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Meningitis and Sepsis

with updates on new vaccination recommendations
and the Detroit-area meningitis outbreak

Meningitis

Meningitis is one of the most serious infections you can have. It is also one of the scariest -- understandably, since untreated some forms of meningitis can cause death or lasting impairment.

The meninges are membranes that enclose the brain and spinal cord. There are actually three layers of membrane: the "dura", which is a tough outer layer, the "arachnoid", which is a lacy, web-like middle layer, and the "pia", which is a delicate, fibrous inner layer containing many of the blood vessels that feed the brain and cord.

Meningitis, strictly speaking, is an inflammation of the meninges. (The suffix "-itis" stands for "inflammation"; inflammation of the brain tissue itself is called "encephalitis", where "encephal-" refers to the brain tissue.) There are many causes for inflammation of tissue, and the meninges are no exception. However, the most common cause of meningeal inflammation is irritation caused by infection with bacteria or viruses. These organisms usually enter the meninges through the bloodstream from other parts of the body. As a matter of fact, many meningitis-causing bacteria are carried in the nose and throat, often without the carrier having symptoms.

Viral meningeal infections are usually (but not always) less severe than bacterial infections. This is quite fortunate, since there are no antibiotic treatments available for most viruses and we must therefore let viral meningitis run its course by itself. Bacterial meningitis, on the other hand, must be treated with antibiotics in most cases to avoid severe consequences. Unfortunately the only way to confirm that meningitis is not bacterial is to culture the spinal fluid (actually the cerebrospinal fluid, since it bathes both the spinal cord and the brain) and see if there are bacteria in it. This can take 3-5 days. Since a bacterial meningitis can do a LOT of damage in 3-5 days, common practice is to start antibiotics immediately after doing the spinal tap and keep giving the antibiotics until the culture has shown no bacteria for 3-5 days. This may seem wasteful (especially to bean-counters), but it is far better to treat all suspected meningitis patients promptly than to have to treat the long-term consequences of an untreated meningitis.

Since inflammation and resulting swelling seem to be the main cause of brain damage from meningitis, steroids have been used in some cases to help lessen the inflammation. Steroids usually are given along with antibiotics, and may not be appropriate in all cases of meningitis.

Sepsis

"Sepsis" is the term we use for an overwhelming bacterial infection. Sepsis usually includes "bacteremia", or bacteria in the blood, although bacteremia can happen without sepsis (you will have bacteria in your blood briefly every time you brush your teeth...). Usually we reserve the term "sepsis" for patients whose infections are so severe that they are in shock; such infections happen more often when the immune system isn't working quite right (because of cancer, AIDS, or malfunctioning organs or bone marrow, or other diseases). Very young babies do not have fully functional immune systems either and are thus susceptible to sepsis; this is why we routinely give IV antibiotics to any child under 2 months old who has a fever -- we cannot risk leaving sepsis untreated.

Among common bacterial causes of meningitis and sepsis are:

Neisseria menigitidis (Meningococcus)

Meningococcus is a bacteria often carried in the nose and throat without symptoms. It can be spread by droplets coughed or sneezed out by an infected person or by a carrier; many outbreaks of meningococcal infection occur in people living in close quarters (like schools, colleges, and military installations). It takes 1-10 days (most often 4 days or less) after exposure to show symptoms; patients are usually contagious until they have been treated for at least 24 hours.

Meningococcal infection can cause meningitis, sepsis, or both. Oddly, someone with meningococcal infection with meningitis may do better than s/he would with sepsis and no meningitis; this does not always happen, though. Signs of meningococcal infection may include fever with chills and a rash; the classic rash of meningococcal infection is "petechial", caused by tiny blood clots just below the skin surface. In severe cases the infection can result in shock and death within a few hours even if treated.

In the past penicillin G has been sufficient treatment for meningococcal infection. However we have seen strains of meningococcus in recent years that are resistant to penicillin G; these require treatment with other antibiotics such as the third-generation cephalosporins. Antibiotics for someone with possible meningococcal infection are chosen initially according to whether or not resistance has been seen in previous patients with meningococcus, since there may not be enough time to culture the patient's own bacteria and test different antibiotics against it.

