Delirium

Delirium: Excerpt from The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter

Linda P. Shields

Delirium, as defined by the Diagnostic and Statistical Manual of Mental Disorders, 4th edition criterion (1), is a condition involving an acute confusional state recognized by the patient’s change in consciousness, attention, cognition, perception, or psychomotor activity level. It is acute in onset, often fluctuates widely throughout the day, and is potentially reversible. Its importance lies in its high incidence (ranging from 5% of young surgical patients to >60% of elderly medical patients) (2,3), increased morbidity and mortality, and the frequency of iatrogenic, and therefore, potentially reversible, causes.

Approach.

 Recognition of the risk factors for, and the onset of, delirium is essential for successful management. It is a psychiatric illness that is unique in that it is always associated with underlying medical illness.

 A. Risk factors. These include advanced age, preexisting dementia, multiple medications, poor nutrition, history of drug or alcohol use, impaired ambulation or use of restraints, decreased sensory input, pain associated with recent trauma, surgery, or medical conditions.

 B. Causes. The precipitating factors in the development of delirium are often multifactorial. Medication, especially anticholinergic and psychotrophic drugs, are the leading cause of delirium. Any medication can be suspect. Common precipitants are infections [urinary tract (UTI), respiratory, human immunodeficiency virus (HIV)]; hypoxemia [congestive heart failure (CHF), myocardial infarction, exacerbation of chronic obstructive pulmonary disease]; and metabolic disorders (abnormalities of electrolytes, thyroid, glucose, renal and hepatic function, calcium, hematocrit, and vitamin B deficiencies). Urinary retention and fecal impaction can present as delirium. Central nervous system sources include meningitis, abscess, stroke, subdural hematoma, and increased intracranial pressure. Withdrawal from alcohol, sedatives, hypnotics or narcotics is a common cause of mental status changes in younger people, but must also be considered in the differential diagnosis for the elderly as well. Finally, remember that sleep deprivation and sudden changes in surroundings, including sensory deprivation, can provoke delirium in all ages.

History

 A. Baseline. Perhaps the most important aspect of taking the patient’s history is establishing the individual’s baseline mental status and level of functioning. In addition to interviewing the patient, family, friends, and acquaintances must be interviewed as well. Other healthcare providers, such as nurses and doctors, who have dealt with the patient previously in an office, nursing home, or hospital setting, can be invaluable sources of information. Try to establish the presence or absence of the signs and symptoms of dementia or depression (section V).

 B. Previous medical history. Look for previously existing medical problems that can precipitate delirium, such as CHF, diabetes, hypothyroidism, benign prostatic hypertrophy or HIV (section I.B). Evaluation of the medications is crucial, including prescription and over-the-counter medications. Is the patient taking them as directed? Is the patient on any medications that could be present in toxic levels (e.g., digoxin, phenytoin or theophylline)? Has there been any recent trauma or surgery? Are there symptoms of infection such as UTI or pneumonia? Be sure to interview friends and family.

 C. Social history. Does the patient have a history of substance abuse? Is the patient currently using any alcohol or illegal substances? When was their last use? Be aware of potential withdrawal. If the patient is abusing alcohol, is there a history of delirium tremors with previous abstinence? Does the patient live alone? Is the patient at risk for poor nutrition?

Physical examination.

Because of the fluctuating nature of delirium, serial examinations are valuable.

 A. Mental status. Observe the patient and take note of changes of level of consciousness, orientation, agitation, combativeness, hallucinations, or inability to concentrate. Evaluate the mental status by using the Mini Mental Status Examination (4) or a similar tool to standardize the findings (Chapter 4.5).

 B. Physical status. Obtain vital signs and evaluate for clinical signs of dehydration, malnutrition, urinary retention, or fecal impaction. The physical examination should be guided by the history, keeping in mind the multifactorial nature of delirium. Evaluate for signs of infection, look for cardiopulmonary decompensation, and complete a thorough neurologic examination with special attention to identifying any focal neurologic deficit.

Testing

 A. Laboratory. All patients should have a complete blood count, serum chemistries including electrolytes, hepatic and renal function, albumin and calcium, and a urinalysis. Additional studies will be directed by clinical suspicions based on the history and the physical examination. These may include thyroid studies, serum medication levels, serum and urine drug screens, lumbar puncture with spinal fluid studies, HIV status, syphilis test, vitamin B₁₂ and folate levels, or serum markers of cardiac damage such as creatine kinase-MB or troponin.

 B. Additional studies. All patients should have an electrocardiogram and a chest roentgenogram as well as arterial blood gases or oxygen saturation level tests. With no history of trauma or focal neurologic deficit, a computed tomography scan is of limited value. An electroencephalogram is also of limited value unless the diagnosis of seizure is being considered.

Diagnostic assessment.

 Delirium can be a medical emergency, and a high index of suspicion must be maintained to accurately diagnose and treat the condition. Diagnosis is complicated by the similarity of presentation of depression, dementia and delirium, and by overlapping signs and symptoms. It is essential to rule out an underlying dementia or depression before the diagnosis of delirium can be made. This has particular impact on the treatment and prognosis of the illness.

 A. Dementia is characterized by a gradual onset of decreased functioning in the areas of memory, execution of the activities of daily living, and social functioning. It is less likely for delirium to cause changes in sensorium, cognition, attention; it is also less likely for delirium to fluctuate from hour to hour. Delirium can coexist with an underlying dementia and should always be considered when a previously diagnosed dementia patient exhibits an acute change in mental status.

B. Depression is characterized by a depressed mood with psychomotor retardation or agitation. Look for a gradual onset of anhedonia, sleep disturbances, fatigue, feelings of guilt or worthlessness, or a previous history of depression (Chapter 3.3).

 C. Other diagnoses. Consider in the differential diagnosis functional psychosis and bipolar disease, especially the manic phase. Both can produce hallucinations, although those of delirium tend to be visual or tactile, whereas those of psychosis tend to be auditory in nature. Epilepsy, especially temporal lobe seizures, can mimic delirium. Multi-infarct dementia, with its characteristic labile emotional state, must be considered. Remember that delirium is a complex, multifactorial condition and can present superimposed on a variety of other medical psychiatric conditions. A careful history and physical examination will help clarify the diagnosis and guide the physician and patient toward the correct treatments.

References

1. American Psychiatric Association. Diagnostic and statistical manual of mental disorders, 4th ed. Washington, DC: American Psychiatric Association, 1994:129–133.

2. Johnson JC. Delirium in the elderly. Emerg Med Clin North Am 1990;8:255–265.

3. American Psychiatric Association Practice Guidelines. Am J Psychiatry 1999;
156:S1–S20.

4. Folstein MF, Folstein SE, McHugh PR. Mini-mental status examination: a practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 1975;12:189–198.

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.

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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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