A brain condition that strikes more than 100,000 Australians each year - resulting in episodes of extreme confusion, terror and paranoia - has been declared a "national emergency" by medical experts.
They are calling for a comprehensive government response into delirium - a sudden, severe episode of confusion and impaired thinking that causes 10 per cent of dementia cases and 900 deaths in Australia each year.
The first Australian study of the burden of this disorder, "The economic impact of delirium in Australia: a cost of illness study", published in BMJ Open, says even though the condition is common, there are no approved treatments available anywhere in the world.
Experts say that in addition to better prevention and care, research is urgently needed to pinpoint biological changes in the brain which are responsible for the condition - an essential first step to developing treatments.
Calling for urgent action, Australasian Delirium Association president Associate Professor Gideon Caplan said: "This is a horrifying illness which traps people in a nightmare state that can last days, weeks or even months.
"It's all too often a case of suffering in silence as those affected cannot ask for help - and there are no treatment options available."
Dr Caplan, director of geriatric medicine at Prince of Wales Hospital in Sydney, said people with delirium may believe they are being attacked by hospital staff or suffer from frightening hallucinations.
"It increases the likelihood of dying, can cause long-term damage to the brain, and result in trauma even when the episode is over," he said.
"This condition strikes the sickest and most vulnerable in hospitals and aged care facilities where they should be at their safest.
Dr Caplan said that with an ageing population, rates of delirium are set to soar. "Chronic missed diagnosis and a dearth of treatments and research makes it even more urgent that governments step in to help end the waking nightmares faced by these patients."
The study found delirium costs the nation $8.8 billion each year, or $66,363 for each person with delirium. Of this, financial costs comprised $3.5 billion, or $26,726 per person with delirium, with the remaining $5.3 billion comprising the value of healthy life lost.
Dr Caplan has written to federal Health Minister Greg Hunt to share the research and to seek a meeting to discuss the urgent need for a national delirium strategy.
"We need federal, state and territory governments to work with us to combat delirium through a National Delirium Strategy that prioritises prevention, care and research..
"This will allow us to establish dedicated delirium units in hospitals, improve the diagnosis and care of these patients, and work towards identifying much needed treatments."
Delirium causes as much mortality as heart attack and disability as stroke, but while most hospitals have dedicated stroke and cardiac units, there are no dedicated delirium units.
Patients with delirium are three times more likely to die in hospital or soon after than patients with the same illness who do not experience delirium.
Despite the severity of the condition, delirium is difficult to diagnose, particularly silent (or hypoactive) delirium, where the person is lying quietly in bed.
There are no diagnostic blood tests, x-rays or scans, and the condition can strike suddenly while patients are not being observed, so it is missed in as many as two-thirds of cases.
Triggers for delirium include pneumonia, urinary tract infections, dehydration, certain medications including antipsychotic medicine, an over-full bladder and constipation.
While no treatments exist, simple interventions can help reduce the risk of delirium, including ensuring patients are properly hydrated, assisted with hearing and visual aids, supported to have a good quality night's sleep and orientating patients to the day and time.
Delirium can happen at any age, including in children who are very unwell, but is most common in vulnerable older people, affecting as many as half those admitted to hospital who are aged 65 or over, almost 90 per cent of intensive care patients and around a quarter of aged care residents.
It occurs in up to a third of all hospital admissions. It can also present in patients with chronic illness or advanced cancer.
"The current approach of ad hoc prevention isn't good enough. Government investment in a National Delirium Strategy is needed to prioritise this condition. Until then, people will continue to suffer," Dr Caplan said.
