Introduction
Coma is a state of unarousable unresponsiveness: the child cannot be woken and does not respond meaningfully to stimuli. Consciousness needs both arousal (brainstem reticular activating system) and awareness (both cerebral hemispheres), so coma means either a lesion in the brainstem, damage to both hemispheres, or a diffuse metabolic or toxic process. In children, most coma is metabolic, toxic or infectious rather than structural.
Measuring the level of consciousness
AVPU: Alert, responds to Voice, responds only to Pain, Unresponsive. “P” or “U” roughly equals a GCS of 8 or less: the airway is at risk.
GCS 8 or below = coma: protect the airway.
Assessment
- ABC first, then D: GCS or AVPU, pupils, posture. Don't Ever Forget Glucose (DEFG): check bedside glucose at once.
- History: onset (sudden: bleed, seizure, toxin; gradual: infection, tumour, metabolic), fever, headache, vomiting, trauma, medicines and poisons at home, diabetes, epilepsy, shunt, previous episodes, family history.
- Examination: temperature; purpuric rash (meningococcal disease); neck stiffness, bulging fontanelle; smell (ketones, alcohol); signs of injury or abuse; liver size; blood pressure.
Clues from the neurological examination
Signs of raised intracranial pressure: falling GCS, headache and vomiting, bulging fontanelle, abnormal pupils, abnormal posture, and the late Cushing triad (hypertension, bradycardia, irregular breathing). Papilloedema may be absent in acute rises.