Delirium

Thomas Bartuska, M.D.

Delirium is one of the most common conditions seen in the inpatient setting, believed to affect 10-15% of inpatients. The etiology of the syndrome is often multifactorial and it is under-diagnosed, yet delirium is a medical emergency associated with high mortality if left untreated.

Delirium is

• a transient disorder of global cognitive function that is acute or sub-acute in onset.
• characterized by an alteration in sensorium (level of consciousness) and abnormal response to environmental stimuli (either lethargy or agitation) often with hallucinations, misperceptions and paranoia.
• manifest by disorientation to time, place and, in more severe cases, person.
• noted to have a fluctuating pattern over the course of the day and is often worse at night (sun-downing).
• distinguished from dementia, which is chronic and not characterized by alterations in sensorium. The two syndromes often co-exist because dementia is a risk factor for development of delirium.
• always caused by an underlying medical condition that must be treated before cognition can improve.

Risk Factors

• advanced age
• sensory impairments
• substance abuse
• pre-existing dementia or other CNS structural damage (i.e., stroke)
• the ICU environment
• infections
• polypharmacy
• a previous episode of delirium
• poor functional status
• post operative status, especially hip fracture

Evaluation

• history and physical examination to determine duration of symptoms, drug use or other risk factors, co-existing illnesses, new physical or neurologic findings. Surrogate historians will be essential. Infection and drug effects are the most common causes of delirium. Diphenhydramine (Benadryl) and OTC medications such as cold treatments are common causes even though they seem innocuous. Infections may present atypically.
• Rule out life threatening processes:

  hypoxemia

  metabolic disorders

  cardiovascular abnormalities

  (MI/arrhythmias, hypotension)

  intracranial events

Laboratory

• electrolytes, calcium, magnesium, phosphorus, CBC, BUN&Cr, glucose, ABG, urinalysis, medication levels, ECG, and thyroid function tests.
• Toxicology screen for alcohol, drugs and poisons.
• Head CT has not been shown to contribute to evaluation of delirium in the absence of focal findings or history of head trauma.
• If clinically indicated: lumbar puncture, EEG, appropriate cultures, HIV titer.
• B12, Folate, and VDRL - the syndromes associated with abnormal values cause chronic cognitive deficit. These tests have no place in the evaluation of acute mental status changes.

Management

• Provide supportive care as urgently required.
• Identify and treat underlying condition.
• Treat agitation to protect patient and staff safety.
• Minimize stimulation and use a sitter (a calm family or staff member) to provide frequent reorientation, simple explanations and soothing encouragement. This will decrease need for medication or restraints. Restraints can actually cause injury. Consult nursing staff on safe use of restraints.

When medication is required to control agitation in delirium

• Haloperidol (Haldol) is the drug of choice because it has minimal anticholinergic effects and is least likely to cause cardiovascular or respiratory compromise.
• In younger adults, a dose of 2-10mg is appropriate but the dose in older adults should be much lower, i.e., 0.5 mg repeated if necessary. Increased total body fat in older adults makes this fat soluble medication exhibit slower onset, wider volume of distribution, increased concentration in brain, slower clearance and prolonged effects (both good and bad).
• Anticipate agitation and treat with scheduled, low, oral doses rather than risk over-sedation, extrapyramidal or other negative side effects with PRN, high, parenteral doses.
• Most patients can be maintained at 0.5-1.0mg BID orally.
• Have a high index of suspicion for alcohol or sedative withdrawal for which benzodiazepines are the drug of choice.

Managing delirious patients can be quite complicated. It may be advisable to obtain geriatrics or psychiatry consultation.