Posts Tagged ‘toddlers’

Reading to your children has demonstrable positive effects on their brain development

August 13, 2015  |  General  |  No Comments

The beneficial effects of stimulating a child’s brain have been known for decades, at least in general terms. That is to say, children who have been regularly played with, read to, and generally interacted with by adults have a great advantage over those children who did not receive these things. The key period for this appears to be up to the age of three years. For an example of this sort of research see here, whose authors conclude:

Child development was strongly associated with socio-economic position, maternal schooling and stimulation.

General observations like this demonstrate how mental growth is entangled with the effects of socioeconomic status. Children who are economically disadvantaged encounter many problems that affect cognitive development, such as poorer nutrition, more chaotic home life, and emotional stress. Any solid information on the effect of stimulation, and of what kind, would help us sort out the relative importance of these various things. Now we some fascinating recent data about that issue.

A recent study used functional magnetic resonance imaging (fMRI) to examine just what reading to a child does to the child’s brain. The reason to examine reading in particular is that literacy and language skills correlate  with later achievement. As the investigators state:

Disparities in home cognitive environment during childhood can have dramatic impact on achievement and health. Parent-child reading has been shown to improve certain emergent literacy skills, though its effect on the brain has not yet been shown.

So a big question here is precisely what does mental stimulation, particularly reading, do to a child’s brain? Can we document what is happening between the ears? Now we have some information about that. The investigators did fMRI scans on children to identify what regions of the brain reading activated. What they found was this (from the American Academy of Pediatrics summary):

Results showed that greater home reading exposure was strongly associated with activation of specific brain areas supporting semantic processing (the extraction of meaning from language). These areas are critical for oral language and later for reading. Brain areas supporting mental imagery showed particularly strong activation, suggesting that visualization plays a key role in narrative comprehension and reading readiness, allowing children to “see” the story. This becomes increasingly important as children advance from books with pictures to books without them, where they must imagine what is going on in the text.

It is important that these observations held up even after controlling for socioeconomic status. I should note that this research is reported in what we term abstract form — the complete details are yet to be published. It also has not been confirmed (as far as I know) by other investigators yet. Even with these caveats, finding a physical locus in the brain for complicated mental events is exciting stuff.

There is a footnote to this research that goes back to the Baby Einstein controversy in 2007. If you didn’t know, the Baby Einstein products were videos whose authors claimed were educational in the sense of improving learning and brain development in infants and toddlers. The company was sued for false advertising claims and the Disney Corporation (the owner) paid out refunds to those who had bought them. More about that controversy here. Research published in 2007 actually showed regression of language in children who watched a lot of these videos. So how can we square that with the experience of reading to your child being good for the brain?

I have no data to offer about this, but I suspect the difference between putting your child in front of a TV and reading to him or her is the personal interaction that accompanies reading.

 

Pediatric Newsletter #12: genetic vs environmental causes for autism and more

November 23, 2014  |  General  |  No Comments

Here is the latest of my more or less monthly newsletter on pediatric topics. In it I highlight and comment on new research, news stories, or anything else about children’s health that I think will interest parents. If you want to subscribe to it and get it in the form of an email each month there is a sign-up form at the very bottom of my home page.

How much of autism is caused by genetic factors and how much by environmental ones?

Autism is always very much in the news. There is intense controversy about its cause, although the bottom line is that we don’t know. It also appears to be increasing, although we don’t know how much of this is what we call ascertainment bias — finding something more when we look for it more. A big part of the controversy is the relative contributions of genetic vs environmental factors.

recent study from Sweden offers useful information about this. The study was immense, over two million children, far larger than any previous ones.

The bottom line is there appears to be more or less a 50/50 split in the relative contributions of nature and nurture. That is, genetics contributes 50% of the causative factors, environment 50%. This is an important finding. Overall, a child with a sibling with autism has a 10-fold higher chance for getting the disorder than does a child without such a family history. The middle part of the article is dense, but the first part and the conclusions are understandable by non-physicians.

Those laundry detergent pods can be quite dangerous for your toddler

recent study examined how common poisoning or other injuries are from those convenient laundry detergent pods. I have seen one severe case myself, causing breathing problems bad enough to land the child on a mechanical ventilator. This study surveyed poison control centers to find out the extent of the problem. It is not trivial.

Between 2012 and 2013 there were over 17,000 exposures to these things, a 600% increase from the previous year, indicating how popular they have become. I can see why they are popular — I use them myself. It’s a lot easier to toss one of them into the wash than pour out detergent from a bottle.

But that convenience comes at a potential risk. Toddlers put anything and everything into their mouths, and the alluring, brightly colored pods quickly dissolve when wet. The survey revealed that there were over a hundred children who required emergency placement of a breathing tube and one death.

So if you use those convenient items, make extra sure your toddler can’t get at them.

Finally we have vaccines for all strains of the deadly meningococcus

Infections from a bacteria called Neisseria meningitides (aka meningococcus) are horrible and often fatal. I have seen probably 20 children die in my career from this, and at least as many suffer terrible complications, such as loss of arms or legs.  This is the bacteria you have probably read stories in the paper about because it can cause lethal mini-epidemics in schools and any place children and adolescents come together in close contact. The infections come in a couple of varieties: meningitis alone, meningitis with septicemia, or septicemia alone. Of the three, the last is generally the worst, with a high mortality rate and serious aftereffects in survivors.

