Delirium prevalence rates in ICUs range between 26.2 to 68.2%, with 9.27 to 59.6% incidence in India. The elderly are considered a high-risk group for delirium. Hence, a proper diagnosing and identification of causative factors and symptoms are required in delirium cases since they may be psychiatric emergencies.

Clinical definition of Delirium

Assessment of Delirium

Common risk factors for delirium in the elderly include:

• presence of dementia
• age >70 years
• severe medical illness
• infection
• ‘high-risk’ medication usage
• reduced daily living activity or immobility
• sensory deprivation/impairment
• presence of in situ urinary catheter
• high serum urea
• electrolyte imbalance
• malnutrition lengthy hospital stay

These should be checked for and may be elicited in the history of the patient.

Treatment of Delirium

Taking history

Elderly patients themselves may not be able to provide a proper history and therefore collateral resources are required to get their information.

Prescribing & reviewing medication

• OTC and prescription medications being taken by the patient must be thoroughly reviewed 
• Bear in mind of any changes in dosages, and/or if new medications have been started recently as there may be a link between this occurring and the onset of delirium

All probable causes of delirium need to be assessed by doing a thorough physical examination. Routine investigations and neuroimaging is usually not warranted unless an intracranial lesion is suspected.

Differential diagnosis

Dementia, depression and psychosis/schizophrenia may be considered as differential diagnosis possibilities of delirium. Since dementia is both a risk factor and a differential diagnosis for delirium, a good history taking is required to assist in differentiating the two disorders. Delirium presents as an acute illness whereas the onset of dementia is usually gradual.

Pharmacotherapy

Medication should be considered when the patient is not settling with mere simple support, or if specifically indicated. The need for pharmacotherapy is mostly seen in cases of severe agitation or severe anxiety which places the patient or others at risk of harm. Treatment of any infection should be done if it is causing the delirium.

1. In delirium due to poisoning or intoxication, a suitable antidote must be used.
2. Benzodiazepines may be used in delirium due to alcohol withdrawal.
3. High doses of thiamine may also be given.
4. Nutritional deficiencies may be seen in the many elderly patients and so multivitamins may be considered.

Antipsychotics are the drugs of choice for managing delirium since they reduce agitation, anxiety, associated psychotic symptoms, and have a sedative effect and improve the cognitive symptoms of delirium. Antipsychotics should be initiated at low doses slowly.

1. Haloperidol is the most desired drug of choice for managing delirium in the elderly at low doses of 0.25–0.50 mg every 4 hours. Doses can be titrated as needed. In elderly patients with Parkinson’s disease or Lewy Body Dementia along with delirium, atypical antipsychotics may be chosen.
2. Benzodiazepines are not considered as the first line agents for the delirium management since they can worsen cognitive functions and lead to excessive sedation. In the elderly with respiratory or hepatic impairment, and/or in patients receiving medications that involve extensive hepatic oxidative metabolism, only low dose benzodiazepines are to be given.

The use of antipsychotics may also be warranted in patients with alcohol withdrawal if their delirium does not respond to benzodiazepines alone.

Family members must be advised to follow up the patient for psychiatric services in further re-evaluations and provide interventions even after the patient is discharged. Currently available guidelines do not recommend antipsychotic agents or other pharmacological agents for the prevention of delirium.