Chapter 20. Delirium and Other Acute Confusional States

The striking event in which a patient with previously intact mentality becomes acutely confused is observed almost daily on the medical, surgical, and emergency wards of a general hospital. Occurring, as it often does, during an infection with fever or in the course of a toxic or metabolic disorder (such as renal or hepatic failure) or as an effect of medication, drugs, or alcohol, it never fails to create grave problems for the physician, nursing personnel, and family. The physician has to cope with the problem of diagnosis, often without the advantage of a lucid history, and any program of therapy is constantly impeded by the patient's inattention, agitation, sleeplessness, and inability to cooperate. Nurses are burdened with the need to provide satisfactory care and a safe immediate environment for the patient, and at the same time, maintain a tranquil atmosphere for other patients. The family must be supported as it faces the frightening specter of a deranged mind with peculiar behaviors and all it signifies.

These difficulties are magnified when the patient arrives in the emergency ward, having behaved in some irrational way, and the clinical analysis must begin without knowledge of the patient's background and underlying medical illnesses. It is our view that such patients should be admitted to a general medical or neurologic ward. Transfer of the patient to a psychiatric service is undertaken only if the behavioral disorder proves impossible to manage on a general hospital service.

The definition of normal and abnormal states of mind is difficult because the terms used to describe them have been given so many different meanings in both medical and non-medical writings. Compounding the difficulty is the fact that the pathophysiology of the confusional states and delirium is not fully understood, and the definitions depend to some extent on their clinical causes and relationships, with all the imprecision that this entails. The following nomenclature has proved useful to us and is employed in this and subsequent chapters.

Confusion is a general term denoting the patient's incapacity to think with customary speed, clarity, and coherence. Its most conspicuous attributes are impaired attention and power of concentration, disorientation—which may be manifest or is demonstrated only by direct questioning—an inability to properly register immediate events and to recall them later, a reduction in the amount and a disruption in the quality of all mental activity, including the normally constant inner ideation and sometimes, by the appearance of bewilderment. Thinking, speech, and the performance of goal-directed actions are impersistent or abruptly arrested by the intrusion of irrelevant thoughts or distracted by the slightest external stimulus. Reduced perceptiveness and accompanying visual and auditory illusions or hallucinations and paranoid delusions (a psychosis) are variable features that may be appended to the picture.

These psychologic disturbances may appear in many contexts. Confusion, as defined in this way, is an essential ingredient of the state called delirium (discussed further on), in which agitation, hallucinations, and sometimes tremulousness accompany the confusional state. Also, as pointed out in Chap. 17, a confusional state may appear at any stage in the evolution and resolution of a number of diseases that lead to drowsiness, stupor, and coma—typically in the metabolic encephalopathies but also in diseases affecting those parts of the brain that maintain normal arousal.

Confusion is also a characteristic feature of the chronic syndrome of dementia, where it is the product of a progressive failure of cognition, language, memory, and other intellectual functions; there it is the long-standing and progressive nature of the mental confusion that differentiates dementia from the acute confusional and delirious states that carry quite different implications. Finally, intense emotional disturbances, of either manic or depressive type, may interfere with attentiveness and coherence of thinking and thereby produce an apparent confusional state.

Special restricted forms of what could be called confusion appear as a result of certain focal cerebral lesions, particularly of the frontal, parietal, and temporal lobe association areas. Then, instead of a global inattention and incoherence, there are specific and circumscribed syndromes, such as unilateral neglect of self or of the environment, inability to identify persons or objects, and sensorimotor defects as described in Chap. 22. Yet another special form of confusion arises as a result of disordered language function, which also alters the stream of thought; this aphasia is a consequence of lesions in the language areas of the left temporal lobe. These are considered separately in Chap. 23.

The many mental and behavioral aberrations that are seen in confused patients, and their occurrence in various combinations and clinical contexts, make it unlikely that all forms of confusion derive from a single elementary psychologic abnormality such as a disturbance of attention. While attention is near the core of confusion, phenomena as diverse as drowsiness and stupor, hallucinations and delusions, disorders of perception and registration, impersistence and perseveration, and so forth are not easily reduced to a disorder of one psychologic or physiologic mechanism. It seems more likely to us that a number of separable disorders of function are involved. Indeed, one view of the confusional state that we find attractive conceptualizes confusion as a loss of the integrative functions among all the elementary and localizable cerebral functions such as symbolic language, memory retrieval, and apperception (the interpretation of primary perceptions). All of these are included under the rubric of the confusional state, for want of a better term.

We reserve the term delirium to denote a special agitated type of confusional state. In addition to many of the negative elements of incoherent thinking mentioned above, delirium is characterized by a prominent disorder of perception; hallucinations and vivid dreams; a kaleidoscopic array of strange and absurd fantasies and delusions; inability to sleep; a tendency to twitch, tremble, and convulse; and intense fear or other emotional reactions. Delirium is distinguished not only by extreme inattentiveness but also by a state of heightened alertness—i.e., an increased readiness to respond to stimuli—and by overactivity of psychomotor and autonomic nervous system functions, sometimes striking in degree. Implicit in the term delirium are its nonmedical connotations as well—namely, intense agitation, or frenzied excitement, and trembling. This distinction between delirium and other acute confusional states is not universally accepted. Many authors attach no particular significance to the autonomic and psychomotor overactivity and the hallucinatory and dream-like features of delirium, or to the underactivity and somnolence that characterize most other confusional states. All such states are categorized together as we continue to find it useful to set delirium apart from other nondescript confusional states because the two conditions are manifestly different and tend to occur in different clinical contexts. Nevertheless, implicit in both designations is the idea of an acute, transient, and usually completely reversible disorder.

An impairment of memory is often included among the symptoms of delirium and other confusional states. Registration and recall are indeed greatly impaired in the states under discussion, but they are affected in proportion to the degree of inattention and the inability to register new material. The term amnesia, however, refers more precisely to an isolated loss of past memories as well as to an inability to form new ones, despite an alert state of mind and normal attentiveness. Amnesia further presupposes an ability of the patient to grasp the meaning of what is going on around him. The failure in the amnesic state is one of retention, recall, and reproduction and must be distinguished from states of drowsiness, acute confusion, and delirium, in which information and events seem never to have been adequately perceived and registered in the first place. In both a confusional state and in amnesia, the patient will be left with a permanent gap in memory for his acute illness.

