Posts Tagged ‘RSV’

New recommendations for the treatment of bronchiolitis: we should do less because it doesn’t help

December 2, 2014  |  General  |  No Comments

Every fall I write about bronchiolitis because it is one of the most common respiratory ailments affecting infants and children under about two years of age. It is the most common reason infants end up in the hospital during the winter and early spring months. Every year we get severe cases in the PICU. Pediatricians have struggled for decades to figure out how to treat bronchiolitis but we don’t have any specific therapies that work very well. (We have some promising treatments on the horizon, though, as I wrote about here.) Recognizing this, the American Academy of Pediatrics has significantly revised its recommendations of what we should and should not do for children with bronchiolitis. Before I describe these new recommendations, however, I should review what bronchiolitis is and why it can make small children, particularly infants, so sick.

Bronchiolitis is caused by a viral infection of the small airways, the bronchioles. By far the most common virus to do this is one we call respiratory syncytial virus, or RSV. 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.

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 is a disorder of blocked small airways. This prevents air from getting in and out normally, primarily out.  The principal source of the blockage 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. This picture 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 move air 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 especially 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.

What can we do to treat bronchiolitis? You read above that we have no specific medicine that will kill the virus. What we have to offer is what we call supportive care: treating the symptoms until the infection clears. Some of that supportive care has been based on how we treat asthma, another condition where air has trouble getting into and out of the lungs. Some years ago we learned that these asthma treatments, such as albuterol breathing treatments and steroids, helped very few children. Even though we knew that fact, a common thing was to try the asthma drugs and see if they helped an individual child, then continue them if it appeared they did.

The new recommendations come down strongly on the side of not even trying these asthma drugs because compelling research argues against it. More than that, the new recommendations say not to take a chest x-ray because it doesn’t help the child and may cause more risk; taking a chest x-ray often leads to physicians over-diagnosing pneumonia and giving antibiotics when they aren’t called for. The new recommendations even suggest we stop testing for the RSV virus, which has been commonly done, because it doesn’t affect anything we do. One thing the recommendations continue from the past is providing good hydration, as well as oxygen if the child needs it — some do, but many do not.

One important point to make, especially for me as a pediatric intensivist, is that these recommendations only apply to children with milder disease. Some children with bronchiolitis become extremely ill and require help with their breathing, either with soft plastic prongs in their nose that deliver oxygen and air pressure or with a mechanical breathing machine. For those children we do what it takes to keep their blood oxygen levels in the safe range.

Old ways die hard, and it will be interesting to see if physicians follow these new recommendations. My guess is that, over time, we will. More and more we are learning that therapies that add risk and cost, without adding any benefit, are not the way to go.

Finally, an effective treatment for respiratory syncytial virus (RSV)?

September 22, 2014  |  General  |  1 Comment

Respiratory syncytial virus infection, aka RSV, is a common infection in children. A key aspect of RSV 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.

The most common form of RSV infection is called bronchiolitis. 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 is a disorder of blocked small airways. This prevents air from getting in and out normally, primarily out. 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. It looks like this, with the arrows showing air movement.

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.

We have never had any specific treatment that works for RSV bronchiolitis. All we can do is what we call supportive care — oxygen, some breathing treatments (which usually don’t help much), IV fluids if the child is too sick to eat, and a few things we can do to help with mucus clearance. But now that may be changing. A recent study looked at a new drug to kill the RSV virus directly, something we’ve never had before.

The drug, which can be given orally, was tested on adults, not children — yet. The results were very encouraging. One of the issues with other anti-viral drugs has been that they only work well if they are given very early in the course of the illness or even before symptoms start. This new anti-RSV drug works even after people are sick with the virus. It greatly reduced the amount of virus in respiratory mucus, where we usually find the virus. Perhaps more importantly for sick infants, it also caused rapid improvement in symptoms.

Dr. Peter Wright, an RSV expert, is excited about the possibilities of the drug. Dr. Wright has worked on RSV for many, many years — so many that he was one of my teachers at Vanderbilt Hospital way back in 1978. I can recall that he does not get excited easily. I’m excited, too, because severe RSV bronchiolitis is a real scourge we see frequently in the PICU. Some infants even die from it. I was also pleased to read that Dr. Wright is still on the RSV case after all these years.

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.

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.

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.

Treatment of bronchiolitis

February 27, 2010  |  General  |  No Comments

Bronchiolitis is the leading cause of hospitalization for very young children in the USA. You’ll find various definitions of what bronchiolitis is, but a standard one is a viral illness that starts in the upper respiratory tract with runny nose, congestion, and cough. This is soon followed by symptoms in the lower respiratory tract — the lungs — such as rapid breathing, wheezing, and sometimes the need for extra oxygen. The culprit in half to three-quarters of cases is what we call respiratory syncytial virus, or RSV, but a variety of viruses can do it. Interestingly, 10-30% of children with bronchiolitis and RSV have another respiratory virus, too. Researchers aren’t sure if this combined infection contributes to how severe the symptoms are.

