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Wednesday, October 19, 2011

Post #27 Proper Swaddling of Babies to Prevent Hip Dysplasia

In ten years of pediatrics I have only had a handful of cases of hip dysplasia. Hip dysplasia is when the hip joint (a ball and socket joint) does not develop appropriately and can lead to dislocation and improper development which in turn can lead to mobility issues in the future. Mostly, I have seen this occur in breech babies (legs are in funny positions in the womb), females (hip anatomy makes it have a higher propensity for issues than males), first born babies (the womb is tightest in the first pregnancy leaving less room for the baby and his/her hips), and low amniotic fluid (less room in the womb).

Recent evidence indicates that improper swaddling may contribute to hip dysplasia. Like other parts of the baby, the hip continues to develop and mature even after the baby is born. Proper assessment of the above risk factors and routine physical exams by your pediatrician can catch infants who have hip dysplasia. Parents can do their part in minimizing risks by using proper swaddling techniques which will allow for proper maturation of the hip joints.

The below information is from the International Hip Dysplasia Institute. There is a link embedded in the text that takes you to their web page where 3 different techniques for proper swaddling are demonstrated in a YouTube video. Although the risks with most current swaddling techniques are minimal, this intervention carries no side effects, incurs no costs, and is easy to do - so there is no reason not to try it!

Hip-Healthy Swaddling

Are you swaddling your baby properly?

Improper swaddling may lead to hip dysplasia or developmental dysplasia of the hip. When in the womb the baby's legs are in a fetal position with the legs bent up and across each other. Sudden straightening of the legs to a standing position can loosen the joints and damage the soft cartilage of the socket.

Many parents find that swaddling can provide comfort for fussy babies, reduce crying, and develop more settled sleep patterns. When babies are swaddled, care should be taken to swaddle properly so the baby is safe and healthy.

There are many ways to swaddle babies by using blankets or commercial products designed for swaddling. In order for swaddling to allow healthy hip development, the legs should be able to bend up and out at the hips. This position allows for natural development of the hip joints.

The baby’s legs should not be tightly wrapped straight down and pressed together. Swaddling infants with the hips and knees in an extended position may increase the risk of hip dysplasia and dislocation.

Instructions on how to swaddle properly

Watch the video at this link to learn three, hip-healthy methods to swaddle your baby:

If you can't view the above video, here is one of the methods described in text:

1. If using a square cloth, fold back one corner creating a straight edge.

2. Place the baby on the cloth so that the top of the fabric is at shoulder level. If using a rectangular cloth, the baby's shoulders will be placed at the top of the long side.

3. Bring the left arm down. Wrap the cloth over the arm and chest. Tuck under the right side of the baby.

4. Bring the right arm down and wrap the cloth over the baby's arm and chest.

5. Tuck the cloth under the left side of the baby. The weight of the baby will hold the cloth firmly in place.

6. Twist or fold the bottom end of the cloth and tuck behind the baby, ensuring that both legs are bent up and out.

It is important to leave room for the hips to move.

What about sleepsacks and commercial products?

Some parents choose to wrap their babies in sleepsacks specifically designed for swaddling, instead of using a simple cloth or blanket. Commercial products for swaddling should have a loose pouch or sack for the baby’s legs and feet, allowing plenty of hip movement. However, even some of these commercial products can confine the legs if they are tightened around the thighs.

It's especially important to allow the hips to spread apart and bend up. In the womb the legs are in a fetal position with the legs bent up across each other. Sudden straightening of the legs to a standing position can loosen the joints and damage the soft cartilage of the socket.

Final Thoughts

When put down to sleep, a swaddled baby should be placed on his or her back, face up.

If the baby can roll onto his or her stomach this may increase the risk of suffocation. Seek the advice of your child’s healthcare provider if swaddling an older or more active baby.

Saturday, September 3, 2011

Post #26 Flu Shot Update 2011

Flu viruses are always changing. Each year, experts study thousands of flu virus samples from around the world to figure out which viruses are making people sick and how these viruses are changing. With this information, they forecast which three viruses are most likely to make the most people sick during the next flu season. These strains are then used to make the flu vaccine for the next flu season.

This year’s three flu strains included in the vaccine remain the same as last year’s vaccine:

* A/California/7/2009 (H1N1)-like virus
* A/Perth/16/2009 (H3N2)-like virus
* B/Brisbane/60/2008-like virus)

As noted above, this year's seasonal flu vaccine will again include the Novel 2009 H1N1 flu strand (A.K.A. A/California/7/2009 (H1N1)-like virus) which was used during the global pandemic and which was also included in last year's flu vaccine. This means your child will only need to get vaccinated with one type of flu immunization this year.