In a similar way, the term dementia (literally, an undoing of the mind) denotes a deterioration of all intellectual or cognitive functions with little or no disturbance of consciousness or perception. Implied in dementia is the idea of a gradual degradation of mental powers in a person who formerly possessed a normal mind. Amentia, by contrast, indicates a congenital feeblemindedness more commonly referred to as mental retardation, or more properly, developmental cognitive delay. Dementia and amnesia are discussed more explicitly in Chap. 21.

The intellectual, emotional, and behavioral activities of the human organism are so complex and varied that one may question the feasibility of using derangements of these activities as reliable indicators of cerebral disease. Certainly they do not have the same tangibility and ease of anatomic and physiologic interpretation as sensory and motor paralysis or aphasia. Yet one observes patterns of disturbed higher cerebrocortical function with such regularity as to make them clinically useful in identifying certain diseases. Some of these disturbances gain specificity because they are combined in certain ways to form syndromes.

The components of mentation and behavior that lend themselves to bedside observation and examination are (1) the processes of attention; (2) perception and apperception (awareness and interpretation of sensory stimuli); (3) the capacity to memorize and recall events of the recent and distant past; (4) the ability to think and reason; (5) temperament, mood, and emotion; (6) initiative, impulse, and drive; (7) social behavior; and (8) insight. Of these, the first two are sensory, the third and fourth are cognitive, the fifth is affective, the sixth is conative or volitional, the seventh refers to the patient's relationships with those around him, and the last refers to the patient's capacity to assess his own functioning. Each component of behavior and intellect has its objective side, expressed in the behavioral responses produced by certain stimuli, and its subjective side, expressed in the thinking and feeling described by the patient in relation to the stimuli. Less accessible to the examiner, but nevertheless possible to study by questioning of the patient, are the memories, planning, and other psychic activities that continuously occupy the mind of an alert person. They, too, are disordered or quantitatively diminished by cerebral disease.

Disturbances of Attention

Critical to clear thinking is a process of maintaining awareness of one or a limited number of external stimuli or internal thoughts for a fixed period of time and to simultaneously disregard the numerous distracting sensations and ideas that constantly bombard the nervous system. Without this ability to focus or "pay attention" and have an "attention span," a coherent stream of thought or action is not possible. The undue interruption of these activities by the intrusion of other thoughts or actions is termed inattention, or distractibility. Two essential components are embodied in the attention mechanism: one, a continuous state of alertness that is normally present throughout waking life (and underlies self-awareness); the other, a process of selecting from the myriad sensations and thoughts those that are relevant to the immediate situation to the exclusion of others.

The confused patient may demonstrate inattention in almost every task undertaken. If the degree of confusion is slight, the patient may report a difficulty with concentration. If severe, there is a parallel lack of insight and the problem is evident by observing easy distractibility by ambient stimuli and by impersistence and perseveration in conversation and motor tasks. Restated, attention has such a pervasive effect on all other aspects of mental performance that it is often difficult to determine whether the confused patient also has primary disorders of memory, executive, or visuospatial function. Indeed, retentive memory may be severely reduced in confusional states. Furthermore, the ability to carry out a series of actions or mental operations wherein one is required to hold in memory the result of the previous operation ("working memory") is intimately tied to attention and is particularly prone to disruption in confusional states.

The general ability to persist in a motor or mental task emphasizes an executive side of attention, but here one encounters a problem because the term attention has been applied to a number of seemingly different mental activities. One can view attention as a separate and unique cerebral function or simply a way of referring to the persistence or impersistence of any activity. We would argue that the entire cerebrum participates in attentiveness and the frontal and perhaps the parietal lobes are responsible for directing its content, but that the thalamocortical system is in a special way responsible for its raw maintenance. Mesulam, who has thought substantially about this problem, considers the frontal and parietal lobes to be at the nexus of an "attentional matrix"; in his model, the prefrontal, parietal association, and limbic cortices direct and modulate attention in an executive manner. Certainly, the temporal lobes and other regions are involved as well.

Attention to a particular sensory modality requires the participation of the sensory cortex, which must simultaneously initiate the perceptive and apperceptive processes discussed later. What are called "modality" and "domain-specific" attentions (for example, face or object recognition) are more complex, and disorders of these functions result in unique types of inattention, such as agnosia and anosognosia (lack of recognition of a part of the body, as discussed in Chap. 22). These are not derived from the all-encompassing loss of attention that is part of general confusional states but can instead be viewed as highly restricted forms of disruption of insight.

Disturbances of Perception

The process of acquiring through the senses a knowledge of the world or, of one's self by cohering what is experienced into apperception, involves much more than the simple sensory process of being aware of the attributes of a stimulus. New visual stimuli, for example, activate the striate cortex and visual association areas, wherein are probably stored the coded past representations of these and similar classes of stimuli. Recognition involves the reactivation of this system by the same or similar stimuli at a later time. Essential elements in the perceptual process are the maintenance of attention, the selective focusing on a stimulus, elimination of all extraneous stimuli, and identification of the stimulus by recognizing its relationship to remembered experience.

The perception of stimuli undergoes predictable derangement in disease. Most often there is a reduction in the number of perceptions in a given unit of time and a failure to synthesize them properly and to relate them to the ongoing activities of the mind. Or, there may be inattentiveness and fluctuations of attention, distractibility (pertinent and irrelevant stimuli having equal value), and inability to concentrate and persist in an assigned task. This often leads to disorientation in time and place. Qualitative changes also appear, mainly in the form of sensory distortions, causing misinterpretations of environmental stimuli (illusions) and misidentifications of persons; these, at least in part, form the basis of hallucinatory experience in which the patient reports and reacts to environmental stimuli that are not evident to the examiner. There is an inability to perceive simultaneously all elements of a large complex of stimuli, a defect that has been termed "failure of subjective organization." These major disturbances in the perceptual sphere, traditionally referred to as "clouding of the sensorium," are characteristic of delirium, and other confusional states.