There are five strains of meningococcus that cause disease. We have had a vaccine for four of them for many years. But one of them, group B, has been difficult to develop an effective vaccine for, and this strain is a common cause of disease. The big news, and it is big, is that we now have a vaccine for group B. Meningococcal vaccine is recommended for adolescents — see your doctor about getting it for your child.

All about caffeine: what is it, where is it, and how does it work?

This one is more for you parents than it is for your children. I ran across an excellent and readable summary of what we know about caffeine. First of all, the stuff is everywhere. It is a brain stimulant that is found in many food and drink products, although the most common sources are coffee, tea, and now energy drinks like Red Bull. Here are some fun facts about it.

  1. 68 million Americans drink 3 cups of coffee per day
  2. 21 million Americans drink more than 6 cups per day
  3. 50% of caffeine users experience unpleasant symptoms when they stop, typically headaches, which can last for a week
  4. 5 grams of it can be fatal, but that is 30-40 cups of coffee
It's bronchiolitis time again: all about respiratory syncytial virus (RSV)

It’s bronchiolitis time again: all about respiratory syncytial virus (RSV)

January 25, 2014  |  General  |  2 Comments

It’s time again for bronchiolitis, which usually comes in winter through spring. In some ways this problem is similar to asthma, but in other important ways it is very different. With winter upon us it’s time to reacquaint ourselves with this common entity. There is a reliable seasonal arrival of the virus we call RSV, the chief cause of bronchiolitis. The letters stand for respiratory syncytial virus, a description of what it looks like when it grows in the laboratory.

To scientists, RSV is a fascinating virus with several unique properties. One of these is its behavior in the population. When it’s present, RSV is everywhere. Then it suddenly vanishes. There are exceptions to everything in medicine — I have seen sporadic cases during the off-months — but generally RSV arrives with a bang in mid-winter and then leaves suddenly in the spring. It’s the only virus that consistently and reliably causes an epidemic every year, although it often alternates more severe with milder visitations. RSV epidemics often have some regional variability. For example, often one city will have a much more severe epidemic than do others in other regions of the country. Right now my colleagues on the East Coast tell me there is quite a lot of it; I haven’t seen so much yet.

Another aspect of RSV that interests medical scientists is how poor a job our immune systems do in fighting it off. Virtually all children are infected with RSV during the first few years of life. Not only that, all of us are reinfected multiple times during our lives. Attempts at devising a vaccine for RSV have all been unsuccessful. In fact, early versions of an experimental vaccine seemed to make the disease worse in some infants, raising the possibility that some aspect of our immune response to the virus actually contributes to the symptoms.

RSV has a high attack rate — the term scientists use for the chances that a susceptible person will get the infection if exposed to it. That, plus our generally poor defenses against it, explain the frequent epidemics. Every year a new crop of susceptible infants enters the population.

So what is bronchiolitis? What does it look like? In medical terminology, adding the ending “itis” to a word means that whatever comes before is inflamed. Thus tonsillitis is an inflammation of the tonsils and appendicitis means an inflamed appendix. So bronchiolitis is an inflammation of the bronchioles, the final part of the system of air-conducting tubes that connect the lungs with the outside world. Beyond the bronchioles are the aveoli, the grape-like clusters of air sacs where the business of the lungs — getting oxygen into our bodies and carbon dioxide out — takes place.

Bronchiolitis, like asthma, is a disorder of blocked small airways. This prevents air from getting in and out normally, primarily out.  But the principal source of that blockage differs between the two lung problems. In bronchiolitis, the main problem is that the bronchiole tubes are blocked from swelling of the walls and from debris caused by the RSV infection — bits of broken airway cells and mucous plugs. The picture above shows what it looks like.

Infants are the ones who have the most trouble breathing with bronchiolitis. There are several reasons for this, but a key one is the construction of an infant’s chest. When small airways get blocked, we use our chest muscles — tightening them — to force air in and out of our lungs. We are helped in doing this by the fact that our lungs are encased in a fairly rigid rib cage; when we use our muscles to squeeze or expand our chest the system works like a bellows. Infants can’t do this well because the ribs across the entire front half of their chest are not yet solid bone — they are still soft cartilage.  So when a small infant tries to suck air in against anything that is restricting airflow, like clogged bronchioles, his chest tends to sink inwards, causing what we call retractions. These are easiest to see just below the last ribs. They also have trouble forcing air out, so their chests become hyperexpanded with air, making it look as if their chests are puffed out a little. The other reason infants have so much trouble handling debris in their bronchioles is that these tubes are already much smaller to start with, so they get more easily clogged up than do the larger airways of older children.

How does a child with bronchiolitis look? Typically they are breathing faster than the normal respiratory rate of 25-35; often they are puffing along at 60-70 breaths per minute. They also will show those chest retractions and have a cough. Fever is uncommon. They may look a bit dusky from not having enough oxygen in the blood. They often have trouble feeding because they are breathing so fast. The fast breathing, along with the poor feeding, often makes them become dehydrated. Our breath is completely humidified, so when we breathe fast we lose more water.

