3.5.2 Delirium

Delirium

Prevalence/Incidence:

Delirium is a common condition in older adults, with a prevalence of approximately 10-30% in hospitalized patients and up to 60% in patients in intensive care units.

Clinical Features:

Delirium is characterized by a rapid onset of confusion, disorientation, and changes in cognition and attention. Patients may also experience perceptual disturbances, such as hallucinations and delusions, as well as changes in the sleep-wake cycle and psychomotor activity.

Temporal course: (i) develop over hours to days, (ii) fluctuating presentation- worse at night, (iii) prodromal features/phase

Diagnostic Features (DSM-V):

• Disturbance in attention and awareness (i.e., reduced ability to direct, focus, sustain and shift attention and reduced orientation to the environment)
• Disturbance develops over a short period of time, is distinctly different from baseline and tends to fluctuate (Fluctuation is hours to a few days)
• Has an additional disturbance in cognition (e.g., memory deficit, disorientation, language, visuospatial ability, or perception)
• Not accounted for by other neurocognitive disorders
• Caused by a general medical condition; can be multiple etiologies (Can be caused by a general medical condition, substance intoxication or withdrawal, toxin exposure or multiple etiologies)
• There is evidence from the history, physical examination or laboratory findings that the disturbance is a direct physiological consequence of another medical condition, substance intoxication or withdrawal (i.e. due to a drug of abuse or to a medication), or exposure to a toxin, or is due to multiple etiologies.

Types of delirium:

Differential diagnosis:

Other causes of acute confusion, such as dementia, depression, and medication side effects, must be ruled out.

Recognizing delirium:

Aetiology:

Delirium can be caused by a variety of medical conditions, including infections, medication side effects, and metabolic disturbances.

	Details
Predisposing factors	Demographics: Advanced age, male gender Comorbidity: Dementia, the severity of comorbid conditions, chronic kidney disease, end-stage liver disease, terminal illness etc. Medications and drugs: Polypharmacy, baseline psychoactive medication use, history of alcohol or other substance abuse Functional status: Functional impairment, immobility Sensory impairment: Hearing impairment, visual impairment Decreased oral intake: Dehydration, malnutrition Psychiatric: Depression
Precipitating factors	Systemic: Infection, inadequate pain control, trauma, dehydration, hypo- or hyperthermia Metabolic: Thiamine deficiency (Wernicke’s encephalopathy), hepatic or renal failure Electrolyte disturbances: Hypoglycemia/hyperglycemia, thyroid dysfunction Medications and drugs: Medication changes, recreational drug use or withdrawal CNS: Cerebrovascular accident, intraparenchymal haemorrhage, subdural/epidural hematoma, seizures and postictal state, meningitis/encephalitis Cardiopulmonary: Acute myocardial infarction, congestive heart failure, respiratory failure, shock Iatrogenic: Procedures or surgeries, indwelling urinary catheters, physical restraints

Management:

Treatment of delirium focuses on identifying and treating the underlying cause. Supportive measures, such as environmental modifications and reorientation techniques, may also be helpful.

Prognosis:

The prognosis of delirium varies depending on the underlying cause and severity of symptoms. If left untreated, delirium can lead to long-term cognitive impairment and increased mortality.

Summary of Delirium

Disorder	Prevalence/Incidence	Clinical Features	Differential diagnosis
Delirium	10-30% in hospitalized patients	Rapid onset of confusion, disorientation, perceptual disturbances	Dementia, depression, medication side effects

Disorder	Aetiology	Management	Prognosis
Delirium	Infections, medication side effects, metabolic disturbances	Treatment of underlying cause, supportive measures	Prognosis varies depending on the underlying cause and severity of symptoms

Reference:

1. Inouye, S. K., Westendorp, R. G. J., & Saczynski, J. S. (2014). Delirium in elderly people. Lancet, 383(9920), 911-922. doi: 10.1016/S0140-6736(13)60688-1
2. National Institute on Aging. (2022). Delirium. Retrieved from https://www.nia.nih.gov/health/delirium