Delirium: an overview of information

Delirium is an acute, transitory, usually reversible, fluctuating violation of attention, perception and level of consciousness. The causes leading to the development of delirium, can be almost any disease, intoxication or pharmacological effects. The diagnosis is established clinically, using clinical and laboratory and visualization studies to clarify the cause that led to the development of delirium. Treatment consists in correcting the cause that led to the delirious state, and maintenance therapy.

Delirium can develop at any age, but still more common in the elderly. At least 10% of elderly patients delivered to clinics have delirium; from 15 to 50% had delirium in previous hospitalizations. Delirium also often occurs in patients who are at home under the patronage of medical personnel. If delirium develops in young people, it is usually the result of the use of medications or the manifestation of any systemic life-threatening condition.

In DSM-IV, delirium is defined as "a disorder of consciousness and a change in cognitive processes that develop over a short period of time" (American Psychiatric Association, DSM-IV). Delirium is characterized by easy distraction of patients, violation of concentration of attention, memory disorder, disorientation, speech disturbance. These cognitive disorders can be difficult to assess because of the inability of patients to concentrate attention and rapid fluctuations in symptoms. Concomitant symptoms include affective disorders, psychomotor agitation or inhibition, perceptual disorders such as illusions and hallucinations. Affective disorders during delirium are highly variable and can be represented by anxiety, fear, apathy, anger, euphoria, dysphoria, irritability, which often succeed each other for a short time. Impairment of perception is especially often represented by visual hallucinations and illusions, less often they have auditory, tactile or olfactory character. Illusions and hallucinations often disturb patients and are usually described by them as sketchy, vague, dreamlike or nightmarish images. Confusion may be accompanied by behavioral manifestations such as pulling systems for intravenous injections and catheters.

Delirium is classified according to the level of wakefulness and psychomotor activity. The hyperactive type is characterized by pronounced psychomotor activity, anxiety, alertness, rapid excitability, loud and persistent speech. For hypoactive type, psychomotor slowness, calmness, detachment, weakening of reactivity and speech production are characteristic. In a "violent" patient, attracting the attention of others, delirium is diagnosed easier than in a "quiet" patient who does not bother other patients or medical personnel. Since delirium carries with it an increased risk of serious complications and death, it is difficult to overestimate the importance of timely recognition and adequate "quiet" delirium. On the other hand, in violent patients, treatment can be limited to suppressing the excitation with the help of pharmacological agents or by mechanically fixing the patient, and there is no appropriate examination that can establish the cause of delirium.

The cause of delirium can not be accurately determined by the level of activity. The level of activity of a patient during one episode may change or not fall into any of the above categories. Nevertheless, hyperactivity is more often observed with intoxication with anticholinergics, alcohol withdrawal syndrome, thyrotoxicosis, while hypoactivity is more typical for hepatic encephalopathy. These types are distinguished on the basis of phenomenology, they do not correspond to any specific changes in the EEG, cerebral blood flow or the level of consciousness. Delirium, in addition, is divided into acute and chronic, cortical and subcortical, anterior and posterior cortical, right and left cortical, psychotic and nonpsychotic. VDSM-IV delirium is classified according to etiology.

The significance of the problem of delirium

Delirium is an urgent health problem, as this very common syndrome can cause serious complications and death. Patients with delirium are hospitalized longer and are more often transferred to psycho-chronicle institutions. Behavioral disorders can interfere with treatment. In this condition, patients often refuse to consult a psychiatrist.

Delirium and forensic psychiatry

This is a state of darkened consciousness combined with confusion, disorientation, perhaps with delirium, bright hallucinations or illusions. This condition can have many organic causes. At the same time, in the basis of protection for medical reasons lies precisely this state of mind, and not what caused it. The commission of a crime in the state of organic delirium refers to extremely rare cases. The court's decision to send such a criminal to the appropriate service will depend on the clinical needs of the person. The choice of the protection option will also depend on the specific situation. It may be appropriate to apply for innocence because of a lack of intent, or to ask for a hospitalization order (or some other form of treatment) on the basis of a mental illness, or to claim (in very severe cases) insanity according to McNaughten's rules ).

