Educational scope notice: This is a study note for medical students, not medical advice, diagnosis, or treatment guidance. Clinical management should follow local protocols and current guidelines.
Once delirium is recognised, identifying and managing the underlying cause or combination of causes is the first treatment act. The sequence runs from bedside to laboratory to selective investigation. There is no mandatory universal panel: testing follows the history and physical examination, and the selectivity is the point.
Collateral history and the baseline change open the sequence. Establish what changed, when it changed, and whether it fluctuates, alongside any worsening systemic illness, recently started or stopped drugs, and minor head trauma. Bedside recognition already demands these answers, and the workup acts on them.
Bedside checks come next: vital signs, oximetry, and bedside glucose, with attention to urinary retention, constipation, skin integrity, and a focused neurological examination. Carry out a full medication review for anyone taking multiple drugs, weighing both the type and number of medications. Look for infection and treat it, and avoid unnecessary catheterisation.
Laboratory and radiographic testing then follows the history and examination. The candidates to consider include infectious causes such as urinary tract infection and meningitis, metabolic disturbances such as hypoglycaemia, electrolytes, and ammonia, and intoxication or withdrawal through urine drug screening. Blood gas analysis and ECG are conditional options where hypoxia, acid-base disturbance, or a cardiac precipitant is suspected. Head imaging enters where a neurological or vascular insult is possible. EEG and lumbar puncture stay strictly indication-driven: the EEG in delirium often shows generalised slowing that tracks severity, but this supports rather than establishes the diagnosis, and neither test belongs in routine workup.
When delirium does not resolve, the sequence repeats: re-evaluate for underlying causes rather than accepting persistence.
Evidence anchors
- NICE. Delirium: prevention, diagnosis and management (CG103): https://www.nice.org.uk/guidance/cg103
- European Delirium Association and American Delirium Society. DSM-5 criteria, level of arousal and delirium diagnosis: https://pmc.ncbi.nlm.nih.gov/articles/PMC4177077/