A 75-year-old woman with a history of chronic obstructive pulmonary disease is evaluated in the intensive care unit (ICU) for altered mental status. She had a repair of an aortic dissection and was extubated uneventfully. Three days later she developed changes in her mental status. In the ICU, she became agitated, pulling at her lines, attempting to climb out of bed, and asking to leave the hospital. Her arterial blood gas values are normal. The patient has no history of alcohol abuse. Calm reassurance and presence of family members have done little to reduce the patient's agitated behavior.
1. What is the diagnosis for the patient's altered mental status?
2. What is the most appropriate therapy for this patient's altered mental status?
This patient has a delirium.
The appropriate treatment is haloperidol. The recommended therapy for delirium is antipsychotic agents. There is no evidence that second-generation antipsychotics are superior to haloperidol for delirium. Haloperidol does not cause respiratory suppression. All antipsychotic agents increase the risk of torsades de pointes and extrapyramidal side effects as well as neuroleptic malignant syndrome.
Delirium is defined as changes in the level of consciousness with difficulty focusing, sustaining, or shifting attention. The changes develop and occur over a short period of time, usually hours to days, and fluctuate during the course of the day. Delirium often involves other cognitive deficits, changes in level of arousal, altered sleep-wake cycle, and may include psychotic features such as hallucinations and/or delusions. It is a clinical syndrome precipitated by an underlying medical condition or medical issue.
Key features of delirium include:
- Altered level of consciousness
- Change in cognition
- Onset over hours to days
- Fluctuating course
- Behavioral changes
- Sleep alterations
Common causes of delirium include certain commonly prescribed medications, including opioids, sedative–hypnotics, and polypharmacy. Medication withdrawal states and medication side effects such as quinolones in the elderly are also common precipitants. Other common causes include infections, metabolic abnormalities, and brain disorders. The infections that most commonly cause delirium include sepsis, pneumonia, and urinary tract infections. Electrolyte abnormalities, hypercarbia, hypoxemia, hyperglycemia, and hypoglycemia may also precipitate delirium. CNS infections, seizures, and hypertensive emergencies can cause delirium. Lack of sleep and poor sleep may also be contributing factors.
A mnemonic of some use to remember the possible etiologies of delirium is I WATCH DEATH:
- Infectious: encephalitis, meningitis, syphilis, pneumonia, and urinary tract infection
- Withdrawal: alcohol and sedative–hypnotics
- Acute metabolic: acidosis, alkalosis, electrolyte disturbances, and hepatic or renal failure
- Trauma: heat stroke, burns, and postoperative
- CNS pathology: abscesses, hemorrhage, seizures, stroke, tumors, vasculitis, and normal pressure hydrocephalus
- Hypoxia: due to anemia, carbon monoxide poisoning, hypotension, pulmonary embolus, and pulmonary or cardiac failure...