Sleep and waking in US adolescents

Sleep and waking in US adolescents

Low blood pressure in VLBW infants: to treat or not Very preterm infants have very low blood pressures relative to term infants or adults. A clear def...

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Low blood pressure in VLBW infants: to treat or not Very preterm infants have very low blood pressures relative to term infants or adults. A clear definition for what is a lower than normal blood pressure for these infants remains elusive. The next conundrum is what to do if a low blood pressure is identified by whatever (almost) arbitrary criteria. If the decision is to treat, then the next decision tree to negotiate is with what to treat. Finally, if treatment is given, what are the criteria for success? Against this insecure background, Batton et al report their experiences with identification and treatment of hypotension in very low birth weight infants. Not surprisingly, infants deemed to have normal blood pressure had better neurodevelopmental outcomes than infants with low blood pressure, but treatment of low blood pressure did not improve outcomes relative to not treating low blood pressure. The observations were more hypothesisgenerating than conclusive because they were retrospective and the selection of patients for treatment of low blood pressure and the given treatments were not controlled. The results do suggest that although treatment may do no (further) harm, treatment of blood pressure in this population may also not do much good.

—Alan H. Jobe, MD, PhD page 351

Simple comfort during vaccine injections In this issue of The Journal, Dilli et al report results of randomized controlled interventions in two age groups of young children to reduce pain at time of injection immunization episodes. During injection, breastfed infants under 6 months of age were randomized to be nursed or not, and infants 6 months through 48 months were randomized to receive sucrose solution orally, lidocaine-prilocaine topically, or no intervention prior to injection. Duration of crying and validated objective pain scores were the primary outcome measurements. Compared with control groups, shorter duration of crying and lower pain scores were found in young infants who were actively breastfed and in older infants and toddlers who received oral sucrose or topical anesthetic. Additional analysis did not find association of pain with injection site, needle length, or injection technique but the mother’s behavior of attempting distraction tended to have beneficial effect. Simple “non-medical” techniques can reduce the trauma of vaccine injections for young children, parents, and healthcare personnel.

Sleep and waking in US adolescents Time diary analysis was performed using cohort data from 1981 and the period 2003-2006 by Knutson and Lauderdale from the University of Chicago. The results show that bed times and wake times were similar in 1981 and 2003-2006. Average time in bed on school days was about 8 hours and 9-10 on non-school days. The greatest predictor of wake time was school start time. Many adolescents spent less than the recommended 9 hours per day in bed on school days. Increased computer use and earlier start school days may contribute to the wide spread lack of adequate sleep among US adolescents.

—Robert W. Wilmott, MD page 426

The broad phenotype of homocystinuria Homocystinuria, an autosomal recessive disorder of sulfurcontaining amino acid metabolism, has a broad range of presentations and severity, and is now included in some newborn screening programs. Most of these screening programs use elevations in blood methionine as the marker. Recent advances in the molecular biology of homocystinuria have demonstrated that it is actually a family of disorders, with a variety of mutations in the cystothionine beta-synthetase gene. As population genetic studies have looked specifically for mutations in this gene, it has become clear that homocystinuria has a very broad range of clinical phenotypes, which may correlate with the specific mutations. In this issue of The Journal, Janosik et al report an elegant, very complex study of one of the mutations associated with homocystinuria: c.1105C⬎T. Some aspects of this study will be of greatest interest to metabolic specialists, but there are also messages here for all clinicians. As we are learning with cystic fibrosis, genetic disorders we once considered fairly uniform in presentation and natural history may actually be quite variable based upon the specific mutation involved. This is clearly the case with homocystinuria; indeed, because elevated methionine in the newborn period is not present in all forms of the disease, it may not always be detected on newborn screening. As we begin to dissect out the way in which specific mutations may (or may not) produce disease, we may also obtain clues to aid in therapy. For now, when clinicians consider homocystinuria in an older child with vascular disease, thrombophilia, or similar complaints, the fact that the child “passed” newborn screening is not sufficient to exclude the diagnosis.

—Thomas R. Welch, MD page 431

—Sarah S. Long, MD page 385

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March 2009

The Journal of Pediatrics