Delirium Flashcards
What is delirium?
Delirium is an acute , transient , global organic disorder of CNS functioning resulting in impaired consciousness and attention . There are different types of delirium: hypoactive , hyperactive and mixed depending on the clinical presentation.
Briefly differentiate between hypoactive, hyperactive and mixed delirium
Hypoactive (40%)
- Lethargy
- ↓ motor activity, apathy and sleepiness
- It is the most common type of delirium but often goes unrecognised
- Can be confused with depression
Hyperactive (25%)
- Agitation, irritability, restlessness and aggression
- Hallucinations and delusions prominent
- May be confused with functional psychoses
Mixed (35%)
- Both hypoand hyperactive subtypes co-exist and therefore there are signs of both
Briefly describe the pathophysiology and aetiology of delirium
Note: HE IS NOT MAAD
Delirium has a number of causes; however, most causes of delirium are multifactorial , each of which may be important at different time points of the illness. The causes can be remembered using the mnemonic ‘HE IS NOT MAAD’:
- Hypoxia
- Respiratory failure, myocardial infarction, cardiac failure and pulmonary embolism
- Endocrine
- Hyperthyroidism, hypothyroidism, hyperglycaemia, hypoglycaemia and Cushing’s
- Infection
- Pneumonia, UTI, encephalitis and meningitis
- Stroke and other intracranial events
- Stroke, raised ICP, intracranial haemorrhage, space-occupying lesions, head trauma, epilepsy (post-ictal) and intracranial infection
- Nutritional
- ↓ Thiamine, ↓ nicotinic acid and ↓ vitamin B12
- Others
- Severe pain, sensory deprivation (for example leaving the person without spectacles or hearing aids), relocation (such as moving people with impaired cognition to unfamiliar environments) and sleep deprivation
- Theatre (postoperative period)
- Anaesthetic, opiate analgesics and other post-operative complications
- Metabolic
- Hypoxia, electrolyte disturbance (e.g. hyponatraemia), hypoglycaemia, hepatic impairment and renal impairment
- Abdominal
- Faecal impaction, malnutrition, urinary retention and bladder catheterisation
- Alcohol
- Intoxication and withdrawal (delirium tremens)
- Drugs
- Benzodiazepines, opioids, anticholinergics and anti-parkinsonian medications and steroids
How common is delirium?
Delirium occurs in about 15– 20% of all general admissions to hospital.
Who is commonly affected by delirium?
Delirium is the most common complication of hospitalization in the elderly population.
Up to two-thirds of delirium cases occur in inpatients with pre-existing dementia.
15% of >65 s are delirious on admission to hospital.
What are the risk factors for delirium?
- Older age ≥65
- Dementia
- Renal impairment
- Sensory impairment
- Multiple co-morbidities
- Recent surgery
- Physical frailty
- Male sex
- Previous episodes
- Severe illness (e.g. CCF)
What are the clinical features of delirium?
Note: DELIRIUM
Delirium has an acute onset and takes a fluctuating course (often worse at night). Other features include:
- Disordered thinking
- Slowed, irrational and incoherent thoughts
- Euphoric, fearful, depressed or angry
- Language impaired
- Rambling speech, repetitive and disruptive
- Illusions, delusions (transient persecutory or delusions of misidentification) and hallucinations (usually tactile or visual).
- Reversal of sleep-wake pattern
- I.e. may be tired during day and hyper-vigilant at night
- Inattention
- Inability to focus and clouding of consciousness
- Unaware/disoriented
- Disoriented to time, place or person
- Memory deficits
Briefly describe the ICD-10 Criteria for diagnosing delirium
- Impairment of consciousness and attention
- Global disturbance in cognition
- Psychomotor disturbance
- Disturbance of sleep-wake cycle
- Emotional disturbances
Briefly differentiate between delirium and dementia
Note: sleep wake cycle, attention, arousal, autonomic features, duration, delusions, course, consciousness level, hallucinations, onset and psychomotor activity
What is hypoactive delirium commonly misdiagnosed as?
Delirium may be unrecognized by doctors and nurses in two-thirds of people. Healthcare professionals often do not recognise delirium and may misdiagnose hypoactive delirium as depression. Remember to always consider delirium in a person, particularly an elderly person who is apathetic, quiet or withdrawn.
Briefly discuss the examination of a patient with delirium
Before or during a history, a thorough physical examination should be performed:
- ABC (Airway, B reathing and Circulation)
- Conscious level (use AVPU or GCS) and vital signs e.g. oxygen saturations, pulse, blood pressure, temperature and capillary blood glucose
- Nutritional and hydration status
- Cardiovascular examination
- Respiratory examination
- Abdominal examination (check for urinary retention and rectal exam for faecal impaction)
- Neurological examination (including speech)
Briefly describe the MSE of delirium
Appearance and behaviour: Hypo- or hyper-alert. Agitated, aggressive, purposeless behaviour.
Speech: incoherent and ambling.
Mood: low mood, irritable and anxious. Mood is often labile.
Thought: confused, ideas of reference and delusions.
Perception: illusions, hallucinations (mainly visual) and misinterpretations.
Cognition: disoriented, impaired memory and reduced concentration/attention.
Insight: poor.
What investigations should be ordered for delirium?
Routine investigations
- Urinalysis (UTI)
- Bloods:
- FBC (infection)
- U&Es (electrolyte disturbance)
- LFTs (alcoholism, liver disease)
- Calcium (hypercalcaemia)
- Glucose (hypo-/hyperglycaemia)
- CRP (infection/inflammation)
- TFTs (hyperthyroidism)
- B12, folate and ferritin (nutritional deficiencies)
- ECG (cardiac abnormalities, acute coronary syndrome)
- CXR (chest infection)
- Infection screen
- Bood culture (sepsis)
- Urine culture (UTI)
Investigations based on history and examination
- ABG (hypoxia)
- CT head (head injury, intracranial bleed, CVA)
- Lumbar puncture (meningitis)
- EEG (epilepsy)
Diagnostic questionnaire (helps with diagnosis but also monitoring)
- Abbreviated Mental Test (AMT)
- Quick easy tool
- Confusion Assessment Method (CAM)
- Usually performed after AMT
- Mini-Mental State Examination (MMSE)
Briefly differentiate between the Abbreviated Mental Test and Confusion Assessment Method (CAM)
What are the 4 principles of managing delirium?
- Treat the underlying cause
- Reassurance and re-orientation
- Provide appropriate environment
- Managing disturbed, violent or distressed behaviour
