Delirium is an acute organic mental disorder that is characterized by impairment of consciousness, disorientation, and disturbance in perception which occurs rapidly within hours to days. Delirium causes disturbances in mental abilities that result in confused thinking and reduced awareness of the environment.

Delirium affects the cognition of the individual. Cognition includes several specific functions, such as the acquisition and use of language, the ability to be oriented in time and space, and the ability to learn and solve problems. It includes judgment, reasoning, attention, comprehension, concept formation, planning, and the use of symbols, such as numbers and letters used in mathematics and writing.

Delirium is of three types −

  • Hypoactive delirium is characterized by inactivity or reduced motor activity, sluggishness, and abnormal drowsiness.

  • Hyperactive delirium is characterized by restlessness, agitation, rapid mood changes, or hallucinations.

  • Mixed delirium includes both hyperactive and hypoactive symptoms. The person may quickly switch back from hyperactive to hypoactive states.

Various causes such as vascular conditions, infections, certain medicines, trauma, and electrolyte imbalance are known to result in delirium

The diagnosis of delirium and its underlying causes is based on the history, presentation, nervous system evaluations, CSF analysis, EEG, imaging tests, blood tests like CBC with ESR, blood grouping, urine examination, and serum electrolytes.

Treating delirium is important, as it can become life-threatening. Treatment options include treating the underlying cause. Sedatives such as benzodiazepines may be used to calm the patient, while antipsychotic medications may be used to control hallucinations and delusions.

Delirium: Causes

Various factors play an important role in the development of Delirium. The following are the important causes of developing delirium −

  • Vascular causes such as hypertensive encephalopathy and intracranial hemorrhage.

  • Various Infections such as Encephalitis, and meningitis

  • Neoplastic diseases such as space-occupying lesions

  • Fever and acute infection, particularly in children

  • Exposure to various toxins

  • Malnutrition or dehydration in children

  • Certain medications can trigger delirium, including painkillers, benzodiazepines, opioids, anticholinergics, anti-allergics, and anti-convulsant medicines

  • People with Sleep deprivation for a long duration or severe emotional distress

  • Following major Surgeries or other medical procedures that include anesthesia

  • Following traumatic injuries in patients having subdural and epidural hematoma, contusion, laceration, and heatstroke.

  • Vitamin deficiency such as thiamine

  • Endocrine and metabolic causes include diabetic coma and shock, uremia, myxedema, hyperthyroidism, and hepatic failure

  • Heavy metals such as lead, manganese, mercury, carbon monoxide, and toxins

  • Decrease in the oxygen supply to the brain in conditions like anemia, pulmonary or cardiac failure

Delirium: Symptoms

Symptoms of delirium usually begin over a few hours or a few days and often fluctuate throughout the day, and there may be periods of no symptoms. Symptoms tend to be worse during the night when it’s dark and things look less familiar. Patients with delirium mainly present with the following symptoms that include −

  • The patient has difficulty staying focused on a topic or switching topics and gets stuck on an idea rather than responding to questions or conversation

  • The patient is easily distracted by unimportant things and is being withdrawn, with little or no activity or little response to the environment

  • Poor thinking skills

  • The patient has poor memory, particularly of recent events

  • Disorientation to time place and person

  • Difficulty speaking or recalling words

  • Rambling or talking nonsense things

  • Face difficulty in understanding what others are talking

  • Difficulty reading or writing

  • Behavior changes such as Hallucinations, restlessness, agitation, calling out, making other sounds, being quiet and withdrawn, slowed movement or lethargy, disturbed sleep habits, reversal of night-day sleep-wake cycle

  • Emotional disturbances such as the individual being either anxious, scared, or depressed., Irritable or very excited sometimes. The mood shifts are rapid and unpredictable

  • Disturbance of the sleep-wake cycle, the patients find difficulty in falling asleep, total sleep loss, daytime drowsiness, and disturbing dreams or nightmares.

Delirium: Risk Factors

Several factors play an important role in the development of delirium which includes −

  • Older age group people are at more risk

  • Patients with a history of brain disorders such as dementia, stroke, or Parkinson’s disease

  • History of previous delirium episodes

  • Certain Infection

  • Certain Medications like pain killers, anti-psychotics and anticonvulsants

  • Individuals with visual or hearing impairment

  • Patients with multiple medical problems

  • Bone fracture

Delirium: Diagnosis

The diagnosis of delirium is mainly done based on history and some of the tests may be required for confirmation and to rule out underlying causes

  • History of symptoms, head injury, and meningitis should be asked for

  • Mental status assessment and neurological exams should be done. That includes checking vision, balance, coordination, and reflexes which help to determine if a stroke or another neurological disease is causing the delirium.

  • Tests for memory such as immediate, recent, and remote should be checked

  • Serum electrolyte to check for metabolic imbalance

  • Electroencephalography to check the electrical activity in the brain

  • Blood tests such as complete blood count, ESR, blood grouping

  • CSF analysis to look for meningitis

  • Urine examination

  • Radiological examinations such as X-ray, CT scan, and MRI are advised

  • Brain biopsy may be required in required some patients

Delirium: Treatment

The treatment is based on the severity of the symptoms. Your doctor may advise conservative or surgical treatment.

Conservative Treatment

Conservative treatment includes −

  • The mainstay of the treatment for delirium includes treating the underlying medical condition which is causing the delirium. This may involve antibiotics for an infection, discontinuing a medication causing delirium, or treating metabolic or electrolyte imbalances.

  • Symptomatic treatment should be done. Treating the symptoms such as agitation, hallucinations, or other behavioral symptoms with antipsychotic medicines is required. Sedatives such as benzodiazepines may be used to calm the patient.

  • Supportive care is important for these patients. These patients require close monitoring and supportive care to prevent complications and ensure their safety.

  • Patients with delirium require close monitoring and follow-up care to ensure that their symptoms are improving and that they are not experiencing any complications.

Surgical Treatment

Surgical treatment may be required in some cases to treat the underlying cause which is causing delirium.

Delirium: Prevention

Some of the measures taken can help to prevent delirium to a certain extent include −

  • Underlying medical conditions should be treated adequately

  • Avoid the medicines that may cause delirium

  • A good amount of sleep

  • A healthy balanced diet containing balanced vitamins and micronutrients

  • Adequate hydration with plenty of water

  • Providing appropriate sensory stimulation such as natural light, music, and engaging activities may help prevent delirium.

  • Family care and support

  • Early recognition and management of delirium are important to prevent complications.

  • The patient should be under close monitoring to prevent the patient from self-harm

  • Regular follow-ups can help to identify the recurrence rate


Delirium is a condition in which the consciousness, orientation, and perception of an individual are altered. The patient is confused, his/her thinking capacity is affected and talks about unrelated things, faces difficulty in remembering things, and is disoriented to time, place, and person. Various causes can result in developing delirium such as vascular conditions, infections, certain medicines, trauma, and electrolyte imbalance. The patient may be agitated or depressed.

The condition is diagnosed based on the symptoms, clinical examination of the nervous system, memory tests, and by observing the patient’s behavior. Investigations like imaging tests, CSF analysis, blood tests, and urine examinations are required to look for the underlying causes. Treatment mainly involves treating the underlying cause, treating the symptoms accordingly, and supportive care. The condition can be prevented by avoiding the triggering factors and medicines, adequate sleep and hydration, adequate treatment of their health problems, and by regular health check-ups.

Dr. Durgesh Kumar Sinha
Dr. Durgesh Kumar Sinha


Updated on: 18-Apr-2023


Kickstart Your Career

Get certified by completing the course

Get Started