Can we do anything to treat this illness, make the symptoms better, make it go away faster? Sadly, the answer is that our toolkit is pretty unsatisfactory. I’ve been taking care of children with RSV for over 30 years, and I’ve seen a long list of things tried — breathing treatments, anti-viral medicines, steroids, medicines intended to open up the small airways. None of them work very well, if at all. Even though the symptoms resemble asthma in some ways, none of the asthma medicines work very well, although often we try them just to see because the occasional child will get just a little better with them. The research over the past few years is conclusive — the best we can do is to use what we call supportive care and wait for the infection to pass, meanwhile helping breathing as needed with oxygen, clearing the lungs of mucous, and sometimes a mechanical breathing machine, a ventilator, in severe cases.

RSV is generally not a serious illness, but for some children it can be life-threatening. Usually these children are very small infants, especially those born prematurely, and those with underlying problems with their lungs or their hearts. For those infants we have a monthly shot (called Synagis) that helps reduce the severity of RSV when they get it, and may even prevent a few cases, but it is not an ideal treatment. But older and otherwise normal children, such as toddlers, can get severe cases. We have no idea why that is.

Since RSV cannot be prevented, the best thing a parent can do is try to postpone it. That is, if you have a newborn infant in the height of RSV season, try to minimize exposure of your child to people with cold symptoms, especially toddlers. And for those who do handle your infant, have them wash their hands first. If your child gets bronchiolitis it is a good idea to take them to the doctor for an evaluation unless the symptoms are very mild. The usual course of the illness is a week or so.

Meet the norovirus, now the most common cause of “stomach flu” in children

January 16, 2014  |  General  |  No Comments

Gastroenteritis, often called “stomach flu,” is common in children. It has nothing to do with influenza, the “true flu,” which is caused by a respiratory virus. Gastroenteritis is caused by a different set of viruses. These viruses are generally transmitted by what physicians call the fecal-oral route, which sounds kind of gross. What we mean by that term is that the bug is in our intestinal tract and gets on our fingers. When we touch things without washing our hands properly we can pass it on to other people who touch the same thing and then touch their mouths. Of course toddlers don’t wash their hands, so the illness is particularly common in them. Gastroenteritis can cause severe vomiting and diarrhea, which can lead to dehydration and a trip to the doctor, but usually it passes within a few days.

For many years rotavirus was a very common cause of gastroenteritis in small children, but now a vaccine has reduced its incidence. Nature being nature, a new virus is taking its place and is emerging as the most common cause for gastroenteritis, accounting for 20% of cases. It’s called norovirus, and it’s a pretty amazing beast. In particular, it’s astonishingly infectious, making transmission quick and easy for it to accomplish. A recent report in the New England Journal of Medicine gives us some information about how it behaves.

The most amazing thing is how few viruses a child (or you) needs to get into their system in order to cause illness. Most micro-organisms need thousands of individual bugs to cause disease. Norovirus needs just 10 to 100. Considering how small a virus is that is quite astonishing, making norovirus one of the most efficient pathogens I’ve ever heard of. It is possible to contract the infection just by walking by someone with it because, unlike rotavirus, norovirus can also spread through the air. In one outbreak, 300 people were infected in a concert hall when they walked through a lobby where an ill person had vomited on the floor. It’s a huge problem in the food industry: in one outbreak a single infected food worker contaminated 76 liters of icing that went on baked products, causing disease in 3,000 people over the course of 4 days. Norovirus is responsible for about half of all cases of food-borne illness in the US.

To put some perspective on how common it is, by the age of 5 years, the authors of the New England Journal article calculate that norovirus will have caused 1 in 6 children to see a doctor in the office and 1 in 14 children will have visited the emergency room because of it. One in 278 will have been hospitalized, usually for dehydration. That’s pretty common. The peak incidence is 6 to 18 months of age.

For a parent, the key to taking care of your child with gastroenteritis is to keep them from becoming dehydrated. Here are some details about how to do that. At this point there is no simple test for norovirus. Knowing it’s there doesn’t affect therapy. But my recent reading about it has given me new respect for it.

All About Croup

February 8, 2013  |  General  |  No Comments

Imagine this scenario. Your two-year-old son has had a runny nose for a day or two and an occasional cough, but seemed no worse to you that everyone else in his preschool class. Two hours after you put him to bed you hear him coughing, only this cough is like none you have ever heard from him before. It sounds like a barking seal at the circus–a brassy, honking noise. In between coughs he his making a strange crowing-like noise. When you snap on the light you see him sitting up in his crib, leaning forward, and coughing that strange cough. You also notice the part of his chest below his ribcage is sinking inwards with each breath, backwards from the way it should go. Your little boy has a scared look in his eyes, and you are more than a little scared yourself. He has croup.

What is croup?

Croup is a disorder caused by inflammation of the trachea, the main breathing tube in the neck, just below the vocal cords, in an area called the subglottic region. Some say it gets its name for the old Anglo-Saxon word kropan, which means to croak or cry out. If true, such venerable terminology tells us this common childhood ailment has been recognized as a distinct entity by parents for a very long time. Physicians sometimes give it a much fancier name, laryngotracheobronchitis. This learned construction merely describes what croup is: inflammation (hence the “itis”) of the breathing tubes extending from the vocal cords (the larynx), through the trachea, and often down to the lower breathing tubes (the bronchi). Even though the inflammation can stretch up and down the airway, it is in the subglottic region where the symptoms happen. Why this is so is because of a simple law of physics–that is where the airway of a toddler is at its narrowest. The symptoms of croup come from blockage of airflow.