Any child can get bronchiolitis, but children who were born prematurely or who have some preexisting problem with their lungs are particularly susceptible to experiencing severe cases of it. But even otherwise normal children can get critically ill. I just cared for such a child, one who needed a week of a mechanical ventilator for it, and all pediatric intensivists have now and then had similar cases.

Because it’s so common, and because some of the symptoms of bronchiolitis resemble asthma, physicians for many years treated it with asthma drugs. Unfortunately, these drugs rarely help. But the urge to do something, anything, for this often frustrating illness is a strong one, and I still often see full-bore asthma treatment given for bronchiolitis. Indeed, in spite of multiple recommendations by panels of experts, more than a few American doctors seem reluctant to concede that little in the way of drug therapy helps. It’s hard-wired into our nature to treat things. The problem is that no drugs are risk-free, so we shouldn’t use them unless there is a reasonable chance they will do good.

What helps bronchiolitis? For a child at high risk of getting a severe case of RSV we can give a monthly shot of a drug called Synagis that can reduce the chances of getting RSV, or, if it happens, having a less severe case. For the rest, we use frequent suctioning of all the nasal mucus, oxygen if a child’s blood oxygen level shows it to be a bit low, and time. For now, that’s about it.

It's respiratory syncytial virus (RSV) time again

January 25, 2010  |  General  |  No Comments

I’ve written before (here and here) about the reliable winter time arrival of RSV. This virus is the most common cause of pneumonia and bronchiolitis in children under six months of age. To scientists, RSV is a fascinating virus with several unique properties.

One of these is its behavior in the population. During its annual visitation, 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 single year. Not even influenza does that. 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.

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 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.

It’s respiratory syncytial virus (RSV) time again

January 25, 2010  |  General  |  No Comments

I’ve written before (here and here) about the reliable winter time arrival of RSV. This virus is the most common cause of pneumonia and bronchiolitis in children under six months of age. To scientists, RSV is a fascinating virus with several unique properties.

One of these is its behavior in the population. During its annual visitation, 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 single year. Not even influenza does that. 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.

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 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.

Wheezing in infants and toddlers — what to do?

June 22, 2009  |  General

Wheezing is common in small children — around a third of all children will have an episode of wheezing before they are three years old. Although it’s common, we still don’t quite know the best thing to do about it. The problem is that wheezing, like fever, is a symptom of a disease, not a disease itself. It’s not one thing. Every physician who treats small children in the office, the emergency department, or the pediatric intensive care unit is often faced by the dilemma of what to do with a wheezing small child.

In such children wheezing is often triggered by a viral illness. When it happens in infants it is often caused by a virus we call RSV (short for respiratory syncytial virus) and causes a disorder called bronchiolitis. For those children, we know that not much of anything helps the symptoms — all we can do is provide supportive care and wait for the illness to run its course. What about wheezing children who don’t have bronchiolitis? Can anything help them?

The problem facing the doctor is that all the treatments we’ve tried over the years for small children who wheeze are taken from how we handle older children who have chronic, frequent wheezing — what we call asthma. These treatments work for asthma, yet they often don’t for wheezing that isn’t. A certain number of children who have their first spell of wheezing will go on, over years, to develop true asthma. But most wheezing toddlers won’t progress to asthma — they will have an episode or two (or three) of wheezing and then “grow out of it.” If you bring your infant or toddler to the doctor for a first (or second) episode of wheezing, the doctor has no way of knowing which of these two things will happen. There are a few clues, such as a family history of asthma, which will increase the chances of future asthma, but there’s no good way to tell.

How do most doctors handle this problem? Most will try a dose or two of asthma medications (inhaled albuterol and/or budesonide, or oral prednisolone are commonly used) just to see if it helps. If the child gets better, they can be continued.

My point is that you should understand that for this problem — wheezing in an infant or toddler — your doctor is handicapped by not being able to predict the future. Only time will tell. It’s a frustrating, but common medical scenario.

Treating respiratory syncytial virus — nothing works

February 13, 2009  |  General  |  8 Comments

It’s that time of year again in the PICU, time for a winter outbreak of respiratory syncytial virus (RSV). RSV is extremely common and highly infectious: its attack rate, meaning the chances of a susceptible person getting the infection if exposed to a case, is among the highest of any virus. Estimates are that as many as 125,000 infants each year are hospitalized with RSV, with many, many more infected less severely. The peak age for those children needing a hospital is between two and five months. It is so common that by early childhood virtually all of us have been infected at least once.

Much of the time RSV causes the symptoms of a cold — cough, runny nose, sometimes a low-grade fever. But in very young children, particularly infants, RSV can cause severe pneumonia or bronchiolitis. The latter disorder is an inflammation of the tiniest of the lung’s air tubes, or bronchioles. This inflammation blocks off the little tubes, making it difficult for air to get in, or most characteristically, to get the air out. Babies with severe RSV often need oxygen and some need mechanical ventilators to breathe for them as we wait out its course until it passes.

Every parent asks: 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. The research of the past few years is conclusive — all we can do is wait for the infection to pass, meanwhile supporting breathing as needed with oxygen, clearing the lungs of mucous, and sometimes a mechanical breathing machine in severe cases.