Pediatric VFRs, Preemies, Adoptees, and Mountaineers

Abstract & Commentary

By Philip R. Fischer, MD, DTM&H

Dr. Fischer is Professor of Pediatrics, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN

Dr. Fischer reports no financial relationship to this field of study.

Synopsis: Recent publications suggest that children traveling to visit friends and relatives are at relatively high risk of increased exposure to infections, that former premature babies without persisting lung disease are safe at oxygen levels of commercial aircraft, that a single screening stool parasite exam might not be adequately sensitive in foreign-born adoptees, and that a child's past experience with altitude sickness is not necessarily predictive of future responses to altitude.

Source: Valerio L, et al. Epidemiologic and biogeographic analysis of 542 VFR traveling children in Catalonia (Spain). A rising new population with specific needs. J Travel Med 2011;18:304-309.

Approximately 2 million children cross internation-al borders each year, and many of them are traveling with older family members to visit friends and relatives (VFR) in the family's country of origin. Previous studies suggest that these children are at particular risk of missing potentially helpful pre-travel interventions and of becoming ill during travel. Now, investigators in Spain have compared demographic features of 542 pediatric VFR travelers and 156 tourist travelers younger than age 15 years.

The VFR travelers were younger and came for pre-travel care closer to the time of departure (22 vs. 32 days) than tourist travelers. They were more likely to stay in private homes and to visit rural areas during their trips. They also stayed overseas longer (52 vs. 17 days).

These data help identify reasons why VFR traveling children might be at greater risk of becoming infected and ill during their trips. It is not because they are "bad" or do something "wrong." Rather, it is because they are younger and have more prolonged exposures to infection vectors than do typical tourist travelers. All children traveling to developing countries should benefit from pre-travel care. We should especially focus our preventive efforts on younger travelers and on travelers embarking on long trips — whether they are visiting friends and relatives or not.

Source: Bossley CJ, et al. Fitness to fly testing in term and ex-preterm babies without bronchopulmonary dysplasia. Arch Dis Child Fetal Neonatal Ed 2011 Sept 13; Epub ahead of print: doi:10.1136/adc.2011.212001.

Commercial aircraft are pressurized to yield an environment similar to that containing 15% oxygen. Former premature infants with chronic lung disease (bronchopulmonary dysplasia) often need oxygen supplementation with air travel, but data were limited for former premature infants without lung disease. Forty-one term babies and 30 former premature babies without chronic lung disease were exposed to 15% oxygen for 20 minutes at 3 and 6 months corrected gestational age. Oxygen saturations dropped a median of 6%, and relative hypoxia was not different based on either gestational age or age at testing. Only 5% of term and 7% of pre-term (not statistically different) infants developed hypoxia (oxygen saturation < 90% for more than 2 minutes). Transient desaturations (an additional 4%-6%) occurred with feeding.

Significant desaturations are not likely in former premature infants during exposure to aircraft-like environments. Routine fitness-to-fly testing is not warranted in these babies unless they have known lung disease. At the same time, however, potential consequences of mild oxygen desaturations have not been fully studied.

Source: Staat MA, et al. Intestinal parasite screening in internationally adopted children: Importance of multiple stool specimens. Pediatrics 2011 Aug 8; Epub ahead of print.

Travel medicine practitioners are often involved in the care of families traveling overseas to adopt children. Returning "home," the adoptees are screened for potentially contagious, but perhaps asymptomatic, intestinal parasite infections. Standards of care have changed from an automatic screening of three stools on separate days to less extensive testing. Is that appropriate?

The authors evaluated 1,042 internationally adopted children who had undergone stool testing. Of these, 27% had a parasite identified. (Some were Blastocystis hominis, a parasite of limited pathogenicity. Giardia was most common and could have been identified by antigen testing rather than microscopic exam.) Parasites were more likely to be found in children from Ethiopia (55%) and Ukraine (74%) than in children from China (13%), Guatemala (9%), or Korea (0%). Of those with at least one positive result, a single stool was positive in 79%, and two separate stools found parasites in 92%.

These data give us a good clue about areas of risk for intestinal parasites (Ukraine and Ethiopia), and they point to the ongoing value of repeated stool samples to find parasitized children. The authors suggest altering current practice standards so as to routinely test multiple stool samples for recently arrived international adoptees.

Source: Rexhaj E, et al. Reproducibility of acute mountain sickness in children and adults: A prospective study. Pediatrics 2011;127:e1445-1448.

Many travel medicine practitioners use a traveler's previous experience at altitude to determine whether to provide acetazolamide for individuals going to high altitudes. Is it wise to withhold preventive treatment from a child going to altitude just because a previous similar trip was not associated with acute mountain sickness?

Swiss and Chilean investigators prospectively evaluated 27 children and 29 adults who resided at low altitudes during two separate trips to 3,450 meters elevation. On the first ascent, 62% of adults and 22% of children had mountain sickness, with 48% of adults and 15% of children becoming symptomatic on the second trip. No child had acute mountain sickness on both trips, but no adult without symptoms on the first trip developed symptoms on the second trip.

These data are novel in showing that acute mountain sickness might indeed be less common in children than in adults; previous experience and research had suggested otherwise. Interestingly, however, lack of mountain sickness on one trip does not imply that the child will be symptom-free on a subsequent trip nor does one symptomatic trip imply that a child is at significant risk of another. One could advocate for acetazolamide use in adults based on seemingly higher risk and repeatability of symptoms, but children are at lower and less predictable risk than their adult companions.