PedSPAM August 1999

Welcome to PedSPAM for August. Here are some more things from my update reading that might interest you.

In the News

Big news on the immunization front:

First, the orally administered rotavirus vaccine Rotashield® was pulled from the market about 10 days ago when an increase in cases of intussusception was noted in recipients of the vaccine. More than 20 cases of intussusception were reported out of about 1,500,000 doses of vaccine given. This exceeded the baseline number of cases that would be expected in the population of infants receiving the vaccine by enough of a margin to cause suspicion of a causative link. The risk of occurrence of the complication seems to be clustered in the first three weeks after administration.

Assuming there is a causal link, I believe the way to understand it is as follows: intussusception occurs when small bowel folds in on itself and becomes trapped (be sure to follow the link to see the crude graphic I made). The inner surface small intestine is ordinarily very smooth and regular. If lymph nodes around the intestine ("Peyer patches") become excessively swollen, as they may do in response to any gastrointestinal infection, these enlarged lymph nodes may serve as a catch point to allow the wall of the bowel to become pushed through into itself. The vaccine produces an artificial, attenuated infection. Lymph node swelling from this infection is probably to blame.

Whether the risk of intussusception following artificial infection with the vaccine is greater or less than the risk of intussusception following natural exposure to rotavirus is anybody's guess right now. That question will have to be studied. It is too early to say if the vaccine will return to the market with additional warnings, or if it will be scrapped.

Thimerosal is a mercury-containing compound that has been used as an effective antibacterial preservative in vaccines since the 1930's. Many of the vaccines used routinely for children in the United States contain tiny amounts of thimerosal. While high doses of organic mercury compounds are known to be harmful (predominantly toxic to the nervous system), until now the only known concern with the low doses used in vaccine manufacture has been occasional allergic reactions. Now there is concern that the total amount of mercury exposure in very small infants receiving thimerosal containing products might cause harm to the exposed infants. This question is tricky because while safe levels of exposure are not really known, there has never been any question of observed ill effects from the thimerosal.

The result of this uncertainty has been that the AAP has recommended delaying the first dose of hepatitis B vaccine until at least the 2 month checkup and preferably until the 6 month checkup. This will end the practice of giving the first dose in the hospital at birth for the foreseeable future. Meantime, the FDA is urging vaccine manufacturers to seek alternative preservatives.

Addendum from a PedSPAM subscriber who is a Smith Kline Beecham representative:

Dr. Hull,
Engerix-B (hepatitis vaccine) "Thimerosal Free" should be available by September. Smith Kline already has it available and ready for shipment upon FDA approval. A point to remember from our product managers, there have been no adverse events with Engerix-B related to thimerosal in over 1/2 billion doses given.

Hope this is helpful,

Pat Starkey

The URLs to read the statements yourself are

Twins do not appear to be at greater risk for SIDS compared with singleton births. In addition, the occurrence of both twins dying of SIDS is uncommon, and the occurrence of both twins dying on the same day is extremely uncommon. Archives of Pediatric and Adolescent Medicine 1999;153:736-740

During episodes of diarrhea, feeding infants a soy-based formula with sucrose (Isomil®, Isomil-DF®) has a better outcome (lower stool output, shorter duration of diarrhea, and lower failure rates) than feeding infants a soy-based formula with lactose (Prosobee®). Archives of Pediatric and Adolescent Medicine 1999;153:675-680

From Pediatrics Vol. 104 No. 2 August 1999, pp. 263-269 comes an explanation of why the back sleeping position (supine) is safer than stomach sleeping (prone). Three Australian researchers found that when they experimentally infused tiny quantities of liquid (0.4 ml) into the pharynx of sleeping babies, the babies exhibited airway protective responses: swallowing (95%) and arousal (54%). There was a significant reduction in swallowing and arousal responses to these infusions when the prone position was compared with the supine position.

This stands as a further endorsement of the Back to Sleep campaign. This study should spur further research and repetition of the study on a larger scale to confirm it.

There has been a dramatic decline in the annual number of Reye's syndrome cases in the United States since 1980, according to a recent report from the Centers for Disease Control and Prevention (CDC). After a high of 555 cases were documented in 1980, the number of cases has declined rapidly, and since 1987 fewer than 37 cases have been reported each year. About 40% of all cases were in children younger than 5 years of age; more than 90% of all cases were in children younger than 15 years. Although Reye's syndrome is rare today, 20 years ago it was more common and was often reported in groups of children during or after outbreaks of influenza or chickenpox. Infectious Disease in Children, June 1999.

Helicobacter pylori is believed to be the causative germ of gastritis and peptic ulcer disease. Children who are infected with Helicobacter pylori but who have no symptoms and are not treated do not shed the infection spontaneously and eventually develop early signs of stomach irritation (gastritis). This progression of deterioration of the stomach lining could lead eventually to ulcer disease or even gastric cancer in adults. This study suggests that children who are colonized with this bacterium should perhaps be treated even if they seem well. Pediatrics Vol. 104 No. 2 August 1999, pp. 216-221

And on a related note, it seems that Helicobacter pylori infections are passed from parents, especially mothers, to their children. A preschool child's likelihood of having a Helicobacter pylori infection strongly correlates with the parents', and particularly the mother's, infection status, according to research from Germany. They speculate it is possible that the mother's oral secretions may be contaminated with H. pylori and that transmission may occur when mother and child share a spoon or taste each other's food. Pediatric News 33(4):28, 1999

Methylphenidate (Ritalin®) does not induce tics or Tourette syndrome in children treated for ADHD, according to research published in the Journal of the American Academy of Child and Adolescent Psychiatry 1999;38:944-951. The researchers found that children with attention-deficit hyperactivity disorder treated with methylphenidate (MPH) are no more likely to develop tics than children who receive a placebo. The researchers did caution that physicians and parents should still monitor for the appearance or worsening of tics until larger studies confirm these findings.

