Confusion

Mark W. Nickels

Acute confusional states represent an etiologically diverse spectrum of disorders that may involve alterations in thinking, perception, memory, orientation, or attention. In addition, present may be physiologic changes, alterations in sleep–wake cycle, or changes in psychomotor behavior. These can be the result of delirium or psychiatric processes, and must be distinguished from dementia. The prevalence of delirium, the most common of these, in general hospital settings ranges between 11% and 16%; it is lower in outpatient practices (Chapter 4.3). This percentage increases significantly in elderly patients, those with preexisting central nervous system disorders, immunodeficient patients, postsurgical and burn patients, substance abusers, those with multiple comorbidities and complex medication regimens, and patients with significant psychosocial stresses.

Approach

. Causative factors include cerebral and metabolic problems and psychiatric disorders. It is important first to consider organic causes.

A. Organic factors. The mnemonic “I WATCH DEATH” is useful for the differential diagnosis:

1. Infection—sepsis, encephalitis, meningitis, syphilis, human immunodeficiency virus, abscesses

2. Withdrawal—alcohol, sedatives

3. Acute metabolic—acid-base or metabolic disturbances, renal or liver failure

4. Trauma—head trauma, burns

 5. CNS pathology—hemorrhage, subdural hematoma, tumors, seizures (nonconvulsive status, postictal states), tumors, hydrocephalus, vasculitis

 6. Hypoxia—cardiopulmonary failure, carbon monoxide (CO) poisoning, hypotension, anemia

7. Deficiencies—B₁₂, folate, niacin, thiamine

8. Endocrinopathies—Addison’s or Cushing’s diseases, hyper- or hypoglycemia, hypo- or hyperthyroidism, hyperparathyroidism

9. Acute vascular—hypertensive crisis, arrhythmia, shock

10. Toxins or drugs—medications, illicit drugs, solvents, pesticides

11. Heavy metals—lead, mercury, manganese

B. Psychiatric factors. The Diagnostic and statistical manual of mental disorders, 4th ed. (1) diagnoses to consider include the acute psychoses of schizophrenia, major depression, or mania; conversion disorder; dissociative episodes; and acute and posttraumatic stress disorders.

 C. Special concerns. Urgent attention is required with hypertensive encephalopathy, intracranial bleeds, meningitis, head trauma, seizures, hypoxia, and acute psychiatric decompensations.

History

. Collateral information is valuable with confused patients.

 A. Characteristics. Is there an altered level of consciousness? Is so, consider urgent factors. Is the patient easily distractible or having difficulty keeping track of what is said? Is there an altered sleep–wake cycle; do symptoms fluctuate and are there changes in psychomotor behavior? If so, delirium is likely. Is thinking disorganized or incoherent? Is speech rambling, irrelevant, or frequently switching subjects? Is the patient disoriented? Do memory problems exist? Are there perceptual disturbances, including hallucinations or thought broadcasting, insertion, or withdrawal? The presence of visual hallucinations suggests organic causes. Are delusions present? Is there an indifference to the symptoms? If so, consider conversion disorder. Are there nightmares or increased startle response? If so, acute or posttraumatic stress disorders should be considered (Chapter 3.1).

 B. Chronology of symptoms. Is the onset acute? In dementia, a chronic degree of confusion exists; however, acute confusion can herald the onset of delirium, warranting further evaluation (Chapter 4.1). Is the course fluctuating and do symptoms occur more often at night? If so, this suggests delirium. Have such symptoms occurred in the past? If so, what caused them then?

 C. Medical history. Confusion is more likely in patients with multiple medical problems, longer lists of medications, or recent medication changes. Medications that can induce confusion include anticholinergics, sedatives, steroids, metronidazole, and digoxin, among others.

 D. Psychiatric history. Are there any prior diagnoses and treatments, or a psychotropic medication history? If so, do current symptoms match prior psychiatric episodes? If so, consider a psychiatric recurrence. Have there been any recent psychosocial stressors? If so, consider the possibilities of dissociative and stress syndromes. It is important to note that a prior psychiatric history does not necessarily imply the confusion is caused by a psychiatric exacerbation; conversely, the absence of a psychiatric history does not rule out a psychiatric cause. Psychotic disorders tend to occur in younger patients, whereas delirium is more likely in older patients.

 E. Other information. Current or past use of alcohol or drugs, recent injuries (particularly head injuries), and exposure to toxins. A review of systems helps detect organic causes.

