Posts Tagged ‘MRI’

Vaccines and parents’ selective worries about medical risks

February 23, 2014  |  General  |  No Comments

I’ve been involved in several boisterous Twitter debates about vaccines, at least to the extent that one can debate using snippets of 140 characters or less. I’ve also been a Super Moderator at a very large Internet message board (AbsoluteWrite) for many years and have seen my share of passionate vaccine debates there. I’ve been a pediatrician for over 30 years and trained in the subspecialty of pediatric infectious diseases before I went into critical care. So I think a lot about vaccines and have watched controversies about them come and go for a very long time. It’s been interesting. One very interesting aspect for me is trying to understand how parents think about the relative risk of medical treatments and procedures for their children. It’s different from how physicians think of risk, and I think this difference is key to understanding the continuing ferment over vaccinations. I’ve previously written about the risk of a vaccine injury (about 1 in a million at worst) compared to the risks of everyday life, but there is another aspect to the issue: in my experience parents are uniquely worried about vaccine risk in ways they are not about other medical procedures and treatments. A few examples illustrate my point.

Stevens-Johnson syndrome is a severe skin reaction to something, most commonly a medication. It varies in severity but can progress to a very bad condition known as toxic epidermal necrolysis. This is a life-threatening condition and often requires a prolonged stay in the intensive care unit. I have seen several life-threatening cases over the years. The drugs that can cause it are quite common ones. Many are antibiotics; sulfa drugs, for example,  are well-known offenders. How common is this condition? There are about 300 cases per year in the USA. This makes it much more common than vaccine injury, yet nearly all parents think of antibiotics as safe drugs. On balance, they are — but they are not risk free.

Medications like antibiotics can cause other kinds of allergic reactions, which can be severe or life-threatening. A very conservative estimate is that about 0.01-0.05 % of all people — about 1-5 per 10,000 individuals — will have such a serious drug reaction in their lifetime. Yet parents accept prescriptions without worrying about that.

Another example is anesthesia. As part of my practice I anesthetize many children for procedures, such as MRI scans. The risk of doing this is low, but it is well above zero. The actual risk of death from an anesthetic is around 1 in 250-300,000 — about 3 times the risk of a serious vaccine reaction. There also may be neuro-developmental risks to young children who receive anesthetics. That risk is very low, too (there are many studies ongoing to define it), but it is not zero. Of course if a child needs emergency surgery the balance of risk versus benefit overwhelmingly favors using the anesthetic, but there are many other situations that are not so clear-cut. Yet virtually all parents willingly allow me anesthetize their child.

My point is that vaccine risk, compared with the risks of other medical interventions, causes particular concern among parents, and I am not sure why that is. However, it is not new. Since the introduction of the very first vaccine, Edward Jenner’s use of smallpox vaccine, people have been particularly suspicious of vaccines. (The name “vaccine” itself is derived from Jenner’s use of the vaccinia virus, the cowpox virus, as a protection against smallpox.) As noted in the essay linked above:

Although the time periods have changed, the emotions and deep-rooted beliefs—whether philosophical, political, or spiritual—that underlie vaccine opposition have remained relatively consistent since Edward Jenner introduced vaccination.

I suppose the notion of putting a foreign substance into a child’s body with the intention of provoking the body to react to it is philosophically distinct from giving a child a medication that is not intended to do that. But I would be very interested in what other people think makes vaccines unique.

 

Medical testing and the risks of idle curiosity

August 30, 2011  |  General  |  No Comments

Doctors use a lot of tests — blood tests, urine tests, x-rays, MRI scans, and quite a few others. Some of these tests carry well-known risks in doing them. For example, a few people have serious allergic reactions to the contrast dye used in certain x-ray tests. For most of the other tests, though, the immediate risk is so low to essentially non-existent. A needle stick hurts for a few minutes, but that soon passes. Getting a simple urine sample doesn’t hurt at all. So what is the harm in getting these kinds of tests because we’re curious what they will show? For example, the “as long as you’re drawing the blood anyway” question comes up frequently; after all, once the needle is in the vein, it’s easy to take a little extra blood for extra tests.

It seems innocent, but what most parents don’t understand is another, more insidious risk, one that using a shotgun approach to testing will bring — the risk the test will give misleading information. A blood or urine test, something of little immediate risk to the child, becomes potentially quite risky if the result will confuse the situation. What can happen is that the test, if just a little (and insignificantly) “abnormal” can lead to further tests and procedures, things that you never would have ordered in the first place. These further tests, in turn, carry further risks. To complicate matters even more, every medical test has a built-in, inherent error rate; the test result may just be flat-out wrong — it’s a statistical possibility. The rule of thumb I’ve often heard is that if you do 20 blood tests, statistically one of them will be falsely abnormal, a fake.

