Clinical description of heat illness in children, Melbourne, Australia--a commentary.

Concerns about the health effects of global warming and the adequacy of the public health response to environmental crises heightened recently when record-high temperatures across France in the summer of 2003 resulted in the death of nearly 15 000 persons, many of them elderly. The accompanying article by Danks and associates highlights another group vulnerable to heat illness, that of young children. The authors describe their experience treating heat illness in young children during a 3- to 7-day heat wave in the region around Melbourne, Australia, in 1959. This heat wave was distinguished as the most intense on record for the previous 50 years. The temperatures were sustained at 35 Ct o 48C (95F– 109F) during the day and 24 to 32C (75F–90F) at night. Of 47 ill children, 6 were pronounced dead on arrival, and 6 more died from heat-related causes after admission. This report presents one of the first and most detailed clinical descriptions of heat illness in children. As is true of many conditions encountered in wilderness and environmental medicine, the early scientific interest in heat illness centered primarily on adults in the military. [A review of the paper by Buskirk, ‘‘Work performance after dehydration: effects of physical conditioning and heat acclimatization,’’ previously appeared in Lessons from History (Wilderness Environ Med. 2000;11:202–203)]. Initial epidemiological study of deaths among civilian populations during environmental heat waves identified the elderly, the poor, and those with pre-existing disease as being at special risk. The authors of the current paper turned a potentially overwhelming influx of critically ill children into a careful analysis that demonstrated the vulnerability to heat illness in the other extreme of the age spectrum. It deserves note that 2 physicians in training (a registrar and a house physician) and a social worker at the children’s hospital in Melbourne formed an unusual and effective team of investigators to perform this study. They present a vivid and useful clinical description based on the classical elements of the medical history (past medical history, history of present illness, review of systems, family and social history) and physical examination, despite their limited access to laboratory and diagnostic resources. All children in the series reported were 6 years of age or younger and only 2 children were older than 4 years. The most striking feature of the case series is the importance of specific medical and social risk factors among the children. The authors report an analysis of preexisting medical conditions, developmental state, acute illnesses, conditions of the home environment, and skills of the mother. The most important predisposing factor for illness or fatal outcome, in 31 of 47 children, was severe chronic disease, most often developmental delay, associated with the history of feeding difficulty. ‘‘Maternal ability’’ and housing conditions were assessed by the social worker, who conducted home visits in 38 cases. Among those patients who were dead on arrival, poor maternal ability (failure to recognize the need for additional fluid or fluids other than cow’s milk) and poor housing (excessive internal temperatures) were notable. The authors did cite delayed or misleading advice from physicians and distance from home to hospital as playing a role in several fatal cases because of the rapidity of the final deterioration. The descriptions of the sequence of clinical signs and the sudden changes that occur with heat illness in young children remain accurate and useful today. ‘‘On arrival at hospital. . . the outstanding features were dehydration, poor peripheral circulation, and impairment of consciousness. . . Rapid deep respiration, without acidotic breath or ketonuria, was frequent, and irregular respirations occurred in the most ill.’’ The authors make the important point that dehydration, rather than hyperpyrexia, was more closely related to severe disturbance of consciousness and to subsequent seizures. They also emphasize the prodromal phases as variable in duration but leading inevitably to decompensation, at which point intervention may be too late. ‘‘The symptoms preceding