Delirium and Dementia

When elderly people develop agitation or acute confusion during or after an illness, after undergoing surgery or after being admitted to a hospital, delirium should be suspected. Delirium and dementia are both altered cognitive states of mind but delirium is acute onset while dementia is of chronic onset.

For the diagnosis of delirium, an algorithm called the Confusion Assessment Method (CAM) can be used. This contains four parameters and the diagnosis of delirium requires both items 1 and 2 AND either 3 or 4.
1. Acute onset and fluctuating course of the altered behaviour
2. Inattention - unable to focus attention on what is being said and easily distractable
3. Disorganised or irrelevant or illogical thinking as evident from what the person says. Delusions and hallucinations may be evident from what the patient says.
4. Altered level of consciousness - may be hyperalert (vigilant) or lethargic and drowsy.

When delirium is diagnosed, it is necessary to try and understand what provoked it. Intracranial diseases like strokes, seizures, infections and injuries may be responsible. In older people it is usually extracranial conditions that precipitate delirium. Any kind of infections like chest or urine infections, for example, can provoke delirium. Metabolic factors, hypoxia, drugs and alcohol as well as stress can provoke it too. Being in an unfamiliar environment is also often a trigger for delirium. The pneumonic DELIRIUM can be used as a check list for evaluating delirium where:
D= drugs, E=electrolyte imbalances, L= lack of needed medicines, I= infection, R=reduced sensory input with poor hearing and poor vision being important, I= intracranial disorders, U=urinary retention and fecal retention, and M=myocardial and pulmonary disorders.

Typically people with delirium are considered to be hyperactive and agitated but this is not true. Patients with delirium can also appear hypoactive and lethargic. The way delirium presents depends on the balance between cholinergic (acetylcholine) and dopaminergic(dopamine) neuronal activity in the brain. Agitated delirium can look like a manic psychiatric episode while subdued delirium can look like depression.

In trying to prevent delirium from developing in elderly people,
1. Pay attention to see that they get enough sleep and an adequate diet. Ensure that they do not develop dehydration.
2. Be careful about starting or suddenly stopping drugs that cross the blood brain barrier like sedatives and antidepressants.
3. Keep them in familiar environments as far as possible.
4. When admitted to hospitals, try to orient them to their surroundings, enable them to get up and walk as soon as possible, ensure that they drink enough water and encourage them to use glasses and hearing aids wherever required.
5. Use non-narcotic analgesics like paracetamol instead of morphine if possible.
6. Avoid physical restraints as much as possible

When agitation or restlessness due to delirium becomes unmanageable with soothing words and gentle reassurances, drug therapy may be needed. Drugs that can be useful are haloperidol, risperidone or lorazepam, all in low doses to start with.

References:
1. Delirium in hospitalized patients (NEJM)
2. Elderly care medicine, Lecture notes 8th Edition (John Wiley & Sons, 2012)

The term dementia indicates a syndrome, not a specific disease. Unlike delirium, it is not of acute onset. The syndrome of dementia can be broadly divided into two broad categories - cortical dementia and subcortical dementia according to the region of the brain that shows the predominant abnormalities. The commonest form of dementia in the elderly is Alzheimer's disease and it is a form of cortical dementia. The prevalence of dementia increases with age - from about 2% above age 65 years to about 20% above age 80 years according to statistics from UK.

Those with cortical dementia (which includes Alzheimer's disease, vascular dementia, fronto-temporal dementia and dementia with Lewy bodies), have a few common clinical features that have been described as the 4 As - Amnesia (they tend to forget things and their short term memory is bad), Aphasia (they cannot express their ideas well in language), Agnosia (they often mistake objects and persons around them), and Apraxia (they have difficulty in following the steps for doing usual tasks).

The suspicion of dementia often arises because of the history of memory loss and behavioural changes. The diagnosis is often confirmed by using tests of mental ability like the Mini Mental Scale Examination or the Alzheimer's disease Assessment Scale (Cognitive). Whether the dementia is due to Alzheimer's disease or another disease will need to be determined by appropriate tests including imaging studies. The pathological hallmark of Alzheimer's disease in the brain is the presence of abnormal protein deposits called beta-amyloid (seen extracellularly) and neuro-fibrillary tangles containing tau protein (within the neurons). The amyloid hypothesis of Alzheimer's disease states that reduced clearance of normally produced beta-amyloid clogs the cellular machinery of the brain and progressively damages neuronal circuits resulting in dementia.

Memory loss is the defining characteristic of Alzheimer's disease. Some degree of memory loss is also seen with ageing and in the condition called mild cognitive impairment. The important thing to know about these conditions is that the memory loss here is not severe enough to affect activities of daily living.

In managing patients with dementia, it is necessary to provide patients with strategies to cope with their memory loss like diaries and reminder alarms. Their hearing and vision must be corrected if defective. Advice must be given regarding driving and other legal matters like advance directives. Medication for improving cholinergic transmission in the brain (drugs like donepezil, galantamine and rivastigmine) can be considered for mild (MMSE score 21 to 26) and moderate (score 10 to 20) forms of Alzheimer's disease. A drug called memantine that helps to prevent glutamate-induced neurotoxicity is available for treatment of moderate to severe Alzheimer's disease. Caution must be used before prescribing antipsychotics for patients with challenging behaviours and dementia because many of these drugs have adverse cardiovascular side effects and can adversely affect cognition and alertness. It is always good to do a functional assessment (antecedent-behaviour-consequence) before prescribing medication for challenging behaviours in dementia.

In trying to prevent Alzheimer's disease, we need to recognise risk factors that lead to the disease: increasing age, head injury, elevated homocysteine levels, obesity, smoking, hypertension and diabetes. The disease is more common in females, those with reduced physical and mental activity. The likelihood of developing dementia before the age of 60 years increases in those with the gene called APOE epsilon 4. Anxiety, depression and sleep disturbances are often seen in dementia patients and, because these may precede the diagnosis of dementia, there is speculation regarding the cause and effect relationship between them and dementia. Currently some of the accepted ways of trying to prevent dementia include advice to get adequate physical activity, intellectual stimulation, social interactions (avoid loneliness), 7 to 8 hours of sleep everyday, good control of all cardiovascular risk factors like diabetes, hypertension and elevated cholesterol, stop smoking, folic acid to reduce elevated homocysteine levels, enough fruits and vegetables in diet and the ingestion of turmeric for its anti-inflammatory properties.


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