Delirium natural history, complications and prognosis

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vishal Khurana, M.B.B.S., M.D. [2]; Pratik Bahekar, MBBS [3]

Duration

Rabges from less than a week to more than 2 months. Typically the symptoms of delirium resolve within 10–12 days; however, up to 15% of patients with delirium have symptoms that persist for up to 30 days and beyond . Elderly patients tends to have longer course which may last for 1 month or longer.

Prognosis

Majority of patients recover fully, delirium may progress to stupor, coma, seizures, or death, particularly if untreated. Full recovery is less likely in the elderly, with estimated rates of full recovery by the time of discharge varying from 4% to 40%. Persistent cognitive deficits are also quite common in elderly patients recovering from delirium, although such deficits may be due to preexisting dementia that was not fully appreciated. Delirium in AIDS patients has poorer prognosis as onlu 27% tends to have complete recovery of cognitive function, perhaps because of an AIDS dementia. Delirium in an elderly, can cause many complications which may include pneumonia and decubitus ulcers, prolonging hospital stays. Elderly who develop delirium during a hospitalization have been estimated to have a 22%–76% chance of dying during that hospitalization. Patients who develop delirium during a hospitalization also have a very high rate of death during the months following discharge. Several studies suggest that up to 25% of patients with delirium die within 6 months and that their mortality rate in the 3 months after diagnosis is 14 times as high as the mortality rate for patients with affective disorders. Patients who develop delirium, particularly after orthopedic surgery, are at increased risk for postoperative complications, longer postoperative recuperation periods, longer hospital stays, and long-term disability.

Duration

The duration of delirium is typically affected by the underlying cause. If caused by a fever, the delirious state often subsides as the severity of the fever subsides. However, it has long been suspected that in some cases delirium persists for months and that it may even be associated with permanent decrements in cognitive function. Barrough said in 1583 that if delirium resolves, it may be followed by a "loss of memory and reasoning power." Recent studies bear this out, with cognitively normal patients who suffer an episode of delirium carrying an increased risk of dementia in the years that follow. In many such cases, however, delirium undoubtedly does not have a causal nature, but merely functions as a temporary unmasking with stress, of a previously unsuspected (but well-compensated) state of minimal brain dysfunction (early dementia).