Meningitis Basics: What you need to know.

Meningitis occurs when a virus or bacteria causes inflammation of our brain or spinal cord. We use several different vaccines to prevent a few types of meningitis, but it's all very confusing. Recent commercials have raised questions about what these vaccines are and if they're needed.

Today we'll go over what meningitis is and what types of germs cause it. Next time I'll discuss some of the new meningitis vaccines in more detail.

What is meningitis?

Both viruses and bacteria can cause meningitis, but not everyone with these germs gets meningitis. Most people have less severe symptoms when they get these infections.

Not everyone gets all the symptoms listed below when they have meningitis. Some of these symptoms are common to many less serious infections, but if your child has these symptoms and appears more sick than normal, he or she should be evaluated immediately.

Symptoms of meningitis include:

• fever

• stiff neck

• body aches and pains

• sensitivity to light

• mental status changes

• irritability

• confusion

• nausea

• vomiting

• seizures

• rash

• poor feeding

Viral meningitis

Viruses are the most common cause of meningitis. Thankfully viral meningitis tends to be less severe than bacterial meningitis.

Most people recover on their own from viral meningitis. As with many infections, young infants and people who have immune deficiencies are most at risk.

There are many types of viruses that can cause meningitis. It's likely that you've had many of these or have been vaccinated against them.

Non-polio enterovirus

The most common virus to cause meningitis is one from the non-polio enterovirus family.

Fever, runny nose, cough, rash, and blisters in the mouth are all symptoms that kids can get from this type of virus.

Most kids are infected with this type of virus at some point. Adults are less susceptible, and can even have the virus without symptoms.

There is no routine vaccine given for non-polio virus strains.

MM(R)V

Measles, mumps and chicken pox viruses can cause meningitis.

We vaccinate against these typically at 12-15 months of age, so it is uncommon to see these diseases. The MMR and varicella vaccines can be given separately or as MMRV. (Rubella is the "R" and can lead to brain damage in a fetus, but does not cause meningitis.)

Influenza

Influenza can cause meningitis, which is one of the reasons we recommend vaccinating yearly against flu starting at 6 months of age.

Herpesviruses

Herpesviruses can cause meningitis. Despite the name, most of these are not sexually transmitted.

This family of viruses includes Epstein-Barr virus,which leads to mono most commonly. Cold sores from herpes simplex viruses are also in this group. Chicken pox (or varicella-zoster virus) is another of these blistering viruses.

Bacterial meningitis

Bacteria that lead to meningitis can quickly kill, so prompt treatment is important. If you've been exposed to bacterial meningitis, you may be treated as well, but remember that most people who get these bacteria do not get meningitis.

Most people who get bacterial meningitis recover, but some have lasting damage. Hearing loss, brain damage, learning disabilities, and loss of limbs can result from various types of meningitis.

Causes of bacterial meningitis vary by age group:

Newborns

Newborns can be infected during pregnancy and delivery as well as after birth. They tend to get really sick very quickly, so this is one age group we take any increased risk of infection very seriously.

Bacteria that tend to infect newborns include Group B Streptococcus, Streptococcus pneumoniae, Listeria monocytogenes, and Escherichia coli.

Mothers are routinely screened for Group B Strep during the last trimester of pregnancy. They are not treated until delivery because this bacteria does not cause the mother any problems and is so common that it could recur before delivery if it's treated earlier. This could expose the baby at the time of delivery. If a mother does not get adequately treated with antibiotics before the baby is born, the baby may have tests run to look for signs of infection or might be monitored in the hospital a bit more closely.

Once the mother's water breaks, we time how long it has been because this opens the womb up for germs to infect the baby. If the baby isn't born during the safe timeframe, your delivering physician or midwife might suggest antibiotics. After delivery your baby might have tests done to look for signs of infection or might be monitored more closely in the nursery.

It is very important that sick people stay away from newborns as much as possible. Everyone should wash their hands well before handling a newborn.

Babies and children

As children leave the newborn period, their risks change. Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae type b (Hib) are the bacteria that cause disease in this age group.

Thankfully we have vaccines against many of these bacteria. Infants should be vaccinated against S. pneumoniae and H. influenzae starting at 2 months of age. (Note: H. influenzae is not related at all to the influenza virus.)

Vaccines against N. meningitidis are available, but are not routinely given to infants at this time. High risk children should receive the vaccine starting at 2 months of age, but it is generally given at 11 years of age in the US.

Teens and young adults

Neisseria meningitidis and Streptococcus pneumoniae are the risks in this age group.

Thankfully most teens in the US have gotten the S. pneumoniae vaccine as infants so that risk is lower than in years past.

Tweens and are routinely given a vaccine against A, C, W, and Y strains of N. meningitis. A vaccine against meningitis B is recommended for high risk people and can be given to lower risk teens. This will be discussed further in my next blog.

Older adults

Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae type b (Hib), group B Streptococcus and Listeria monocytogenes affect the elderly. 

Talk to your parents to be sure they're vaccinated and follow the vaccine recommendations for yourself too. Vaccines are not just for kids!

'NI, Leptomeningitis purulenta cerebralis. Alfred Kast' . Credit: Wellcome Collection. CC BY