Pediatrics - Merck Manuals Professional Edition

Symptoms in Infants and Children

Colic is frequent and extended periods of crying for no discernible reason in an otherwise healthy infant.
Health Supervision of the Well Child

Well-child visits aim to do the following:
Childhood Vaccination

Vaccination has been extremely effective in preventing serious disease and in improving health worldwide. Because of vaccines, infections that were once very common and/or fatal (eg, smallpox, polio, diphtheria) are now rare or have been eliminated. However, except for smallpox, these infections still occur in medically underserved parts of the world.
- Childhood Vaccination
- Vaccine Hesitancy
Behavioral Concerns and Problems in Children

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, for example, they interfere with emotional maturation or social and cognitive functioning. Severe behavioral problems may be classified as mental disorders (eg, oppositional defiant disorder, conduct disorder).
Bone Disorders in Children

Congenital hypophosphatasia is absence or low levels of serum alkaline phosphatase due to mutations in the gene encoding tissue-nonspecific alkaline phosphatase (TNSALP).
Care of Newborns and Infants

Hand washing is critical for all personnel to prevent transmission of infection.
Caring for Sick Children and Their Families

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

Child maltreatment includes all types of abuse and neglect of a child under the age of 18 by a parent, caregiver, or another person in a custodial role (eg, clergy, coach, teacher) that results in harm, potential for harm, or threat of harm to a child. Four types of maltreatment are generally recognized: physical abuse, sexual abuse, emotional abuse (psychologic abuse), and neglect. The causes of child maltreatment are varied. Abuse and neglect are often associated with physical injuries, delayed growth and development, and mental health issues. Diagnosis is based on history, physical examination, and sometimes laboratory tests and diagnostic imaging. Management includes documentation and treatment of any injuries and physical and mental health conditions, mandatory reporting to appropriate government agencies, and sometimes hospitalization and/or foster care to keep the child safe.
- Overview of Child Maltreatment
- Female Genital Mutilation
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Chromosome and Gene Anomalies

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).
Common Viral Infections in Infants and Children

Measles is a highly contagious viral infection that is most common among children. It is characterized by fever, cough, coryza, conjunctivitis, an enanthem (Koplik spots) on the oral mucosa, and a maculopapular rash that spreads cephalocaudally. Complications, mainly pneumonia or encephalitis, may be fatal, particularly in medically underserved areas. Diagnosis is usually clinical. Treatment is supportive. Vaccination is effective for prevention.
Congenital Cardiovascular Anomalies

Congenital heart disease is the most common congenital anomaly, occurring in almost 1% of live births ( 1). Among birth defects, congenital heart disease is the leading cause of infant mortality.
Congenital Craniofacial and Musculoskeletal Abnormalities

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.
Congenital Gastrointestinal Anomalies

Most congenital gastrointestinal (GI) anomalies present as intestinal obstruction and frequently manifest as feeding difficulties, distention, emesis, and an inability to pass gas and stool at birth or within 1 or 2 days of age. Some congenital GI malformations, such as malrotation, have a very good outcome, whereas others, such as congenital diaphragmatic hernia, have a poor outcome (including having a mortality rate of 10 to 30% or even higher depending on the study) ( 1).
Congenital Neurologic Anomalies

Congenital brain anomalies cause a spectrum of neurologic deficits; although some may be barely noticeable, others may be fatal.
Congenital Renal and Genitourinary Anomalies

Congenital anatomic anomalies of the genitourinary tract are more common than those of any other organ system.
Congenital Renal Transport Abnormalities

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 (for Bartter syndrome) and electrolyte replacement.
Connective Tissue Disorders in Children

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 (CF)

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.
- Cystic Fibrosis
Dehydration and Fluid Therapy in Children

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.
- Dehydration in Children
- Oral Rehydration
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Miscellaneous Ear, Nose, and Throat Disorders in Children

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.
Endocrine Disorders in Children

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.
Eye Defects and Conditions in Children

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.
Gastrointestinal Disorders in Neonates and Infants

Gastrointestinal disorders can affect neonates and infants:
Growth and Development

Physical growth is an increase in size. Development is growth in function and capability. Both processes depend on genetic, nutritional, and environmental factors.
Hereditary Periodic Fever Syndromes

Hereditary periodic fever syndromes are hereditary disorders characterized by recurrent fever and other symptoms that are not explained by other causes.
How To Do Pediatric Urologic Procedures

Urethral catheterization is insertion of a flexible catheter through the urethra into the urinary bladder.
Human Immunodeficiency Virus (HIV) Infection in Infants and Children

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 medications.
- Human Immunodeficiency Virus (HIV) Infection in Infants and Children
- Antiretroviral Therapy in Children
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Hypertension in Children

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.
Infections in Neonates

Neonatal infection can be acquired
Inherited Disorders of Metabolism

Most inherited disorders of metabolism (also called inborn errors of metabolism) are caused by mutations in genes that code for enzymes; enzyme deficiency or inactivity leads to
Inherited Muscular Disorders

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

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.
- Juvenile Idiopathic Arthritis (JIA)
Learning and Developmental Disorders

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.
Psychiatric Disorders in Children and Adolescents

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 psychiatric disorder that causes distress and functional impairment ( 1). With increasing age, the prevalence of psychiatric disorders increases. All told, approximately 27.9% of US adolescents aged 13 to 17 are reported to meet criteria for 2 or more disorders ( 2). 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 psychiatric disorders have been reported to show high expression throughout the lifespan, beginning in the fetus 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.