The inflammation of the subglottic region makes the lining of the trachea swell. Since the trachea is more or less round, this swelling makes the diameter of the airway smaller. Sometimes the swelling of the tissues gets so bad the size of the child’s airway is narrowed to that of a small straw. What happens next is simple physics, and is analogous to what happens in cold water pipes if they have their diameter narrowed by mineral deposits in them: flow through a tube is proportional to the fourth power of the radius of the tube. This may sound esoteric, but the principle has important practical implications for small children with croup.

Imagine an adult whose airway has a diameter of twelve millimeters. Then imagine the lining of this tube develops one millimeter of swelling all around its lining, thereby reducing its diameter to ten millimeters. If one does the calculations, this slight reduction in size reduces airflow by about half. Now consider a toddler with a  five millimeter airway who has the same one millimeter of swelling all the way around it, reducing it to three millimeters in diameter. The adult in this example loses about half the airflow, something easily compensated for by just breathing a little harder. In contrast, the toddler has his airflow reduced to only thirteen percent of what it was. This reduction is too much to compensate for, although the child tries. His trying causes the symptoms of croup.

It is air rushing turbulently through a newly tiny airway that causes the crowing sound characteristic of the breathing of a child with croup. It is called stridor, and an experienced person can often make the diagnosis of croup based upon that sound alone, even over the telephone. Additionally, the front portion of a toddler’s ribcage is not yet solid bone–it is still partly cartilage. This means that, since a child’s chest is not yet firm in the scaffolding of the ribs, the increased effort of breathing makes the chest cave in the wrong way with each breath. These are called retractions. They are not specific to croup, but happen in a child with respiratory distress from a variety of causes. The final characteristic finding of croup, the seal-like barking cough, is from irritation of the vocal cords.

One of the characteristic attributes of croup is how sudden the onset of the stridor, the sign of upper airway, often is. For some reason croup tends to be worse at night; most visits to emergency departments for croup occur between ten in the evening and four in the morning. A typical story is that parents put their child to bed with just a mild cough only to awaken in the middle of the night to the sound of severe stridor. This is a predictable result of the place where the inflammation is happening. Since airflow is dependent upon the fourth power of the radius of the child’s trachea, he may not have much distress during the early stages of the illness. But as the airway gets smaller, subsequent reduction in size becomes critical. The analogy to water pipes is a good one: loss of half the space inside the pipe from mineral deposits causes only slight reduction in water flow when one turns on the tap, but just a little more blockage severely cuts down flow.

How common is croup and what causes  it?

Croup is an extremely common childhood illness. Estimates vary, but studies suggest as many as fifteen percent of all children have croup at least once, and five percent have it more than once. Some have estimated croup accounts for fifteen percent of all respiratory tract disease seen in pediatric practice. The peak time for croup is fall and early winter, but it can occur any time of year, even summer. The peak risk age for children to get croup is eighteen months, and boys are one-and-one-half times more likely to get it than are girls.

Croup is caused by infection with a respiratory virus. Although there are a few ailments that resemble croup and are caused by something else (more on them below), standard croup symptoms are brought on by viral infection. There are multiple viruses that can do it, but nearly three-quarters of all cases stem from infection from a single family of three closely-related viruses–the parainfluenza viruses, which are cousins of true influenza. Less commonly croup is caused by the true influenza virus, respiratory syncytial  virus (RSV), or a few others.

All these viruses are spread from child to child in the manner of most respiratory viruses–tiny droplets of infected mucous or saliva. These droplets can fly through the air after a cough or sneeze and be inhaled by someone nearby. Alternatively, virus-laden mucous gets deposited on a child’s hands when she puts them in her mouth or nose and the virus then moves on to someone else when the child touches them.

Either way, the first step is for the virus to infect the back of the throat, causing cold-like symptoms of nasal congestion, cough, and low-grade fever. For reasons we do not understand, some children get no more than that. Often, however, and especially with the parainfluenza viruses, the infection moves to the subglottic area of the trachea. There it causes the local irritation and inflammation that leads to the airway swelling and subsequent symptoms of obstructed airflow.

How is croup diagnosed?

Croup is entirely a clinical diagnosis; there is no specific test for it. This means the doctor decides it is croup based upon a typical story (cough, congestion, stridor, and mild fever). Sometimes, though, a doctor will get an x-ray of the child’s neck, which often shows some narrowing of the airway. The figure below is an example of this. Air on an x-ray appears black, bones are white, and tissue is grey. The central black column of this child’s trachea is narrowed abnormally at the point of the arrowhead. (The bones stacked like coins in the neck are part of the spinal column.) Doctors do not always get such an x-ray, especially if everything points to croup. If the story is atypical, a common reason for getting the x-ray is to make sure the child’s symptoms are not from something else. Those other possibilities are divided into infectious ones and non-infectious ones.

