Considerations for the Pediatric Coma Patient: Not Just Small Adults

José Augusto Bragatti

Pediatr Health. 2010;4(6):581-589.

Abstract and Introduction

Abstract

Coma is a relatively common condition in the pediatric intensive care unit. Although the principles of diagnosis and management are basically the same for both children and adults, there are some age-specific aspects related to infants and children under 16 years of age that influences the pediatric intensive care practitioner's conduct. Several aspects regarding neuroplasticity, raised intracranial pressure and epileptogenesis in the immature brain are considered in this article. Importantly, the role of new technologies employed for neurophysiologic monitoring is also reviewed. The aim of this article is to evaluate the main issues comprising the comatose state in childhood and their differences from the same condition in adulthood. Several differences in the physiology of immature brains can affect clinical and neurophysiologic expression in a disorder of consciousness and may need special proceedings for its management. Future perspectives in the field are referred in the final part of this article.

Introduction

Coma is a relatively common condition in critical pediatric care.^[1] Epidemiological studies generally divide studies by traumatic and nontraumatic causes. In a population-based study in the Northern region of the UK, the incidence of nontraumatic coma was five-times greater in children under 16 years of age than in the general population (30.8 per 100,000 vs 6.0 per 100,000 per year, respectively), with a notably higher incidence in the first year of life (160 per 100,000 children per year).^[2]

Infection is the most common overall cause of coma in childhood, with an overall mortality of 46%.^[2] Regarding traumatic brain injury in children, there were an estimated 546,240 children with head injuries not associated with motor vehicles in the USA during 1978 who required emergency room care.^[3] Head injuries account for 11% of hospital emergency room visits by children with nonmotor vehicle trauma. A fifth of head injuries among adolescents were associated with concussion. Among the 33,635 cases of concussion in children studied, twice as many males had concussion than females.

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Table 1. First assessment of coma etiologies.
Clinical examination	Possible causes
Intact brainstem function, no meningism and no lateralizing signs	Intoxication (alcohol, carbon monoxide or neuroleptic drugs) Extrapiramidal (malignant neuroleptic syndrome) Seizures (status epilepticus) Metabolic (hypoglycemia, hepatic encephalopathy or Addison`s disease) Electrolytic disequilibrium (hyponatremia or hypermagnesemia)
Meningism	Infection (meningitis or encephalitis) Vascular (subarachnoid hemorrhage)
Lateralizing signs	Asymmetrical signs (hemorrhage, venous thrombosis, abscess or tumor) Symmetrical (diffuse axonal injury or bilateral subdural hematoma)
Focal brainstem dysfunction	Herniation syndrome, posterior fossa tumor or vertebrobasilar occlusion

Table 2. Child`s Glasgow Coma Scale.
Glasgow Coma Scale score	Criteria
Glasgow Coma Scale score	Age >5 years	Age <5 years
*Eye opening*
4	Spontaneous
3	To voice
2	To pain
1	None
*Verbal*
5	Oriented	Alert, babics, coos, words or sentences – normal for age
4	Confused	Less than usual ability, irritable cry
3	Inappropriate words	Cries to pain
2	Incomprehensive sounds	Moan to pain
1	No response to pain
*Motor*
6	Obey commands	Normal spontaneous
5	Localize supraorbital pain (>9 months old)	Withdraws to touch
4	Withdraws from nailbed pain
3	Flexion to supraorbital pain
2	Extension to supraorbital pain
1	No response to supraorbital pain

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Executive Summary

Definition of coma

Coma is a state of unarousable unresponsiveness.
Subjective definitions of coma emphasize the absence of inner consciousness or awareness from the perspective of the patient.
Objective definitions of coma consider a certain set of external signs from the perspective of an observer.
Coma can be produced by bihemispheric structural lesions, focal brainstem lesions or metabolic disorders.

Coma in childhood

Nontraumatic coma is five-times greater in children under 16 years of age than in the general population.
Genetic factors may influence brain injury severity and outcome in comatose children.
The APOE ɛ 4 allele has a key role in the physiopathogenesis of diffuse cerebral processes and neuronal plasticity.

Plasticity in the developing brain

Neuronal plasticity is enhanced in the developing brain.
Plasticity is positively influenced by environmental enrichment.
Developing neurons are vulnerable to loss of stimulation by excitatory neurotransmitters.
Signaling pathways involved in neuroplasticity and apoptosis show different behaviors according to gender.
Hypothermia seems to be more protective in females than in males.

Brain swelling & raised intracranial pressure

There is an age-dependent susceptibility to brain swelling in children.
Raised intracranial pressure has different clinical presentations in infants compared with older children.
Mortality is increased in children with brain swelling secondary to traumatic brain injury.

Epileptogenesis in comatose children

Epileptogenesis is the process of developing epilepsy after an initial insult.
Seizure susceptibility is enhanced in the early years of life.
GABA, normally an inhibitory neurotransmitter, can be excitatory and depolarizing in the immature brain.
Comatose children aged from 2 months to 17 years have a lower prevalence of epileptic seizures and a shorter length of intensive care unit (ICU) stay compared with adults and neonates.
Nonconvulsive status epilepticus, a condition diagnosed only with EEG, is a frequent condition in comatose patients and carries a poor prognosis.

Coma assessment in childhood

There are many difficulties in applying the Glasgow Coma Scale (GCS) to pediatric patients.
Modified GCS is a reliable tool for assessment of coma in childhood. Motor and verbal responses are adequately included in this scale.
Neurophysiologic monitoring has two general purposes: overall prognosis and seizure detection.
Amplitude-integrated EEG is a useful tool for detecting seizures in the pediatric ICU.

Future perspective

Studies on genetic variations regarding the APOE alleles, GABA and Na–K–Cl cotransporter 1 are required.
Specific pharmacological agents, such as bumetanide, need development.
More studies regarding the role of amplitude-integrated EEG in the neonatal ICU are also required.

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Considerations for the Pediatric Coma Patient: Not Just Small Adults

Abstract and Introduction

Abstract

Introduction

Tables

Tables

References

Authors and Disclosures

Authors and Disclosures

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Executive Summary

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