Vaccination has been profoundly effective in preventing serious disease. Given their modest cost (particularly in comparison to drugs that must be taken long-term), vaccines are one of the most cost-effective medications. Vaccines have been so effective that many health care practitioners currently in practice have seen few or no cases of diseases that were once extremely common and often fatal.
Many behaviors exhibited by children or adolescents concern parents or other adults. Behaviors or behavioral patterns become clinically significant if they are frequent or persistent and maladaptive (eg, interfere with emotional maturation or social and cognitive functioning). Severe behavioral problems may be classified as mental disorders (eg, oppositional defiant disorder, conduct disorder). Prevalence rates vary according to how behavioral problems are defined and measured.
Difficulties arise when a sick or premature infant must be taken away from the family after birth because of illness. The parents may not be able to see a critically ill infant during stabilization and may be separated from the infant because of transport to a different hospital. Some infants require prolonged separation from their families because of lengthy hospitalizations and treatments. Experts recommend that neonatal transport teams encourage physical contact between parents and their sick infant before moving the infant to the specialty care center as long as the contact does not put the infant at risk of infection.
Child maltreatment is behavior toward a child that is outside the norms of conduct and entails substantial risk of causing physical or emotional harm. Four types of maltreatment are generally recognized: physical abuse, sexual abuse, emotional abuse (psychologic abuse), and neglect. The causes of child maltreatment are varied and not completely understood. Abuse and neglect are often associated with physical injuries, delayed growth and development, and mental problems. Diagnosis is based on history, physical examination, and sometimes laboratory tests and diagnostic imaging. Management includes documentation and treatment of any injuries and urgent physical and mental conditions, mandatory reporting to appropriate state agencies, and sometimes hospitalization and/or foster care to keep the child safe.
Chromosomal anomalies cause various disorders. Anomalies that affect autosomes (the 22 paired chromosomes that are alike in males and females) are more common than those that affect sex chromosomes (X and Y).
Craniofacial and musculoskeletal abnormalities are common among children. They may involve only a single, specific site (eg, cleft lip, cleft palate, clubfoot) or be part of a syndrome of multiple congenital anomalies (eg, velocardiofacial syndrome, Treacher Collins syndrome). Careful clinical assessment may be necessary to distinguish an isolated abnormality from an atypical or mildly manifested syndrome.
Most congenital gastrointestinal (GI) anomalies result in some type of intestinal obstruction, frequently manifesting with feeding difficulties, distention, and emesis at birth or within 1 or 2 days. Some congenital GI malformations, such as malrotation, have a very good outcome, whereas others, such as congenital diaphragmatic hernia, have a poor outcome (mortality rate of 10 to 30%).
Bartter syndrome and Gitelman syndrome are autosomal recessive renal disorders characterized by fluid, electrolyte, urinary, and hormonal abnormalities, including renal potassium, sodium, chloride, and hydrogen wasting; hypokalemia; hyperreninemia and hyperaldosteronism without hypertension; and metabolic alkalosis. Findings include electrolyte, growth, and sometimes neuromuscular abnormalities. Diagnosis is assisted by urine electrolyte measurements and hormone assays but is typically a diagnosis of exclusion. Treatment consists of nonsteroidal anti-inflammatory drugs, potassium-sparing diuretics, low-dose angiotensin-converting enzyme inhibitors, and electrolyte replacement.
There are over 200 disorders that involve connective tissue. Certain disorders are characterized by overactivity of the immune system with resulting inflammation and systemic damage to the tissues (eg, systemic lupus erythematosus [SLE] and juvenile idiopathic arthritis [formerly known as juvenile rheumatoid arthritis]). Other disorders involve biochemical abnormalities or structural defects of the connective tissue. Some of these disorders are inherited, and some are of unknown etiology.
Cystic fibrosis is an inherited disease of the exocrine glands affecting primarily the gastrointestinal and respiratory systems. It leads to chronic lung disease, exocrine pancreatic insufficiency, hepatobiliary disease, and abnormally high sweat electrolytes. Diagnosis is by sweat test or identification of 2 cystic fibrosis-causing gene variants in patients with a positive newborn screening test result or characteristic clinical features. Treatment is supportive through aggressive multidisciplinary care along with small-molecule correctors and potentiators targeting the cystic fibrosis transmembrane conductance regulator protein defect.