[1], [2], [3]

Epidemiology of delirium

Among hospitalized patients, the incidence of delirium is 4-10% of patients per year, and the prevalence is 11-16%. By

According to one of the studies, most often postoperative delirium occurs in patients with hip fracture (28-44%), less often in patients undergoing hip replacement surgery (26%) and myocardial revascularization (6.8%). The prevalence of delirium largely depends on the characteristics of the patient himself and the hospital. For example, delirium is more often observed in hospitals where complex surgical interventions are performed, or specialized centers that are sent to especially severe patients. In regions with a higher prevalence of HIV infection, delirium is more common, caused by complications of HIV infection or its treatment. The prevalence of abuse of various psychoactive substances - another common cause of delirium - varies widely in different communities, which, along with the properties of the substances themselves and the age of the patients, significantly affects the frequency of delirium. Delirium was registered in 38.5% of patients over 65 who were taken to a psychiatric hospital. At the same time, delirium was detected in 1.1% of people over 55 who were registered with the Eastern Baltimore Mental Health Service.

In patients hospitalized in a psychiatric hospital from care facilities, delirium is more common (64.9%) than in patients who lived before hospitalization under normal conditions (24.2%). This is not surprising, since patients placed in care institutions are usually older and have more serious illnesses. Age-related changes in the pharmacokinetics and pharmacodynamics of drugs may partially explain the high incidence of delirium in the elderly. 

[4], [5], [6], [7], [8], [9], [10], [11], [12], [13]

What causes delirium?

Many states and drugs (especially anticholinergic, psychotropic and opioids) can cause delirium. In 10-20% of patients, the cause of delirium can not be established.

The mechanisms of the appearance of delirium have not been fully elucidated, but can be accompanied by reversible disturbances of redox metabolism of the brain, various changes in the metabolism of neurotransmitters and the production of cytokines. Stress and any circumstances that lead to the activation of the sympathetic nervous system, a decrease in parasympathetic influences, a violation of the cholinergic function contribute to the development of delirium. In elderly people, especially sensitive to a decrease in the cholinergic transmission, the risk of developing delirium increases. It is also impossible not to take into account, of course, the violation of the functional activity of the cerebral hemispheres and the thalamus and the decrease in the influence of the stem activating reticular formation.

Differential diagnosis of delirium and dementia

Symptom	Delirium	Dementia
Development	Sudden, with the possibility of determining the timing of onset of symptoms	Gradual and gradual, with an uncertain time of onset of symptoms
Duration	Days or weeks, but may be longer	Usually constant
Cause	Usually it is always possible to identify a causal relationship (including infection, dehydration, use or withdrawal of medications)	Usually there is a chronic brain disease (Alzheimer's disease, dementia with Levy bodies, vascular dementia)
Flow	Usually reversible	Slowly progressing
Severity of symptoms at night	Almost always more pronounced	Often more pronounced
Attention function	Significantly impaired	Does not change until dementia becomes severe
Severity of impaired consciousness	Varies from slowness to normal	Does not change until dementia becomes severe
Orientation in time and place	It can be different	Disrupted
Speech	Slow, often unrelated and inappropriate situation	Sometimes there are difficulties in the selection of words
Memory	Wobbles	Disrupted, especially at recent events
The need for medical care	Immediate	Required, but less urgent

Differences, as a rule, are significant and help to establish a diagnosis, but exceptions are possible. For example, traumatic brain damage occurs suddenly, but can lead to heavy, irreversible dementia: hypothyroidism can lead to slowly progressive dementia, which is completely reversible in treatment.