There are many different groups or "serotypes" of meningococci, at least 8 of which can infect people. The most common infectious groups are labelled A, B, C, X, Y, Z, 29-E, and W-135 (and no, I don't know exactly how the labels were assigned...). Groups B and C are the groups most often seen in the United States. Unfortunately we do not yet have a good vaccine for group B. There is, however, a vaccine available that protects against groups A, C, Y, and W-135 (it is actually a combination of vaccines against each of the 4 groups); it is usually given in a single dose, although it may have to be given in two doses to children younger than 18 months. The A vaccine will provide immunity to patients 3 months or older, but the C component is effective in children 2 years or older. We do not routinely vaccinate children against meningococcus in the United States, but travelers to countries where meningococcus is more common should receive the vaccine, as should patients whose spleens have been removed or no longer work properly (such as patients with sickle-cell anemia, whose spleens eventually fail). Certain groups of people, such as military personnel, routinely receive the vaccine.

Streptococcus pneumoniae (Pneumococcus)

Pneumococci are even more common than meningococcus; in fact pneumococci are the most common cause of ear infections and sinus infections, as well as the most common bacteria found in the blood of children under 2 years old with fevers, many of whom have no obvious site of infection. Again, like meningococcus, many people have pneumococci in their noses and throats but have no symptoms. The bacteria is transmitted from one person to another, usually by droplets. Like viral upper respiratory infections, pneumococcal infections are more common in winter. Infection can begin as little as 1-3 days after exposure.

The signs of pneumococcal meningitis and sepsis can be the same as those of meningococcal meningitis. Often, however, pneumococcal infection can appear first as a high fever with a very high white-blood-cell count (where almost all of the white cells are neutrophils or bacteria-fighting cells) and no obvious site of infection.

Again, like meningococcus, pneumococcal infections could be treated with penicillin G, but penicillin-G-resistant pneumococci have become more and more common, especially with antibiotic overuse (this is one reason why we use so many different antibiotics to treat ear infections). We usually start meningitis or sepsis treatment with third-generation cephalosporins such as ceftriaxone, until the cultures have been completed and we know what antibiotics can be used.

There are over 80 different know serotypes of pneumococcus. Some are more prevalent in different areas; some are more prevalent in children, while others are more common in adults. There is a vaccine available that protects against 23 of the known serotypes; as with meningococcus, the vaccine is given mainly to those at risk of severe infection, including those whose spleens no longer work properly. The vaccine does not provide complete or lifetime protection, nor does it necessarily help prevent ear infections. However, there is now a new vaccine available and intended for infants and children that, although it only protects against 7 different serotypes, provides much better immunity. See my pneumococcus page for more information.

Viral Meningitis

Although it is quite possible to have an overwhelming viral infection, generalized viral infections are common enough -- and usually not dangerous enough -- that we don't often consider viral sepsis as a separate problem. (Besides, we have no antibiotics to treat most viral infections, anyway.)

However, viral meningitis is a separate problem, and a common one at that. We can't treat viral meningitis either, but viral meningitis is usually less severe and causes less damage than bacterial meningitis. (I had a viral meningitis myself as a teenager. I may not be quite normal, but it doesn't seem to have done too much damage...)

Many commmon viruses can cause meningitis. Among these are enteroviruses (like the polio viruses), varicella (the chickenpox virus), the mumps virus, adenoviruses, and many others. Notice that many of these viruses are ones we have vaccines for; a child who has been properly immunized against these viruses will likely not develop meningitis from them. However, if there is no vaccine for the virus there is no really good way to prevent a meningitis caused by that virus except to stay away from people who have the virus -- which can be very hard, because a particular virus may infect hundreds of people but cause meningitis in only 1 or 2 of them.

Meningitis Outbreaks in the Detroit Area

In early September, 2000 we saw a number of cases of meningitis in the Detroit, Michigan area, mainly among school-age children. Almost every case I saw (4 or 5 in a week) proved to be viral; we do, of course, culture the spinal fluid to make sure that there is no bacterial cause, but I did not see a meningitis patient whose spinal fluid showed bacteria. Since these cases of meningitis are viral, the meningococcus vaccines (see below) will NOT protect you against them.

In October, 2000 several cases of bacterial meningitis were reported in the northeastern suburbs of Detroit among school-age children; at least three deaths were reported. Reports in the newspapers on October 11 indicated that these were cases of pneumococcal meningitis, rather than meningococcal meningitis as first reported. We did not, to my knowledge, see cases of meningococcal meningitis in the hospitals where I admit patients and teach, although we have occasionally seen cases of pneumococcal meningitis (but no more frequently than we usually do). Currently (April, 2001) I know of one child hospitalized in the Detroit area with pneumococcal meningitis.

