To summarize, the entire group of acute confusional and delirious states is characterized principally by an alteration of consciousness and by prominent disorders of attention and perception, which interfere with the speed, clarity, and coherence of thinking, the formation of memories, and the capacity for performance of self-directed and commanded activities. Three major clinical syndromes can be recognized. One is an acute confusional state in which there is manifest reduction in alertness and psychomotor activity. A second syndrome, alluded to as a special form of confusion, delirium, is marked by overactivity, sleeplessness, tremulousness, and prominence of vivid hallucinations, sometimes with excessive sympathetic activity. These two illnesses tend to develop acutely, to have multiple causes and, except for a few cerebral diseases, to remit within a relatively short period of time of days to weeks, leaving the patient without residual damage. The third syndrome is one in which a confusional state occurs in persons with an underlying chronic cerebral disease, particularly a dementia. Dr. Raymond Adams designated this frequently encountered disposition to a superimposed acute confusional state in the context of dementia as a beclouded dementia but the term, while apt, seems not to have caught on.
From the neurologic perspective, the generic term psychosis applies to states of confusion in which elements of hallucinations, delusions, and disordered thinking comprise the prominent features. An important point to be made here is that psychoses typically leave the sensorium relatively unclouded and allow for normal attentions and high-level performance of many mental tasks. These syndromes and some aspects of psychotic confusion are elaborated below.
Characteristically, the confusional states fluctuate in severity, typically being worse at night (“sundowning”). In the mildest form, the patient appears alert and may even pass for normal; only the failure to recollect and accurately reproduce happenings of the past few hours or days reveals the subtle inadequacy of his mental function. The more obviously confused patient spends much of his time in idleness, and what he does may be inappropriate and annoying to others. Only the more automatic acts and verbal responses are performed properly, but these may permit the examiner to obtain a number of relevant replies to questions about age, occupation, and residence. Orientation to the date, day of the week, and place is imprecise, often with the date being off by several days, the year being given as several years or one decade previous, or with the last two numbers transposed, for example, 2015 given as 2051. Such patients may, before answering, repeat every question that is put to them, and their responses tend to be brief and mechanical. It is difficult or impossible for them to sustain a conversation. Their attention wanders and they constantly have to be brought back to the subject at hand. They may even fall asleep during the interview, and if left alone are observed to sleep more hours each day than is natural or to sleep at irregular intervals.
As the confusion deepens, conversation becomes more difficult, and at a certain stage these patients no longer notice or respond too much of what is happening around them. Questions may be answered with a single word or a short phrase, spoken in a soft tremulous voice or whisper, or the patient may be mute. Asterixis is a common feature if a metabolic or toxic encephalopathy is responsible for the confusional state. In the most advanced stages of the illness, confusion gives way to stupor and, finally, to coma (see Chap. 16). With improvement in the underlying condition, they may pass again through the stages of stupor and confusion in the reverse order. All this informs us that at least one category of confusion is but a manifestation of the same disease processes that affect awakeness and alertness and, in their severest form, cause coma.