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Delirium
Delirium
FREQUENCY
In the weeks or months before death, delirium is uncommon, although it may be significantly underdiagnosed. However, delirium becomes relatively common in the
hours and days immediately before death. As many as 85% of patients in the active
stages of dying from cancer may experience terminal delirium.
ETIOLOGY
Delirium is a global cerebral dysfunction characterized by alterations in cognition and
consciousness. It is frequently preceded by anxiety, changes in sleep patterns
(especially reversal of day and night), and decreased attention. In contrast to dementia,
delirium has an acute onset and is reversible, although reversibility may be more
theoretical than real for patients near death. It is possible to have delirium in a patient
with dementia.
Causes of delirium include metabolic encephalopathy arising from liver failure,
hypoxemia, or sepsis; electrolyte imbalances such as hypercalcemia; nutritional
deficiencies such as vitamin B12 deficiency; paraneoplastic syndromes; and primary
brain tumors or brain metastases. Commonly, among dying patients, delirium can be
caused by side effects of treatments, including radiation for brain metastases, and
medications, including opioids, glucocorticoids, anticholinergic drugs, antihistamines,
antiemetics, and many chemotherapeutic agents. In many terminally ill patients, the
etiology will be multifactorial; e.g., dehydration may exacerbate opioid-induced delirium.
ASSESSMENT
Delirium should be recognized in any terminally ill patient with new onset of
disorientation, impaired cognition, somnolence, fluctuating levels of consciousness, or
delusions, with or without agitation. Delirium must be distinguished from acute anxiety
a nd depression,
as well as dementia. In some cases, use of formal assessment tools such as the Mini-
Mental Status Examination (which does not distinguish delirium from dementia) or the
Delirium Rating Scale (which does distinguish delirium from dementia) may be helpful in
distinguishing delirium from other processes. The patient's list of medications must be
carefully evaluated. Nonetheless, a reversible etiologic factor for delirium is found in
fewer than half of terminally ill patients. Because most terminally ill patients
experiencing delirium will be very close to death and may be at home, extensive
diagnostic evaluations, such as lumbar punctures or neuroradiologic examinations, are
usually inappropriate.
INTERVENTIONS
One of the most important objectives of terminal care is to provide terminally ill patients
the lucidity to say goodbye to the people they love. Delirium, especially with agitation
during the final days, is distressing to family and caregivers. A strong determinant of
bereavement difficulties is witnessing a difficult death. Thus, terminal delirium should
be treated aggressively.
At the first sign of delirium, such as day-night reversal with slight changes in mentation,
let the family know that it is time to be sure that everything they want to have said has
been said. The family should be informed that delirium is common just before death.
If medications such as opioids are suspected of being a cause of the delirium, then unnecessary agents should be discontinued. Other reversible causes such as
constipation, urinary retention, and metabolic abnormalities should be treated.
Supportive measures aimed at providing a familiar environment should be instituted,
including restricting visits only to individuals with whom the patient is familiar and
eliminating new experiences; orienting the patient, if possible, by providing a clock and
calendar; and gently correcting the patient's hallucinations or cognitive mistakes.
Pharmacologic management focuses on the use of neuroleptics and, in the extreme,
anesthetics (Table 9-7). Haloperidol remains first-line therapy. Usually, patients can be
controlled with a low dose (1 to 3 mg/d), although some may require as much as 20
mg/d. It can be administered orally, subcutaneously, or intravenously. Intramuscular
injections should not be used, except when it is the only way to get a patient under
control. Chlorpromazine (10 to 25 mg every 4 to 6 h) can be useful if sedation is
desired. Dystonic reactions resulting from dopamine blockade are a side effect of
neuroleptics, although they are reported to be rare when used to treat terminal delirium.
The new atypical neuroleptics—risperidone and olanzapine—have also been used
successfully and are especially helpful for patients with longer anticipated life spans
since they are less likely to cause dysphoria and have a lower risk of dystonic
reactions. If patients develop dystonic reactions, benztropine should be administered.
Neuroleptics may be combined with lorazepam to reduce agitation when the delirium is
the result of alcohol or sedative withdrawal.
If no response to first-line therapy is seen, a specialty consultation should be obtained
with a change to a different medication. If patients fail to improve after a second
neuroleptic, then sedation with an anesthetic such as propofol or continuous-infusion
midazolam may be necessary. By some estimates, at the very end of life as many as
25% of patients experiencing delirium, especially restless delirium with myoclonus or
convulsions, may require sedation.
Physical restraints should be used with great reluctance only when the patient's
violence is threatening to self or others. If used, their appropriateness should be
reevaluated frequently. |
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