Armando Hasudungan
Biology and Medicine videos

Delirium

Overview

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 disordered
Dementia: Cognitive impairment typically caused by anatomic changes in the brain, has slower onset, and is generally irreversible. Dementia mainly affects memory.

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

Signs and Symptoms

  • Acute confusional state
  • Inattention
Remember 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

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

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

Management

Remember 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

  • Antipsychotics
    • Risperidone
    • Haloperidol
    • Quetiapine
  • Benzodiazepine (mainly to treat withdrawal delirium)

References

Oxford Handbook of Geriatric Medicine
UpToDate
BestPractice