CHILDHOOD DISEASES AND DISORDERS

any illness, impairment, or abnormal condition that affects primarily infants and children. There are a number of infectious illnesses that strike primarily during childhood. These include such familiar contagious diseases as chicken pox, measles, mumps, and German measles (rubella). These diseases impart long-term immunity, which is why they are infrequent among adults, who have often had them as children. Infectious diseases remain a leading cause of infant and child mortality in developing countries. This circumstance stems from poor nutrition, insufficient hygiene, insanitary water supplies, sparse immunization programs, and a shortage of medical facilities. Congenital disorders-i.e., those that are present at birth-affect a small percentage of infants. Severe congenital disorders, such as inborn errors of metabolism (e.g., Tay-Sachs disease) and gross defects of the heart, nervous system, immune system, or digestive tract, frequently are fatal within the first year or two of life. Other congenital disorders, including Down syndrome, clubfoot, and cleft palate, can lead to lifelong disabilities of varying degrees. Respiratory diseases peculiar to childhood include infections of the tonsils and adenoids, croup, whooping cough, allergic rhinitis, asthma, and respiratory distress syndrome, also called hyaline membrane disease. Most childhood diseases of the cardiovascular system are the result of congenital malformations of the heart and its major vessels, or of rheumatic heart disease. Childhood disorders of the blood and blood-forming tissues include Rh disease, hereditary anemias, hemophilia, and leukemia. A number of congenital defects, such as anencephaly, hydrocephaly, and spina bifida, affect the nervous system. The endocrine (hormone-producing) system is also subject to various diseases during childhood. Underactivity of the thyroid gland can lead to cretinism. The failure of the pancreas to secrete sufficient amounts of the hormone insulin results in diabetes mellitus. Other endocrine disorders of childhood include pituitary gigantism, dwarfism, and precocious puberty. Children are particularly sensitive to dietary deficiencies, because the rapidly growing body of a child has high nutrient requirements. A diet that provides too few calories will lead to general malnutrition. A diet with sufficient caloric content but still deficient in protein content produces kwashiorkor. These two disorders are major health problems in many developing countries. Other deficiency diseases stem from the lack of a specific micronutrient (vitamin or mineral). For example, anemia due to iron deficiency is common in infants and young children. Accidents rank as a major cause of childhood death and disability in developed countries. Road-traffic accidents are the most common problem, but the accidental ingestion of poisons, along with falls, burns, and other mishaps in the home, also account for substantial numbers of childhood injuries and deaths. Child abuse and neglect have become increasingly recognized as important pediatric concerns. Children may be abused not only physically but emotionally and sexually as well. Emotional disorders are particularly prevalent during adolescence, as the individual struggles with the social and sexual changes that accompany the passage from childhood to adulthood.