However, if your child is under 9 years of age AND did not receive the seasonal flu vaccine last year (the 2010-2011 flu vaccine), they will need to get 2 immunizations this year. This rule applies to both the nasal flumist and the injectable vaccine.

Flu shots given prior to the 2010-2011 flu vaccine (including the single strand Novel 2009 H1N1 vaccine) do not factor into this year's decision making tree. Please note that this is a different policy from previous years.

Here is a decision tree to help you know how many flu vaccines your child needs this year (you must answer both questions in the order shown):

Is your child 9 years or older?

Yes: Only one immunization is needed this year.
No: Go to the next question -->

Did your child receive at least one 2010-2011 seasonal flu vaccine?

Yes: Only one immunization is needed this year.
No: Two immunizations are needed this year.

If your child needs 2 flu vaccines this year, they should be spaced apart by a minimum of 4 weeks. There is no deadline by which the 2nd flu vaccine needs to be completed, but once the minimum 4 weeks has passed, the sooner the better.

Yearly flu vaccination should begin in September or as soon as the vaccine is available and continue throughout the influenza season, as late as March or beyond. The timing and duration of influenza seasons vary.

While influenza outbreaks can happen as early as October, most of the time influenza activity peaks in February or later. About 2 weeks after vaccination, antibodies that provide protection against influenza virus infection develop in the body.

In general, it is best to get your flu shot a.s.a.p. because you never know when the flu season will start!

For more information on the flu vaccine from the CDC click on this link.

Sunday, June 26, 2011

Post #25 Pediatrics is Priceless

An extra blue scrub top is tucked away in the lower right cabinet of the nurse's station. Every so often, after being sprayed with bodily fluid, I have to make a midday swap of my work clothes. However, it's a small price to pay to be a part of children's lives; one day the baby who spits up on your shoulder will be the same kid who runs down the hall screaming your name and clings to your leg with the dexterity of a koala. What makes pediatrics so rewarding is the long-term relationships that you build with children and their families who every day make you feel like a small hero.

Practicing general pediatrics often feels like searching for a needle in a haystack. Hidden in a sea of upper respiratory infections, reflux, eczema, and diaper rashes is a cystic fibrosis diagnosis, for example, that the astute clinician must not overlook. There are enough challenging cases to keep you on your toes to make everyday clinic interesting, but they don't overwhelm you. As a result, you'll have plenty of time each day to build new relationships and foster old ones. These relationships create the backbone of a successful pediatrician's practice.

To finish reading click here.

Friday, April 15, 2011

Post #24 A Follow-up to the Risks of Cell Phones

I think employing the precautionary principle with cellphones is a reasonable idea depending on the circumstances. If it starts to impair your quality of life, I would argue the current safety profile of cellphones justifies a fairly liberal approach to their usage.

For example, as a pediatrician I get a lot of calls and I try to use my cellphone to return calls during downtime moments of my life so that when I get home I can maximize my time with my kids. I use my cellphone a lot (rather than waiting to arrive home and use my landline) and would not change this facet of my life as the risk of a brain tumor to me seems so remote and the time with my kids is tangible and valuable.

However with my kids, I will likely employ a stricter application of the precautionary principle. My children's skull bones are thinner secondary to physical immaturity and their brains are more plastic and still developing. Furthermore, their lifestyles will not dictate a heavy need for constant connectivity (at least not early on in life). Perhaps a cellphone that will only connect to my phone and my wife's phone? I doubt that this would be over-utilized!

I realize that this sounds contradictory to my previous blog where I concluded that I felt comfortable sending my kids to a school where a new cell phone tower is being built. My wife and I remain comfortable with that decision. As written previously, we are happy with our neighborhood elementary school and the good certainly outweighs any risk I might ascribe to radiaton from a cell phone tower (risk that I still believe is very low as further supported by a NYT article from April 13, 2011 - snippets of which I have posted below).

However, when it comes to the weighing of pros and cons in regards to my child carrying a cell phone and using it habitually, not many pros come to mind. Of course safety and better communication are a few positives, but I hope to achieve that with other means and I would not be opposed to a cell phone programmed to only communicate with a set directory.  Of course, as my child matures - both physically and emotionally - I will likely liberalize their phone usage. 

