Pediatrics is the branch of medicine that dealing with the medical care of infants, children, and adolescents. The upper age limit ranges from age 14 to 21. A medical practitioner who specializes in this area is thus known as a pediatrician. Pediatrics differs from adult medicine in many respects. The obvious body size differences are paralleled by maturational changes differences. The smaller body of an infant or neonate is quite different physiologically from that of an adult. Congenital defects, genetic variance, and developmental issues are of greater concern to pediatricians than they usually are to adult physicians. Many inherited diseases are treated by pediatricians because only recently did the majority of these patients survive into adulthood. Well-known example are the thalassemias, sickle cell anemia and cystic fibrosis. Infectious diseases and immunizations are also dealt with primarily by pediatricians. Childhood is the period of greatest growth and maturation of the various organ systems in the body. Many years of training and experience (above and beyond basic medical training) goes into recognizing the difference between normal variants and what is actually pathological. Treating a child is not like treating a miniature adult. A major difference between pediatrics and adult medicine is that children cannot make decisions for themselves. The issues of guardianship, privacy, legal responsibility and informed consent must always be considered in every pediatric procedure. In a sense, pediatricians often have to treat the parents and sometimes the family as well, rather than just the child. Adolescents are in their own legal class, having rights to their own health care decisions in certain circumstances only, though this is in legal flux and varies by region of he country.
Like other medical practitioners, pediatricians begin their training with college, then medical school, an internship, then specialty training. All of this may requirue up to 13 years and on top of that, sub-specialization may require a few more years. Practising a sub-specialty in Pediatrics is similar in some respects to practising the relevant adult specialty, but a major difference is in the pattern of disease. Typically, diseases commonly seen in children are rare in adults (eg bronchiolitis, rotavirus infection), and those seen in adults are rare in children (eg coronary artery disease, deep vein thrombosis). For examples, Pediatric Cardiologists deal with the heart conditions of children, particularly congenital heart defects, and Pediatric Oncologists most often treat types of cancer that are relatively common in children (eg certain leukemias, lymphomas and sarcomas) rarely seen in adults. Each sub-specialty of adult medicine also exists in pediatrics, with the obvious exception of geriatrics. Pediatric Neurologists deal with diseases of the nervous system. Adolescent Medicine is a growing sub-specialty. The pattern of diseases in adolescents in part resembles that seen in older adults, and specialists or sub-specialists in adolescent medicine are also drawn from practitioners of internal medicine or family medicine. Another major sub-specialty, which is unique to pediatrics, is Neonatology, the medical care of newborn babies.