The causes of delirium

Category	Examples
Medicinal products	Alcohol, anticholinergic drugs, antihistamines (including diphenhydramine), antihypertensive, antiparkinsonics (levadopa), antipsychotics, spasmolytics, benzodiazepines, cimetidine, glucocorticoids, digoxin, hypnogenic drugs, muscle relaxants, opioids, sedatives, tricyclic antidepressants, restorative drugs
Endocrine disorders	Hyperparathyroidism, hyperthyroidism, hypothyroidism
Infections	Colds, encephalitis, meningitis, pneumonia, sepsis, systemic infections, urinary tract infection (UTIs)
Metabolic disorders	Violations of acid-base balance, changes in water-electrolyte balance, hepatic or uremic encephalopathy, hyperthermia, hypoglycemia, hypoxia, encephalopathy Wernicke
Neurological diseases	Post-contraction syndrome, condition after epileptic seizure, transient ischemia
Organic diseases of the nervous system	Brain abscesses, cerebral hemorrhages, cerebral infarction, primary or metastatic brain tumors, subarachnoid hemorrhage, subdural hematoma, vessel occlusion
Vascular / circulatory disorders (circulatory disorders)	Anemia, heart rhythm disturbances, heart failure, volley, shock
Vitamin deficiency	Thiamine, vitamin B 12
Cancellation Syndromes	Alcohol, barbiturates, benzodiazepines, opioids
Other reasons	Changes in the environment, prolonged constipation, prolonged stay in the intensive care unit (ICU), postoperative condition, sensory deprivation, sleep deprivation, urinary retention

Predisposing factors include CNS diseases (eg, dementia, stroke, Parkinson's disease), advanced age, decreased perception of the environment, multiple co-morbidities. The provoking factors include the use of more than 3 new drugs, infection, dehydration, immobility, malnutrition and the use of a urinary catheter. The recent use of anesthesia also increases the risk, especially in situations where the use of anesthesia has been prolonged and anticholinergic drugs have been used during surgery. Decreased sensory stimulation at night can be a trigger for the development of delirium in patients at risk. For elderly patients in intensive care units, the risk of delirium (psychoses of intensive care units) is especially high.

Delirium - Causes and pathogenesis

Diagnosis of delirium

The diagnosis is established clinically. All patients with any cognitive impairment need a formal assessment of their mental status. First of all, attention must be paid attention. Simple tests include repeating the names of 3 objects (objects), a digital account (the ability to repeat 7 digits in a straight line and 5 digits in the reverse order), naming the days of the week in a forward and reverse order. Inattention (the patient does not perceive commands or other information) must be distinguished from the decrease in short-term memory (that is, when the patient perceives information, but quickly forgets it). Subsequent cognitive testing is useless in patients who do not record information.

After a preliminary assessment, standard diagnostic criteria are used, such as the Diagnostic and Statistical Manual for Mental Disorders (DSM) or the Confusion Status Assessment Method (CAM). Criteria of diagnosis are acute developmental disturbance of thinking with fluctuations in day and night time of attention disturbance (violation of focus and attention), plus additional signs: according to DSM - impaired consciousness; by SEL - or changes in the level of consciousness (ie, excitement, drowsiness, hysteria, coma), or disorganized thinking (ie jumping from one thought to another, irrelevant talk, an illogical stream of thoughts).

A survey of family members, guardians and friends can determine if there has been a change in the mental state recently, or they occurred earlier. Anamnesis collection helps to separate psychiatric disorders from delirium. Psychiatric disorders, unlike delirium, almost never cause inattention or fluctuations in consciousness, and their onset, as a rule, is subacute. The history should also include clarification of the use of alcohol and illicit drugs, OTC, clarification of the list of prescribed (used) medicines, special attention should be paid to taking medications that have an effect on the central nervous system, drug interactions, discontinuation of drugs, dosage changes, including overdose.

In case of physical examination, attention should be paid to identifying signs of CNS trauma or infection (including fever, meningism, symptoms of Kernig and Brudzinsky). Tremor and myoclonus indicate uremia, hepatic insufficiency, or drug intoxication. Ophthalmoplegia and ataxia testify to the syndrome of Wernicke-Korsakov. Focal neurological symptoms (including cranial nerves paresis, motor or sensory deficiency) or edema of optic discs indicate organic (structural) damage to the CNS.

The examination should include the determination of blood glucose level, assessment of thyroid function, toxicological screening, assessment of the level of electrolytes in the blood plasma, urine analysis, microorganism culture (especially in urine), cardiovascular and lung examination (ECG, pulse oximetry, chest X-ray ).

