Nelson Textbook of Pediatrics

Transgender Care

Transgender individuals have a gender identity that differs significantly from the sex they were assigned at birth (see Chapter 133 ). They may experience gender dysphoria , defined as clinically significant distress or impairment in social, school/occupational, or other important…

Gay, Lesbian, and Bisexual Adolescents

Understanding a child's or adolescent's sexual and emotional development is an essential part of any comprehensive pediatric evaluation. For youth who are or might be gay, lesbian, or bisexual ( GLB ), such understanding is particularly important. GLB youth as…

Gender and Sexual Identity

Terms and Definitions Sex and Sexual Identity Sex is multifaceted, with at least 9 components: chromosomal sex, gonadal sex, fetal hormonal sex (prenatal hormones produced by the gonads), internal morphologic sex (internal genitalia), external morphologic sex (external genitalia), hypothalamic sex…

Adolescent Physical and Social Development

See also Part XV and Chapters 577 and 578 . During the preteen, teenage, and young adult years, young people undergo not only dramatic changes in physical appearance, but also rapid changes in physiologic, psychological, and social functioning. Hormonally driven…

Congenital and Perinatal Infections

Infections are a frequent and important cause of neonatal morbidity and mortality. Congenital or intrauterine infections (i.e., those transmitted across the placenta) and perinatal infections (i.e., those transmitted from the mother to the fetus or newborn infant during the birth…

Healthcare-Acquired Infections

Premature and very-low-birthweight (VLBW) infants often have prolonged hospitalizations and are particularly prone to healthcare-acquired infection ( HAI ) because of their inefficient innate immunity, deficient skin barriers, presence of indwelling catheters and other devices, and prolonged endotracheal intubation (…

Epidemiology of Infections

Infections in the newborn are often classified by their timing relative to birth and include congenital, perinatal, early-onset, and late-onset disease. These are clinically useful designations because the mechanisms of infection, etiologies, and outcomes are distinct at each stage. Congenital…

Dysmorphology

Dysmorphology is the study of differences in human form and the mechanisms that cause them. It has been estimated that 1 in 40 newborns, or 2.5%, have a recognizable birth defect or pattern of malformations at birth; approximately half these…

The Endocrine System

Endocrine emergencies in the newborn period are uncommon, but prompt identification and proper treatment are vital to reduce morbidity and mortality. Pituitary dwarfism (growth hormone deficiency) is not usually apparent at birth, although male infants with panhypopituitarism may have neonatal…