There are other infections besides viral ones that can infect a child’s airway and block airflow. Serious bacterial infection can do this also. The principal one of these is epiglottitis, a severe and rapid swelling of the epiglottis, a structure that sits just above the opening of the trachea at the back of the throat. The epiglottis is what keeps food from going into the trachea during swallowing. When it becomes severely swollen, which is what happens with epiglottitis, it can completely block the airway and cause a life-threatening emergency. Another infection that can mimic croup is bacterial tracheitis, a severe infection of the entire trachea that causes so much infected pus that a child’s airway can become obstructed. It, too, can be life-threatening.

Fortunately, both epiglottis and bacterial tracheitis are extremely rare. Epiglottis was once not uncommon, but near universal vaccination of children against the bacterium Hemophilus influenzae, the main causative organism, has dramatically reduced the incidence of the disorder. Both these serious conditions usually behave quite differently from croup. The main difference is that both cause high fever (croup’s fever is nearly always low-grade) and the children appear quite ill. The key distinction between croup and epiglottis is that the latter not only makes breathing difficult but also makes swallowing painful or even impossible for the child. Thus a child with epiglottis will not only have stridor, but will sit hunched forward and drool, unable to swallow.

An x-ray of the neck can help distinguish croup from these more serious infections. However, if the doctor thinks epiglottis is possible the standard way to proceed is for the child to be given a sedative and have his airway directly inspected using a procedure called laryngoscopy. If this is necessary, it is usually done by an airway specialist, such as an otolaryngologist, commonly called an ENT specialist.

There also are non-infectious things that can cause upper airway obstruction and stridor, since anything blocking the airway gives the same symptoms. Overall, what distinguishes these non-infectious causes of upper airway obstruction from the infectious ones is the lack of any other evidence of infection, such as nasal congestion, fever, or malaise.

If the onset of a child’s breathing problems is quite sudden, the doctor might consider the possibility of a foreign body stuck in the airway. Toddlers put anything into their mouths–toys and bits of food are frequent offenders when this happens. On the other hand, if the progression of a child’s symptoms is progressive over days or weeks, the doctor might think about several kinds of tissue growths that can occur within the airway. If either of these possibilities is likely, the child usually needs laryngoscopy or bronchoscopy, inspection of the trachea and lower airway, for diagnosis.

A few children have recurrent, sudden episodes of croup symptoms without any other evidence of viral infection. These attacks from what is called spasmodic croup also generally happen at night. The cause is unknown, but it may be related to allergies. It is generally treated the same way as viral croup (see below).

The walls of the trachea are stiffened with bands of cartilage; this is what holds them open and keeps them that way. Some children have an airway that is intrinsically less stiffened with cartilage than most, causing it to collapse a bit when the child breathes, causing stridor that can sound like croup. In this condition, called tracheomalacia, the symptoms are chronic and are often worse when the child is lying on his back because the weight of the tissue in the neck compresses the airway more. It requires bronchoscopy to diagnose for certain.

Croup ranges in severity from quite mild to the rare case of near total obstruction of the airway. To help categorize this severity doctors have devised various scoring systems to rate the child’s symptoms. One commonly used of these “croup scores” is the Westley scale. The scale assigns points for various symptoms and groups children into “mild,” (less than three points), “moderate,” (three to six points), and “severe” (more than six points). It uses five criteria to do this: severity of retractions, degree of stridor, how well the air is getting into the child’s lungs as assessed with the examiner’s stethoscope, if the child is dusky-colored from insufficient air, and if the child is becoming poorly responsive from lack of oxygen. Generally mild croup can be treated at home; moderate and severe croup require medical attention, and usually the more ill children will be admitted to the hospital.

How is croup treated?

Once a doctor decides a child has croup, it is fairly well-accepted how to treat it. Therapy is directed at two things: making the child feel better and reducing the airway inflammation to improve airflow. Mist has been a mainstay of treatment for mild croup for many years.

Most physicians believe steam often gives a child significant relief from the pain and raspy, dry feeling in the throat, although whether it actually helps reduce the inflammation of the airway itself and improves air flow is doubtful. Mist may also help loosen airway mucous and allow the child to cough it up easier. Throat pain and fever are helped by treatment with acetaminophen or ibuprofen.

The traditional home remedy for mild croup is to close the bathroom door and run a tap until the room is completely steamy, then turn it off and sit with the child in the mist. A parent needs to be careful with this, of course; children have been burned from scalding water. Exposure to cool night air (since croup happens mostly at night) is also a traditional remedy. Although widely practiced and certainly benign, it, too, has never been validated.

Doctors typically use one or both of two ways to reduce the inflammation and swelling in the child’s airway. Direct application of the drug epinephrine (adrenaline) to the swollen tissues shrinks them by constricting the tiny blood vessels under their surface; it is the virus-induced engorgement of these vessels and leakage of fluid out of them that causes the swelling in the first place. The drug is given by nebulization, blowing high-flow air or a mixture of air and oxygen through the liquid epinephrine and thereby dispersing it into a fine mist, which the child then breathes to carry the drug to the subglottic area. Epinephrine works within minutes and usually gives a child prompt relief from the stridor and retractions. Unfortunately the effects of epinephrine only last a few hours at most. It can then be repeated, although dose after dose of epinephrine can rarely lead to worse swelling when the drug wears off.