CT or MRI should be performed if clinical studies confirm CNS damage or in cases where the initial examination does not reveal the causes of delirium, especially in patients older than 65 because they are most likely to have primary CNS damage. Lumbar puncture can be indicated for the exclusion of meningitis, encephalitis or CAA. If it is assumed that the patient develops an unconvulsive status epilepticus, which is rare (based on anamnesis, hardly noticeable motor twitching, automatism or the presence of permanent but less intense manifestations of drowsiness and confusion), EEG should be performed. 

Delirium - Diagnosis

[14], [15], [16], [17], [18], [19],

Treatment of delirium

Treatment consists in eliminating the cause and eliminating the provoking factors (i.e., stopping the use of medications, the liquidation of infectious complications), providing patient support to family members, correcting anxiety to ensure patient safety. Adequate drinking and nutrition should be provided, in case of nutritional deficiencies, avitaminosis (including thiamine and vitamin B ₁₂ ) should be corrected .

The environment should be stable, calm, friendly and include visual reference points (in the form of a calendar, hours, family photos). Regular patient orientation in the environment and patient insurance with the help of medical personnel or family members can also be helpful. Sensory deficiency in patients should be minimized (including regular replacement of batteries in the hearing aid, encouragement of patients who need glasses and hearing aids when using them).

The approach to treatment should be multidisciplinary (involving a doctor, an occupational therapist, nurses, a social worker), it should include a strategy of expanding mobility and range of motor activity, treating pain and discomfort, preventing skin damage, alleviating incontinence problems and minimizing the risk of aspiration.

Excitation of the patient can be dangerous for him, caring for him and medical personnel. The simplification of the drug regimen and the refusal of intravenous administration of drugs, the Foley catheter and the restriction of activity (especially when the patient is in hospital for a long time) can prevent the patient from being excited and reduce the risk of damage. However, in some circumstances, limiting physical activity can prevent damage to the patient and his environment. Restriction of patient activity should only be used under the supervision of specially trained personnel, which should be replaced at least every 2 hours to prevent damage and eliminate them as soon as possible. The use of staff members of hospitals (nurses) as permanent observers can help to avoid the need to limit physical activity.

Drugs, usually haloperidol in low doses (0.5 to 1.0 mg orally or intramuscularly), reduce anxiety and psychotic symptoms, but do not correct the underlying cause of the disease and may contribute to the prolongation or exacerbation of delirium. Alternatively, atypical second-generation antipsychotics (including risperidone 0.5 to 3.0 mg orally every 12 hours, olanzipine at a dose of 2.5-15 mg orally once daily) can be used instead of these, which have fewer ekstra-pyramidal side effects , but with prolonged use in the elderly, they increase the risk of stroke.

These drugs are usually not administered intravenously or intramuscularly. Benzodiazepines (including lorazepam in a dose of 0.5-1.0 mg) have a faster onset effect (5 min after parenteral administration) than antipsychotics, but usually lead to worsening disorientation and sedation in patients with delirium.

In general, both antipsychotics and benzodiazepines are equally effective in treating anxiety in patients with delirium, but antipsychotics have fewer side effects. Benzodiazepines are more preferable in patients with delirium to eliminate the sedative withdrawal syndrome and in patients who tolerate antipsychotics badly (including Parkinson's disease, dementia with Lewy bodies). Dosage of these drugs should be reduced as soon as possible.

Delirium - Treatment

Forecast of delirium

Morbidity and mortality are higher in patients who are hospitalized with delirium, and in those who have developed delirium during hospitalization.

Some causes of delirium (eg, hypoglycemia, intoxication, infection, iatrogenic factors, drug intoxication, electrolyte imbalance) are resolved fairly quickly during treatment. However, recovery may be slow (for days and even weeks or months), especially in the elderly, as a result of prolonged hospitalization, due to the increase in complications, increased costs of treatment, and continued disadaptation. Some patients after the development of delirium do not fully regain their status. Over the next 2 years, the risk of cognitive and functional abnormalities increases, transforming them into organic changes and increasing the risk of death.

The flow and outcome of delirium

If delirium develops in a hospital, then in about half of cases it occurs on the third day of hospitalization, and at the time of discharge from the hospital, its manifestations may persist. On average, for every sixth patient, delirium symptoms persist for 6 months after discharge from the hospital. At the subsequent two-year observation in such patients there was a higher risk of death and faster loss of domestic independence.