Even if there were no health concerns, there are other issues at stake - sexting, distractions at school, driving and dialing, and over-usage to name a few.  The bottom line is that the health risks seem small and possibly zero. However, there are many reasons to limit the habitual use of a cell phone in a young child and the precautionary principle adds one more reason to the list, but it likely is just that - a precaution.

From the April 13, 2011 NYT. . . here are some excerpts from an excellent article titled "Do Cellphones Cause Brain Cancer" written by Siddhartha Mukherjee who is an assistant professor of medicine in the division of medical oncology at Columbia University. He is the author of “Emperor of All Maladies: A Biography of Cancer.”

The most exquisite — and arguably the most sensitive — means to identify a carcinogen is to study the effects of the substance not on humans or animals but on cells. In the 1970s, a Berkeley biochemist named Bruce Ames devised a cellular test to do just that. Ames’s test is based on a series of simple principles. Normal cells in the body grow through cell division, or mitosis, which is carefully regulated by genes. Certain genes accelerate growth, while other genes dampen or stop it. Cancer originates when the “accelerator” genes are permanently activated or when the “brake” genes are permanently damaged. Since genes are encoded by DNA, chemicals that mutate DNA — mutagens — can alter the growth-controlling genes and thereby cause cancer. Ames devised a special strain of bacterial cells that act as a “sensor” for mutations and therefore can also detect mutagenic chemicals. Chemical mutagens are so commonly carcinogenic that versions of the Ames test represent the gold standard by which most carcinogens are found.

Cellphone radiation is not a chemical, of course, but the rules about mutagenicity still apply (X-rays, for instance, are known to cause cancer and are detectable by Ames’s test). Laboratory experiments that link phone radiation to DNA mutation using a version of the Ames test have been largely contradictory. In 2005, a panel of experts, including a biomedical engineer, an epidemiologist, a genetic toxicologist and a radiation biologist, published a review of nearly 1,700 scientific papers on the cellular effects of radiation emitted by phones. In the review of more than 50 experiments linking phone radiation to DNA damage in animal or bacterial cells, evidence of damage has been negative in more than two-thirds of the studies. Since nonionizing radiation cannot directly affect the structure of DNA, experiments linking phone radiation to DNA damage are generally unconvincing. The most striking study linking cellular phone radiation to DNA damage, published in 2005 by researchers from the Medical University of Vienna, has recently been embroiled in even deeper scientific controversy: researchers studying the data intensively have argued that the original study is fraudulent.

But it is possible for something to be a carcinogen without directly damaging DNA. Some chemicals might activate growth pathways or survival pathways in cancer cells (eventually damaging DNA and mutating genes — but indirectly). Exogenous estrogen, for instance, activates growth pathways in breast cells and can cause breast cancer but doesn’t damage DNA. Others may provoke inflammation, creating a physiological milieu in the body that allows malignant cells to grow and survive. Yet others — the class of substances that we know least about — might not damage DNA directly but chemically modify genes so that their regulation is changed. These substances are like the dark matter of the carcinogenic world: they are barely visible to our current tests for carcinogens and thus lie at the boundaries of the knowable universe. Cellphones and their radiation have been tested for many of these properties — for instance, their ability to chemically modify DNA without causing mutations — but evidence linking this form of radiation to such cellular changes remains largely negative.

This section is about animal studies. . .

Nonetheless, biologists have exposed mice and rats to chronic nonionizing radiation (comparable to that emitted by phones) to determine whether it causes cancer. In rats prone to developing breast cancer, there was no acceleration of breast cancer. In another experiment, rats were treated with a chemical carcinogen in utero (to “prime” them to develop brain tumors) and then exposed to radiant energy comparable to cellphone radiation for two hours per day, four days a week, for 22 months. The experiment revealed no increased incidence of brain tumors in rats. Nor was there any accelerated growth in previously established brain tumors. From 1997 to 2004, six independent experiments on mice and rats studied the effects of chronic radiation on brain cancer. No experiment revealed an increased risk of brain cancer.

An excellent article and if you would like to read it in full here is the link.

Wednesday, March 23, 2011

Post #23 Assessing the Risk of Cell Phones to Children's Health

Recently, our local elementary school allowed a cellular company to hoist a cell phone tower next to the cafeteria. Apparently, the school district will receive some monetary subsidy in exchange for allowing the tower to be built. I am unaware of the politics, legislation and deal-making that allowed this to happen; however, as a local pediatrician (with one child and many patients who attend this school) I felt compelled to do some cursory research into the potential health hazards (if any) regarding long term exposure to a cell tower.