Physical examination

 A. Focused physical examination. This should include vital signs, psychomotor characteristics, assessment of skin, hair, and nail beds; and
a funduscopic examination. A screening neurologic examination should include a check for nuchal rigidity, and an assessment of Kernig’s and Brudzinski’s signs. Positive findings warrant further testing. The Folstein Mini-Mental State examination (2) can help assess cognitive functioning (Chapter 4.5). The Confusion Assessment Method may be used to help detect delirium (3).

Testing

 A. Clinical laboratory tests. These should include a complete blood count with differential, urinalysis, toxicology screen, serum chemistry panel, and appropriate medication levels. Vitamin B₁₂ and folate levels, serologic test for syphilis, and thyroid function studies can be drawn. As clinically indicated, blood gases can also be checked. Based on history and examination, additional studies may include cerebrospinal fluid examination, heavy metals screen, and erythrocyte sedimentation rate (and others, as needed for vasculitis). An electroencephalogram (EEG) can be particularly useful in distinguishing delirium from psychiatric presentations—in delirium, the EEG will show diffuse slowing, except in cases of sedative drugs and withdrawal when low amplitude fast activity is seen; the EEG is normal in psychiatric syndromes.

 B. Diagnostic imaging. Magnetic resonance imaging is indicated for first psychotic breaks, new onset of confusion after age 50 years, and in the presence of focal neurologic findings.

Diagnostic assessment

. Assume organic causes until proved otherwise. Delirium is more likely in those populations noted above, and is typically characterized by disorientation, a fluctuating symptom course, and alterations in the sleep–wake cycle. Paranoia may be seen. Be alert to the presence of visual hallucinations, which can suggest the possibility of delirium. A dementia history is typically one of long intellectual decline with usual levels of alertness and attention. Orientation is often impaired, as are recent and remote memory. Perceptual disturbances are often absent, unlike delirium (4). Acute psychoses caused by schizophrenia are often characterized by hallucinations, delusions, and formal thought disorder and do not typically include disorientation or altered levels of consciousness. Symptoms tend not to fluctuate and memory is intact. Psychoses that develop as part of major depression or mania follow the onset of affective symptoms. Conversion disorders can involve hallucinations in the absence of other psychotic symptoms. La belle indifference may be present, but no symptom fluctuation or sleep–wake alteration is seen. Dissociative states can include loss of memory, including personal data, and perhaps disorientation, but these are not embedded in other changes. Episodes are usually short and perceptual disturbances are rare. Anxiety-like symptoms may precede dissociation. Acute and posttraumatic symptoms follow traumatic events. Acute stress disorder, by definition, remits within 4 weeks, but has symptoms similar to posttraumatic stress disorder. Orientation is intact, concentration can be impaired, and increased vigilance may be present. Patients may seem detached or in a daze. Nightmares and flashbacks often occur but no perceptual disturbances or thought disorganization is seen. Memory is intact, except perhaps for the traumatic event. Signs of autonomic arousal may be seen, especially with recall of the event. EEG changes are absent in psychiatric disorders.

References

1. American Psychiatric Association. Diagnostic and statistical manual of mental disorders, 4th ed. Washington, DC: American Psychiatric Association, 1994.

2. Folstein MF, Folstein SE, McHugh PR. The Folstein Mini-Mental State Examination: a practical method for grading the cognitive state of patients for the clinician. J Psychiatric Res 1975;12:189–198.

3. Inouye SK, vanDyck CH. Clarifying confusion: the confusion assessment method. Ann Intern Med 1990;113:941–946.

4. Lipowski ZJ. Delirium (acute confusional states). JAMA 1987;258:1789–1792.

Book Source Details

• Book Title: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter
• Author(s): Robert B. Taylor (editor)
• Year of Publication: 2000
• Copyright Details: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, Copyright © 2000 Lippincott Williams & Wilkins.

Other Book Chapters Related to Confusion

Read excerpts from these other book chapters related to Confusion:

Copyright Details: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, Copyright © 2008 Williams & Wilkins.

More About Causes of Confusion

• Back to symptom: Confusion: Introduction (review 725 causes)
• Next Book Extract About Confusion: Dementia (Field Guide to Bedside Diagnosis)
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More About This Book: Title: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter Authors: Robert B. Taylor (editor) Publisher: Lippincott Williams & Wilkins Copyright: 2000 ISBN: 0-78172-094-X

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