for the first time in late life, medical causes must be ruled out first. A detailed history, including collateral information from other sources, includes:
- premorbid function
- psychiatric history, including history of affective illness
- family history of schizophrenia, affective illness, and Alzheimer’s disease
- medical history, including risks for cerebrovascular disease.
The examination should include a complete medical and neurologic evaluation, giving special attention to sensory loss, prescribed and over-the-counter drugs, recent changes in drug regimen, and cognitive screening. Laboratory work-up includes:
- in all cases: CBC/differential, BUN, TFT, B12/folate, and RPR
- in selected cases: MRI, HIV screening, toxicology screen, neuropsychological testing
- in rare cases: lumbar puncture, PET or SPECT imaging.
If the suggested work-up leads to diagnosis of medical illness, begin appropriate treatment. Behavioral symptoms during medical illness, such as with delirium, may require concurrent psychotropic medication until the medical illness is controlled.
If the medical work-up is negative, the clinician then needs to make the appropriate psychiatric diagnosis and institute antipsychotic treatment as indicated.
Table 2
CLINICAL DIFFERENCES BETWEEN DEMENTIA AND SCHIZOPHRENIA
| Characteristic | Dementia | Late-onset schizophrenia |
|---|---|---|
| Incidence | 50 to 70% | 1 to 2% |
| Bizarre delusions | Uncommon | Common |
| Hallucinations | Usually visual | Usually auditory |
| History of psychosis | Rare | Common |
| Misidentification | Common | Less common |
| Maintenance treatment | Usually unnecessary | Common |
| Antipsychotic dosage | 25% of dosage for adult schizophrenia | 50% of dosage for adult schizophrenia |
Table 3
USE OF ATYPICAL ANTIPSYCHOTICS IN OLDER PATIENTS
| Drug | Administration |
|---|---|
| Clozapine | Use limited by potential for agranulocytosis, need for weekly blood counts Higher risk for diabetes, hyperglycemia, pancreatitis Very sedating “Black box” warning for myocarditis (March 2002) NOT a first-choice drug for older persons |
| Risperidone | Usual geriatric dosage 1 to 2 mg/d Risk of EPS increases significantly with dosages > 2 mg/d Can cause persistent hyperprolactinemia |
| Olanzapine | Usual geriatric dosage 2.5 to 12.5 mg/d (qd dosing) Excellent choice as first-line drug in older patients Anticholinergic side effects ordinarily not a problem in vivo despite receptor profile of M1-M5 antagonism May be weight-neutral in older patients |
| Quetiapine | Geriatric dosage 25 to 400 mg/d Very low potential for EPS Can be a first choice for patients with Lewy body dementia and Parkinson’s disease Sedation increases with dosages > 200 mg/d |
| Ziprasidone | Geriatric dosage 40 to 160 mg/d Significant concern about QT prolongation in older patients, especially women and those with pre-existing cardiac disease, chronic mental illness, hypokalemia, and hypomagnesemia Not recommended as first-line therapy in elderly (“bold” warning) Not approved for IM use in United States; restrictions on use in many European countries |
| EPS: Extrapyramidal symptoms | |
Prescribing antipsychotics
Prescribing psychoactive medications for older patients is similar to pediatric prescribing. You need to distinguish between behaviors that are “disturbed” as a result of a psychotic process or “disturbing,” for which behavioral interventions may be more appropriate. In any case, pharmacologic and behavioral interventions are used concurrently.
When prescribing for older patients, consider the possible interaction of comorbid medical conditions and altered pharmacokinetics and pharmacodynamics, which increase the potential for drug-drug interactions. Start low and go slow to minimize the potential for adverse side effects and to ensure optimal preservation of function.
In general, atypical antipsychotics are considered first-line therapy, unless there is a compelling reason not to use them in an individual patient. Conventional neuroleptic antipsychotics carry a much higher risk of adverse drug reactions and functional loss without providing substantially greater efficacy.14 Atypical antipsychotics differ not only from the older neuroleptics but also from each other—including their safety profiles for use in older patients (Table 3).
Clozapine is a dibenzodiazepine that is indicated for treatment-resistant schizophrenia. The first atypical antipsychotic, clozapine significantly reduced the incidence of extrapyramidal symptoms (EPS) seen with the neuroleptic antipsychotics. Clozapine also was effective against the “negative” symptoms of schizophrenia such as apathy, anhedonia, and emotional blunting, which severely limited the ability of patients with schizophrenia to function in society.
The limitations of clozapine include its potential to cause agranulocytosis and the requirement for weekly blood tests. It is also fairly sedating. A number of reports have suggested a link between the use of clozapine and the development of type 2 diabetes, hyperglycemia, and pancreatitis.15,16 Earlier this year, the FDA issued a “black box” warning linking the use of clozapine with myocarditis. For all of these reasons, clozapine is not recommended for use in older patients.