As I am not an expert in epidemiology, radiation, cellular technology or cancer, I have posted snippets of the most relevant research I have found. And although I have my personal misgivings about the actual process that led to the cell tower being erected, I have tried to stick to the facts in regards to the health risks (the editorializing comes mostly at the end).

The main bias may be in the selection of websites that I chose to research - mostly government agencies - which I realize may be a problem for some.

Like most debates, evidence for both sides can be found on the web. The evidence in general seems to favor that there is no appreciable risk from cell phone radiation. Most organizations that I trust (CDC, WHO, FDA, NIH) all post evidence on their websites that generally conclude that cell phone usage has not shown a statistically relevant risk in developing cancer.

1. National Cancer Institute
This link is a nice primer on the health risks of cell phone use and a good summary of the reputable information available. The general conclusion is that "there is currently no conclusive evidence that non-ionizing radiation emitted by cell phones is associated with cancer risk."

The National Cancer Institute also reports that a "Nordic study is expected to provide some results on children in the next few years. Plans are also under way for a study called MOBI-KIDS, which would evaluate risk from new communications technologies, including cell phones, and other environmental factors in people between age 10 and 24."

2. National Institutes of Health
This link is to a subsection of the NIH website which summarizes an interview with Toxicologist, Dr. Michael Wyde, who is overseeing the National Toxicology Program (NTP) cell phone studies.

In the interview Dr. Wyde states, "Currently, there’s little or no evidence to suggest that cell phone usage is associated with brain tumors or any other adverse health effects in humans."

3. World Health Organization
Key facts listed in this link show:
• Mobile phone use is ubiquitous with an estimated 4.6 billion subscriptions globally.
• To date, no adverse health effects have been established for mobile phone use.
• Studies are ongoing to assess potential long-term effects of mobile phone use.
• There is an increased risk of road traffic injuries when drivers use mobile phones (either handheld or "hands-free") while driving.

4. Center for Disease Control
This blog commented on a large epidemiologic study called INTERPHONE which was funded by the European Union and health agencies in 13 countries. From 2000 to 2005, INTERPHONE interviewed 14,000 adults about their cell phone use, other exposures to RF radiation, and other factors conceivably related to brain cancer.

The study concluded that, "overall, no increase in risk of [brain cancer] was observed with use of mobile phones. There were suggestions of an increased risk... at the highest exposure levels... However, biases and errors limit the strength of the conclusions we can draw from these analyses and prevent a causal interpretation... The possible effects of long-term heavy use of mobile phones require further investigation."

5. Food and Drug Administration
This webpage focuses on the risks of cell phone radiation to children. "The scientific evidence does not show a danger to any users of cell phones from RF exposure, including children and teenagers."

6. Wikipedia
Under the cancer subheading in this Wikipedia entry there are is a list of studies both for and against the risks of cell phone radiation.

7. British Medical Journal

BMJ 2010; 340:c3077 doi: 10.1136/bmj.c3077 (Published 22 June 2010)

This case-control study looks at mobile phone base stations and early childhood cancer risk in children born to mothers who lived near cell phone towers during pregnancy.

Paul Elliott, professor of epidemiology and public health medicine, head of department, director, MRC-HPA centre for environment and health, concludes that "there is no association between risk of early childhood cancers and estimates of the mother’s exposure to mobile phone base stations during pregnancy."

Overall the current body of evidence gives me solid relief about cell phones and the lack of health risk they pose.

However, one thing that frustrated me in my research was that I could not find a significant amount of information on health risk secondary to cell phone towers. Understandably, most of the research is concentrated on cell phone usage.

Several articles did comment that cell phone usage exposed the body (and more specifically the brain) to higher radiofrequency energy then a cell phone tower did; however none of the articles really went into detail about distance from the tower, hours near the tower, etc.

One could then extrapolate that if studies are showing that cell phone usage is safe, then exposure to a cell phone tower must also be. But as a parent, I would obviously feel safer and less anxious if there were clear studies in regards to cell phone towers.

The BMJ article cited above discusses cell phone towers and finds no risk to the children of woman who lived near the towers during pregnancy. However there were some debatable flaws to the study and although the conclusion is assuaging, the more studies the merrier.

Interestingly, several websites cautioned that the risks of driving while using a mobile phone were greater than the risks from the radiation exposure itself. Guilty as charged!

In the end my research made me feel better about my child's (and patients') exposure to a cell phone tower, but not completely at ease. It's the unknown that gnaws at me – but I suppose there will always be some level of unknowing.

