Delirium- In Depth Explanation

Delirium- In Depth Explanation

DSM-IV Criteria for Delirium:
A. Disturbance of consciousness (i.e., reduced clarity of awareness of the environment, reduced ability to focus, sustain or shift attention)
B. Change in cognition (i.e., memory deficit, disorientation, language disturbance) not better accounted by a preexisting dementia.
C. Disturbance develops over a short period of time (usually hours to days) and fluctuates.
D. Evidence from the history, physical examination, or laboratory findings that the disturbance is caused by the direct physiological consequences of a (underlying condition like: General medical condition, Substance intoxication, Substance withdrawal etc)

Summary
delirium is characterized by a disturbance of consciousness and a change in cognition that develop over a short time.

Four subcategories based on several causes:
(1) General medical condition (e.g., infection)
(2) Substance induced (e.g., cocaine, opioids, phencyclidine [PCP])
(3) Multiple causes (e.g., head trauma and kidney disease)
(4) Delirium not otherwise specified (e.g., sleep deprivation)

Common Causes of Deliriium
D Dementia
E Electrolyte disorders
L Lung, liver, heart, kidney, brain
I Infection
R Rx Drugs
I Injury, Pain, Stress
U Unfamiliar enviroment
M Metabolic (Diabetes)

Clinical Cues
- Highest rate of delirium is found in postcardiotomy patients (> 90% in some studies).
- Advanced age is a major risk factor.
- Male gender is an independent risk factor for delirium according to DSM-IV-TR.
- More likely to diagnose delirium in patients without premorbid psychiatric history.
- Visual hallucination predominate.
- Patient is observed picking at things or manipulating imaginary items.
- Incoherent speech that is not patient's baseline pattern of speech.
- Autonomic instability (follow vital signs); abnormal lab findings (increased WBC, abnormal urinalysis or electrolyte disturbances)
- Delirium is a poor prognostic sign:
(a) Rates of institutionalization are increased threefold for patients > 65 years who exhibit delirium while in the hospital.
(b) Elderly patients who experience delirium while hospitalized have a 20- 75% mortality rate during that hospitalization.
- When evaluating patients with delirium, clinicians should assume that any drug that a patient has taken may be etiologically relevant to the delirium.
- After identification and removal of the causative factors, the symptoms of delirium usually recede over a 3-7 day period, although some symptoms may take up to 2 weeks to resolve completely.
- The major neurotransmitter hypothesized to be involved in delirium is acetylcholine (so remember the role of medications with anticholinergic activity)
- The major neuroanatomical area is the reticular formation (principal area regulating attention and arousal).
- The major pathway implicated is the dorsal tegmental pathway (projects from the mesencephalic reticular formation to the tectum and thalamus).
- EEG characteristically shows a generalized slowing of activity (useful in differentiating delirium from depression or psychosis).
- Severe agitation that responds poorly to several administration of antipsychotic treatment

Coding note:
- If delirium is superimposed on a preexisting vascular dementia, indicate the delirium by coding vascular dementia, with delirium.
- Include the name of the general medical condition on Axis I, (e.g., Delirium due to hepatic encephalopathy); also code the general medical condition on Axis III.

Laboratory Workup
- Assess ABCs (Airway, Breathing, and Circulation)
- Check vitals, pulse oximeter
- Basic lab (CBC, BMP, LFTs, UA, UDS, Etoh)- in ER
- HIV, RPR, Hep panel, TSh- Upon admission
- Chest X-ray
- Head CT
- EEG (if suspect seizure activity)
- LP (if suspect infection)
- Culture- Blood, urine, CSF (if suspect infection)
- B12, Folate, Ammonia (if indicated)

