About 10% of Australians over the age of 70 have delirium at the time of admission to the hospital, and a further 8% will develop delirium while in hospital. The incidence of delirium is higher in certain hospital wings, with more than 30% of patients with delirium following hip or cardiac surgery (Delirium Clinical Care Standard | Australian Commission on Safety and Quality in Health Care, 2019). Delirium is defined as an cute impairment in the global cognitive function that develops over a short period of time and tends to fluctuate during the day. Delirium represents a decomposition of cerebral function in response to one or more pathological stressors. People with delirium have an increase risk of death, falls and have a greater chance of developing dementia. (Gual et al., 2018) in a study done in a subacute unit found that, dementia was one of the main risk factors for delirium and delirium itself led to poor clinical and functional outcomes. Another cause of delirium in the elderly is infection. (Kuswardhani & Sugi, 2017) found infection to be an important cause of delirium in elderly patients. In the elderly patients with infection, the a high IL-6 and sepsis have a strong relationship with the severity of delirium. Interleukin-6 (IL-6)is a protein that is produced by a number of cells, it helps regulate immune response, it can be elevated with inflammation, infection, autoimmune disorders, CV diseases, and some cancers (O’Reilly et al., 2013). Delirium can often be traced to one or more contributing factors, such as chronic illness, changes to metabolic imbalance, medication, infection , and drug intoxication or withdrawal (Top Four Evidence-Based Nursing Interventions for Delirium.: Library Search, 2017).
Delirium can also be considered a disorder of consciousness as experience is altered. During the state of delirium, delusions and hallucinations may occur as the patients experience their own alternate reality (Sanders, 2011). Delirium presents with a wide range of symptoms and a continuum of psychomotor behaviours. Hypoactive delirium is characterised by apathy, decreased responsiveness, and withdrawal. Hypoactive delirium tends to receive less clinical attention than hyperactive delirium. Like all deliriums it can happen in a variety of patients and settings, it can be more difficult to recognise and is associated with worst outcomes than hyperactive delirium. Hyperactive delirium is characterised by restlessness, agitation, and emotional liability. Because patient with hyperactive delirium are at increased risk of self-harm, they tend to be perceived as higher risk by clinical staff (Hosker & Ward, 2017).
Drugs have widely been associated with the development of delirium in the elderly and they represent the most common reversible cause of this condition. Knowing this is important because treatment of delirium is dependent on identifying the underlying cause. Medication known to increase the risk of delirium in the elderly include; anticholinergic, tranquilizers, pain killers, and narcotics. For example, in the elderly disopyramide which has a strong anticholinergic effect can induce delirium (Alagiakrishnan & Wiens, 2004). As people age, there is a general reduction in the renal clearance, sometimes even in normal doses medications such as digoxin can accumulate and cause delirium. Also, medications like diuretics can cause delirium due to dehydration and electrolyte imbalance. Another risk factor in the elderly, is polypharmacy, studies indicate that the number of medications the elderly take is a risk factor for delirium (Nikooie et al., 2019). This is because residents using a lot of medications tend to have a significant number of co-morbidities. Sometimes it is due to the way drugs interact in the body. For example, heart failure patients are at increased risk of delirium. Patients with heart failure have reduced metabolism due to hepatic congestion and reduced elimination of drugs caused by renal insufficiency. Also, in stroke and dementia patient there is an impairment of the blood brain barrier integrity. This allows more and more, potentially toxic drugs to reach the brain. Because of the relative increase in fat mass as people age, medications that have a high affinity to fat, tend to have increased volume of distribution. Which then affects how long it takes for half of the drug to be eliminated (Alagiakrishnan & Wiens, 2004).
Several global systems are thought to be involved in the development of brain dysfunction. There are several neurotransmitters believed to be involved in the development of delirium, these include; acetylcholine, serotonin, dopamine, and gammaaminobutyric acid. Areas of the body that are most sensitive to changes in the neurotransmitters are the cerebral cortex, striatum, substantia nigra, and thalamus (Ali et al., 2011). When there is a neurotransmitter imbalance through disease or psychoactive medication, thalamic dysfunction may lead to sensory overload and hyperarousal. For example, dopamine is responsible for regulating mood, behaviour and cognitive function. In general, a deficiency in dopamine causes extrapyramidal symptoms such as restlessness, muscle rigidity, and tremors. While an excess in dopamine is associated with a range of psychotic disorders. A deficiency or excess of dopamine in delirium may be associated with hypoactive or hyperactive subtypes of delirium (Smith et al., 2009).
Management of delirium requires a fast identification of the cause and good supportive care therapy. Pharmacological management of delirium is usually not needed and should never be used as the first line management (Delirium and Behaviourally Disturbed Older Patients – Management | Emergency Care Institute, 2017). Food and fluid intake should be given carefully, because the patient may be unwilling or physically not able to maintain a balanced intake. For individuals suspected of having alcohol toxicity or withdrawal, therapy should include multivitamins, especially thiamine. The environment should also be stable, quiet, well lit, and discourage daytime napping to aid night- time sleep. In addition, re-orientation techniques or memory cures such as calendar, large clocks, and family photos may also be helpful. The aim of nursing management for delirium is to maintain agitation at manageable levels and prevent the patient from becoming violent. And to also prevent the patient from harming themselves and others (Victoria State Government, 2020).
If nonpharmacological interventions and verbal de-escalations are not successful, use of medications may be necessary. Once’s prescribed these medications must be evaluated frequently, especially in people with dementia. All available antipsychotics and benzodiazepines are listed as potentially inappropriate, even at low doses. These medications may increase adverse effects such as prolonged sedation or paradoxical agitation in older patients (Shenvi et al., 2020). (Nikooie et al., 2019) in a systematic review on the use of antipsychotics for the management of delirium found that, there routine use for treatment of delirium in adult patient did not improve patient outcome. The study review further found that, even though there was little evidence for neurological harm, antipsychotics had a tendency for more frequent and potentially serious cardiac effects. When medications are used for agitation in delirium patients the aim is not sedation, but rather sufficient treatment for safe symptoms management (Shenvi et al., 2020).
Delirium V Dementia
In order to make a diagnosis of dementia, delirium must be ruled out. However, individuals with dementia are at increased risk of delirium and in some cases, they may have both (Dementia and Delirium, 2020).
This paper has covered what delirium is, the role the dopaminergic system has in the development of delirium and the effect certain medications, infections, and chronic illnesses have in the development of delirium in the elderly. The paper looks at some ways to manage delirium, both pharmacologically and non-pharmacologically. The paper ends by looking at some of the differences between delirium and dementia. It is important to remember that if delirium is suspected, seek medical help straight away.
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