Pediatrician’s Perspective: Ear Infections

What happens when we get an ear infection?

Ear infections occur in the middle ear—the part of the ear that has the little bones that conduct the sound from the ear drum to the inner ear. The middle ear is a small, completely enclosed chamber with a tube (the Eustachian tube) that is able to open and that connects to the back of the throat behind the nose. When things are going well, the chamber is filled with air and the tube can open and allow the pressure inside the middle ear to be equal to outside air pressure. The tube also opens and closes to allow the middle ear to keep itself clean and empty.

But there are several ways that problems can occur. The nearby nose and throat are full of bacteria that have been trapped there as they try to enter our bodies. These bacteria live in uneasy harmony with us, but they are always ready to infect us if they can find a way to do so. Some of these bacteria will find their way up the tube to the middle ear, but in a healthy person with a fully functioning response system and Eustachian tubes, the bacteria will be repulsed or killed.

So ear infections happen when an environment is created that allows the bacteria to get into an area where it will be safe, where it can grow and expand and “raise a family”. That area is often the middle ear. Most commonly this occurs when we have gotten a cold. The cold virus weakens our ability to fight off bacterial infection in many ways. And the virus irritates the linings of our nose and throat. The irritation can make the Eustachian tubes function poorly. Tonsils and adenoids get large in an effort to fight off the virus, and so they too can block the function of the Eustachian tubes.

Now we have irritating viruses and possibly irritating bacteria in our middle ears. Just as our eyes and noses pour out fluid to wash away irritating substances (the runny nose of a cold, the tearing eyes when exposed to smoke), our ears produce fluid which they hope will wash away the bacteria. Also, a blocked Eustachian tube prevents the entry of new air, and after a while, the oxygen in the air in the middle ear is used up, creating a vacuum and causing the ear to produce fluid to compensate for that vacuum.

The bacteria now think they are in heaven. They have warm fluid with lots of nutrients, and they can flourish. But our body is gathering its resources. It increases the blood flow to the area (so the ear looks red). It may give us a fever to make things uncomfortable for the bacteria. It sends certain blood cells to the middle ear to fight the invaders, which makes pus. Things are getting pretty crowded now, with the fluid, the growing bacteria, and our cells that have come to fight. The eardrum bulges and there can be significant pain if the bulging has come on rapidly. Pain is also caused by the bacteria’s action on our tissues and by the resulting inflammation.

Usually it all ends happily for us. People with reasonably good immune systems—and that is almost all people—will ultimately recover in most cases. Very occasionally, however, there are complications that can endanger your hearing, your health, and even your life.

Babies and toddlers get far more ear infections than older children and adults. Why is that?
There are lots of reasons why ear infections are so much a part of many young children’s lives. They get frequent colds, both because they are immunologically immature and because they are meeting the cold viruses for the first time and haven’t yet made the cells to fight them off. Many children are in daycare or group activities that expose them to colds. (Though if they aren’t in daycare, they will meet the viruses later and will need to learn how to deal with them then.) Tubes, spaces, and passages in babies are smaller and easier to block.

There are lots of reasons why ear infections are so much a part of many young children’s lives. They get frequent colds, both because they are immunologically immature and because they are meeting the cold viruses for the first time and haven’t yet made the cells to fight them off. Many children are in daycare or group activities that expose them to colds. (Though if they aren’t in daycare, they will meet the viruses later and will need to learn how to deal with them then.) Tubes, spaces, and passages in babies are smaller and easier to block.

The “architecture” of a baby’s ears, nose and throat is different from an older child’s or adult’s. In an older child, the Eustachian tubes have a down hill course, so gravity helps them drain. In babies, the middle ear and the point where the Eustachian tube enters the back of the throat are nearly level, so they drain less well. It is possible that sleep position, reflux, and feeding positions can increase the irritation at the exit of the Eustachian tube and make it function less well. Allergies are a lot like colds in their effects on the throat and nose, and like colds, they can produce an environment that makes ear infections more likely.

Inherited predisposition may play a roll. Many families report that one or both parents had a particularly hard time with ear infections. Their child is probably at greater risk.

What to do about ear infections.
Like many problems involving our health, it is not easy to decide what to do when a child develops an ear infection. There are lots of options: no treatment, pain relievers, antibiotics, tympanocentesis, Pressure Equalization Tubes (PE tubes). Most children will do fine no matter what we do, but it isn’t easy to pick out in advance the children who will go on to have serious complications.

There are pluses and minuses with every course of action. When I was a child, ear infections were not treated. Most children did well, but many didn’t. Those who didn’t got permanent hearing loss, chronic active infections, destruction of their ear structures, mastoiditis, meningitis, but there are many differences between then and now. In those days there was almost no daycare and societal patterns were very different, so children did not get infections as early as they do now. There was less antibiotic resistance (good), but fewer antibiotics to treat complications effectively (bad). We now have immunizations that can prevent serious invasion of some key bacteria that cause meningitis (good). We also now have more mothers breastfeeding. Breastfeeding reduces the number of ear infections but does not prevent them all. And there are probably many other changes in our world that impact the patterns of ear infections that we either don’t perceive or don’t perceive the importance of.

Ear infections, even uncomplicated ones, cause pain and fever and disruption of sleep and behavior and family schedules and obligations, and that can be pretty miserable for every one. Prolonged or recurrent ear infections undoubtedly reduce hearing acuity for the duration of the infection and recovery period (that can extend for weeks to months), and this could possibly impact speech and language development.

We—both parents and pediatricians—want to fix things. What should we do? Studies are done and experts confer. Guidelines are drawn up, changed, and drawn up again. We worry both about antibiotic resistance and how we’ll live with this child until he gets better. And what are the chances of complications?

So
I recommend Antibiotic treatment if the baby is under 1 year old, all babies and children with other health problems that make it harder for them to conquer the infections, babies and children whose have a history of significant problems with ear infections (for example, perforation of the ear drum, or febrile seizures), and children who respond well to treatment and whose parents desire it. If we elect not to treat a baby or child, it is important to see him in a day or two to be sure he is not getting sicker. As we get to know a baby or child, we know if he clears up quickly with antibiotics or if he needs more aggressive therapy. If a child has recurrent or persistent ear infections or persistent and prolonged (uninfected) fluid in his ear, we may recommend exploring the option of PE tubes with an ear specialist. For all children who get significant or frequent ear infections, we will need to pay close attention to speech and language development and other signs that the child is not hearing well. We are also lucky that we have the immunizations against the two most common causes of meningitis in babies and young children—Haemophilus influenza B and Pneumococcus—and hope all babies are getting them.