The subglottic swelling of croup is from inflammation in the area, so standard treatment of moderate or severe croup also consists of using a drug to reduce the inflammation–a steroid. Steroids are also being used increasingly for mild croup, both to make the child feel better and to interrupt in its early stages progression of the swelling. Steroids can be given orally, by intramuscular injection, or even nebulization like the epinephrine. A commonly used steroid for croup is dexamethasone (Decadron), a single dose of which is usually sufficient to reduce the inflammation. Unfortunately, steroids do not act immediately like inhaled epinephrine–they take four to six hours at least to work.

A typical treatment scenario for a child coming to the emergency department with croup would be to have him breathe some cool mist, followed by a nebulized epinephrine treatment. Usually the best way to do this is to have the child sit in a parent’s lap, since he is most comfortable there and agitation makes the stridor and retractions worse. Then the child receives a dose of steroids. Often by then the child’s symptoms are much better, but it is important to keep the child in the emergency department for at least an hour or two more to make sure the symptoms do not recur after the epinephrine wears off and the child needs more treatment. A child who has continues to have symptoms after  epinephrine or who needs repeated doses of epinephrine needs admission to the hospital. What doctors particularly look for is continued stridor when the child is completely calm; called “stridor at rest,” it is a standard indication for hospital admission.

A child with severe croup needs more complicated management, although this is very uncommon. If the child is clearly not getting enough air to stay alert and keep his blood oxygen levels up he needs immediate placement of a breathing tube, called an endotracheal tube. It is placed by a procedure known as intubation. A child with less severe croup, but who remains in significant distress and begins to tire from the effort of breathing also needs intubation.

What is the typical course of a child with croup?

Croup usually runs its course in five to seven days, typically with one day of worst symptoms and several more of cough and hoarseness. Since the symptoms characteristically get better in the day, it is common during the middle of the illness for a child to have minimal symptoms during the day but several nights of worse cough.

What is the risk of a child getting croup again and are there any long-lasting effects?

There is no clear-cut evidence that children who have one episode of croup are more likely to get it again. There is some evidence children who have group are more at risk later to develop reactive airways disease–asthma–than children who never have croup. However, if true, this may not be a cause-and-effect association; the propensity for a child to get croup when infected by a respiratory virus may reflect the same innate tendency to develop asthma. They may be different manifestations of the same thing. There are no long-term after-effects of typical viral croup.

It's time once again for bronchiolitis and respiratory syncytial virus (RSV)

It’s time once again for bronchiolitis and respiratory syncytial virus (RSV)

November 8, 2011  |  General  |  No Comments

My last post was about asthma. This one is about another very common breathing problem in children — bronchiolitis. In some ways it is similar to asthma, but in other important ways it is very different. With winter nearly upon us it’s time to reacquaint ourselves with this common entity.

I’ve written before (here and here) about the reliable seasonal arrival of the virus we call RSV, the chief cause of bronchiolitis. To scientists, RSV is a fascinating virus with several unique properties.

One of these is its behavior in the population. When it is present, RSV is everywhere. Then it suddenly vanishes. There are exceptions to everything in medicine — I have seen sporadic cases during the off-months — but generally RSV arrives with a bang in mid-winter and then leaves suddenly in the spring. It is the only virus that consistently and reliably causes an epidemic every year, although it often alternates more severe with milder visitations. However, RSV epidemics may still have some regional variability. For example, often one city will have a much more severe epidemic than do others in other regions of the country.

Another aspect of RSV that interests medical scientists is how poor a job our immune systems do in fighting it off. Virtually all children are infected with RSV during the first year of life. Not only that, all of us are reinfected multiple times during our lives. Attempts at devising a vaccine for RSV have all been unsuccessful. In fact, early versions of an experimental vaccine seemed to make the disease worse in some infants, raising the possibility that some aspect of our immune response to the virus actually contributes to the symptoms.

RSV has a high attack rate — the term scientists use for the chances that a susceptible person will get the infection if exposed to it. That, plus our generally poor defenses against it, explain the frequent epidemics.

So what is bronchiolitis? What does it look like? In medical terminology, adding the ending “itis” to a word means that whatever comes before is inflamed. Thus tonsillitis is an inflammation of the tonsils and appendicitis means an inflamed appendix. So bronchiolitis is an inflammation of the bronchioles, which are the final part of the system of air-conducting tubes that connect the lungs with the outside world. Beyond the bronchioles are the aveoli, the grape-like clusters of air sacs where the business of the lungs — getting oxygen into our bodies and carbon dioxide out — takes place.

Bronchiolitis, like asthma, is a disorder of blocked small airways. This prevents air from getting in and out normally, primarily out.  But the principal source of that blockage differs between the two lung problems. In bronchiolitis, the main problem is that the bronchiole tubes are blocked from swelling of the walls and from debris caused by the RSV infection — bits of broken airway cells and mucous plugs. Here’s what it looks like.

