Delirium

For further information, see CMDT Part 25-20: Neurocognitive Disorders

For further information, see CMDT Part 24-14: Dementia

Essentials of Diagnosis

• Acute confusional state

• Transient global disorder of attention, with clouding of consciousness

• Usually a result of systemic problems (eg, drugs, hypoxemia)

General Considerations

• The organic problem may be a primary brain disorder or a secondary manifestation of some general disorder

• The causes of cognitive disorders are listed in Table 25–11

• Should be considered a syndrome of acute brain dysfunction analogous to acute kidney injury

• Terminal delirium occurs commonly at the end of life

  • May be related to multiple medical causes, including organ failure

  • May be unrecognized

Demographics

• Alcohol or substance withdrawal is the most common cause of delirium in the general hospital

Symptoms and Signs

• Onset is usually rapid

• The mental status fluctuates (impairment is usually least in the morning), with varying inability to concentrate, maintain attention, and sustain purposeful behavior

• “Sundowning"—mild to moderate delirium at night

  • More common in patients with preexisting dementia

  • May be precipitated by hospitalization, drugs, and sensory deprivation

• There is a marked deficit of memory and recall

• Anxiety and irritability are common

• Orientation problems follow the inability to retain information

• Perceptual disturbances (often visual hallucinations) and psychomotor restlessness with insomnia are common

• Physical findings vary according to the cause

Laboratory Tests

• Comprehensive physical examination including a search for neurologic abnormalities, infection, or hypoxia

• Routine laboratory tests may include

  • Serum electrolytes

  • Serum glucose

  • Blood urea nitrogen

  • Serum creatinine

  • Liver biochemical tests

  • Thyroid function tests

  • Arterial blood gases

  • Complete blood count

  • Serum calcium, phosphorus, magnesium

  • Serum vitamin B₁₂, folate

  • Blood cultures

  • Urinalysis

  • Cerebrospinal fluid analysis

• Table 25–11

Imaging Studies

• The following may be helpful in diagnosis

  • Electroencephalography (EEG)

  • CT

  • MRI

Diagnostic Procedures

• EEG usually shows generalized slowing

Medications

• The first aim of treatment is to identify and correct the etiologic medical problem

• Discontinue drugs that may be contributing to the problem, such as

  • Analgesics

  • Corticosteroids

  • Cimetidine

  • Lidocaine

  • Anticholinergic drugs

  • CNS depressants

  • Mefloquine

• Ideally, the patient should be monitored without further medications while the evaluation is carried out

• Two indications for medication in delirious states

  • Behavioral control (eg, pulling out lines)

  • Subjective distress (eg, pronounced fear due to hallucinations)

• If there is any hint of alcohol or substance withdrawal, a benzodiazepine such as lorazepam (1–2 mg every hour) can be given parenterally

• If there is little likelihood of withdrawal syndrome, haloperidol is often used in doses of 1–10 mg every hour

• Once the underlying condition has been identified and treated, adjunctive medications can be tapered

Therapeutic Procedures

• In addition to the medication, a pleasant, comfortable, nonthreatening, and physically safe environment with adequate nursing or attendant services should be provided

Prognosis

• The prognosis is fair to good for recovery of mental functioning in delirium when the underlying condition is reversible

• The average duration is about 1 week, with full recovery in most cases