More specific partial losses of perception are manifest in the "neglect syndromes." The most dramatic examples are observed with right parietal lesions, which render a patient unaware of the left half of his body and the environment on the left side. There are numerous other examples of focal cerebral lesions that disturb or distort sensory perceptions, each subject to neurologic testing; these are discussed in Chap. 22. Their close connection to spatial experience makes them understandable as alterations of apperception in the spatial-sensory sphere.

Disturbances of Memory

The retention of learned information and experiences is involved in all mental activities. Memory may be arbitrarily subdivided into several parts: (1) registration; (2) fixation, mnemonic integration, and retention; (3) recognition and recall; and (4) reproduction. As stated above, there is a failure of learning and memory in patients with impaired perception and attention because the material to be learned was never registered and assimilated in the first place. In almost all circumstances, the formation of new memories and the ability to recall old ones are disturbed in tandem.

In the Korsakoff amnesic syndrome, newly presented material appears to be correctly registered but cannot be retained for more than a few minutes (anterograde amnesia, or failure of learning). In this syndrome, there is always an associated defect in the recall and reproduction of memories that had been formed several days, weeks, or even years before the onset of the illness (retrograde amnesia). The fabrication of stories, called confabulation, constitutes a third feature of the syndrome but is neither specific nor invariably present. Intact retention with failure of recall (retrograde amnesia without anterograde amnesia) when it is severe and extends to all events of past life and even personal identity, is usually a manifestation of hysteria or malingering. Certain other characteristic defects occur in almost all memory disorders, for example, the relative retention of older memories in preference to newer ones (Ribot's rule). Chapter 22 discusses this subject more fully.

Disturbances of Thinking

Thinking, the highest order of intellectual activity, remains the most elusive of all mental operations. If by thinking one means the selective ordering of symbols for learning, organizing information, and problem solving, as well as the capacity to reason and form sound judgments, then the working units of this type of mental activity are words and numbers. The substitution of words and numbers for the objects for which they stand (symbolization) is a fundamental part of the process. These symbols are formed into ideas or concepts, and the arrangement of new and remembered ideas into certain orders or relationships constitutes an intricate part of thought, presently beyond the scope of analysis. Reference is made further on to Luria's analysis of the steps involved in problem solving in connection with frontal lobe function, but actually, as he points out, the whole cerebrum is implicated in all forms of thinking. In a general way, one may examine thinking in terms of its speed and efficiency, ideational content, coherence and logical relationships of ideas, and the quantity and quality of associations to a given idea. Feelings and behaviors engendered by an idea are more in the realm of emotion and affect. Aphasic disturbances are uncommon in global confusional and delirious states, but Geschwind has emphasized misnaming as an important feature among the "nonaphasic disorders of speech" in these conditions. Spontaneous speech is normal, but there may be slight inaccuracies in repetition that are most likely the result of inattention rather than a focal cerebral lesion.

Disorders of thinking are quite prominent in delirium and other confusional states, in mania, dementia, and schizophrenia. In confusional states of all types, the organization of thought processes is disrupted, with fragmentation, repetition, and perseveration; this is spoken of as an "incoherence of thinking." Derangements of thinking may also take the form of a flight of ideas; patients move too facilely from one idea to another, and their associations are numerous, and loosely linked. This is a common feature of hypomanic and manic states, and of some schizophrenic psychoses. The opposite condition, poverty of ideas, is characteristic both of depressive illnesses, in which it is combined with gloomy thoughts, of schizophrenia, and of dementing diseases, in which it is part of a reduction of all inner psychic intellectual activity. This overall reduction in thought and action is the most prominent feature of diseases that damage the frontal lobes.

A related condition of slowed thought, or bradyphrenia, is comparable to the bradykinesia of extrapyramidal disorders. The two often coexist and the patient, for example with Parkinson's disease, can articulate that thinking is so slow as to be virtually blocked. The content of thought is not much altered, but it may be rendered almost useless when slowed to this degree. The outward manifestation of bradyphrenia is what one would expect, a delay in response and slowness in gathering one's thoughts to express ideas.

Thinking may be distorted in such a way that ideas are not checked against reality. When a false belief is maintained in spite of convincing evidence to the contrary, the patient is said to have a delusion. This abnormality is common to several illnesses, particularly bipolar, schizophrenic, and paranoid states, as well as the early stages of dementia. Often the story related by the patient has internal logic but is patently absurd. Psychotic patients may believe that ideas have been implanted in their minds by some outside agency, such as the internet, radio, television, or atomic energy; these thought control or "passivity feelings" are highly characteristic of schizophrenia, and sometimes of manic episodes. Also diagnostic of some forms of schizophrenia are distortions of logical thought, such as gaps in sequential thinking, intrusion of irrelevant ideas, and condensation of associations. Chapter 53 discusses these aspects of psychoses.

Disturbances of Emotion, Mood, and Affect

The emotional life of the patient is expressed in a variety of ways. It is widely appreciated that there are marked individual differences in basic temperament in the normal population; throughout their lives some persons are cheerful, gregarious, optimistic, and free from worry, whereas others are just the opposite. The state of emotionality, and changes that are uncharacteristic to the individual lend themselves to observation and have clinical significance. Furthermore, some inherent personality traits may precede the development of overt mental disease. For example, the volatile, cyclothymic person is said to be liable to bipolar disease, and the suspicious, withdrawn, introverted person to schizophrenia and paranoia, but there are frequent exceptions to these statements.

Strong, persistent emotional states, such as fear and anxiety, may occur as reactions to life situations and are accompanied by numerous derangements of visceral function. If excessive, prolonged, and disproportionate to the stimulus, they are usually manifestations of an anxiety state or depression. In depression, almost all stimuli also tend to enhance the somber mood of unhappiness. Affective displays that are excessively labile and poorly controlled or uninhibited are a common manifestation of many cerebral diseases, particularly those involving the corticopontine and corticobulbar pathways. This disorder constitutes part of the syndrome of spastic bulbar (pseudobulbar) palsy, as discussed in Chap. 25, but it may occur independently of any problem with brainstem function. Affect being the external appearance of emotional life, the pseudobulbar state is characterized by a relative disconnection between the patient's reported emotional feelings and the outward display, most often being in the same general direction, but excessive in appearance. Conversely, all emotional feeling and expression may be lacking, as in states of profound apathy or depression. Or excessive cheerfulness may be maintained in the face of serious, potentially fatal disease or other adversity—a pathologic euphoria. Finally, a patient's emotional responses may be inappropriate to the stimulus, e.g., a depressing or morbid thought may seem amusing and be attended by a smile, a bizarre affective state as in schizophrenia.

