Crecimiento Normal

in brief

In Brief Normal Growth and Revised Growth Charts Centers for Disease Control and Prevention 2000 Growth Charts for the United States: Improvements to the 1977 National Center for Health Statistics Version. Ogden CL, Kuczmarski RJ, Flegal KM, et al. Pediatrics. 2002;109:45– 60 www.cdc.gov/growthcharts Developmental and Behavioral Pediatrics. Sulkes SB, Dosa NP. In: Behrman RE, Kliegman RM, eds. Nelson Essentials of Pediatrics. 4th ed. 2002. Philadelphia, Pa: WB Saunders; 2002:4 Obesity Evaluation and Treatment: Expert Committee Recommendations. Barlow SE, Dietz WH. Pediatrics. 1998;102:e29. Available at: http:// www.pediatrics.org/cgi/content/full/ 102/3/e29 Clinical Assessment of Growth. Berhane R, Dietz WH. In: Kessler DB, Dawson P, eds. Failure to Thrive and Pediatric Undernutrition. Baltimore, Md: Paul H. Brookes; 1999:195–214

When monitoring children’s growth, it is helpful to remember several rules of thumb: ●

●

●

●

●

Term infants usually lose 5% to 10% of their birthweight immediately after birth, but regain their birthweight within 2 weeks. Term infants double their birthweight in 4 to 5 months and triple it by 1 year of age. A child’s height doubles from that at birth by 3 to 4 years of age. The average size of 4-year-old children is 40 in and 35 lb. From 3 to 10 years of age, children grow an average of 2.5 in/y.

The pediatrician can monitor children’s growth more accurately by using growth charts, and the charts should be used at all health supervision visits. In

January 2002, the Centers for Disease Control and Prevention (CDC) published in Pediatrics the revised growth charts for children to replace those published in 1977. The revised charts, accompanied by technical reports, are also available at www.cdc.gov/growthcharts. The revision provides technical improvements in the infant charts. The old charts were based on a small sample of children from 1929 to 1975; the revised charts are based on five recent, ethnically diverse, national samples. The old charts were based largely on bottle-fed infants; the revised charts include infants who were breastfed. The old charts had a disjunction when making the transition from length (measured recumbent) in the infant sample (based in Ohio) to height (measured standing) for older children in the national sample; the revised charts all are based on the same national samples. Finally, the revised charts are for all ethnic groups. The revised charts include three new features: 1) The age range has been extended up to the 20th birthday; 2) The back of the charts for children ages 2 to 20 years shows the body mass index (BMI), a measure of obesity; and 3) Although clinicians generally use charts that have the 5th and 95th percentile lines, charts showing the 3rd and 97th percentiles (for cases at the extremes of growth) are available at the website. A statistical program, Epi Info, enables the clinician to calculate exact percentiles and standarddeviation scores (z-scores) for statistical summaries and comparisons. The website offers “clinical” growth charts, with the grids for graphing data aligned with metric units, and English units (pounds and inches) on the secondary scale. There are tables for data

entry and two charts to a page. Also available are “individual” growth charts, with grids aligned to English units and metric units on the secondary scale, but with no tables for data entry and only one chart to a page. It is important to use the back of the growth charts to monitor not only the growth of the head, but also to identify children who are becoming thin or fat. For children younger than 3 years, the charts show weight-for-length. This index is important for detecting children who are becoming thin because of inadequate nutrition, illness, or other factors. If these children are tall for their age, their weight may not be below the 5th percentile, and their thinness may be missed without the use of the weight-for-length measurement. Other children’s poor growth may manifest in poor linear growth, which may be due to normal shifting percentiles and family growth patterns but can also be due to undernutrition and illness. For children younger than 24 months, the clinician measures recumbent length; for those older than 3 years, standing height is measured. Between 24 and 36 months, infant charts (0 to 36 mo) or charts for older children (2 to 20 y) can be used. The infant chart requires measurement of recumbent length, and the older chart requires measurement of standing height. The infant charts show data more clearly; those for older children allow earlier use of the BMI. For children ages 2 to 20 years, the back of the revised growth charts provides the BMI. Because BMI varies with age, the charts show BMI-for-age. The BMI correlates well with body fat in measurements of body composition and Pediatrics in Review Vol.23 No.7 July 2002 255

