Pneumonia | Why It Is So Deadly?

Our immune system has a whole arsenal, like macrophages, cytokines, t-cells and many more, to fight off an infection. But when it comes to some diseases, the way the body defends itself can have unintended consequences. In the case of Pneumonia, the immune system’s response can be very lethal hence earning it the nickname the ‘captain of the men of death.’

Pneumonia doesn’t just refer to a single virus or bacteria. It’s a condition that can actually be caused by a number of different bacteria, viruses or even fungi. The most common being the bacteria streptococcus pneumoniae, who will be our main bad guy today. So when we are talking about pneumonia, we are really referring to something that is happening to our lungs.

So pneumonia is an infection of the lungs and it is a very common infection. The problem is that the lungs are thought to be sterile, in fact, the lungs aren’t sterile. But generally, there are very few bugs in your lungs. The problem is that our mouth and our nose are actually filled with bacteria and viruses and these can something get down into the lungs.

We are constantly being exposed to the bacteria and viruses that cause pneumonia-like Streptococcus pneumoniae. These pathogens can live in your upper respiratory tract without you even knowing it. That’s because, for most people, the immune system should be able to step in and stop them in their tracks, leading to immunity.

You become immune to the bugs that you encounter when you are very young and by about five years of age, you are pretty much immune. But, for children under 5, the immune system is weaker, leaving the body susceptible to infection. 

It’s not just children who are at risk. Unfortunately, pneumonia risk comes back again in the elderly. “Who is elderly?” you might say. Generally defined as people older than 65. So pneumonia is a disease of the extremes of life, the very young and the very old.

Now, it’s not only young children and older adults, anyone with a compromised immune system is at risk. With the immune system unable to mount a defence in the respiratory tract, the bacteria are able to pass into the lungs. Once there, the immune system will still try to defend the body.

But unfortunately, they have a lot of side effects when this response occurs. Macrophages first try to fight off the infection, but they can become overwhelmed, triggering the release of cytokines. These cytokines lead to inflammation of the lungs, causing air sacs called alveoli to fill with fluid.

So alveoli are air sacs in the lungs that are where the exchange of oxygen and carbon dioxide takes place. It is these alveoli that get filled with the fluid that’s come from your bloodstream. Now, there’s no particular reason for red cells to get out of the bloodstream but white cells that are included in the bloodstream are very potent cells able to kill bacteria and they move in from the bloodstream out into the tissues at the site of infection.

But, filling the alveoli with fluid does more than just fight off the infection. That’s because, basically, your lung sacs are filling with pus. The lungs are there and exquisitely designed for oxygen to pass from the air into your bloodstream. 

So, unfortunately, instead of having nice, clear air pockets where this exchange can take place, they are filled with fluid. Then the exchange of oxygen and the release of carbon dioxide, which you breathe out, is impaired.

This causes difficulty breathing as well as a whole host of symptoms that vary greatly in severity. The effects of walking or atypical pneumonia can be so mild, someone might not know even know they have it. In other cases, the infection can lead to death.

But, while pneumonia is still a disease that kills millions of people worldwide, there isn’t a good reason why it should still be so lethal. The main driver of mortality from pneumonia is access to treatment or lack thereof.

There are vaccines that work to protect from both bacterial and viral pneumonia. In fact, the most successful vaccine for prevention of pneumonia is a bacterial vaccine. So pneumonia deaths are really preventable by vaccines and can also be treatable by antibiotics.

Because of this, pneumonia deaths are much more common in poorer countries with fewer resources. Which is why Doctors are working on ways to develop more effective treatments in these areas of the world. 

But pneumonia deaths can still happen in places like USA, UK, Franch or any developed nation especially if something were to lead to people having compromised immune systems. That could happen from contracting other illnesses, some of which are entirely preventable. 

There have been outbreaks of measles recently in some developed country. And globally, measles has not been eradicated. One of the major problems with measles is that it diminishes your immune response. Kids who have measles can get bacterial and viral pneumonia after their measles. 

So, in fact, pneumonia is a major killer following measles exposure. And measles prevention is a very important way of preventing deaths from pneumonia. That’s why you should take the vaccine and there’s a very potent vaccine for measles avalable as well.

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