The only treatment for viral meningitis is supportive: we try to keep the patient comfortable and support vital functions as needed. We do give antibiotics until spinal fluid cultures show no bacteria for 48 hours, to make sure that there is no bacterial infection, but once the cultures are negative we stop the antibiotics and send the child home -- and usually a child with viral meningitis feels better in a day and is chomping at the bit to go home.

As for pneumococcal meningitis: although there are vaccines available for some strains of pneumococcus, most children above age 2 have immunity to many of the strains of pneumococcus out there already. Also, again according to news reports, each of the children with pneumococcal meningitis was infected with a different strain of pneumococcus. This means that the "cluster" of meningitis cases was sheer coincidence, not an epidemic. (This may yet change, but this is the best information I have yet been able to obtain on the current "outbreak".) Unless your child is unusually susceptible to pneumococcal infections (see the pneumococcus page for details) s/he probably does not need the 23-strain vaccine. As always, talk to your child's doctor for the best possible information on what your child needs.

The Michigan State University Meningitis Outbreak

Early in Spring, 1998, three children in Rhode Island died of meningitis, and -- not unreasonably -- many parents were concerned about the possibility of their children contracting meningitis. I had a couple of inquiries from Rhode Island parents regarding the problem, and according to news reports Rhode Island doctors were deluged with phone calls. Many parents sought vaccination against meningococcus (the apparent organism responsible for most of the cases in the outbreak) for their children.

In a similar incident, but more isolated, a sophomore at Michigan State University, in East Lansing, Michigan, was hospitalized in early October, 1999, with meningococcal meningitis. Publicly-available information does not give the serotype of the bacteria this student had. According to news reports, MSU gave meningococcus vaccine to almost 10,000 students and others on campus.

The meningococcus vaccine, as I described above, protects against four of the known serotypes of meningococcus -- and does NOT protect against type B, the most common type. It does protect against serotypes C and Y, which caused 70% of cases of meningitis among college students in 1998-1999, but it does not give 100% protection against C and Y. Also, the vaccine does not work well in children younger than 2 years. It isn't a bad idea to vaccinate 2-year-olds and older children against meningococcus IF they have been exposed to a person with proven meningococcus, along with antibiotics to kill any meningococcus they might have in their noses and throats. However, mass immunization against meningococcus may not be necessary if meningococcus is not the cause of the meningitis outbreak, or if you live far from the reported cases.

However, the Advisory Committee on Immunization Practices (ACIP), which includes representatives from the Centers for Disease Control and Prevention (CDC), the American Academy of Pediatrics (AAP), and several other medical and public-health organizations, now recommends (as of October 20, 1999) that physicians who care for college dorm residents, especially freshmen, discuss the meningococcal vaccine with those students and their parents and give the vaccine to those students who ask for it. Some physicians and public-health officials are now publicly advocating meningococcus vaccine (the four-serotype version) for all college students.

Although giving "prophylactic" antibiotics to try to prevent meningitis from developing is often recommended for people in close contact with an infected person, trying to give prophylactic antibiotics to everyone on, for example, a college campus is -- at least in my opinion -- not worth the trouble, the expense, or the possibility of the meningitis bacteria or other bacteria becoming resistant to the antibiotic. People who have been in close contact with someone with proven meningococcal meningitis, though, should take prophylactic antibiotics.

As always, you should talk to your doctor about the vaccine, or about prophylactic antibiotics, and about their pros and cons before deciding whether to get it for your children or yourself.

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PLEASE NOTE: As with all of this Web site, I try to give general answers to common questions my patients and their parents ask me in my (real) office. If you have specific questions about your child you must ask your child's regular doctor. No doctor can give completely accurate advice about a particular child without knowing and examining that child. I will be happy to try and answer general questions about children's health, but unless your child is a regular patient of mine I cannot give you specific advice.

ALL INFORMATION, DATA, AND MATERIAL CONTAINED, PRESENTED, OR PROVIDED HERE IS FOR GENERAL INFORMATION PURPOSES ONLY AND IS NOT TO BE CONSTRUED AS REFLECTING THE KNOWLEDGE OR OPINIONS OF THE PUBLISHER, AND IS NOT TO BE CONSTRUED OR INTENDED AS PROVIDING MEDICAL OR LEGAL ADVICE. THE DECISION WHETHER OR NOT TO VACCINATE IS AN IMPORTANT AND COMPLEX ISSUE AND SHOULD BE MADE BY YOU, AND YOU ALONE, IN CONSULTATION WITH YOUR HEALTH CARE PROVIDER.

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