Delirium

Definition

Clinical dx of acute, fluctuating LOC/confusion/cognitive changes. Classically consists of attention deficit with other symptoms such as altered sleep-wake cycles, hallucinations, delusions, changes in affect, and autonomic symptoms.

Can be hyperactive or hypoactive or mixed.

Delirium is a CNS manifestation of usually a non-CNS problem. It is a medical emergency unless proven otherwise.

Risk Factors

Major RF are age (65+), baseline cognitive dysfunction or dementia (MMSE > 24), sensory deprivation, poor overall health, infection and acute illness (APACHE II > 16), surgery, pain, poor vision (<20/70), dehydration.

Major precipitating factors are physical restraint, Foley catheter, malnutrition, new medications, iatrogenic events.

Outcomes

Increases LOS, infections, functional decline, institutionalization, recidivism.

High mortality risk, about 25-33% in-hospital.

Associated with persistent cognitive dysfunction.

Pathogenesis

Occurs from widespread disturbances in cortical and subcortical brain regions with diffuse cerebral dysfunction. This is a result of an insult to a predisposed individual.

Theories range from cholinergic failure hypotheses, to dopamine excess, to HPA axis stress response, to cytokines in inflammation.

Etiology

Category Example
Drugs Rx drugs, overdose/abuse, poisoning/toxidrome
Infection Pneumonia, UTI, skin, CNS, etc.
Metabolic electrolytes, glucose, temperature, oxygenation, liver and renal, thyroid, vitamins/thiamine/B12, hydration, nutrition
Environment hospitalization, poor vision, etc.
Structural CNS lesions, strokes, blood pressure, etc.

Pay particular attention to:

Assessment

The Confusion Assessment Method (CAM) is a 4-question screen for delirium. It requires (1) and (2). It is 82% sens and 99% spec for delirium. It is the best bedside instrument for dx of delirium.

Form and investigate the differential based on DIMS. Decide on level of care needed (may need to escalate with hemodynamic instability, hypoxemia, hypercapnia, methemoglobinemia, new focal neurologic signs, severely altered LOC).

Neuro examination would consist of the minimum:

  1. Level of consciousness
  2. speech and language
  3. attention
  4. orientation
  5. cranial nerves
  6. gross muscle strength
  7. respiratory pattern and withdrawal to noxious stimuli, if unconscious

Tests of Attention

Other Common Features

Head CT

Really only indicated with:

Treatment

  1. Rule out alternatives such as depression, dementia.
  2. Treat reversible causes
  3. Supportive measures
    1. sitter, family
    2. sensory optimization
    3. mobility (i.e. remove physical restraints if possible)
    4. hydration
    5. self-care
    6. address fall risk
  4. Antipsychotics are indicated if they're a physical threat to themselves or other, interfering with necessary medical treatment to resolve the underlying cause, or with extreme patient emotional distress. It doesn't improve outcomes but can convert hyperactive to hypoactive delirium. Start LOW and go SLOW. Benefit must outweigh the significant risks (below).
    1. Haloperidol 0.25-0.5 mg PO/IV/SC/IM BID -- try to avoid IV due to arrhythmia risk
    2. Risperidone 0.25-0.5 mg PO BID
    3. Olanzapine 2.5-5.0 mg PO daily
    4. Quetiapine 6.25-25 mg PO BID/TID
  5. Benzos have a limited role; they are reserved for sedative drug/ETOH withdrawal, catatonia and when antipsychotics are contraindicated such as severe QT prolongation. They can worsen confusion and sedation. Less effective overall. Dangerous in elderly.

With antipsychotics, keep in mind the risks of EPS/Parkinsonism, stroke, dysrhythmias like QT prolongation/TdP/SCD, pneumonia, falls, incontinence, NMS.