CHILDHOOD DISEASE AND DISORDER

any illness, impairment, or abnormal condition that affects primarily infants and children-i.e., those in the age span that begins with the fetus and extends through adolescence. Childhood is a period typified by change, both in the child and in the immediate environment. Changes in the child related to growth and development are so striking that it is almost as if the child were a series of distinct yet related individuals passing through infancy, childhood, and adolescence. Changes in the environment occur as the surroundings and contacts of a totally dependent infant become those of a progressively more independent child and adolescent. Health and disease during the period from conception to adolescence must be understood against this backdrop of changes. Although, for the most part, the diseases of childhood are similar to those of the adult, there are several important differences. For example, certain specific disorders, such as precocious puberty, are unique to children; others, such as acute nephritis-inflammation of the kidney-are common in children and infrequent in adults. At the same time, some diseases that are common in adults are infrequent in children. These include essential hypertension (high blood pressure of unknown cause) and gout. Finally, a major segment of pediatric care concerns the treatment and prevention of congenital anomalies, both functional and structural. Apart from variations in disease due to differences between children and adults, certain other features of diseases in children need to be emphasized. Infectious disorders are prevalent and remain a leading cause of death, although individual illnesses are often mild and of minor consequence. Most instances of the common communicable diseases, such as measles, chicken pox, and mumps, are encountered in childhood. Disorders of nutrition, still of great concern, especially but not exclusively in developing countries, are of extreme importance to the growing and developing child. The unique nutritional requirements of children make them unusually susceptible to deficiency states: vitamin-D deficiency causes rickets, a common disorder of children in developing countries, and only rarely causes any disease in adults. The major environmental hazards that endanger the health of young children are either unavoidable, as in air pollution, or accidental, as in poisoning and in traffic injuries. Older children, especially adolescents, are exposed, as are adults, to environmental hazards that they deliberately seek, such as cigarette smoking and the use of alcohol and other drugs. This article reviews the scope of diseases that affect children, with particular emphasis on the ways in which the unique attributes of the growing child and special aspects of his environment serve to modify the course, effects, and treatment of particular diseases. Additional reading Benjamin Spock and Steven J. Parker, Dr. Spock's Baby and Child Care, rev. and updated 7th ed. (1998), provides comprehensive coverage of current medical practices and parental concerns. Comprehensive pediatric texts include Abraham M. Rudolph, Julien I.E. Hoffman, and Susan Axelrod (eds.), Pediatrics, 18th ed. (1987); Richard E. Behrman, Victor C. Vaughan III, and Waldo E. Nelson (eds.), Nelson Textbook of Pediatrics, 13th ed. (1987); Harry C. Shirkey (ed.), Pediatric Therapy, 6th ed. (1980); Stephen H. Sheldon and Howard B. Levy, Pediatric Differential Diagnosis, 2nd ed. (1985); and Morris Green, Pediatric Diagnosis: Interpretation of Symptoms and Signs in Different Age Periods, 6th ed. (1998). Specific aspects of child care are explored in Tomas Silber (ed.), Ethical Issues in the Treatment of Children and Adolescents (1983); Morris Green (ed.), The Psychological Aspects of the Family: The New Pediatrics (1985); and James H. Humphrey (ed.), Stress in Childhood (1984). S. Roy Meadow Chester Monroe Edelmann Henry Lewis Barnett Disorders of later infancy and childhood Sudden infant death syndrome (SIDS) In developed countries, SIDS (also called crib death or cot death) accounts for 20 percent of deaths between the ages of one month and one year. SIDS is a categorization rather than an explanation, for the label is given when no reason for death can be found from the infant's medical history or even after autopsy. Most crib deaths occur in the first five months of life and strike at home during the night. They are more common in the winter and in poor social circumstances. A preceding minor respiratory infection is common. This has prompted some investigators to suggest that the underlying defect is the presence of a virus in the bloodstream, leading to instability of cardiac and respiratory mechanisms. Many other hypotheses have been proposed to explain such deaths, however, and it is likely that several different causes may be involved. Failure to thrive Failure to thrive is the term used to describe the condition in which a young child fails to gain weight satisfactorily. Common reasons for such poor weight gain are parental neglect or lack of food. On the other hand, a large number of important gastrointestinal disorders may be responsible, including those associated with vomiting, such as food intolerance or obstruction of the upper bowel by pyloric stenosis; disorders of digestion and absorption, including celiac disease and cystic fibrosis; and bowel infections. Alternatively, the body, because of other serious disorders (e.g., chronic infection or heart or kidney disorder), may fail to use the food that is given and absorbed appropriately.