Let me let you listen in on a typical conversation between a pediatrician and parents of an infant, child or adolescent who is quite ill.
"Mr. and Mrs. Brown, your boy looks quite ill, but I can't be sure of the cause of the illness until we run some tests."
"It might be just a virus that is making his neck stiff and giving him a fever or something more serious such as meningitis. Are you familiar with that term and how we make the diagnosis?"
"No."
"Well, let me explain some things. If you have any questions, stop me. OK? Meningitis is an infection of the membrane which forms a cushioning sack surrounding the brain and spinal cord.
"The brain and the long, slender spinal cord attached to it are such important structures that they are encased in a thin balloon-like sack filled with fluid.
"The fluid in the sack provides a cushion inside the hollow skull and backbone.
"Because of its blood supply and other reasons, this sack can become infected with either a virus or a bacteria.
"Now, virus infections are usually mild, and there is no treatment; but bacterial infections must be treated rapidly in order to prevent very serious consequences.
"I will make the diagnosis by taking a sample of the fluid from inside of the sack and analyzing it."
"Well, how do you get the fluid? Do you drill a hole in the skull?"
"No, fortunately that's not necessary. The sack which surrounds the brain also surrounds the spinal cord down inside the hollow backbone.
"This sack continues down the backbone and then fortunately goes a little past the end of the spinal cord, forming a little pouch of fluid.
"If we insert a needle through the skin, between the vertebrae and into this pouch, we can draw off some of the fluid for analysis."
"Will it hurt him?"
"Well, there is a needle, but usually it hurts about like a shot. But you know, often the most uncomfortable thing for the child is being held down tightly so that he can't move.
"It's very important that he remain absolutely restrained during the procedure so as not to cause damage to the back or anything else. This may cause younger children to cry. Especially if they can see the parents in the room and wonder why you are not helping them."
"What will you do with the spinal fluid?"
"We send it to the lab for several different tests. First, they look at it under the microscope to count the number of pus cells in the fluid and see if the are 'lymph's' or 'poly's'.
"If there are more than one or two pus cell, then we know there is an infection. If they are poly's, then the infections is probably bacterial; which we treat with antibiotics for about two weeks in the hospital.
"If they are lymph's, then the infection is probably a virus, which will get better on its own.
"We also have the lab measure the fluid glucose level which goes down in bacterial infections and protein level which tends to go up in virus infections.
"Of course they also culture the fluid to see if any bacteria might grow.
"All of this usually takes a couple of hours for the lab to do."
"Are there complications?"
"Well, anytime we do anything there is always a risk of complications. There is a risk of introducing an infection with the needle. That's why we scrub and do it under sterile conditions.
"Occasionally the fluid sack is torn and produces a leak of spinal fluid, which takes longer to heal and may produce a headache. That's why we go very carefully and strongly restrain the child during the procedure.
"Rarely, if the needle hits a nerve, it will cause pain down the leg and might injure it; and I have heard of one case where the needle broke off and had to be removed surgically.
"All of these complications are so extremely rare, however; and the disease we are trying to prevent is so bad that the benefits far outweigh the risks.
"That's why many medical school professors tell their student doctors that 'if you even think about meningitis, then do a spinal tap.'
"And a professor told me once that 'if you're not getting 50 to 60 percent normal spinal taps, then you are not thinking about the diagnosis often enough and one of these days you will miss a meningitis until it is too late."
"Now, I hope that your son's stiff neck and fever is merely from a flu-like virus that will resolve on its own. But if it is meningitis, however, we will want to get him on antibiotics as quickly as possible. The studies show that the earlier a bacterial meningitis is treated the fewer complications that arise."
This discussion is not intended to relate to any specific case. Any questions should be thoroughly discussed with your child's own pediatrician if the necessity arises.
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