Temperament, mood, and other emotional experiences are evaluated by observing the patient's behavior and appearance while questioning him about his feelings. For these purposes, it is convenient to divide emotionality into mood and affect. By mood is meant the prevailing internal emotional state of an individual. By contrast, affect (or feeling) refers to the outward emotional reactions evoked by a thought or an environmental stimulus. As such, it is the observable aspect of emotion. Emotionality may only be inferred from a person's affect and any more accurate assessment of the emotional state is made largely by the patient's self-report. It may be cheerful and optimistic or gloomy and melancholic. The patient's language (e.g., the adjectives used), facial expression, attitude, posture, and speed of movement reflect prevailing mood. These distinctions are at times rather tenuous, but they are clinically valuable because pathologic processes may dissociate the two to an extreme degree, as mentioned above. Chapter 25 more fully discusses the emotional disturbances relating to neurologic disease and Chap. 57 addresses depression.

Disturbances of Impulse (Conation) and Activity

Reference was made in Chaps. 3 and 4 to weakness, akinesia, and bradykinesia as manifestations of corticospinal and extrapyramidal disease. Disorders of these parts of the motor system interfere with voluntary or automatic movements, much to the distress of the patient. But motility and activity can be impaired in more general ways in which the overall tone of the motor system is enhanced or diminished. One such disorder is a lack of conation, or impulse. These terms designate that the basic biologic urges, driving forces, or purposes by which every organism is motivated to achieve an endless series of objectives. Indeed, motor activity is ostensibly a necessary and satisfying objective in itself, for few individuals can remain still for long before they become fidgety or doodle, and the severely retarded apparently obtain gratification from certain rhythmic movements, such as rocking, head banging, and hand flapping. These are all presumed to be driven by mental impulses. As discussed in Chap. 6, tics and compulsions apparently also represent the fulfillment of some psychic urge.

It is our impression that a quantitative reduction in spontaneous activity, i.e., in the amount of activity per unit of time, is one of the most frequent manifestations of cerebral disease. An important aspect of this state, called abulia is the concomitant reduction and prominent delay in producing movement, speech, ideation, and emotional reaction (apathy). The terms bradyphrenia, and "psychomotor retardation," referred to above may be a related or perhaps identical phenomena. With certain cerebral diseases the disinclination to move and act may reach an extreme degree, to a point where a person who is wide awake and perceptive of the environment does not speak or move for weeks on end (akinetic mutism). Such patients seem indifferent to what is happening around them, and unconcerned about the consequences of their inactivity.

Abulia and akinetic mutism must be distinguished from two allied states, catatonia and the psychomotor retardation of depression. Kahlbaum, who first used the term catatonia in 1874, described it as a condition in which the patient sits or lies silent and motionless, with a staring countenance, completely without volition and without reaction to sensory impressions. Sometimes there is resistance to the examiner's efforts to move the patient, or the patient repeats certain movements or phrases hour after hour. If the limbs are moved passively, they may retain their new position for a prolonged period (flexibilitas cerea, or "waxy flexibility"), but more often there is no actual motor rigidity except that of voluntary resistance, termed paratonia. Profound depression or other psychosis is the usual cause of catatonia. The psychomotor retardation of depression and catatonia may be so profound that the patient makes no attempt to help himself in any way and ultimately starves unless fed with a nasogastric tube.

Less easy to understand is a form of "lethal catatonia," originally described by Stauder, in which the completely inert catatonic patient develops a high fever, collapses, and dies. In some respects, this state resembles the neuroleptic malignant syndrome, an idiosyncratic consequence of intoxication with neuroleptic drugs. In abulia, catatonia, and depression, the mind is usually sufficiently alert to record events and later to recount them, which differentiates these states from stupor. But this distinction is not always valid, for we have seen catatonic schizophrenic and greatly slowed depressive patients who could not recall what had happened during the period of illness.

Pathologic degrees of motor or mental restlessness and hyperactivity represent the opposite extreme from abulia. Akathisia refers to constant restless movements and inability to sit still; in some patients, this is a consequence of the prolonged use of phenothiazines, butyrophenones, newer antipsychosis drugs, and L-dopa, but it is also seen in agitated depressions. Hyperactivity-inattention disorders describe yet another form of excessive motor activity that usually accompanies an attention deficit syndrome of children, mostly boys (attention-deficit hyperactivity disorder [ADHD]). In the manic form of bipolar disease (and to a lesser extent in hypomania), continuous activity and insomnia are added to the flight of ideas and the euphoric (although somewhat irritable) mood. Following certain cerebral diseases, notably some forms of encephalitis and during recovery from traumatic lesions of the frontal lobes, the patient may remain in a state of constant uncontrollable and sometimes destructive activity. Kahn referred to this state as "organic drivenness."

Disorders of Social Behavior

Behavioral disturbances are common manifestations of all delirious–confusional states, particularly those of toxic–metabolic origin, but also those caused by more obvious structural disease of the brain. The patient may be completely indifferent to all persons around him, or the opposite, when any approach may excite anger and aggressive action. Family members may be treated with disrespect, regarded with suspicion, or falsely accused of harming the patient, stealing his possessions, or trying to poison him. The embarrassment consequent to urinating in public or soiling the bed may be absent and, particularly in men, there may be lewd behavior toward the opposite sex. In its most extreme form, usually seen in the later stages of dementing diseases, irascible behavior degenerates to kicking, screaming, biting, spitting, and an aversion to being touched, making it entirely impossible to approach the patient. These aspects of disordered mental function are the most alarming to the family and are difficult to manage in the hospital. Previously upstanding, socially appropriate, and abstemious persons may lose all regard for their actions and become profligate, gamblers, or alcoholics. In cases of damage to the frontal lobes, even beyond a neglect for social conventions, there is an indifference to others and to the consequences of the patient's actions on other members of society.