The scenario of an abnormal result in a test done for dubious reasons, leading in turn to more tests, and ultimately to some bad medical decision making, is a well known phenomenon.

My point is that it is never a good idea to ask your doctor to do tests on your child just because you (or your doctor) are simply curious about the result. Any test needs to be clearly justified by a child’s specific situation.

Children need sedation for painful or scary procedures

April 14, 2011  |  General  |  No Comments

When I started training in pediatrics nearly 35 years ago it was common practice when an infant or child needed something done that was going to be painful, anxiety-producing, or both, the child was often merely held (or tied) down. Looking back on it now, it reminds me of the 19th century, a time when somebody might just be given a stick to bite down on. I wonder how we could have been in the same place with children a century later.

To be fair, there were several reasons we did things that way. Chief among them was the notion — one we now know to be false — that children (infants in particular) did not feel pain in the same way as older persons. The other reason was that we simply didn’t have available many of the medications we have now to counteract pain and anxiety, and the few that we had had not been studied much in children.

Things are much different now. We have a menu of things we can use to prevent pain, ranging from numbing cream we can put on the skin to lessen (or even eliminate) the pain of a needle stick to powerful, short-acting anesthetic drugs we can use to put the child into a deep (and brief) slumber. We have reliable ways of greatly reducing or eliminating both pain and anxiety when a child needs medical procedures as varied as an MRI scan or some stitches in the scalp.

Most doctors who do these procedures are well aware of these things. But if you run across one who doesn’t seem to be, don’t be shy about speaking up and asking what can be done to make your child more comfortable.

Concussions in children

September 25, 2010  |  General  |  No Comments

Football season is upon us again, so it’s time to think about sports injuries. We frequently have children admitted to the PICU (or to what we call the intermediate or step-down unit) for observation, typically overnight, who have struck their head. They have had concussions. What is a concussion, and what does it mean for the child?

The term itself is centuries old, but even thirty-five years ago, when I was in training, the actual definition of concussion was a bit vague. What was usually meant was that the patient got hit on the head and either lost consciousness briefly or at least wasn’t quite himself for some period of time afterward. These days we’re more precise than that, but concussion is still a somewhat inexact term. This is mainly because of our ignorance of the subtleties of how the brain works.

The formal definition of concussion is a transient interruption in brain function. By implication, various scans of the brain, such as CT scans or MRI scans, show no abnormalities. Since all the imaging studies are normal, defining concussion is necessarily inexact. I’m sure one day we’ll have some kind of machine that detects the reason for the symptoms of concussion, but right now we don’t have such a thing — concussion is an entirely clinical diagnosis, meaning there’s specific no test for it.

There are several systems for grading concussions. Here’s how the American Academy of Neurology grades their severity:

Grade I: confusion, no loss of consciousness, symptoms last for < 15 minutes, has memory of the event Grade II: confusion, may lose memory of the event but no loss of consciousness, symptoms last for > 15 minutes
Grade III: loss of consciousness and no memory of the event

The list of symptoms that can come from a concussion is a long one. Headache, dizziness, vomiting, and ringing in the ears are common. Various behavioral changes are also common, such as lethargy, difficulty concentrating, and irritability.

What are the effects of concussion on a child? Years ago we pooh-poohed the idea that mild concussions cause brain problems. For example, football players were sent right back into the game after experiencing a concussion. We now know that is dangerous. As a general rule, we don’t recommend any contact sports for at least a week (some authorities say longer) after all symptoms have cleared. This is because a repeat blow to the head, even a very mild one, can cause severe injury to a brain that has not fully recovered from the last injury.

What about long term effects of concussions? The overwhelming majority of children who suffer a concussion, especially a mild one, recover completely. But around a fifth or so of children who have had severe concussions continue to have problems many months afterward.

You can read much more about concussions at this site, from the federal Centers for Disease Control, this one, from the Mayo Clinic, and this one, from the respected Brain Trauma Foundation.

Why we doctors order far too many scans

July 23, 2010  |  General  |  6 Comments

There’s a provocative editorial in a recent New England Journal of Medicine about the explosive rise in high-tech medical imaging. Everyone knows doctors order a lot of CT scans, MRI scans, and ultrasound studies, and that the number of these has been steadily increasing. And the cost is enormous. From the article: ” . . . these costs were the fastest-growing physician-directed expenditures in the Medicare program, far outstripping general medical inflation.”

To be fair, rising use of new medical technology is expected because, well, it’s new. What is unclear is that how much of this increased use has led to improved health to justify the cost. Clearly much of it doesn’t, and unnecessary scans, particularly CT scans, lead to risk with no benefit.

