Delirium in hospital: the complication nobody warns families about

Families are prepared for the operation, the infection, the recovery time. They are almost never prepared for the moment on day three when a lucid eighty-four-year-old does not recognise them, believes they are in a hotel, and is trying to leave.

Delirium is an acute disturbance of attention and awareness that develops over hours to days and fluctuates. It affects roughly 20 to 30 per cent of older patients on general medical wards, more than half after hip fracture surgery, and up to 80 per cent in intensive care. It is one of the most common complications of hospitalisation in older adults and one of the most consistently under-recognised.

Why it gets missed

The stereotype is the agitated patient pulling out a cannula. That is hyperactive delirium, and it is the minority presentation.

The commoner form is hypoactive delirium: quiet, withdrawn, drowsy, slow to respond, not making trouble. It is routinely recorded as the patient being tired, or low, or simply old, and it carries a worse prognosis than the agitated form. Because it does not disrupt the ward, nobody investigates it.

It is also frequently mistaken for dementia, particularly in patients whose baseline is unknown to the staff. The distinguishing features are onset and course: delirium develops over hours or days and fluctuates markedly, often worse in the evening; dementia develops over months to years and is relatively stable through a day. Attention is the core deficit in delirium — the patient cannot sustain focus on a simple task — whereas early dementia affects memory with attention relatively preserved.

The two coexist constantly. Pre-existing dementia is the single strongest risk factor for delirium, and delirium superimposed on dementia is easily dismissed as the dementia worsening.

What causes it

Delirium is a final common pathway with a long list of precipitants, and typically several are operating at once. The useful framework is vulnerability plus insult: a frail, cognitively impaired ninety-year-old may become delirious from a urinary tract infection, while a robust seventy-year-old requires major surgery and sepsis.

Common precipitants: infection of any kind, dehydration, electrolyte disturbance, pain — particularly undertreated pain — constipation and urinary retention, hypoxia, and drugs. Opioids, benzodiazepines, anticholinergics and abrupt withdrawal of alcohol or of a long-standing benzodiazepine are the usual pharmacological culprits.

Environmental factors matter more than they intuitively should: sleep deprivation from ward noise and observations, immobility, sensory deprivation from absent glasses and hearing aids, and the absence of any orienting cue such as a clock, a window or a familiar face.

Prevention works, and it is unglamorous

This is the encouraging part. The Hospital Elder Life Program, developed by Sharon Inouye's group, is a multicomponent non-pharmacological intervention that reduced delirium incidence by roughly a third in the original trial and has been replicated widely.

Its components are almost aggressively mundane: orientation and therapeutic activities; early mobilisation; ensuring glasses and hearing aids are worn; sleep protection through noise reduction and avoidance of night-time observations where safe; hydration; and avoidance of the drugs listed above.

None of that requires technology. All of it requires staffing and attention, which is why it is inconsistently delivered.

What families can do

More than they usually realise, and hospitals are increasingly explicit about welcoming it.

• Bring the glasses and the hearing aids, and check daily that they are being worn. Sensory deprivation is a major contributor and this is the easiest thing on the list.
• Bring familiar objects — photographs, a clock with large numerals, a calendar.
• Visit at varied times, particularly early evening, when delirium characteristically worsens.
• Reorientate gently and repeatedly rather than testing or correcting. "It's Tuesday afternoon, you're in St Mary's, you had your hip fixed on Sunday" beats "don't you remember?"
• Encourage getting out of bed. Immobility is both a cause and a consequence.
• Ask about pain and about the bowels. Both are commonly missed and both precipitate delirium.

Treatment

Find and treat the cause; everything else is supportive. Antipsychotic medication does not treat delirium and does not shorten it — several trials, including in palliative and intensive care settings, have found no benefit and some harm. It is reserved for severe distress or danger, at the lowest dose for the shortest time, and it is specifically hazardous in dementia with Lewy bodies.

Physical restraint worsens delirium and should be avoided.

The part that is not widely known

Delirium was long described as transient and fully reversible. The longitudinal evidence does not support that.

Episodes are associated with longer admissions, higher rates of institutionalisation, and increased mortality. More significantly, cohort studies show accelerated cognitive decline afterwards — patients with dementia who experience delirium decline faster subsequently than those who do not, and a proportion of previously unimpaired patients do not return fully to baseline. Symptoms can persist for months.

Which reframes prevention. It is not about avoiding a difficult few nights on the ward. It is about protecting the cognitive trajectory of the years that follow.