Delirium in children and adolescents — formative SAQs

SAQ 1 (10 marks)

A four-year-old boy is on day three after cardiac surgery. He was extubated yesterday and initially chatted with his parents, but today he does not recognise them, pulls repeatedly at his central line, and alternates between agitation and drowsiness. His nurse reports he was sleeping all day and awake all night. He is on a midazolam infusion that has been weaning. ^{[2] [6]}

1. Give the most likely diagnosis with the features that support it, and list three differential diagnoses with discriminators. (3) ^[6]
2. Outline your immediate assessment, including the screening tool you would use and your cause-finding investigation plan. (4) ^{[2] [6]}
3. Describe the stepped-care management plan, naming the prevention bundle and the sedation preference. (3) ^{[1] [5]}

Model answer — SAQ 1

(1) Diagnosis and differentials (3). The picture fits delirium in a critically ill child — acute onset (change from yesterday), fluctuating course (alternating agitation and drowsiness), impaired attention (does not recognise parents), disrupted sleep–wake cycle, and the direct context of cardiac surgery and sedative exposure. The motoric subtype is mixed (features of both hyperactive and hypoactive). Differentials: opioid or benzodiazepine withdrawal (the weaning midazolam is a clue, and withdrawal overlaps with delirium); uncontrolled pain (must be assessed and treated as a cause and mimic); CNS pathology (stroke, bleed, or raised ICP after cardiac surgery — exclude with neuroimaging if focal signs or deteriorating GCS). ^{[6] [7]}

(2) Assessment and investigation (4). Screen with the Cornell Assessment of Pediatric Delirium (CAPD) — the validated tool for all PICU ages including the post-cardiac surgery child — and a structured mental state and neurological examination. The cause-finding investigation follows the Identify-then-Investigate principle: review the medication list (the weaning midazolam is a causal risk factor for delirium); check for infection (cultures, inflammatory markers); correct metabolic derangement (sodium, calcium, glucose, renal and hepatic function, blood gas); assess oxygenation and perfusion; and assess pain using a validated paediatric pain score. Consider neuroimaging if there are new focal signs or a deteriorating GCS, and an EEG if non-convulsive status epilepticus is suspected. ^{[2] [6]}

(3) Stepped care (3). Safety and cause-finding first — ensure physical safety (one-to-one nursing, protect the central line), treat reversible contributors (pain, infection, metabolic), and review the sedation plan. The ABCDEF bundle is first-line: Assess and manage pain, Both awakening and breathing trials where appropriate, Choice of sedation (prefer dexmedetomidine over benzodiazepines given the causal link), Delirium screening (CAPD twice daily), Early mobility, and Family engagement. The SCCM PADIS 2022 guideline recommends dexmedetomidine over benzodiazepines — so accelerate the midazolam wean and switch to dexmedetomidine if ongoing sedation is needed. Antipsychotics are reserved for severe distress or safety risk only, not as a first response. ^{[1] [5]}