The practice of “defensive medicine,” of doctors ordering tests out of a fear of being sued for missing rare conditions, is often given as a cause for overuse of scans. There is some truth to that: the article cites a Massachusetts study showing that 28% of scans are done for that reason. Lawsuits over failing to diagnose things are common; lawsuits about overuse of tests are vanishingly rare.

Physician conflict-of-interest also plays a part. Through a loophole in Medicare regulations, physicians are allowed to refer patients for scans from which the physician benefits financially. That is wrong and needs to be fixed.

But there are deeper reasons. The root cause may well be “the style and content of clinical education and their impact on medical practice.” In other words, how doctors are trained. We use scans unthinkingly, and, unthinkingly, can cause harm. Again from the editorial: “The greatest risk that patients face with unnecessary imaging is the needless exposure to downstream testing and inappropriate treatment related to misdiagnosis and the overdiagnosis of common but unimportant findings.” I’ve seen that happen more than a few times.

Sedation for children who need procedures — yes, of course

February 12, 2010  |  General  |  No Comments

When I started training in pediatrics, nearly 35 years ago, it was common practice when an infant or child needed something done that was going to be painful, anxiety-producing, or both, the child was often merely held (or tied) down. Looking back on it now, it reminds me of the 19th century, a time when somebody might just be given a stick to bite down on. I wonder how we could have been in the same place with children a century later.

To be fair, there were several reasons we did things that way. Chief among them was the notion — one we now know to be false — that children (infants in particular) did not feel pain in the same way as older persons. The other reason was that we simply didn’t have available many of the medications we have now to counteract pain and anxiety, and the few that we had had not been studied much in children.

Things are much different now. We have a menu of things we can use to prevent pain, ranging from numbing cream we can put on the skin to lessen (or even eliminate) the pain of a needle stick to powerful, short-acting anesthetic drugs we can use to put the child into a deep (and brief) slumber. We have reliable ways of greatly reducing or eliminating both pain and anxiety when a child needs medical procedures as varied as an MRI scan or some stitches in the scalp.

Most doctors who do these procedures are well aware of these things. But if you run across one who doesn’t seem to be, don’t be shy about speaking up and asking what can be done to make your child more comfortable.

Traumatic brain injury in children

March 16, 2008  |  General  |  2 Comments

Most children with significant brain injury spend time in a PICU. Like most experienced pediatric intensivists, I have seen hundreds of these children over the years, with dozens at least in the severe category. In one sense the term “traumatic brain injury” has limited usefulness because it covers such a wide range of injuries, from mild concussions to more extensive injury, to lethal damage. In another sense, however, it is a very useful diagnostic category because the brain responds to a wide variety of injuries in a very similar, stereotypic way.

Our understanding of the manifestations of TBI has grown over the years considerably. When head CT scans became available we could for the first time assess such things as bleeding inside the skull or swelling of the brain easily and safely. I remember how exciting it was in 1974 to see the first simple CT images taken on grainy Poloroid snapshots. Now we have sophisticated computer reconstructions of the brain. The technology represented such a breakthrough that its inventors received the Nobel Prize for it.

We soon realized, however, that some injuries to the brain, particularly what we call shear injury, are not well seen on CT — it takes an MRI scan to do that. We also came to realize that the most important thing we could do in the PICU for a child with severe TBI was to make sure the injury did not get worse: simple supportive measures like relieving pain and keeping the heart and lungs working well were key supportive measures to use while we waited for the child’s brain to heal.

Increasing understanding of milder forms of TBI have made us realize it is much more common than we once thought. For children, although the long-term outcome for mild to moderate TBI is good, persistent problems with such things as headache, mood changes, and difficulties in school are not uncommon, and these can last for months. There is a great deal of information available about TBI. There are many misconceptions about it, too. You can find authoritative, respected advice from the National Institutes of Health here and from the Brain Trauma Foundation here, and many more useful links here.

Medical tests and the risks of curiosity

November 26, 2007  |  General  |  No Comments

Doctors use a lot of tests, such as blood tests, x-rays, MRI scans, and quite a few others. Some of these tests carry well-known risks in doing them. For example, some people have serious allergic reactions to the contrast dye used in x-ray tests. When doctors order these tests on children we are making a judgment that the information the test will give us is useful enough, or important enough, to justify taking the risk. Most parents understand this notion.

What most parents don’t understand, though, is the risk the test will give misleading information. A blood test, something of little immediate risk to the child, becomes potentially quite risky if the result will confuse the situation, leading to further tests and procedures that might not be appropriate, or which carry further risks. In addition, every medical test has a built-in, inherent error rate; the test result may just be flat-out wrong — it’s a statistical possibility.

My point is that it is never a good idea to ask your doctor to do tests on your child just because you (or your doctor) are simply curious about the result. Any test needs to be clearly justified by a child’s specific situation.