Dealing with delirium in older people
Last scene of all, That ends this strange eventful history, Is second childishness and mere oblivion, Sans teeth, sans eyes, sans taste, sans everything
As You Like It (2.7.143-70)
The Sri Lankan population is aging. The proportion of population over 60 years of age is expected to increase from 12.5% to 16.7% in 2021, and by 2041, one out of every four persons is expected to be elderly. The prevalence of mental disorders, particularly dementia, increases with age leading to a disproportionate increase in the demand for psychiatric care for the elderly.
The psychiatric disorders of the elderly have some special features but do not differ greatly from psychiatric disorders in younger adults. It is the needs of the elderly psychiatric patients that are different.
Until the mid-1950s even in Europe there were only a few scientific studies on mental disorders of the elderly. It was Professor Sir Martin Roth, one of the great psychiatrists of the last century who made a significant contribution to the study of psychiatric problems in old age. As the professor of psychiatry at Newcastle University he pioneered studies into dementia that still continue today. He also showed that many elderly patients lying neglected in hospital labelled as incurable were suffering from treatable conditions such as depression or delirium.
In this article I will be discussing about delirium or acute confusional state as it was called in the past. Delirium is a syndrome of acute cognitive impairment occurring in the context of physical illness. The onset of delirium is typically sudden and lasts for one to two weeks. It is not a disease in itself but a reaction of the brain to an underlying medical problem. It resolves when the underlying condition subsides. The cognitive problems recover after physical recovery.
Impairment of consciousness is the classic sign of delirium. But it is often fluctuant and not always easy to discern.
The degree of impairment may range from difficulty in maintaining attention to unconsciousness. The milder degrees are more common and easily missed. Careful testing for disorientation is essential for early diagnosis. Perceptual disturbance in the form of illusions (distortion of sensory perception) and hallucinations (perceptions without a sensory stimulus) are seen. Visual hallucinations predominate and are strongly suggestive of delirium. These hallucinations are usually frightening and lead to agitation. Logical thinking is impaired in delirium. Combined with attention deficits this results in the characteristic incoherent muttering of a patient in delirium. Impairment of memory, which is partly due to attention deficit, is a definitive sign in delirium.
There are two types of delirium – the agitated type and the lethargic type. The lethargic type is more common in the elderly and is easily missed. The patient may alternate between the two types. Disturbances of the sleep- wake cycle are common, and there may be inversion of the normal sleep- wake cycle leading to night time wandering and agitation and daytime drowsiness.
Apathy is common but a wide range of emotions including anxiety, depression, fearfulness and perplexity may be present. There are many causes for delirium. Children and the elderly have a higher risk of delirium.
Dementia is the main risk factor and may be as high as 30% (It is important to look for dementia in all patients who recover from delirium). Other forms of brain damage such as stroke, Parkinson’s disease and head injury also predispose to delirium. Visual impairment and deafness reduce sensory input, a risk factor for perceptual disturbances of delirium. Social isolation leading to sensory deprivation and sudden moves to new surroundings also increase the risk of delirium. Sleep deprivation is a risk factor and insomnia an early sign of delirium.
Medicines are an important cause. The drugs that affect the central nervous system increase the risk of delirium. Opioid analgesics, long acting benzodiazepines, and psychoactive medications pose the highest risk. Environmental changes such as admission to hospital especially intensive care units, increase risk.
Medical problems such as dehydration, common infections such as pneumonia, and urinary tract infection, lack of nutrition during medical and surgical care, and limitation of movement by physical or medical restraints, and even constipation can precipitate delirium in the elderly.
Delirium occurring after surgery is common. Emergency surgical procedures carry a higher risk than elective procedures. Some surgeries such as coronary artery bypass graft and hip replacement carry a particularly higher risk.
Delirium is a syndrome and the underlying cause should be identified and treated. Because there are many causes several treatments may have to be given together. History, examination and investigations should guide these treatments. While looking for specific causes the following general measures are useful.
All non-essential medicines should be stopped. Medicines started just before the onset of delirium and those likely to cause cognitive side-effects should take priority. Medicines that cannot be stopped should be reduced or substituted with less harmful alternatives. Surroundings should be adjusted to improve orientation, sensory input and the sleep- wake cycle. Orientation can be improved by repeated reorientation (telling the patients the time, place, and identifying the people around), clocks, calendars and message boards.
Simple interventions such as provision of eye glasses, hearing aids are useful. Often the psychiatrist is called in when a patient in delirium becomes restless in a medical ward. It is important to remember that treatment of restless behaviour does not amount to treatment of the delirium. As mentioned earlier the lethargic type of delirium is more common in the elderly and likely to be missed.
It is important to diagnose delirium early. It is a medical emergency as the mortality is high. The principle object of the treatment of delirium is to treat and manage the underlying cause. Management of associated agitation is necessary but should not prevent the doctor seeking vigorously for a cause.