Would I rather the cell phone tower not be built? Yes. But this may be more NIMBYism than true health concern.

Would I vote to stop it? Yes.

Am I going to fight a long battle to stop it? There are probably better and more productive ways my time could be spent for my child (unless of course the risk of cell phone towers becomes more real in future research).

Am I going to move schools because of this? I doubt it. Our family as a whole is very happy with the school and this potential but unlikely risk doesn't seem to warrant a move.

As in life, every decision carries some risk. We take some risk every time we send our child to school, but as parents we have to decide if the good outweighs the bad. And while my wife and I would rather not see a cell phone tower erected, ultimately, as of this writing, the research leads me to believe very little has changed with the bad.

Wednesday, March 9, 2011

Post #22 Fever Phobia Deconstructed

An excellent article detailing how parents and pediatricians should approach fever. I absolutely agree that the comfort of the child supersedes the fear-driven need to bring the number of the fever down.

My motto in the office is "treat the child, not the fever". In fact this motto can be extended to almost any other symptom, i.e. "treat the child, not the cough". As with all symptoms, it is far more important to elucidate the source of the fever rather than to focus on the fever itself.

The same goes with cough, runny nose, rashes, etc. If the source is benign then one need not worry about the symptom itself. Which does not mean you shouldn't treat the symptom - if there is discomfort it should be addressed.

On the otherhand, if a pediatrician suspects that the source may be of concern, i.e. pneumonia, meningitis, kidney infections - a more extensive evaluation, closer monitoring and treatment will be called for.

Sweating Out a Fever
Focus on Symptoms, Not Just the Number on the Thermometer, Doctors Advise
Wall Street Journal March 1, 2011

When a child's temperature begins to rise, worried parents often spring into action, marshaling cool washcloths and pain relievers, making frantic calls to the doctor or even visiting an emergency room.

Now, the American Academy of Pediatrics is telling parents that the number the thermometer displays is just a number—and that making a feverish child comfortable is far more important than bringing his temperature to 98.6 on the dot.

Fevers are the main reason for one-third of calls and visits to pediatricians.

"The signs and symptoms provide much more information than just the fever itself," says Janice E. Sullivan, a professor of pediatric critical care at the University of Louisville School of Medicine in Kentucky and co-author of an AAP report on fevers, released Monday.

The report, aimed at calming what it calls "fever phobia," also says there is no evidence that lowering a fever will help a child get well faster, or that leaving a fever untreated could cause seizures, brain damage or death, as some caregivers fear.

Many pediatricians have given parents a similar message for decades, but it hasn't sunken in. There's widespread confusion over what fevers in both children and adults signify, when to treat them—even what constitutes an official "fever" (100 degrees Fahrenheit? 100.4?) Many parents also rely on the thermometer to tell them how sick a child is when he's too young to talk. To some, it's an objective measure, which can't be faked, of whether an older child should be packed off to school or sent back to bed.

Fevers are the main reason for one-third of calls and visits to pediatricians, the report notes. Yet many beliefs about them are based more on culture, tradition and playground chatter than scientific evidence. Ads showing parents fretting over thermometers confuse things further.

Drugstore Dangers
These days, navigating the world of children's pain relievers is almost as tricky as interpreting a child's temperature.

Johnson & Johnson's McNeil Consumer Healthcare unit recalled 136 million bottles of liquid Tylenol, Motrin, Zyrtec and Benadryl for infants and children last year after federal investigators found bacterial contamination and other problems at a plant in Pennsylvania. Subsequent recalls included Children's Tylenol Meltaway strips in bubblegum flavor, Junior Strength Motrin caplets and Children's Benadryl Allergy Fast Melt tablets in cherry and grape.

Problems ranged from moldy smells to floating metal particles to the possibility of excess concentrations of an ingredient. In a legal filing last week, Johnson & Johnson said alternative supplies are expected to be available in the second half of this year.

In their absence, many parents have turned to generics and drugstore brands, children's Advil or Triaminic, another liquid acetaminophen for children.

Experts are still concerned about combination cough-and-cold syrups. Manufacturers voluntarily withdrew those labeled for children under age 2 in 2007 after pediatricians complained that they didn't work well and posed a risk of accidental overdose. But this week's American Academy of Pediatrics report warns that parents should not give cough-and-cold products containing acetaminophen even to older children, given the risk that they might unknowingly take other products with acetaminophen, which can cause fatal liver damage at high doses.

