Session Fourteen (Delirium) Flashcards
Which surgical procedures are most strongly associated with the development of delirium?
Cardiac surgery and hip replacements.
On which wards is it most important to look out for delirium?
ICU (has highest rates)
Geries
Surgical
What % of delirium cases go unnoticed
12-35%
What are the main negative outcomes associated with delirium?
Increased risk of DEATH 6 month after leaving hospital:
- 2-4x if D in ICU
- 1.5x if D on another medical ward
Increased risk of cognitive impairment generally, but a 9x increase in relative DEMENTIA risk
Why does developing delirium in hospital increase risk of death 6 months after leaving hospital?
Delirium causes…
- Immobilisation
- Increased medication use
these then increase risk of…
- DVT/PE
- Ulceration
- Falls
- UTIs
- Poor hydration and nutrition
- Aspiration pneumonia
All of which are associated with increased mortality in the elderly
Why does developing delirium in hospital increase chances of becoming cognitively impaired or developing dementia?
Still sort of unclear, but probably due to the disease processes that occur during delirium, such as:
- Neurotoxicity
- Inflammation
- Neuronal damage
- Acceleration of dementia pathology
Furthermore, if anaesthetics use is what caused the delirium you are likely to see accelerated dementia pathological processes
What are the states of alertness, and where does delirium fit in these?
- Alertness
- Somnolence (light stimulation required to make them fully alert)
- Stupor (high level of stimulation required to make them fully alert)
- Coma (no level of stimulation makes them alert)
Delirium falls in the space between alertness and somnolence, but importantly fluctuates between being nearly alert and nearly somnolent.
Outline the alertness system of the brain, and roughly how does it relate to delirium?
Two important pathways to remember:
- Two nuclei in the brain stem (the LDT and PPT) use ACh to stimulate the thalamus, which in turn stimulates the cortex
- Independently of this, a number of midbrain nuclei (e.g. the vPAG, LH, TMN, and Raphe nuclei) stimulate the cortex using GABA and Glutamate (monoamines).
These two pathways are responsible for most of what we’d consider consciousness, it is believed disruption to these pathways is the cause of delirium.
What are some predisposing factors for the development of delirium?
- Older age (70+)
- Alcohol abuse
- TIA and stroke
- Functional impairment
- Sensory impairment
- Dementia (and other forms of cog impairment)
What are some precipitating factors for the development of delirium?
- Drugs
- Alcohol or drug withdrawal
- Infection (UTI or res most common)
- Epilepsy
- Head trauma
- Multifocal and diffuse brain disease
- Metabolic dysfunction
What drugs can cause delirium?
3 broad categories:
- Psychotropics (opioids, benzos)
- Anticholinergic (TCAs, bronchodilators, antihistamines, antispasmodics)
- Randoms (antihypertensives, antiarrhythmics, steroids, chemo)
What metabolic disturbances are associated with the development of delirium?
- Acid base imbalance
- Any electrolyte imbalance
- Hypoxia
- Hypercapnia
- Hypoglycaemia
- Organ failure
- Endocrine
- Wernicke’s
- Vitamin B deficiency
Briefly, what causes delirium (from a neurology perspective)?
- Global disturbance of the ascending arousal systems
- Caused by multi-factorial predisposing and precipitating factors
Who are at greatest risk of delirium?
- Elderly
- Young (often forgotten about)
- Those with pre-existing cognitive impairment
What are the main clinical features of delirium?
Acute onset of:
Key Two (for diagnosis) =
- Disturbance of Attention
- Disordered thinking
Others:
- Psychomotor disturbance
- Emotional disturbance
- Memory impairment
- Sleep-wake disturbance
- Perceptual distortion