Differential Diagnosis

(1) Dementia
------------------------------------ Dementia ------------------------------------ Delirium
Onset ---------- Slow (Except: vascular dementia caused by stroke)-------- Rapid
Duration ------------- Months to years ----------------------- Hours to weeks
Attention ------------- Preserved ---------------------------- Fluctuates
Memory ------------- Impaired remote memory -------- Impaired recent & immediate memory
Speech ------------- Word-finding difficulty --------------- Incoherent (slow or rapid)
Sleep wake cycle -- Fragmented sleep -------------- Frequent disruption (e.g., day night reversal)
Thoughts ------------- Impoverished ------------------------- Disorganized
Awareness ----------- Unchanged --------------------------- Reduced
Alertness ------------- Usually normal ---------------------- Hypervigilant or reduced vigilance

(2) Schizophrenia
- Hallucinations and delusions: more constant and better organized in schizophrenia.
- No change in their level of consciousness or in their orientation.

(3) Depression
Patients with hypoactive symptoms of delirium may appear somewhat similar to severely depressed patients, but they can be distinguished on the basis of an EEG

(4) Factitious disorder
Inconsistencies on their mental status examinations, and an EEG can easily separate the two diagnoses.


Treatment

Non pharmacological:
(a) Primary goal: treat the underlying cause
[Ex: In anticholinergic toxicity, the use of physostigmine salicylate (Antilirium), 1-2 mg i.v or i.m, with repeated doses in 15 to 30 minutes may be indicated
If delirium is caused by severe pain or dyspnea, a physician should not hesitate to prescribe opioids for both their analgesic and sedative effects.]
(b) Provide physical, sensory, and environmental support:
- Having a friend or relative in the room or by the presence of a regular sitter.
- Familiar pictures and decorations
- Presence of a clock or a calendar


Pharmacological:
• Required for two major symptoms of delirium: - psychosis and insomnia.
Psychosis:
• Commonly used drug for psychosis is haloperidol (Haldol):
Initial dose may range from 2-6 mg i.m (depending on age, weight & physical condition), ---> repeated in an hour if the patient remains agitated ---> as soon as patient is calm --> oral medication in liquid concentrate or tablet form should begin ---> Two daily oral doses should suffice, with two thirds of the dose being given at bedtime ---> To achieve the same therapeutic effect, the oral dose should be approximately 1.5 times the parenteral dose ---> effective total daily dose of haloperidol may range from 5-40 mg for most patients.
• Droperidol (Inapsine):
Available as an alternative intravenous formulation
Careful monitoring of the electrocardiogram may be prudent with this treatment (*)
• Phenothiazines should be avoided in delirious patients because these drugs are associated with significant anticholinergic activity.
• Second-generation antipsychotics:
Clinical trial experience with these agents for delirium is limited
Ziprasidone (Geodon) may not be appropriate in delirium management- because have an activating effect
Olanzapine (Zyprexa) is available for intramuscular (IM) use and as a rapidly disintegrating oral preparation
For patients with Parkinson's disease and delirium who require antipsychotic medications, clozapine or quetiapine have some support in the literature and are less likely to exacerbate parkinsonian symptoms. (*)

Insomnia:
• Best treated with benzodiazepines with short or intermediate half-lives (e.g., lorazepam[Ativan] 1-2 mg at bedtime)
• Benzodiazepines with long half-lives and barbiturates should be avoided unless they are being used as part of the treatment for the underlying disorder (e.g., alcohol withdrawal)


ECT:
- Routine consideration of ECT for delirium is not advised
- Case reports of improvement in or remission of delirious states caused by intractable medical illnesses


Treatment of Delirium in Parkinson's disease:

- Note: Antiparkinsonian agents are frequently implicated in causing a delirium
- Decreasing the dosage of the antiparkinsonian agent has to be weighed against a worsening of motor symptoms
- If the antiparkinsonian agents cannot be further reduced, or if the delirium persists after attenuation of the antiparkinsonian agents ---> Clozapine
- If patient is not able to tolerate clozapine or the required blood monitoring, alternative antipsychotic agents ---> Quetiapine (not been as rigorously studied as clozapine and may have parkinsonian side effects)