Infants are the ones who have the most trouble breathing with bronchiolitis. There are several reasons for this, but a key one is the construction of an infant’s chest. When small airways get blocked, we use our chest muscles — tightening them — to force air in and out of our lungs. We are helped in doing this by the fact that our lungs are encased in a fairly rigid rib cage; when we use our muscles to squeeze or expand our chest the system works like a bellows. Infants can’t do this well because the ribs across the entire front half of their chest are not yet solid bone — they are still soft cartilage.  So when a small infant tries to suck air in against anything that is restricting airflow, like clogged bronchioles, his chest tends to sink inwards, causing what we call retractions. They also have trouble forcing air out, so their chests become hyperexpanded with air. The other reason infants have so much trouble handling debris in their bronchioles is that they are already narrow to start with, so they get more easily clogged up than do larger, adult-sized airways.

How does a child with bronchiolitis look? Typically they are breathing faster than the normal respiratory rate of 25-35; often they are puffing along at 60-70 breaths per minute. They also will show those chest retractions and have a cough. Fever is uncommon. They may look a bit dusky from not having enough oxygen in the blood. They often have trouble feeding because they are breathing so fast. The fast breathing, although with the poor feeding, often makes them become dehydrated. Our breath is completely humidified, so when we breathe fast we lose more water.

Can we do anything to treat this illness, make the symptoms better, make it go away faster? Sadly, the answer is no. I’ve been taking care of children with RSV for 30 years, and I’ve seen a long list of things tried — breathing treatments, anti-viral medicines, steroids, medicines intended to open up the small airways. None of them work very well, if at all. Even though the symptoms resemble asthma in some ways, none of the asthma medicines work very well, although often we try them just to see because the occasional child will get just a little better with them. The research of the past few years is conclusive — the best we can do is to use what we call supportive care and wait for the infection to pass, meanwhile helping breathing as needed with oxygen, clearing the lungs of mucous, and sometimes a mechanical breathing machine in severe cases.

RSV is generally not a serious illness, but for some children it can be life-threatening. These children are very small infants, especially those born prematurely, and those with underlying problems with their lungs or their hearts. For those infants we have a monthly shot (called Synagis) that helps reduce the severity of RSV when they get it, and may even prevent a few cases, but this is not ideal.

Since RSV cannot be prevented, the best thing a parent can do is try to postpone it. That is, if you have a newborn infant in the height of RSV season, try to minimize exposure of your child to people with cold symptoms, especially toddlers. And for those who do handle your infant, have them wash their hands first.

Car seats: still both a good idea and . . . the law

August 8, 2011  |  General  |  No Comments

I would think by now, midway through 2011, that I wouldn’t have to write anything about the importance of child car seats. But I find I do, because as I drive around I still see adults holding babies and toddlers over their shoulder, often while sitting in the front seat. This has been illegal in most places for many years, but it is still common and it is still stupid and dangerous. I also still see the results–several children each year come through the PICU who were unrestrained passengers in a car accident, and a few of them die.

Here are some statistics on car seats and motor vehicle accidents. (The most recent I could find come from 2003.) For that year nearly 59,000 children under the age of 5 were injured, 8% of them seriously, and about 1% died. This amounted to 471 children. Significantly, over one third of the children who died were unrestrained.

Most of us have been lectured to about these things, but I have found many parents have difficulty understanding notions of statistical risk. For example, one study showed 72% of parents were seriously afraid their child would be abducted by a stranger. That is a legitimate fear, but it is not very likely to happen; in fact, it is vanishingly unlikely. It is only one-fourth as likely as you getting struck by lightning.

My point is that parents should do what they can to reduce the chances of their child suffering harm: by all means tell your child about what to do when approached by strangers, but also please buckle them into a car seat, preferably in the back seat, when you drive anywhere with them, even a short distance.

You can find an excellent overview of all manner of car seats and how to use them here at the American Academy of Pediatrics site.

Toddlers getting into Grandpa’s medicines

May 16, 2011  |  General  |  No Comments

From time to time have children, mostly toddlers, in the PICU who are there because of an overdose of a medication meant for somebody else. I frequently see this scenario happen: parents are careful to keep all medicines locked away from curious toddlers, but then the child visits grandparents who, not having small children regularly around the house, are not so diligent. Many older persons take one or more of a wide variety of powerful medications that can cause serious or even lethal poisoning in small children. Child-proof caps are sometimes difficult for the elderly to open, so they may not use them. I deal with the results of what this can lead to at least several times each year. A parent whose small child spends significant time at another house, especially if someone living there takes medicines, should make sure those medicines are stored safely. Toddlers are amazingly quick at getting into trouble.

The best and fastest way to get advice about poisonings in children is to call your regional Poison Control Center. To make this easy to do, the telephone number is the same across the nation: 1-800-222-1222.

Where does fever come from?

February 4, 2011  |  General  |  No Comments

Here is an excerpt from my recent book, How Your Child Heals. It’s about fever, from the chapter about symptoms and signs.

Fever means an abnormal elevation of body temperature. But what is abnormal? Most of us have heard or read that “normal” is 98.6 degrees Fahrenheit, which is 37 degrees centigrade. In fact, normal temperature varies throughout the day. It is as much as one degree lower in the morning than in the afternoon, and exertion of any kind raises it. Where you measure it also matters. Internal temperature, such as taken on a child with a rectal thermometer, is usually a degree or so higher than a simultaneous measurement taken in the mouth or under the arm pit.