in brief

so indicates overweight. The charts show the 85th percentile line as representing “at risk of overweight” and the 95th as “overweight.” In revising the growth charts for children 6 years and older, the most recent national survey (NHANES III) was not used because the proportion of children who were overweight had increased. BMI is defined as weight divided by the square of height. It can be calculated directly from metric units (meters and kilograms); with English units (inches and pounds), the data must be multiplied by 703. In clinical practice, BMI can be derived in four ways: with a pocket calculator; with an online cal-

culator available at the CDC website; with a table available at the CDC website; and with a PDA (personal digital assistant), using the program STAT Growth Charts (available at no charge from www.statcoder.com). Training modules at the website provide additional information about use of the revised charts. One module gives instructions and practice in calculating and graphing the BMI. The modules on proper weighing and measuring can enhance the training of pediatric office staff to make accurate measurements. The modules emphasize not weighing children wearing too many clothes and the use of a length

board for infants and a wall-mounted stadiometer for older children. The module on special-needs children contains special measurement techniques and advises caution in the use of growth charts specific to special conditions such as Down syndrome. Other modules address growth in head size, poor growth in infants and toddlers, growth and changes in the BMI during adolescence, summary and comparison of the growth of groups of children, and recommendations for overweight children and adolescents. Peter Dawson, MD, MPH Boulder, CO

In Brief Effects on the Fetus of Maternal Drugs During Labor Drugs in Pregnancy and Lactation. 5th ed. Briggs GG. Baltimore, Md: Williams & Wilkins; 1998:100 –104, 122–123, 432– 433, 539 –547, 578 –571, 610 – 612 629 – 630, 641– 646, 672– 674, 746 –748, 752–753, 768 –771, 947–952, 1004 –1008 The Impact of Maternal Illness on the Neonate. Landy HJ. In: Avery GB, Fletcher MA, MacDonald MG, eds. Neonatology: Pathophysiology and Management of the Newborn. 5th ed. Philadelphia, Pa: Lippincott, Williams & Wilkins; 1999:187–208 Obstetric Analgesia and Anesthesia. Rosen MA. In: Avery GB, Fletcher MA, MacDonald MG, eds. Neonatology: Pathophysiology and Management of the Newborn. 5th ed. Philadelphia, Pa: Lippincott, Williams & Wilkins; 1999:237–253 Obstetric Analgesia and Anesthesia. Fishburne JI Jr. In: Scott JR, ed. Danforth’s Obstetrics and Gynecology. 8th ed. Philadelphia, Pa: Lippincott, Williams & Wilkins; 1999:111–126 Maternal Analgesia During Labor Dis256 Pediatrics in Review Vol.23 No.7 July 2002

turbs Newborn Behavior: Effects On Breastfeeding, Temperature, and Crying. Ransjo-Arvidson AB, Matthiesen AS, Lilja G, Nissen E, Widstrom AM, Uvnas-Moberg K. Birth. 2001:28:5–12

For pediatricians, the concern during labor and delivery is the welfare of the baby. Many of the drugs routinely administered to the mother can have profound effects on the newborn that the pediatrician in the delivery room and nursery must manage. This brief considers the drugs commonly administered to healthy mothers in labor. (See also the article by Boyle RJ. Pediatr Rev. 2002;23:17–24.) Although some women prefer to give birth without pain medicine, most do receive analgesia. Several types of analgesics, including mepivacaine, bupivacaine, and meperidine, have been shown to delay spontaneous breastseeking of the newborn and breastfeeding behaviors in the newborn period

