Delirium
Delirium is an acute, fluctuating disturbance in attention, awareness, and cognition, caused by an identifiable medical condition, substance intoxication or withdrawal, or medication side effect. It is a medical emergency that requires urgent identification and treatment of the underlying cause.
Why Does This Happen? (First Principles)
💡 FIRST PRINCIPLE: Delirium represents an acute disruption of brain function due to systemic or cerebral insult. Unlike dementia (progressive neurodegeneration) or schizophrenia (chronic neurodevelopmental disorder), delirium is acute, reversible, and directly linked to an identifiable physiological disturbance — infection, metabolic derangement, drug effect, or organ failure.
Aetiology & Risk Factors
📝 TODO: Needs source — common causes (infection, electrolyte disturbance, drugs, organ failure), predisposing factors (age, pre-existing cognitive impairment, sensory impairment), and the PINCH ME mnemonic.
Clinical Features
- Acute onset — develops over hours to days.
- Fluctuating course — symptoms wax and wane throughout the day, often worse at night (“sundowning”).
- Attention deficit — difficulty focusing, sustaining, or shifting attention.
- Cognitive impairment — disorientation, memory deficits, language disturbance.
- Perceptual disturbances — visual hallucinations are common.
- Psychotic symptoms — paranoid delusions may occur.
- Sleep-wake cycle disruption.
Key Distinguishing Features from Dementia
| Feature | Delirium | Dementia |
|---|---|---|
| Onset | Acute (hours-days) | Insidious (months-years) |
| Course | Fluctuating | Progressive |
| Consciousness | Impaired/fluctuating | Clear until late stages |
| Attention | Severely impaired | Relatively preserved early |
| Reversibility | Potentially reversible | Progressive and irreversible |
Investigations
📝 TODO: Needs source — workup for underlying cause (bloods, infection screen, imaging, electroencephalogram [EEG]).
Management
📝 TODO: Needs source — treat underlying cause, environmental measures, antipsychotics for agitation (haloperidol or atypical antipsychotics).
Differential Diagnosis
| Condition | Distinguishing Features |
|---|---|
| dementia | Chronic, progressive, clear consciousness until late stages. |
| schizophrenia | Chronic course, no fluctuating consciousness, no identifiable medical trigger. |
| mania | Elevated mood, grandiosity, increased psychomotor activity rather than fluctuating consciousness. |
Exam Focus
Viva Questions
- How do you differentiate delirium from dementia? (Acute vs chronic onset, fluctuating vs progressive course, impaired vs clear consciousness.)
- What are the most common causes of delirium in elderly patients? (Infection, electrolyte disturbance, medication side effects.)
MCQ Traps
- ⚠️ EXAM DETAIL: Delirium is a medical emergency — the priority is identifying and treating the underlying cause, not just managing the behavioural disturbance.
- ⚠️ EXAM DETAIL: Visual hallucinations are more characteristic of delirium than auditory hallucinations (which are more typical of schizophrenia).
Source Notes
📝 TODO: Needs source — this is a stub page created to resolve a broken wiki-link. Needs content from an ingested source.