In contrast, docility and amiable social behavior characterize certain conditions such as Down and Williams syndromes, and social indifference and a lack of ability to interpret the emotional state of others are major features of autism (see "Delirium" later on).

Loss of Insight

The state of being aware of the nature and degree of one's deficits and their consequences becomes manifestly impaired or abolished in relation to many cerebral diseases, not just those of the frontal lobes. Lack of insight is a far more complex phenomenon than the operational definition given above suggests. In particular, there are many restricted forms of unawareness of gross neurologic deficits. These are the agnosias, discussed in Chap. 22. Patients with these diseases rarely seek advice or help for their illnesses; instead, the family usually brings the patient to the physician. And, after the diagnosis has been made, the loss of insight may be reflected in a lack of compliance with planned therapy. It follows that diseases that produce abnormalities of insight also reduce the patient's capacity to make accurate introspections concerning his psychic function.

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, already 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. Such cerebral disease may be focal or diffuse. Dr. Raymond Adams had designated this disposition to a superimposed acute confusional state in the context of dementia as a beclouded dementia but the term, while very 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, these abnormalities 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, e.g., 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 to 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 accompaniment 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. 17). 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.

Etiology

Table 20-1 lists some of the many causes of this common type of confusional state. The most frequent in general practice are drug intoxications and endogenous metabolic encephalopathies, mainly electrolyte and water imbalance (hypo- and hypernatremia, hyperosmolarity), hypercalcemia, disorders of acid–base balance, renal and hepatic failure, hyper- and hypoglycemia, febrile and septic states ("septic encephalopathy" discussed further on), and chronic cardiac and pulmonary insufficiency.

Diffuse or multifocal disease of the cerebral hemispheres is another class of transient or persisting confusional states. Concussion and seizures, especially petit mal or psychomotor status, and certain focal (e.g., right parietal and temporal) cerebral lesions may also be followed by a period of confusion. Focal lesions, most often infarctions but also hemorrhages, of the right cerebral hemisphere may evoke an acute confusional state. Such syndromes have been described with strokes mainly in the territory of the right middle cerebral artery (Mesulam et al; Caplan et al; Mori and Yamadori); usually the infarcts have involved the posterior parietal lobe or inferior frontostriatal regions, but they have also occurred with strokes in the territory of one posterior cerebral artery. A variety of more generalized or multifocal cerebral diseases may be associated with transient or persistent confusional states. Among these are meningitis, encephalitis, thrombotic thrombocytopenic purpura (TTP), disseminated intravascular coagulation, tumors, subdural hematoma, and cranial trauma.

A more restricted group of focal cerebral diseases, including drug and alcohol withdrawal and systemic infections cause delirium, as discussed below.

Pathophysiology of Confusional States

All that has been said on this subject in Chap. 17 regarding coma is applicable to at least one subgroup of the confusional states. In most cases, no consistent pathologic change is found because the abnormalities are metabolic and subcellular. As discussed in Chap. 2, the electroencephalogram (EEG) is almost invariably abnormal in even mild forms of this syndrome, in contrast to delirium, where the changes may be relatively minor. Bilateral high-voltage slow waves in the range of 2 to 4 per second (delta) or 5 to 7 per second (theta) are the usual findings with confusion. These changes surely reflect one aspect of the central problem—the diffuse impairment of the cerebral mechanisms governing alertness and attention and the property of coherence imparted by these functions. If only metaphorically, this mental incoherence and the disorganized thinking and behavior of the confusional states reflect the loss of integrated activity of all of the associative regions of the cortex as mentioned earlier in the chapter.

Delirium

This is best depicted in the patient undergoing withdrawal from alcohol after a sustained period of intoxication. The symptoms usually develop over a period of 2 or 3 d. The first indications are difficulty in concentration, restless irritability, increasing tremulousness, and insomnia. There may be momentary disorientation, an occasional inappropriate remark, or transient illusions or hallucinations.

These initial symptoms rapidly give way to a clinical picture that is one of the most colorful in medicine. The patient is inattentive and unable to perceive the elements of his situation. He may talk incessantly and incoherently, and look distressed and perplexed; his expression may be in keeping with vague notions of being annoyed or threatened by someone. From his manner and the content of speech, it is evident that he misinterprets the meaning of ordinary objects and sounds, misidentifies the people around him, and is experiencing vivid visual, auditory, and tactile hallucinations, often of a most unpleasant type. At first the patient can be brought into touch with reality and may identify the examiner and answer other questions correctly; but almost at once he relapses into a preoccupied, confused state, giving incorrect answers and being unable to think coherently. As the process evolves, the patient cannot shake off his hallucinations and is unable to make meaningful responses to the simplest questions and is profoundly distracted and disoriented. Sleep is impossible or occurs only in brief naps. Speech is reduced to unintelligible muttering.

The signs of overactivity of the autonomic nervous system, more than any others, distinguish delirium from other confusional states. Tremor of fast frequency and jerky restless movements are practically always present and may be violent. The face is flushed, the pupils are dilated, and the conjunctivae are injected; the pulse is rapid, blood pressure elevated, and the temperature may be raised. There is excessive sweating. Most of these signs are reflections of overactivity of the sympathetic nervous system.

The most certain indication of the subsidence of the attack is the occurrence of lucid intervals of increasing length and sound sleep. Recovery is usually complete. In retrospect, the patient has only a few vague memories of his illness or none at all. Single seizures may punctuate the syndrome at any time, including before its development.

Fragments of the full syndrome are common. Brief disorientation, isolated hallucinations, or restlessness with mild hypersympathetic features all occur in withdrawal states, febrile illnesses, and with various intoxications.

The brains of patients who have died in delirium tremens without associated disease or injury usually show no pathologic changes of significance. Intoxication with a number of medications, particularly those with atropinic effects, and certain abused drugs, such as the hallucinogens, causes a delirious state. Delirium may also occur in association with a number of recognizable cerebral diseases, such as viral (herpes) encephalitis or meningoencephalitis, Wernicke disease, cerebral trauma, cerebral hemorrhage after surgery for craniopharyngioma or other tumors in the same region, or multiple embolic strokes caused by subacute bacterial endocarditis, cholesterol or fat embolism, or following cardiac or other surgery. An unusual type arises in young women with ovarian teratomas and circulating antibodies against the NMDA receptor.

