Delirium

Delirium is a sudden change in mental state that affects attention, awareness and thinking. It usually develops over hours to days and can fluctuate throughout the day. People with delirium may seem confused, disorientated, drowsy, agitated, or may see or hear things that are not there.

Delirium is common in older adults, especially after illness, surgery or hospital admission, but it can affect anyone. It is usually caused by an underlying medical problem and is often reversible once the cause is identified and treated. However, delirium can be a sign of serious illness and needs prompt assessment.

At the Royal Buckinghamshire Hospital, we provide consultant-led assessment to identify the cause of delirium, treat underlying triggers, and support recovery.

---

Types of delirium

Delirium is often described by how it presents:

• Hyperactive delirium
  Restlessness, agitation, anxiety, irritability, wandering, hallucinations, disturbed sleep.
• Hypoactive delirium
  Drowsiness, reduced alertness, slowed responses, withdrawal, poor appetite.
  This type can be harder to recognise and is sometimes mistaken for depression or “just being tired.”
• Mixed delirium
  Fluctuates between hyperactive and hypoactive features.

---

Common causes and triggers

Delirium is usually caused by one or more underlying factors, including:

• Infections (e.g., chest infections, urinary infections)
• Dehydration or poor nutrition
• Pain or constipation
• Medication effects or withdrawal (including sedatives, strong painkillers, some anticholinergic medicines)
• Low oxygen levels or breathing problems
• Metabolic issues (low sodium, high calcium, low blood sugar, kidney or liver problems)
• Alcohol withdrawal
• Sleep deprivation and change in environment (especially in hospital)
• Post-operative delirium after anaesthetic/surgery
• Stroke or other acute neurological problems

People with dementia, sensory impairment (poor vision/hearing), frailty, or multiple long-term conditions are at higher risk.

---

Symptoms of delirium

Delirium typically involves a noticeable change from a person’s usual mental state. Symptoms may include:

• Confusion or disorientation (not knowing where they are or what day it is)
• Reduced attention (unable to follow conversation, easily distracted)
• Fluctuating alertness (better or worse at different times)
• Memory problems
• Drowsiness or being unusually sleepy
• Agitation, restlessness, or distress
• Hallucinations (seeing/hearing things) or paranoid ideas
• Changes in sleep pattern (awake at night, sleepy in day)
• Changes in speech (rambling, slowed, or incoherent)
• Reduced mobility or sudden decline in function

Delirium can develop quickly and may come and go during the day.

---

Delirium vs dementia

Delirium and dementia can look similar, but they are different:

• Delirium: sudden onset (hours/days), fluctuates, attention is impaired, usually triggered by illness/medication and can improve with treatment.
• Dementia: gradual onset (months/years), steady decline, attention is often normal early on, not caused by a single acute trigger.

Delirium can occur on top of dementia (this is common), and it can be harder to spot-families often notice the change first.

---

Diagnosis at Royal Buckinghamshire Hospital

Assessment focuses on confirming delirium and identifying the cause. This may include:

• History from the patient and family/carers (what’s changed and when)
• Physical examination and vital signs (temperature, oxygen levels, blood pressure)
• Review of medications (including recent changes)
• Cognitive/attention screening assessments
• Investigations where appropriate, such as:
  • Blood tests (infection markers, electrolytes, kidney/liver function, glucose)
  • Urine testing if infection is suspected
  • ECG if heart rhythm issues are possible
  • Chest X-ray or other imaging if needed
  • Brain imaging in selected cases (e.g., concern for stroke/head injury)

You’ll be given a clear explanation of likely triggers and the treatment plan.

---

Treatment and management

Treatment is centred on finding and treating the underlying cause, alongside supportive care.

Treat the cause

Depending on what’s identified, treatment may include:

• Antibiotics for infection (if bacterial infection is suspected/confirmed)
• Fluids for dehydration
• Adjusting or stopping medications contributing to delirium
• Managing pain, constipation, or urinary retention
• Correcting metabolic issues (e.g., electrolytes, glucose)
• Oxygen support if needed

Supportive delirium care

Support often improves recovery and reduces distress:

• Calm, well-lit environment and reassurance
• Orientation support (clock, calendar, familiar objects)
• Ensuring glasses/hearing aids are used
• Regular hydration and nutrition
• Sleep support (daytime light/movement, quiet at night)
• Early mobilisation and physiotherapy where appropriate
• Involving family/carers where possible

Medicines for agitation (only when needed)

Medication to calm agitation may be considered only if someone is at risk of harm to themselves/others or is severely distressed, and after addressing reversible causes. The safest option depends on the individual and medical context.

---

Recovery and outlook

Many people improve within days once the cause is treated, but recovery can take weeks in some cases-especially after major illness or surgery. Some people may have lingering concentration or memory issues for a period.

Delirium can be associated with a longer recovery time and may signal vulnerability to future illness, so follow-up and prevention planning can be helpful.

---

When to seek urgent help

Seek urgent same-day medical advice (or emergency care) if someone has:

• Sudden new confusion or marked change in behaviour
• High fever, severe infection symptoms, or worsening breathlessness
• Chest pain, collapse, or severe dehydration
• New weakness, facial droop, slurred speech, seizures, or severe headache
• Very reduced responsiveness (difficult to wake) or extreme agitation

---

If you or a family member has a sudden change in confusion, alertness, or behaviour—particularly following illness, infection, surgery, or new medication—contact Royal Buckinghamshire Hospital for assessment and guidance. There is no need to be registered with the hospital, or live locally.

If you have insurance which covers consultations, we can in most cases invoice the insurer directly. Where you are paying directly, any costs will always be discussed.