Many liquid medications for children still on the market have confusing dosing information, according to a study in the Journal of the American Medical Association in December. For example: a label calling for a one-teaspoon dose packaged with a cup marked in milliliters. Since the study was conducted, the Food and Drug Administration issued voluntary guidelines for making children's medication labels easier to understand. The researchers, from New York University, plan to repeat the study to see if the guidelines have made a difference.

In the meantime, experts say, parents should pay very careful attention to dosing information since even small errors can have big consequences in children.

Melinda Beck ."There's a huge desire to do the right thing, but when we think we're healing the child, we may be really treating ourselves" by taking action, says Glen Stream, president-elect of the American Association of Family Physicians.

Experts stress that a fever isn't an illness, it's a response, probably an evolutionary adaptation to help fight infection. Setting the body's thermostat (the hypothalamus gland in the brain) a few degrees higher slows the reproduction of bacteria and viruses and boosts white blood cells.

There's some evidence that illnesses may resolve faster when fevers are left untreated, the report notes. At the same time, elevated temperatures themselves can cause discomfort in children by interfering with sleep, appetite and activities.

"If your child looks uncomfortable, then treat the discomfort with acetaminophen or ibuprofen," says Dr. Sullivan. But she says a fever alone with no other symptoms doesn't need treating. "The fever itself doesn't tell us how ill the child is. There isn't a good correlation."

The report, which is aimed at pediatricians, not parents, doesn't specify other ways to make a sick child more comfortable. But Dr. Sullivan says parents should be on the lookout for rashes, irritability and altered mental status.

"Anytime you have a significant change in behavior, you need to talk to your doctor," says Henry Farrar, who practices pediatric emergency medicine at Arkansas Children's Hospital and co-authored the report. It also stresses the need for rest and proper fluid intake.

If a fever-reducing medicine is warranted to make a sick child more comfortable, the report says there is no substantial difference between acetaminophen and ibuprofen in safety or effectiveness. But it warns against combining them or alternating them—which some doctors recommend—because it compounds the risk of errors.

Some temperatures are cause for concern all by themselves. But going strictly by the numbers on a thermometer can be misleading, since people can react differently to the same infections.

The report also stresses the importance of checking package labels for the correct dosages, which are based on weight and age in children. As many as half of all U.S. parents give children incorrect doses, according to the report.

And if a child is asleep, he shouldn't be awakened just for medication, the report notes. In one study, 85% of parents said they had done so.

There are some cases where a fever alone can be worrisome. Parents should contact a doctor immediately if an infant under 3-months old has a fever of 100.4 or higher, which could signal a serious infection. Children with underlying conditions, such as weak heart muscles, may not be able to tolerate a fever and should get medical attention if one appears.

Children and adults can spike fevers as high as 106 due to hyperthermia, or "heat stroke," a malfunction in the body's ability to cool itself, often after physical exertion in hot weather. Drinking fluids and being immersed in cool water can help; fever-reducing drugs don't.

Fevers can occur in children and adults for many other reasons, including auto-immune diseases like lupus, cancers like leukemia and lymphoma and just normal teething. Some people routinely run fevers even with minor illnesses, and some people seldom get them. (Rare fevers that last for weeks with no apparent reason are known as FUOs—fevers of undetermined origin.)

Even the classic 98.6 isn't so much "normal" as "average," experts note. A healthy person's temperature varies much as a full degree during the day, reaching highest in the evening and lowest between about 6 a.m. and 9 a.m. (just when tough school-or-bed decisions are being made.)

Given all that variability, does it make sense to check the thermometer at all?

Yes, doctors say. Since most fevers accompany viral infections, experts agree that children with temperatures above 100.4 should stay home until they are fever free, without medication, for at least 24 hours, whether they have symptoms or not.

The same goes for adults—and they shouldn't be under the illusion that lowering a fever with medication also lowers their chance of infecting coworkers, experts say. "We really don't want people with fevers to be in the workplace," says Robert Hopkins, a University of Arkansas professor of internal medicine who serves on the American College of Physician's clinical guidelines committee.

The illnesses with little or no fever pose more of a dilemma. Some viruses are most contagious in the early stages, before a fever has developed. Others, like last year's H1N1 virus, made many people miserable but seldom caused fevers.

That can make for tough calls for parents and school nurses when it comes to deciding whether a child who complains of illness, but doesn't have a fever, should be in school.

"Sorting out the difference between a math-anxiety headache and an illness that could be contagious or prevent a child from learning is a judgment call," says Amy Garcia, executive director of the National Association of School Nurses. It helps to know the child very well, she says. "I had three boys myself, so I know the drill pretty well."