The topography of the lesions in most of the deliriums that are symptomatic of underlying destructive processes is of interest; they tend to be localized in the rostral midbrain and hypothalamus or in the temporal lobes, where they involve the reticular activating and limbic systems. Involvement of the hypothalamus perhaps accounts for the autonomic hyperactivity that characterizes delirium in some cases of cerebral disease and the autoantibody condition. That these are not the only sites implicated is emphasized by the observations that an acute agitated delirium has occurred, albeit infrequently, with lesions involving the fusiform and lingual gyri and the calcarine cortex (Horenstein et al); the hippocampal and lingual gyri (Medina et al); or the middle temporal gyrus (Mori and Yamadori).

Electrical stimulation studies of the human cerebral cortex during surgical exploration and studies by positron emission tomography (PET) have emphasized the importance of the temporal lobe in the genesis of complex visual, auditory, and olfactory hallucinations. Subthalamic and midbrain lesions may give rise to visual hallucinations that are not unpleasant and are accompanied by good insight ("peduncular hallucinosis" of Lhermitte). For reasons not easily explained, with pontine-midbrain lesions, there may be unformed auditory hallucinations.

The EEG in delirium may show symmetrical mild generalized slow activity in the range of 5 to 10 per second. In milder degrees of delirium, there is usually no abnormality at all; this is in stark contrast to the generalized slowing and disruption of EEG activity that accompany most other forms of confusion in proportion to the severity of the clinical state.

Analysis of the conditions conducive to delirium suggests several physiologic mechanisms. Alcohol and sedative drugs are known to have a strong depressant effect on certain regions of the central nervous system; presumably, the disinhibition and overactivity of these parts after withdrawal of the drug are the basis of delirium. Another mechanism is operative in the case of bacterial infections with sepsis and poisoning by certain drugs, such as atropine and scopolamine, in which visual hallucinations are a prominent feature. Here the delirious state probably results from the direct action of the toxin or chemical agent on the same parts of the brain. It has long been suggested that some persons are much more liable to delirium than others, but there is reason to doubt this. Many years ago, Wolff and Curran showed that randomly selected persons developed delirium if the causative mechanisms were strongly operative. This is not surprising, for any normal person may, under certain circumstances, experience phenomena akin to those of delirium. A healthy person can be induced to hallucinate by being isolated for several days in an environment free of sensory stimulation (sensory deprivation). A relationship of delirium to dream states has also been postulated; both are characterized by a loss of appreciation of time, a richness of visual imagery, indifference to inconsistencies, and "defective reality testing." Formulations in the field of dynamic psychiatry seem more reasonably to explain the topical content of delirium than its occurrence. Wolff and Curran, having observed the same content in repeated attacks of delirium from different causes, concluded that the content depends more on the age, gender, intellectual endowment, occupation, personality traits, and past experiences than on the cause of the delirium.

Confusional States and Delirium Induced by Medications (See Also Chap. 43)

In considering the pathophysiology of delirium and confusion, it must be again emphasized that drug intoxication—predominantly with drugs prescribed by physicians—is among the most common causes in practice. The most distinctive syndromes are those from drugs that have direct or indirect anticholinergic properties. The delirium associated with these agents is centrally mediated but may be accompanied by peripheral anticholinergic manifestations. This point is critical in the differential assessment of agitated confusional states because other compounds, particularly serotonergic agents used to treat depression, also can produce delirium. Thus, in addition to confusion, toxic levels of anticholinergic compounds typically cause dry skin, dry mouth, diminished bowel motility, and urinary hesitancy, if not frank retention. (The clinical maxim that applies is "red as a beet, dry as a bone, blind as a bat, hot as a hare, and mad as a hatter." The last part of this mnemonic has been also attached to the dementia of mercury intoxication [see Mintzer and Burns].) By contrast, in the toxic serotonergic syndrome associated with excessive doses of the newer antidepressant drugs, salivation is normal, sweating is increased, and the gut is hyperactive; diarrhea is common. Moreover, the deep tendon reflexes may be exaggerated, and there may be clonus and myoclonus as described by Birmes and associates. Drugs with dopaminergic activity used in the treatment of Parkinson disease are notorious for the induction of confusion or delirium, but it appears that the underlying disease provides an important substrate. Allied compounds with sympathomimetic actions such as cocaine and phencyclidine produce a hallucinatory delirium and yet others with different pharmacologic properties such as glutaminergic activity may result in a variety of delirious fragments or pure hallucinosis. Another entity that arises in this context is the neuroleptic malignant syndrome, a state associated with an agitated confusion followed by stupor. However, the characteristic features in neuroleptic malignant syndrome (NMS) are progressive muscle rigidity and evidence of myonecrosis as indicated by elevations of the serum creatine kinase; usually there is in addition some elevation of body temperature. The clinical examination and a thorough history aid greatly in determining which category of drug is implicated.

Diffuse Cerebral and Dementing Disease Complicated by Confusional States

Physicians are all too familiar with the situation of an elderly patient who enters the hospital with a medical or surgical illness or begins a prescribed course of medication and displays a newly acquired mental confusion. Presumably, the liability to this state is determined by preexisting brain disease, most often Alzheimer disease but sometimes Parkinson disease, multiple small deep cerebral infarctions, or another dementing process, which may or may not have been obvious to the family before. All the clinical features that one observes in the acute confusional states may be present, but their severity varies greatly. Confusion may be reflected only in the patient's inability to relate the history of the illness sequentially, or it may be so severe that the patient is virtually non compos mentis.

Although almost any complicating illness may bring out a confusional state in an elderly person, the most common are febrile infectious diseases; trauma, notably concussive brain injuries; surgical operations, general anesthesia and pre- and postoperative medication; even small amounts of pain or sedative medications used for any cause; and congestive heart failure, chronic respiratory disease, and severe anemia, especially pernicious anemia. With regard to medications, those with atropinic effects have the highest tendency to cause confusion, but others, even seemingly innocuous ones, may do the same (e.g., histamine blockers used to reduce gastric acid, anticonvulsants, corticosteroids, and L-dopa as mentioned earlier and described in Chap. 39).