There is also a range of what is normal for each individual — not all people are the same. So what is a fever in me may not be a fever in you. As a practical matter, most doctors stay clear of this controversy by choosing a number to label as fever that is high enough so this individual variability does not matter. Most choose a value of 100.4 degrees Fahrenheit, or 38 degrees centigrade, as the definition of fever. It is not a perfect answer, but it is a number that has stood the test of time in practice.

We maintain our normal body temperature in several ways. Chief among them is our blood circulation. Heat radiates from our body surface, so by directing blood toward or away from our skin we can unload or conserve heat. We can also control body temperature by sweating — evaporation of sweat cools us down. We know how important a mechanism this is because the rare person who cannot sweat, or who is taking a medicine that interferes with sweating, has trouble keeping his body temperature regulated when he gets sick. If a swing in blood flow inwards to raise temperature happens very fast, we respond by shivering. This is also why we shiver if we go outside without a coat in the winter; our bodies are redirecting blood flow from our skin to our core in order to maintain temperature.

All parents know that a common cause of fever in children is infection. A more precise way to think about it is that a common cause of fever is actually inflammation. Since in children infection is the most common cause of inflammation, we generally assume a child with a fever has an infection somewhere in her body unless we can prove otherwise.

Our brains have a kind of thermostat built into them. Like the thermostat in a house, it senses the temperature of the blood passing by it and uses a series of controlling valves in the blood circulation to fine-tune the temperature. Also like your house thermostat, it continues to sense the temperature, and adjust it as necessary, until it has reached the value for which the thermostat is set. Fever happens when the thermostat is reset, just as happens when you twist the dial on the wall for your furnace — the body reacts to bring itself to the new setting. What twists the knob on the brain’s thermostat to cause fever are substances in the blood.

These fever-inducing substances belong to a family of inflammatory molecules that are released from body cells. Mostly they come from a cell called a macrophage, but germs themselves can also release things that have the same effect. The sudden rises and falls a parent often sees in their child’s temperature when they have an infection reflect the usually brief time these substances are in the blood. Sustained fever for many hours can happen if these materials are steadily present.

Opinions vary among doctors about when fever needs treatment. Fever itself virtually never causes harm on its own. The only times it can do harm is when it gets very, very high — 106 degrees or more — for a sustained period. That only happens in highly unusual situations; ordinary childhood infections never get it that high. It is true fever can make a child uncomfortable, although children generally tolerate it much better than adults. For that reason alone many doctors advise treatment.

There is another reason to treat fever. Toddlers may experience brief convulsions – seizures — when their body temperature rises very fast. These so-called febrile seizures cause no harm to the brain itself, and often run in families, but fever treatment makes good sense for a child who has had them in the past.

We have two effective drugs to treat fever — acetaminophen (Tylenol) and ibuprofen (Motrin). Both work the same way: they reset the brain thermostat back down to a lower lever. Both only last a few of hours or so in their effect, which is why you will see your child’s fever go back up again when they wear off if there are still any of those fever-causing substances from the inflamed site still in the circulation.

Respiratory syncytial virus (RSV): here today, gone tomorrow

January 28, 2011  |  General  |  No Comments

I’ve written before (here, here, and here) about RSV, one of the most common causes of respiratory illness in infants and toddlers, and the most common cause of illness severe enough to land them in the hospital. It’s so common that virtually 100% of children have gotten the infection by the time they’re two years old. RSV generally causes an illness called bronchiolitis. In this post I’ll tell you about why it causes such sudden and explosive epidemics.

I’ve hardly seen any RSV yet this year. But all of us know it will come; generally we see a few cases, quickly followed by an explosion of cases. The way RSV behaves in the population is fascinating. It’s also utterly predictable, based upon what we know about the properties of the virus and our immune response to it.

The first thing to know is that RSV is highly contagious — one of the most contagious of all viruses. It’s spread by droplets of respiratory secretions, and it can survive for several hours at least on objects, such as shared toys or cookies. Its attack rate, the number of people who are susceptible to the infection and who get it if exposed — is well over 90%. So once cases appear, if there is a large population of people susceptible to it, we would predict a lot of infections.

The second thing to know is that there is always a large number of susceptible people. This is because our immunity to RSV is not good; most of us, especially if we are exposed to small children, get the infection every few years. For some reason RSV doesn’t induce a very good immune response, so when we get it we don’t develop very good protective antibodies to it. This is why we haven’t been able to develop a vaccine against it.

It also explains why infants get it so easily. Babies are born with a dose of antibodies they get from their mothers, protection that lasts a couple of months or so. In the case of RSV, though, mothers can’t give them this protection. So they’re all susceptible, and it’s generally the infants, especially those born early, who have the most trouble from it. (Adults generally get only mild to moderate cold symptoms.)

So why do we have the explosive epidemics from RSV? The answer is that each year a whole new crop of susceptible infants are born for the virus to infect. That, plus the high attack rate, causes RSV to rampage through the population once a few cases appear.

Although all children will eventually get RSV, there are a few things you can do to reduce the chances of your infant getting it during the typical epidemic of mid to late winter and early spring. Simply postponing infection until your child gets out of infancy is very helpful, because older children rarely need to come into the hospital for treatment. Avoid close exposure of your infant to anybody who has cold symptoms, and have everybody wash their hands before handling your baby.

In sum, although RSV infection is a rite of passage in childhood, there are a few practical things you can do to keep your child out of the hospital.