See Chapters 4 and 24 for detailed discussion.
Delirium should be considered a syndrome of acute brain dysfunction analogous to acute kidney injury. The first aim of treatment is to identify and correct the etiologic medical problem. Evaluation should consist of a comprehensive physical examination including a search for neurologic abnormalities, infection, or hypoxia as well as laboratory tests. Laboratory tests may include serum electrolytes, serum glucose, BUN, serum creatinine, liver biochemical tests, thyroid function tests, arterial blood gases, complete blood count, serum calcium, phosphorus, magnesium, vitamin B12, folate, blood cultures, urinalysis, and cerebrospinal fluid analysis. Medications that may be contributing to the problem (eg, analgesics, corticosteroids, cimetidine, lidocaine, anticholinergic medications, central nervous system depressants, mefloquine) should be discontinued as able. Electroencephalography, CT, and MRI evaluations of the brain may be helpful in diagnosis. Ideally, the patient should be monitored without further medications while the evaluation is carried out. There are, however, at least two indications for medication in delirious states: behavioral control (eg, pulling out lines) and subjective distress (eg, pronounced fear due to hallucinations). If there is suspicion of alcohol or substance withdrawal (the most common cause of delirium in the general hospital), a benzodiazepine such as lorazepam (1–2 mg every hour) can be given parenterally. If there is little likelihood of withdrawal syndrome and the patient is at risk for self-harm from agitation, haloperidol is often used in doses of 1–10 mg every hour, though evidence does not demonstrate efficacy in reducing duration of delirium or improving long-term outcomes. Given intravenously under ECG monitoring, it appears to impose slight risk of extrapyramidal side effects. Beyond medication, a pleasant, comfortable, nonthreatening, and physically safe environment with adequate nursing or attendant services should be provided. Once the underlying condition has been identified and treated, adjunctive medications can be tapered.
Behavioral techniques include operant responses that can be used to induce positive behaviors, eg, paying attention to the patient who is trying to communicate appropriately, and extinction by ignoring inappropriate responses. Patients with Alzheimer disease can learn skills and retain them but do not recall the circumstances in which they were learned. Arranging the physical environment to maximize autonomy as much as feasible and promote regularity of routine, helps the individual cope with their limited intellectual reserves. Simple, direct statements are more easily comprehended by these individuals. Understanding how their decreased cognitive function limits their abilities is important. For example, one elderly man in a residential apartment kept complaining that someone was stealing his ice cream at night. Realizing that he was unable to recall eating it himself, his "delusion" made a certain sense. Once his caregivers understood this, they were able to be more compassionate in listening to his complaints and less worried about an ice cream burglar.
Formal psychological therapies are not usually helpful and may make things worse by taxing the patient's limited cognitive resources.