compared with infants of mothers who did not receive analgesia. Meperidine can cause decreased respiratory effort, decreased behavioral response, and electroencephalographic changes for several days after birth. Other narcotics, such as butorphanol and nalbuphine, cause a sinusoidal fetal heart rate pattern that can mimic signs of hypoxia, although these drugs do not cause hypoxic injury. Lorazepam sometimes is used to potentiate the effects of opioids and provide anxiolysis. Its use may prompt the “floppy infant syndrome,” which resolves spontaneously with no sequelae. Ketamine is used occasionally and can increase muscle tone, which subsequently can cause respiratory distress and lead to difficulties in intubation. Local anesthetics are used for epidural infusion and for direct injection at the site of an episiotomy. Although rare, there is a possibility of directly injecting the anesthetic into

in brief

the fetus. A local anesthetic entering the bloodstream of the fetus could cause apnea, hypotonia, tachycardia, and seizures. Oxytocin is a natural hormone that causes uterine contraction and is used to induce or augment labor. Oxytocin can cause the uterus to become tetanic, which can compromise placental blood flow and cause fetal distress. The drug also has the potential for producing forceful contractions of the uterus before the cervix dilates completely, which could lead to uterine rupture and trauma to the infant. Misoprostol is used for cervical ripening and labor induction, although the United States Food and Drug Administration has not approved it for this indication. Uterine hyperstimulation, with changes in the fetal heart rate and frequency of meconium-stained amniotic fluid, were more common among women given misoprostol than women given other uterine stimulants, but the birth outcomes were the same. Among the drugs used for tocolysis,

indomethacin can have deleterious effects on the newborn, although it has been reported to be less of a problem when administered before 32 weeks’ gestation. When administered at delivery, it can cause acute renal failure, bleeding (eg, intraventricular hemorrhage) due to inhibition of platelet aggregation, and intestinal perforation. When administered chronically for tocolysis, it can cause oligohydramnios and possibly premature closure of the ductus arteriosus. An additive constrictive effect occurs when betamethasone is administered to mothers in preterm labor to aid in fetal lung maturation. When women on beta blockers receive indomethacin, the interaction can cause severe hypertension and fetal death. Other tocolytic drugs are better tolerated. It has been hypothesized that magnesium sulfate reduces the risk of neonatal brain lesions in lowbirthweight infants. However, magnesium can make an infant areflexic and neurologically depressed and may cause

a reduction in calcium concentrations due to inhibition of parathyroid hormone. Nifedipine is generally welltolerated. Ritodrine is a beta-mimetic drug that, because of its sympathetic action, increases glycogen breakdown and causes hyperglycemia in the mother and hyperinsulinemia in the newborn. The baby may be hypoglycemic at birth. Ritodrine also can cause septal hypertrophy when used long term. Tocolytic, analgesic, and laborstimulating drugs are among the most common agents administered to healthy mothers. Awareness of the adverse effects associated with these medications, such as respiratory distress, whether from opiates or a prematurely closed ductus arteriosus, is essential to providing care for newborns.

RC, Bresee JS, et al. Pediatr Infect Dis J. 1998;17:605– 611

about viral diarrheal disease in infants and young children. Incubation periods are brief, usually 1 to 3 days. Infections can be asymptomatic, but if diarrhea develops, it frequently is associated with vomiting and fever. With the exception of rotavirus, the diarrhea produced by viral infection typically is mild to moderate. If stool studies are performed, they rarely reveal white blood cells or occult blood in the stool, and results of stool cultures are negative. Second only to rotavirus in frequency is adenovirus, which accounts for 5% to 10% of pediatric hospitaliza-

Andrew Hoyer, MD Children’s National Medical Center Washington, DC

In Brief Viral Causes of Diarrhea Rotavirus and Other Viral Causes of Gastroenteritis. Lieberman JM. Pediatr Ann. 1994;2310:529 –535 Viral Gastroenteritis. Matson DO, Pickering LK, Mitchell DK. In: McMillan JA, DeAngelis CD, Feigin RD, Warshaw JB, eds. Oski’s Pediatrics: Principles and Practice. 3rd ed. Philadelphia, Pa: Lippincott, Williams & Wilkins; 1999:1147–1151 Gastroenteritis. Northrup RS, Flanigan TP. Pediatr Rev. 1994;15:461– 472 Epidemiology of Diarrheal Disease Among Children Enrolled in Four West Coast Health Maintenance Organizations. Parashar UD, Holman