Very often, it is difficult to determine which of several possible factors is responsible for the patient's confusion, and often there may be more than one. In a cardiac patient, for example, fever, hypoxia or hypercarbia, one or more drugs, and electrolyte imbalance each may contribute.

Infectious and Postoperative Confusional States

In the instance of fever and confusion, particularly in the elderly person, the problem of "septic encephalopathy" is offered as an explanation, but it may simply be a rephrasing of the well-known problem of infection such as pneumonia leading to a global confusion or delirium. Young has called attention to the high frequency of this disorder in critically ill patients, 70 percent of their bacteremic patients, and its accompaniment by a polyneuropathy in a high proportion of cases. Paratonic rigidity of the limbs (an oppositional action on the patient's part that is proportioned to the effort of the examiner in moving the limbs) is an almost universal accompaniment; according to these authors, focal cerebral or cranial nerve signs are not encountered. All other potential causes of a confusional state must, of course, be excluded before attributing the state to an underlying infection. The EEG is slowed in approximation to the level of consciousness, but it shows mild changes even in the bacteremic patient who is fully alert. The spinal fluid is normal or has a slightly elevated protein concentration. While there is no doubt that young and healthy patients may become confused when affected with high fever and overwhelming infections such as pneumonia, most cases of septic encephalopathy are of the "beclouded dementia" type in the older patient. The point made by Young is that subtle degrees of confusion are ubiquitous with serious infections of many varieties. Among the most perplexing cases of this type have been healthy older persons we have observed who acquired an agitated delirium following spinal column infection after surgery. The delirium ceased within hours of drainage of an abscess. The older literature contains similar examples with closed space infection in other locations. The chapter by Young can be consulted for an exposition of the various theories of pathogenesis of this state. High fever itself (above 40.6°C [105°F]) is probably an adequate explanation for confusion in some cases. A similar global confusional state occurs in patients with severe burns (burn encephalopathy).

All that has been stated above is true of the patient with a nondescript postoperative confusional state, in which a number of factors, such as fever, infection, dehydration, and drug and anesthetic effects, are implicated. In a study of 1,218 postoperative patients by Moller and colleagues, older age was by far the most important factor associated with persistent confusion after an operation; but a number of other factors—including the duration of anesthesia, need for a second operation soon after the first, postoperative infection, and respiratory complications—were also predictive of mental difficulty in the days after the procedure. Unacknowledged alcoholism and withdrawal effects undoubtedly cause the same problem quite often on surgical services (see also "Stroke with Cardiac Surgery" in Chap. 34).

When such patients recover from the medical or surgical illness, they usually return to their premorbid state, though their shortcomings, now drawn to the attention of the family and physician, are far more obvious than before. For this reason, families will date the onset of a dementia to the time of the medical illness or surgical procedure, and continue to minimize the previous gradual decline in cognition. In other cases, however, the acute medical illness seemingly marks the beginning of a persistent decline in mental clarity that over time can be identified as a dementing illness. A related problem that has recently come under study is persistent cognitive loss after critical illness. The rates of this irreversible change are apparently high, up to one-quarter of severely ill patients in some series, but accurate estimates are difficult to obtain because of the lack of pre-illness psychometric testing.

Nonconvulsive Status Epilepticus

This problem has attracted increasing attention in the past decades as a cause of otherwise obscure confusional states. It is discussed in Chaps. 16 and 17, but here we only comment that the process may be portrayed clinically only because of small myoclonic twitches or eyelid fluttering. The only certain way to arrive at, or exclude the diagnosis is with EEG monitoring for more than the usual 30 minute recording if possible. One suspects nonconvulsive seizures particularly in known epileptics, septic patients, and in certain medical diseases such as TTP.

Schizophrenic or Bipolar Psychosis during a Medical or Surgical Illness

A small proportion of psychoses of schizophrenic or bipolar type first become manifest during an acute medical illness or following an operation or parturition and need to be distinguished from an acute confusional state. Rarely, a catatonic state will make its first appearance in these circumstances. A causal relationship between the psychosis and medical illness is sought but cannot be established. The psychosis may have preceded the medical illness but was not recognized. The diagnostic study of the psychiatric illness must then proceed along the lines suggested in Chaps. 52 and 53. Close observation will usually disclose a clear sensorium and relatively intact memory, features that permit differentiation from an acute confusional or delirious state or dementia.

The syndromes themselves and their main clinical causes are the only satisfactory basis for classification until such time as their actual causes and pathophysiology are discovered (Table 20-1).

The first step in diagnosis is to recognize that the patient is confused. This is obvious in most cases but, as pointed out earlier, the mildest forms, particularly when some other alteration of personality is prominent, may be overlooked. Sometimes, the patient's attention can be best engaged by whispering rather than shouting or using a conversational amplitude of voice. A subtle disorder of orientation may be betrayed by an incorrect response regarding dates (off by more than one day of the month or day of the week), or in misnaming the hospital. The ability to retain a span of digits forward (normally 7) and backward (normally 5), spelling a word such as world or earth forward and then backward, reciting the months of the year in their reverse order, and serial subtraction of 3's from 30 or 7's from 100 are useful bedside tests of the patient's capacity for attentiveness and sustained mental activity, though some of these presuppose that the patient is literate or has a knowledge of mathematics. Another is the efficiency in performing dual tasks such as tapping alternately with each hand while reading aloud. Memory of recent events is one of the most delicate tests of adequate mental function and is readily accomplished by having the patient relate the details of entry to the hospital; examinations undertaken in the previous days; naming the president, vice president; and summarizing major current events, as outlined in Chap. 21. Errors in performance should not be minimized or attributed to age, for they may presage serious upcoming problems during the hospitalization.

