Learning Objectives
Master the clinical presentation, etiology, and management of Delirium. Understand its hallmark “waxing and waning” nature, recognize common medical triggers, and identify high-yield non-pharmacological interventions for the USMLE Step 1.
1. Clinical Presentation & Characteristics
Delirium is an acute, typically reversible syndrome of altered sensorium. It is the most common cause of altered mental status in the inpatient setting.
| Feature | Clinical Hallmark |
|---|---|
| Onset & Course | Acute onset with a “waxing and waning” level of consciousness throughout the day. |
| Attention | Significant decrease in attention span and level of arousal. |
| Cognition | Disorganized thinking, visual hallucinations, and illusions (misperceiving real stimuli). |
| EEG Findings | May show diffuse background rhythm slowing. |
2. Etiology and Secondary Causes
Delirium is almost always secondary to an underlying medical condition or medication effect, especially in older adults or ICU patients.
| Category | High-Yield Triggering Factors |
|---|---|
| Infection/Medical | UTI, pneumonia, sepsis, electrolyte disturbances, or urinary/fecal retention. |
| CNS/Trauma | Stroke, hemorrhage, head trauma, or hypoxia. |
| Substances | Intoxication or withdrawal (e.g., alcohol/benzodiazepine withdrawal). |
| Medications | Anticholinergics, benzodiazepines, opioids, or steroids. |
3. Management and Treatment
The primary goal is to identify and reverse the underlying condition.
| Intervention Type | Specific Management Strategies |
|---|---|
| Non-Pharm | Orientation protocols (clocks, calendars), cognitive stimulation, and frequent staff reorientation. |
| Environment | Maintain a regular sleep-wake cycle; provide adequate lighting during the day. Avoid restraints. |
| Pharmacological | Low-dose Antipsychotics (e.g., Haloperidol) if the patient is agitated/dangerous. |
Activity
High-Yield Clinical Pearls:
- The “Sundowning” Effect: Delirium often worsens in the evening/night due to decreased sensory input.
- Drug Choice: Avoid Benzodiazepines in delirium unless the cause is alcohol or sedative withdrawal, as they can worsen the confusion.
- Hallucinations: Visual hallucinations are more common in delirium (organic), whereas auditory hallucinations are more classic for schizophrenia (primary psychiatric).