- Clinical science
Delirium (also known as toxic or metabolic encephalopathy) is a neurocognitive disorder characterized by impaired attention and cognitive function. Symptoms develop acutely and tend to fluctuate throughout the day. Delirium can occur as a complication of almost any medical condition. It is most often a complication of polypharmacy, especially in the elderly, and is also commonly seen in patients admitted to the ICU. Although delirium is a reversible confusional state, it warrants urgent medical attention because it may be the first sign of serious underlying disease. Treatment of delirium focuses on treating the underlying illness and reducing exposure to exacerbating factors. Antipsychotic medications are used for the treatment of agitation in delirious patients.
- The exact mechanism by which delirium occurs is unknown.
- Nearly any disease can present with delirium.
- Recreational drugs (intoxication/withdrawal) and medications are a common cause.
- Pre-existing brain disease (e.g., dementia, stroke)
- Polypharmacy, particularly with psychoactive drugs (but also drugs such as thiazide diuretics, which may cause electrolyte abnormalities)
- Advanced age
- Major surgery
- Trauma (e.g., hip fracture)
- Inadequate pain management
- Infection; (e.g., UTI's are common in the elderly; pneumonia)
- Critical or terminal illness
- Alcohol use
- Electrolyte abnormalities
- Pre-existing motor or sensory deficits
- Ongoing symptoms, including:
- The main symptom is an acute (hours to days) alteration in the level of awareness and attention. Other symptoms may include:
- The severity of symptoms fluctuates throughout the day and worsens in the evening.
Alterations in psychomotor activity may occur. Delirium is commonly described based on the type of alteration that is seen:
Mixed type delirium
- Psychomotor activity fluctuates or stays at baseline.
- Most common type in the general population
- Decreased psychomotor activity
- Most common type in the elderly
- Increased psychomotor activity, mainly seen as agitation
- Usually seen in delirium due to substance use or substance withdrawal
- Mixed type delirium
- The duration of symptoms depends on the underlying illness (usually lasting weeks).
Delirium is a clinical diagnosis. However, the underlying cause of the delirium must be identified. Diagnostic tests should be tailored to the patient's history and physical examination.
- If the cause of delirium is not obvious based on the patient history and physical findings, diagnostics may include:
- Start with complete blood count, serum glucose, electrolytes, and urinalysis
- If medication or substance use is suspected: urine toxicology or serum drug levels
- If a metabolic etiology is suspected: serum creatinine, BUN, liver function tests, arterial blood gas
- If pneumonia is suspected: chest x-ray
- If a cardiac etiology (e.g., myocardial infarction, arrhythmia) is suspected: ECG
- If the patient has focal neurological deficits or the initial workup is negative, further tests may include
- Further diagnostics that may be considered: blood culture, thyroid function tests, vitamin B12, HIV, syphilis serology
- Management of delirium focuses on identifying and treating the underlying cause.
- Reduce exposure to modifiable risk factors and reorient the patient regularly.
- Minimize the use of restraints as much as possible.
- If the patient is agitated and poses a harm to himself or others, antipsychotics are indicated (most commonly haloperidol).