Rotavirus is the most commonly recognized viral pathogen that produces diarrheal disease in children and the most common cause of severe gastroenteritis requiring hospitalization. However, a number of other viruses can cause diarrhea, and their clinical manifestations are important to recognize in the care of children who have gastroenteritis. The viruses include adenovirus, Norwalk virus, astrovirus, and calicivirus. Some generalizations can be made

Pediatrics in Review Vol.23 No.7 July 2002 257

in brief

tions for acute gastroenteritis (compared with the 30% to 70% attributed to rotavirus). Serotypes 40 and 41 are the enteric strains known to cause gastroenteritis in children; these strains do not cause any of the respiratory symptoms commonly associated with other adenoviruses. The mean age of clinical illness in children is 1 to 2 years of age. Like rotavirus, transmission is by the fecal-oral route. Adenovirus has an incubation period of 8 to 10 days, which is considerably longer than that of the other common viruses. Symptoms last 5 to 12 days on average, with one third of children experiencing diarrhea for longer than 14 days. Patients may have vomiting or fever with adenoviral infection. Unlike rotavirus, there is very little seasonality associated with adenoviral gastroenteritis. An enzyme immunoassay test is available for detection of adenovirus, but it is not used frequently outside of research studies. Norwalk virus is also an important cause of viral gastroenteritis. This virus is spread both by the fecal-oral route and via contaminated food and water

258 Pediatrics in Review Vol.23 No.7 July 2002

sources. Outbreaks of diarrheal disease can occur in child care, schools, and other settings, commonly affecting older children and adults. The incubation period is usually less than 48 hours. Unlike adenovirus, the course of illness with Norwalk virus gastroenteritis is brief, lasting fewer than 48 hours, and generally is characterized by vomiting. Less commonly recognized causes of viral diarrhea include astroviruses and caliciviruses. Astrovirus infections can be asymptomatic, but also can cause diarrheal illness, with more than 50% of children also experiencing vomiting and fever. Detected most commonly in the winter, astroviruses have a short incubation period of 1 to 2 days. Caliciviruses also can cause mild diarrhea in infants and toddlers, although symptoms are seen in older children and adults as well. Both of these virus families have been associated with outbreaks at child care centers and in association with consumption of contaminated food or water. The primary concern for all diarrheal disease is prevention and treatment of

dehydration. Oral rehydration solutions, which are very effective in preventing and treating dehydration, are commercially available for children, and appropriate intravenous solutions may be used for fluid resuscitation of patients who do not tolerate oral fluids. All of the viral gastroenteritides are selflimited, and antibiotics play no role in their treatment. Marsha D. Spitzer, MD Guam Memorial Hospital Tamuning, Guam Comment: Worldwide, viruses are the leading cause of diarrhea. Among viruses, rotavirus is the major cause of severe diarrhea (Pediatr Rev. 1999;20: 39 –71). Unfortunately, vaccines have not provided the answer to rotaviral disease prevention. Handwashing and ensuring safe food and water supplies continue to be the mainstays of prevention of viral diarrhea. Tina L. Cheng, MD, MPH Associate Editor, In Brief

Experienced clinicians and specialists have much to teach us. Although textbooks and journal articles can be valuable sources of information, the person who deals regularly with specific clinical situations often can provide important insights that may be overlooked in general education. We would like to offer readers a chance to submit questions regarding problems they have encountered in their clinical practices to experts in the field. Have you noticed a changing clinical trend in your practice that you can’t explain? Did you have a patient just last week whose presentation caused you to think twice before proceeding with treatment? Have you read of new medications or techniques, but have not had a chance to apply them to your patients? Whatever your question, please submit it to us, and we will pass it on to an expert in the field to provide you with the information you need. Send your questions to: Robert J. Haggerty, MD Department of Pediatrics University of Rochester School of Medicine and Dentistry 601 Elmwood Avenue, Box 777 Rochester, NY 14642 We will handle your question promptly and publish a reply as quickly as possible.

Pediatrics in Review Vol.23 No.7 July 2002 259