Delirium

Overview

Delirium is a neuropsychiatric syndrome characterized by a disturbance in consciousness and cognition. It typically presents as an acute confusional state, with inattention as its core symptom. Unfortunately, the diagnosis of delirium is often delayed or missed, especially the hypoactive form that is common in older persons.

Definition

Delirium: Cognitive impairment typically caused by acute illness or drug toxicity (sometimes life threatening) and is often reversible. Delirium mainly affects attention.
Confusion: disturbed orientation in regard to time, place, or person, sometimes accompanied by disorderedDementia: Cognitive impairment typically caused by anatomic changes in the brain, has slower onset, and is generally irreversible. Dementia mainly affects memory.

Aetiology & Risk Factors

Aetiology

A particular case of delirium is often multifactorial. One or more precipitating factors combine to push a predisposed patient across his or her threshold to delirium.

Precipitating factors

Medications (anticholinergic drugs, psychotropics and opiates)
Infection
Metabolic disorder – hypo- or hyperglycemia, dehydration, electrolyte imbalance (Na, K, Ca), acid–base disturbance, uremia, renal encephalopathy, hepatic encephalopathy, hypoalbuminemia, thyroid dysfunction
CNS pathology – CNS infection, stroke, seizure, head trauma, mass.
Cardiopulmonary disorder – myocardial infarction (MI), arrythmia, congestive heart failure.
Alcohol or drugs
Surgery and trauma. Delirium in the postoperative state is particularly common in older people
Fever or hypothermia
Constipation or urinary retention
Unrecognized or inadequately treated pain

Drugs causing delirium

Anticholinergics

Benzodiazepines

Antipsychotics

Anticonvulsants

Tricyclic Antidepressants

Lithium

Opiates

Alcohol

AntiParkinsons

Diuretics

Corticosteroids

Polypharmacy is a risk factor for developing delirium. Make sure to review medications.

Risk Factors

Dementia or other cognitive disorder
Advanced age (i.e., 65 and older)
Male gender
Physically frail or immobile
Sensory impairment (i.e., hearing or vision)
Malnutrition or dehydration
Polypharmacy, especially multiple psychoactive drugs
History of excessive alcohol intake
Severe illness or multiple medical comorbidities

Clinical Manifestation

Acute confusional state
Inattention

Confusion is not specific to delirium; it may be found in other psychiatric disorders, such as dementia or depression.

Difference between Dementia and Delirium
	Dementia	Delirium
Onset	Sub-acute	Acute
Conscious level	Normal	Fluctuates
Hallucinations	Late event	Common
Agitation/agression	Uncommon until late	Common
Thought form	Poverty of thought late	Flight of ideas
Memory	Slow decline	Poor

Differential Diagnosis

Medication induced – anticholinergic drugs, psychotropics and opiates
Infection
Metabolic disorder – hypo- or hyperglycemia, dehydration, electrolyte imbalance (Na, K, Ca), acid–base disturbance, uremia, renal encephalopathy, hepatic encephalopathy, hypoalbuminemia, thyroid dysfunction
CNS pathology – CNS infection, stroke, seizure, head trauma, mass.
Cardiopulmonary disorder – myocardial infarction (MI), arrythmia, congestive heart failure.
Alcohol or drugs
Surgery and trauma. Delirium in the postoperative state is particularly common in older people
Fever or hypothermia
Constipation or urinary retention
Unrecognized or inadequately treated pain

Investigations

There are two important aspects to the diagnostic evaluation of delirium: recognizing that the disorder is present and uncovering the underlying medical illness that has caused delirium.

Full Blood count
EUC
Blood sugar level
Liver Function Test
Chest X-ray
ECF
Urinalysis
ABG
Blood cultures
Thyroid function test
Urine drug screen
Drug levels (lithium, digoxin)

Diagnosis

Delirium is a clinical diagnosis. Thorough chart review is essential in making a proper diagnosis.

Diagnostic and Statistical Manual, 5th edition (DSM-V) for delirium:

Disturbance in attention (reduced ability to direct, focus, sustain, and shift attention) and awareness.
Acute onset, and fluctuating course. The usual onset of delirium is over hours or a few days.
Change in cognition. Cognitive changes are typically global, with disorientation (especially to time), memory impairment (recent memory in particular), and language disturbance (e.g., dysgraphia, dysnomia).
The disturbances are not better explained by another preexisting, evolving or established neurocognitive disorder, and do not occur in the context of a severely reduced level of arousal, such as coma
There is evidence from the history, physical examination, or laboratory findings that the disturbance is caused by a medical condition, substance intoxication or withdrawal, or medication side effect.

Additional features that may accompany delirium and confusion include the following:

Psychomotor behavioral disturbances such as hypoactivity, hyperactivity with increased sympathetic activity, and impairment in sleep duration and architecture.
Variable emotional disturbances, including fear, depression, euphoria, or perplexity.
Alteration of the sleep-wake cycle
Poor insight

Treatment

There are two important aspects to the diagnostic evaluation of delirium: recognizing that the disorder is present and uncovering the underlying medical illness that has caused delirium.

Non-Pharmacological

Supportive care – fluids, nutrition, oxygen
Discontinue and review medication
Create a calm, comfortable environment with appropriate lighting (normalize sleep-wake cycle) and orienting influences
Optimize visual and auditory acuity with glasses and hearing aids.
Reorient and reassure the patient frequently. Explain all procedures.

Pharmacological