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]

SAQ 2 (10 marks)

A six-year-old girl with leukaemia is on the oncology ward, two weeks post-haematopoietic cell transplantation. The nursing staff report she has become withdrawn and quiet, barely responds to voice, and has stopped interacting with toys. She is afebrile, her observations are stable, and her electrolytes are normal. [3] [7]

1. State the most likely diagnosis and explain why it may be missed. (3) [7]
2. Describe the screening and assessment you would perform, and the investigations to find the cause. (4) [2] [6]
3. Explain how the management differs from a child with hyperactive delirium, including the role of antipsychotics. (3) [1]

Model answer — SAQ 2

(1) Diagnosis and why it may be missed (3). The most likely diagnosis is hypoactive delirium — acute behavioural change with withdrawal, reduced responsiveness, and reduced interaction in the context of serious illness. Hypoactive delirium is the commonest subtype in the PICU and ward and the most-missed, because the child looks quiet and apparently comfortable, does not demand attention, and may be documented as settled rather than screened. Missing it delays treatment of the underlying cause and is a serious clinical error. [7]

(2) Screening and investigation (4). Screen with the CAPD (appropriate for all ages including oncology ward patients) and perform a structured mental state and neurological examination. The cause-finding investigation in an immunocompromised oncology patient is broader: review the medication list (opioids, antiemetics, corticosteroids, anticholinergics); check infection markers and cultures aggressively given immunocompromise (bacterial, viral including CMV and respiratory viruses, fungal); assess metabolic and hepatic function; review for hypoxia or occult shock; assess pain and withdrawal; and consider neuroimaging and EEG if there are new neurological signs or a deteriorating picture. The Ista 2023 meta-analysis confirms that younger age, severity of illness, and sedative exposure are the key risk factors — all present here. [2] [6] [3]

(3) Management difference and antipsychotic role (3). The management is cause-first and multidomain, just as for hyperactive delirium, but the emphasis is different. Hypoactive delirium does not present a safety risk from agitation, so antipsychotics are never indicated for hypoactive delirium alone — there is no agitation to manage and no evidence of benefit. The focus is on the ABCDEF bundle applied to the ward setting (pain assessment, sedation review, sleep and environment, early mobility, family engagement), treatment of the underlying cause, and structured re-screening. Antipsychotics are reserved for severe hyperactive distress or safety risk that cannot be managed with non-pharmacologic measures. [1] [5]