Delirium

By definition, delirium is a transient, reversible impairment of consciousness and reduced ability to focus or sustain attention that commonly has an acute onset. Patients are often disoriented to time and place, but are rarely disoriented to person. The perceptual disturbances of delirium can include auditory and visual hallucinations. ★Visual hallucinations are more common (68%) than auditory hallucinations (42%).

On surgical wards, delirium is rather common and appears in approximately 15% of patients, although this incidence can increase in patients after CABG (30%), hip surgery (40%), and patients who are intubated (81%). ★Older patients have an increased risk of delirium, as do patients with HIV, Parkinson's, severe burns, and pre-existing brain damage.

The major risk factors for delirium are:

Constitutional

Age - the most relevant risk factor. >60 increases risk, >80 greatly increases risk

Cognitive impairment

CNS disorders - dementia, stroke, TIA, aneurysm, Parkinson's, epilepsy, neoplasm

Medical

Severe illness or burns

AIDS

Organ failure

Infection

Fracture

Fever or hypothermia

Metabolic disturbance - hypoglycemia, acidosis, alkalosis, uremia, hypophosphatemia, anemia, hyperparathyroidism

Dehydration

Hypoalbuminemia

Surgical

Postoperative - usually starts after the third post-op day

Higher incidence with aortic, hip, and transplantation surgeries

Longer duration of surgery

Environment

Isolation

Visual or auditory impairment

Sensory extremes

Medications

Polypharmacy

Drug/alcohol dependence or withdrawal

Anticholinergic drugs

Subtypes of delirium

★One taxonomy of hypoactive and hyperactive delirium is as follows:

For hyperactive delirium (3 or more of the following): hypervigilance, restlessness, rapid speech, anger, combativeness, impatience, uncooperativeness, laughing, swearing, euphoria, wandering, easy startling, distractibility, nightmares, persistent thoughts

For hypoactive delirium (4 or more of the following): unawareness, lethargy, decreased alertness, staring, slow speech, apathy, decreased motor activity