Summary

Delirium is an acute, fluctuating disturbance of consciousness, attention, and cognition caused by an underlying medical condition. It develops over hours to days and is typically reversible once the cause is treated. Delirium is extremely common in hospitalised older patients (affecting up to 30% of medical inpatients >65) and is a medical emergency – it indicates serious underlying pathology and is associated with increased mortality, prolonged hospital stays, and long-term cognitive decline. There are three subtypes: Hyperactive (agitated, hallucinations), Hypoactive (drowsy, withdrawn – often missed), and Mixed. Causes are summarised by "PINCH ME" (Pain, Infection, Nutrition, Constipation, Hydration, Medication, Environment). The 4AT is the recommended screening tool. Management focuses on treating the underlying cause, non-pharmacological strategies (reorientation, environment), and last-resort sedation (Haloperidol) only if patient is at risk to themselves or others.

Key Facts

• Definition: Acute, fluctuating disturbance of consciousness and attention. Onset hours/days.
• Types: Hyperactive (Agitated), Hypoactive (Drowsy – Often missed), Mixed.
• Causes (PINCH ME): Pain, Infection (UTI/Pneumonia), Nutrition, Constipation/Retention, Hydration, Medication (Opioids/Anticholinergics), Environment.
• Screening Tool: 4AT (Alertness, AMT4, Attention, Acute Change). Score ≥4 = Likely Delirium.
• Treatment: Treat Cause. Environmental/non-pharmacological measures. Sedation last resort.

Clinical Pearls

"Hypoactive Delirium is Often Missed": Quiet, drowsy patients are often mistakenly thought to be "just tired". Hypoactive delirium carries a worse prognosis.

"Delirium is NOT Dementia": Delirium is ACUTE and FLUCTUATING. Dementia is chronic and stable. Delirium can occur ON TOP OF dementia.

"4AT is Your Friend": Quick (<2 min), validated bedside screen. Use it for any acutely confused patient.

"Treat the Cause, Not Just the Symptoms": Sedation only masks the problem. Find and treat the UTI, the constipation, the hypoxia.

Why This Matters Clinically

Delirium is associated with increased mortality (~30% inpatient mortality in some studies), prolonged hospital stays, falls, pressure ulcers, and accelerated cognitive decline. Early recognition and cause identification saves lives.

Additional Causes

Cognitive Assessment: 4AT

Physical Examination

• Reversible: Most cases resolve once cause treated.
• Duration: Days to weeks.
• Persistent Delirium: Up to 30% have symptoms at discharge.
• Mortality: ~30% inpatient mortality in some series. Higher than matched controls.
• Long-Term: Accelerated cognitive decline. Increased dementia risk.

Key Guidelines

Scenario 1:

• Stem: An 82-year-old man with dementia is admitted with a hip fracture. On the ward, he becomes agitated at night, pulls at his catheter, and talks to people who are not there. What is the most likely diagnosis?
• Answer: Delirium (Hyperactive) superimposed on dementia.

Scenario 2:

• Stem: What is the mnemonic for common causes of delirium?
• Answer: PINCH ME – Pain, Infection, Nutrition, Constipation/Retention, Hydration, Medication, Environment.

Scenario 3:

• Stem: Which subtype of delirium has the worst prognosis?
• Answer: Hypoactive Delirium. Often missed. Associated with higher mortality.

What is Delirium?

Delirium is a sudden change in how someone thinks and behaves. It makes people very confused, and they may not know where they are or what time it is. It often happens because of an illness or infection.

Why does it happen?

• An infection like a urine infection or chest infection.
• Dehydration (not enough fluids).
• Constipation.
• Pain.
• Medications.
• Being in hospital (unfamiliar environment).

How can you help?

• Stay calm and reassuring.
• Remind them where they are and what day it is.
• Bring in familiar objects or photos.
• Make sure they have their glasses and hearing aids.

Key Counselling Points for Families

1. It's Caused by Illness: "This confusion is because of an underlying medical problem, like an infection. It's not your relative's fault."
2. It's Usually Reversible: "Once we treat the cause, the confusion usually gets better."
3. It Can Take Time: "It may take days or weeks for them to fully recover."
4. You Can Help: "Familiar faces and objects can really help. Please visit and talk to them."

• Hippocrates (400 BC): Described "phrenitis" (Delirium with fever) and "lethargus" (Delirium with stupor).
• Term "Delirium" (Latin): "De" (Away from) + "Lira" (Furrow/Track) – "Off the track".
• Hospital Elder Life Programme (HELP, 1999): Landmark non-pharmacological delirium prevention protocol still used today.