Once it is established that the patient is confused, the differential diagnosis must be made between an acute confusional state associated with psychomotor underactivity, delirium, a beclouded dementia, and a confusional state that complicates focal cerebral disease. This is done by taking into account the degree of the patient's alertness, wakefulness, psychomotor and hallucinatory activity, and disturbances of memory and impulse, as well as the presence or absence of asterixis or myoclonus or signs of overactivity of the autonomic nervous system and of generalized or focal cerebral disease. In the neurologic examination, particular attention should be given to the presence or absence of focal neurologic signs and to asterixis, myoclonus, and seizures.

In the chronically demented patient, there are usually a number of "frontal release" signs, such as picking at the bedsheets and clothes, grasping, groping, sucking, and paratonic rigidity of the limbs. However, some demented patients are as bewildered as those with confusional psychosis, and the two conditions are distinguishable only by differences in their mode of onset and chronicity. This suggests that the affected parts of the nervous system may be the same in both conditions.

At times, a left hemispheral lesion causing a mild Wernicke's aphasia resembles a confusional state in that the stream of speech and thought are incoherent. The prominence of paraphasias and neologisms in spontaneous speech, difficulties in auditory comprehension, and normal nonverbal behavior mark the disorder as aphasic in nature. However, a problem with naming may be more common in non-aphasic global confusional states, as alluded to earlier in the chapter and emphasized in a brief piece by Geschwind. Spontaneous speech in these circumstances is unaffected.

The distinction between an acute confusional state and dementia is difficult at times, particularly if the mode of onset and the course of the mental decline are not known. The patient with an acute confusional state is said to have a "clouded sensorium" (an ambiguous term referring to a symptom complex of inattention, disorientation, perhaps drowsiness, and an inclination to inaccurate perceptions and sometimes to hallucinations and delusions), whereas the patient with dementia usually has a clear sensorium.

As indicated earlier, schizophrenia and bipolar psychosis can usually be separated from the confusional states by the presence of a clear sensorium and relatively intact memory function.

Once a case has been appropriately classified, it is important to determine its clinical associations as outlined in Table 20-1.

A thorough medical and neurologic examination, CT or MRI, and—in cases with fever or with no other apparent cause—blood count, chest X-ray, and lumbar puncture should be performed. The medical, neurologic, and laboratory findings (including measurements of Na, Ca, CO2, blood urea nitrogen [BUN], NH3, calcium, glucose, PAO2, PCO2, "toxic screen") determine the underlying disease and its treatment, and they also give information concerning prognosis. An approach to the laboratory tests that are useful in revealing the common conditions that give rise to the confusional state when the cause is not self-evident from the history and physical examination is given in Table 20-2; but as always, the choice of tests is governed by the clinical circumstances.

These details are of the utmost importance. It has been estimated that 20 to 25 percent of medically ill hospital inpatients will experience some degree of confusion; moreover, elderly patients who are delirious have a significant level of mortality, variously estimated at 22 to 76 percent according to Weber and colleagues. Optimal care begins with the identification of individuals at risk for delirium, including those who have an underlying dementia, preexisting medical illnesses, or a history of alcoholism or serious depression. Furthermore, delirium is more common in males and, not surprisingly, is more likely when sensory function is already impaired (loss of vision and hearing) (Burns et al; Weber et al).

The primary effort is directed toward elimination of the underlying medical problem, particularly to discontinuing offending drugs or toxic agents. Other important objectives are to quiet the agitated patient and protect him from injury. A nurse, attendant, or member of the family should be with a seriously confused patient if this can be arranged. A room with adequate natural lighting will aid in creating a diurnal rhythm of activity and reduce "sundowning." It is often better to let an agitated patient walk about the room than to restrain him in bed, which may increase his fright or excitement and cause him to struggle to the point of exhaustion, collapse, or self-harm. The less-active patient can be kept in bed by side rails, wrist restraints, or a restraining sheet or vest. Sensitive explanations of these restraints to the family should be made in terms that emphasize the patient's health and safety. The fully awake but mildly confused patient should be permitted to sit up or walk about part of the day unless the primary disease contraindicates this.

All drugs that could possibly be responsible for the acute confusional state or delirium should be discontinued if this can be done safely. These include sedating, antianxiety, narcotic, anticholinergic, antispasticity, and corticosteroid medications, L-dopa, metoclopramide, and cimetidine, as well as antidepressants, antiarrhythmics, antiepileptics, and antibiotics. Despite the need to be sparing with medications in these circumstances, haloperidol, quetiapine, and risperidone are helpful in calming the severely agitated and hallucinating patient, but they too should be used in the lowest effective doses. An exception is alcohol or sedative withdrawal, in which chlordiazepoxide or other diazepines are favored by most physicians (see Chap. 42). In delirious patients, the purpose of sedation is to assure rest and sleep, avoid exhaustion, and facilitate nursing care, but one must be cautious in attempting to suppress delirium completely. Warm baths were also known in the past to be effective in quieting the delirious patient, but hospitals no longer have facilities for this valuable method of treatment.

It would seem obvious that attempts should be made to preempt the problem of confusion in the hospitalized elderly patient. Inouye and colleagues devised an intervention program that includes frequent reorientation to the surroundings with signs, verbal reminders, and a clock; mentally stimulating activities; ambulation several times a day or similar exercises when possible; and attention to providing visual and hearing aids in patients with these impairments. They recorded a 40 percent reduction in the frequency of a confusional illness in comparison to patients who did not receive this type of organized program. Preventive strategies of the type they outline are most important in the elderly, even those without overt dementia, but a routine plan is advisable so that nurses and ancillary staff are able to apply them consistently.

Finally, the physician should be aware of the benefit of many small therapeutic measures that allay fear and suspicion and reduce the tendency to hallucinations. The room should be kept dimly lighted at night, and, if possible, the patient should not be moved from one room to another. Every procedure should be explained to the patient, even such simple ones as the taking of blood pressure or temperature. It may be some consolation and also a source of professional satisfaction to remember that most confused and delirious patients recover if they receive competent medical and nursing care (and are almost always amnestic for the ordeal). The family may be reassured on this point but forewarned that improvement may take several days or weeks and that episodes of confusion may be exposing an underlying dementia. They must also understand that the patient's abnormal behavior is not willful but rather symptomatic of a transitory brain disease. (See also Chaps. 42 and 43 for specific aspects of management of delirium due to withdrawal of alcohol and other sedative-hypnotic drugs.)