Residency · Residency · Child Adolescent Psychiatry
Delirium in Hospitalized Children
Introduction
Pediatric delirium is an acute disturbance in attention and awareness with fluctuating cognitive dysfunction caused by an underlying medical condition. It is a medical emergency that signals serious physiological derangement. Despite affecting up to 25-50% of critically ill children, delirium remains significantly underrecognized in pediatric settings, in part because its presentation in children, particularly the hypoactive subtype, differs substantially from the classic adult presentation.
Epidemiology
The prevalence of delirium in pediatric intensive care units ranges from 25-50%. On general pediatric wards, prevalence is estimated at 10-20%. Higher rates occur in children who are mechanically ventilated, post-surgical, or receiving sedation. Mortality is significantly higher in children with delirium compared to those without. Delirium is associated with longer hospital stays, increased costs, and poorer long-term cognitive outcomes. Hypoactive delirium accounts for up to 50% of cases and is the subtype most frequently missed.
Pathophysiology
The pathophysiology of pediatric delirium involves several interacting mechanisms. Neuroinflammation occurs when systemic inflammatory mediators cross the blood-brain barrier. Neurotransmitter imbalance is characterized by reduced cholinergic activity, dopaminergic excess, and GABAergic and serotonergic dysregulation. Oxidative stress impairs cerebral oxidative metabolism. Blood-brain barrier disruption occurs in critical illness. The developing brain may be more vulnerable to these insults due to immature neurotransmitter systems.
Clinical Presentation
Subtypes
Hyperactive delirium presents with agitation, restlessness, pulling at lines and tubes, and hallucinations. Hypoactive delirium manifests as withdrawal, reduced responsiveness, decreased activity, and flat affect. Mixed delirium involves alternating features of both subtypes.
Key Features in Children
The cardinal features include a fluctuating course with symptoms that wax and wane over hours, inattention as the core feature with difficulty sustaining or shifting attention, and altered level of consciousness ranging from hyperalert to obtunded. Disorganized thinking manifests as illogical speech and confabulation. Perceptual disturbances, with visual hallucinations more common than auditory, may be present. Sleep-wake cycle disturbance with reversal of day-night patterns is typical. Emotional lability, including inconsolable crying, fearfulness, and irritability, is common.
Risk Factors
Predisposing Factors
Predisposing factors include younger age, especially under two years though diagnosis in this age group is challenging, pre-existing developmental delay or intellectual disability, prior history of delirium, and baseline cognitive or sensory impairment.
Precipitating Factors
Medications are a major precipitant, with benzodiazepines having the strongest association, followed by anticholinergics, opioids, and corticosteroids. Infection and sepsis trigger delirium through the systemic inflammatory response. Metabolic derangements including electrolyte imbalances, hypoglycemia, and hepatic or renal failure are common causes. Hypoxia and respiratory failure, post-operative states particularly after cardiac surgery, sleep deprivation and environmental disruption in the ICU, and physical restraints with immobility all contribute.
Screening and Diagnosis
Validated Screening Tools
The Cornell Assessment of Pediatric Delirium (CAPD) is validated for ages 0-21, including non-verbal children, with a score of 9 or higher indicating a positive screen. The Preschool Confusion Assessment Method (psCAM) is designed for children under five. The Pediatric Confusion Assessment Method for the ICU (pCAM-ICU) is used for children aged five and older. The Sophia Observation Withdrawal Symptoms Scale helps differentiate delirium from withdrawal.
| Tool | Age Range | Setting | Key Features | Positive Screen |
|---|---|---|---|---|
| CAPD | 0-21 years | PICU, general wards | Validated for non-verbal and pre-verbal children; observational | Score ≥ 9 |
| psCAM | < 5 years | PICU | Designed for preschool-age children | Algorithm-based |
| pCAM-ICU | ≥ 5 years | PICU | Adapted from adult CAM-ICU for older children | Algorithm-based |
| SOS | All pediatric ages | PICU | Differentiates delirium from iatrogenic withdrawal | Score-based |
Diagnostic Evaluation
The workup includes a comprehensive metabolic panel, blood gas, and blood cultures. Medication reconciliation should identify deliriogenic agents. Neuroimaging is indicated if focal neurological signs are present or if structural pathology is suspected. EEG may be needed to rule out non-convulsive status epilepticus. Urinalysis and lumbar puncture are performed as clinically indicated.
Management
Non-Pharmacological Interventions (First-Line)
Treating the underlying medical cause is the most important intervention. Reorientation through familiar objects, family photos, clocks, and windows for natural light helps ground the child. Family presence at the bedside is encouraged, as familiar voices are calming. Sleep hygiene measures should minimize nighttime disruptions and reduce noise and light. Deliriogenic medications, particularly benzodiazepines and anticholinergics, should be tapered when possible. Early mobilization through physical and occupational therapy should proceed as medically tolerated. Sensory aids such as glasses and hearing aids should be provided when applicable.
Pharmacological Interventions
Pharmacological treatment is reserved for cases where delirium poses safety risks or is unresponsive to non-pharmacological measures. Antipsychotics are the most commonly used agents. Haloperidol at 0.01-0.05 mg/kg intravenously or orally requires QTc monitoring. Risperidone at 0.25-0.5 mg orally is useful when the oral route is available. Quetiapine at 12.5-50 mg orally is more sedating and may help with sleep-wake disturbance. Benzodiazepines should be avoided except in alcohol or sedative withdrawal delirium. Dexmedetomidine, an alpha-2 agonist, is increasingly used in the PICU as an alternative to benzodiazepines for sedation and may reduce delirium incidence. A baseline ECG should be obtained before starting antipsychotics to monitor for QTc prolongation.
Prevention
Delirium prevention bundles modeled on adult ICU protocols should be implemented in the PICU. These include minimizing benzodiazepine use for sedation, promoting sleep hygiene protocols, implementing early mobilization programs, performing routine delirium screening with the CAPD twice daily, and encouraging family engagement and environmental optimization.
Clinical Pearls
Hypoactive delirium is more common than hyperactive delirium in children and is frequently mistaken for depression, fatigue, or "being a good patient"; routine screening is essential to avoid missing it. Benzodiazepines are the strongest modifiable risk factor for delirium, and their use should be minimized with alternatives such as dexmedetomidine considered. Treating the underlying cause, not just the symptoms, is paramount because delirium is always secondary to a medical condition. The CAPD is the only validated tool that can screen pre-verbal and non-verbal children and should be part of routine PICU assessment.
References
- Traube C, et al. "Cornell Assessment of Pediatric Delirium: A Valid, Rapid, Observational Tool for Screening Delirium in the PICU." Critical Care Medicine. 2014;42(3):656-663.
- Smith HAB, et al. "Delirium: An Emerging Frontier in the Management of Critically Ill Children." Anesthesiology Clinics. 2011;29(4):729-750.
- Silver G, et al. "Pediatric Delirium and Associated Risk Factors: A Single-Center Prospective Observational Study." Pediatric Critical Care Medicine. 2015;16(4):303-309.
- Schieveld JNM, et al. "Pediatric Delirium in Critical Illness: Phenomenology, Clinical Correlates, and Treatment Response." Intensive Care Medicine. 2007;33(6):1033-1040.