Dehydration is significant depletion of body water and, to varying degrees, electrolytes. Symptoms and signs include thirst, lethargy, dry mucosa, decreased urine output, and, as the degree of dehydration progresses, tachycardia, hypotension, and shock. Diagnosis is based on history and physical examination. Treatment is with oral or IV replacement of fluid and electrolytes.
Common causes of hearing loss are genetic defects in neonates and ear infections and cerumen in children. Many cases are detected by screening, but hearing loss should be suspected if children do not respond to sounds or have delayed speech development. Diagnosis is usually by electrodiagnostic testing (evoked otoacoustic emissions testing and auditory brain stem response) in neonates and by clinical examination and tympanometry in children. Treatment for irreversible hearing loss may include a hearing aid or cochlear implant.
Diabetes mellitus involves absence of insulin secretion (type 1) or peripheral insulin resistance (type 2), causing hyperglycemia. Early symptoms are related to hyperglycemia and include polydipsia, polyphagia, polyuria, and weight loss. Diagnosis is by measuring plasma glucose levels. Treatment depends on type but includes drugs that reduce blood glucose levels, diet, and exercise.
Amblyopia is functional reduction in visual acuity of an eye caused by disuse during visual development. Severe loss of vision can occur in the affected eye if amblyopia is not detected and treated early in childhood. Diagnosis is based on detecting a difference in best corrected visual acuity between the two eyes that is not attributable to other pathology. Treatment depends on the cause.
Human immunodeficiency virus (HIV) infection is caused by the retrovirus HIV-1 (and less commonly by the related retrovirus HIV-2). Infection leads to progressive immunologic deterioration and opportunistic infections and cancers. The end stage is acquired immunodeficiency syndrome (AIDS). Diagnosis is by viral antibodies in children > 18 months and virologic nucleic acid amplification tests (such as polymerase chain reaction testing) in children 18 months. Treatment is with combinations of antiretroviral drugs.
Hypertension is sustained elevation of resting systolic blood pressure, diastolic blood pressure, or both; the pressures considered abnormal in children vary based on age up to age 13. Hypertension with no known cause (primary) is most common as with adults. Hypertension with an identified cause (secondary hypertension) is relatively uncommon in children. Usually, children have no symptoms or complications of hypertension during childhood, although these may develop later. Diagnosis is by sphygmomanometry. Tests may be done to look for causes of secondary hypertension. Treatment involves lifestyle changes, drugs, and management of treatable causes.
Muscular dystrophies are inherited, progressive muscle disorders resulting from defects in one or more genes needed for normal muscle structure and function; dystrophic changes (eg, muscle fiber necrosis and regeneration) are seen on biopsy specimens. Facioscapulohumeral dystrophy is the most common form of muscular dystrophy, and Duchenne dystrophy and Becker dystrophy are the second most common. Duchenne dystrophy is a more severe form; Becker dystrophy, although closely related to Duchenne, has a later onset and causes milder symptoms.
Juvenile idiopathic arthritis is a group of rheumatic diseases that begins by age 16. Arthritis, fever, rash, adenopathy, splenomegaly, and iridocyclitis are typical of some forms. Diagnosis is clinical. Treatment involves intra-articular corticosteroids and disease-modifying antirheumatic drugs.
Attention-deficit/hyperactivity disorder (ADHD) is a syndrome of inattention, hyperactivity, and impulsivity. The 3 types of ADHD are predominantly inattentive, predominantly hyperactive/impulsive, and combined. Diagnosis is made by clinical criteria. Treatment usually includes drug therapy with stimulant drugs, behavioral therapy, and educational interventions.
Although it is sometimes assumed that childhood and adolescence are times of carefree bliss, as many as 20% of children and adolescents have a diagnosable mental disorder that causes impairment ( 1). With increasing age, more children develop one or more disorders. All told, about 27.9% of US adolescents aged 13 to 17 are reported to meet criteria for 2 or more disorders ( 2). Recent studies that follow children from birth to adulthood indicate that most adult mental health disorders begin in early childhood and adolescence ( 3, 4). Genes associated with mental health disorders have been reported to show high expression throughout the lifespan, beginning in the 2nd trimester and impacting neurodevelopmental processes, which may explain the early ages of onset ( 5). Most of these disorders may be viewed as exaggerations or distortions of normal behaviors and emotions.