1. An Infection of the Brain's Shock Absorber
To protect the brain from trauma, Mother Nature has surrounded it with fluid. The meninges are the membranes that cover the brain and spinal cord. These membranes produce fluid. The fluid serves to carry nutrients to the brain as well as offering a means of cushioning the brain from the shock of trauma. If bacteria or viruses invade these membranes, they may become infected. The fluid they produce also becomes infected thus called meningitis.
2. Viral and Bacterial Meningitis
There are two forms or meningitis, aseptic meningitis (viral) and septic meningitis (bacterial). Within these two classes, there are a variety of specific organisms that can cause infection, some much more deadly than others. In general, bacterial meningitis is more serious than viral meningitis, but they are both very serious illnesses.
3. Spinal Tap Required
To diagnose meningitis, meningeal fluid is obtained. A spinal tap is the only way this can be done. The doctor inserts a needle between vertebrae (back bones) and through the outside of the ligament that overlays the meningeal membrane. An infant is placed on his or her side for the procedure and curled into a ball to "open up" the space between the backbones. Fluid is removed and sent for examination with a microscope to look for white blood cells (associated with infection) and bacteria. The fluid is also cultured, analyzed for protein (which increases with infection) and glucose (which decreases with infection).
4. Meningitis Symptoms Aren't Always Obvious
One of the difficulties with infantile meningitis is its presentation. Babies can't tell parents or doctors that they have a heck of a headache. Sometimes all an infant may have is a high temperature. They may also have a low grade temperature and be slightly irritable. For this reason, the Academy of Pediatrics has established criteria suggesting when a spinal tap is required. It is generally true that when performed by an experienced clinician, the risks of doing a spinal tap on an infant are less than the risks of missing the diagnosis of meningitis.
5. Treat for the Worst, Hope for the Best
Until culture results are available, it's not clear what kind of meningitis an infant has. The spinal fluid may have shown white blood cells, a low glucose and an elevated protein, all of which substantiate meningitis, but without culture results, it is impossible to tell what organism has caused the infection. So, doctors begin by treating for the worst possibility, certain kinds of bacteria. This treatment usually involves two antibiotics for bacteria and one anti-viral agent.
