In children, acute global brain injury from traumatic brain injury (TBI) and nontraumatic coma has a substantial cost to the child, the family, and the society. There have historically been relatively few studies looking at long-term cognition and behavioural outcomes. Long-term follow-up studies, population-based studies, and meta-analyses are now available for TBI in children as well as adults and suggest that there is a significant cognitive cost, particularly for processing speed, working memory, and intelligence quotient (IQ) in severe TBI. Poor attention is often a premorbid deficit. Children surviving a cardiac arrest typically have a reduction in IQ. The available data for meningitis suggest that IQ is within the normal range at follow-up in most but is lower than that of matched controls. For encephalitis, the main advances have been in the recognition of additional mechanisms for postinfectious causes, including autoimmune disorders and demyelination. MRI assists with diagnosis, particularly in infectious causes, and there is some evidence that it may be useful for prognosis, particularly in TBI. For the essential randomized control trials of acute treatment and rehabilitation, cognitive or MRI endpoints may become feasible as otherwise the time frame for follow-up is too long for the implementation of change.