Parents of children with severe milk allergy often seek out kosher food products labeled "pareve," a label that signifies the absence of milk. A recent report (Pediatric News 33(4):4, 1999) warned that dark chocolate labeled pareve or milk free contains significant amounts of milk allergy producing substances, due to the difficulty in completely cleaning all traces of milk from mixing equipment used for both milk chocolate and milk-free chocolate.

The Department of Health and Human Services has recommended mandatory warning labels for cigars because of increasing cigar use among teenagers. In 18 focus groups conducted by the HHS Office of the Inspector General, more than a third of 227 young people said they had smoked a cigar in the last 30 days, and 54% had done so at some point in their lives. Several teens mentioned that many of their peers use cigars as "blunts"; the tobacco inside the cigar wrapper is removed and replaced with marijuana.

About 500 preventable deaths occurred in improperly restrained children in auto accidents in 1997, according to a study by the Department of Transportation and the National Highway Traffic Safety Administration. They recommend that all states require

It has long been known that alcohol consumption during pregnancy results in small babies because of intrauterine growth retardation. Now, Dr. Robert J. Sokol and his associates at Wayne State University, Detroit, have found that drinking also shortens the duration of gestation. They found that half of the reduction in size (an average of 5-1/2 ounces birth weight smaller) came from intrauterine growth retardation, and the other half was caused by shortened gestation time in the womb.

Removing allergens from the home environment is probably going to be easier. A solution of 1 part chlorine bleach and 20 parts water completely neutralized allergenic proteins within 1-3 minutes in clinical tests, according to Dr. Peyton Eggleston, professor of pediatrics at Johns Hopkins University in Baltimore. He urged caution before advising patients about the benefits of chlorine bleach, lest they begin dousing their homes with it. One concern is that chlorine bleach fumes could worsen asthma. Because of the low concentrations required, this may not be a problem. He does recommend using chlorine bleach on bedding to remove allergens, and speculates that other agents, such as peroxide, may prove even better.

There has been a "stunning and unprecedented surge in infectious diseases in Russia" since the breakdown of the Soviet Union. Due to a lack of medications and a crippled public health structure, "tuberculosis, HIV infection, and diphtheria are among the diseases absolutely exploding today in Russia." Next year, according to a January Atlantic Monthly article, an estimated 1.75 million deaths due to TB are predicted in Russia -- more than for heart disease and cancer combined. Pediatric News 33(4):20, 1999

The risk of sudden cardiac death from the use of tricyclic antidepressants is probably very low, according to a pediatric cardiologist at the annual scientific sessions of the American Heart Association. Seven sudden deaths have been reported in pediatric patients taking the tricyclic antidepressants desipramine (six deaths) and imipramine (one death) since 1986. Review of the cases found possible links in several cases, but the medication was probably exonerated in half of them. (Imipramine is a recognized treatment for enuresis (bedwetting) and is probably prescribed most often for this indication.) Pediatric News 33(4):31, 1999

There has floated about a purported link of the measles-mumps-rubella vaccine (MMR) to autism. According to the results of a large epidemiologic study published in Britain, there is no evidence to support this link. Lancet 1999;353:2026-2029

"Somatization," excessive complaining with vague aches and pains, may be an early warning of probable major depression in young adulthood, according to the results of a Canadian study. The researchers warned that as teens leave pediatric care and move on to internists and family medicine practitioners, their doctors should be on the watch for symptoms of major depression. Pediatrics 1999;103:1203-1209.

Many parents are still allowing their babies to sleep in the prone (stomach) position, despite the "Back to Sleep" campaign. A practice-based study conducted by the Children's National Medical Center Pediatric Research Network in Washington, DC found that only 34% of infants maintained a consistent sleep position. Prone sleeping increased from 12% at birth to 32% at 6 months. Only one third of pediatricians discussed sleep position beyond the newborn period. Male sex of the baby, lower maternal education level, single marital status, having siblings, and black race were all associated with lower rates of back sleeping. Perceived infant comfort was the main reason for prone sleeping. This is very distressing, since the evidence is overwhelming that it leads to preventable SIDS deaths. Archives of Pediatric and Adolescent Medicine 1999;153:512-517

A flurry of controlled trials of the gastrointestinal hormone secretin have begun with the blessing of the National Institutes of Health (NIH) in response to an unprecedented wave of reports that the hormone improves the function of autistic children. The discovery in 1996 that an autistic child who was given porcine (derived from pigs) secretin had a dramatic improvement in mental function within three weeks of receiving the hormone has led to further uncontrolled trials with some apparent success. The hormone was given as a routine part of endoscopy for an unrelated gastrointestinal problem. It is known that there are secretin receptors in the brain, and various biochemical mechanisms have been proposed for a possible mode of action. Until now, there have only been uncontrolled and anecdotal reports; the NIH wants to scientifically study this possible treatment to determine whether it truly works, if it is safe, and if so how best to administer therapy.

On a personal note: I will be undergoing elective surgery on August 23 and will be off-line for about a week. I will be back online from home after that, and back in the office September 13. Please let your friends know on the various chat boards that I will indeed be back and answer all emails just as soon as I can.

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