Meningitis and Encephalitis: Causes, Symptoms & Treatment

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  • 0:31 What Are Meningitis…
  • 1:45 What Causes Meningitis…
  • 3:33 Signs and Symptoms of…
  • 4:02 Diagnosing Meningitis…
  • 5:58 Treating Meningitis…
  • 6:48 Lesson Summary
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Lesson Transcript
Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

This lesson will go over a lot of cool things. We'll detail meningitis and encephalitis, what causes them, how your immune system plays a role, how to diagnose these conditions, and how to treat them.

Deadly Problems in the Nervous System

Tired? Irritable? Maybe you're also having trouble seeing and have a headache? And, if you swear to me it's not because you're stressed, had too much to drink, or haven't been eating properly, then you may have something far more sinister going on - sinister enough to kill you. This lesson will go into a couple of important conditions that involve the nervous system, their causes, and possible treatments among some other things.

What Are Meningitis and Encephalitis?

Some of the scariest medical conditions that could possibly affect you involve the nervous system. That's because this system is like the remote control of your TV. Without the remote control, the TV will not be able to turn on or switch channels. Likewise, without your nervous system, your body is toast!

The most important button of your body's remote control is known as the brain. Because your brain is so precious, it is encased in a helmet. Well, more technically, it's known as your skull, but you know what I mean. In addition to the skull, there are protective membranes that cover the brain and spinal cord, known collectively as the meninges. You can liken the meninges to that thin plastic covering some people put over their remote control in order to keep it nice and clean.

Anyway, a condition involving the meninges, known as meningitis, may develop due to a wide variety of causes. Meningitis is the inflammation of the meninges, where 'itis' is a suffix that refers to inflammation. Very similarly, many different things may cause a condition known as encephalitis. Encephalitis is the inflammation of the brain. The prefix 'encephalo' in encephalitis refers to the brain. Furthermore, the inflammation of the brain and meninges, at the same time, is known as meningoencephalitis.

What Causes Meningitis and Encephalitis?

Just like there are many different things that can cause your remote control to malfunction, like you spilling a drink on it or the batteries running low, similarly, there's a whole host of reasons why someone may develop inflammation of the brain or meninges. These reasons include:

  • Toxins and drugs
  • Bacteria
  • Viruses
  • Fungi
  • Parasites
  • Cancer

All of these can cause meningitis and encephalitis.

The Pathophysiology of Meningitis and Encephalitis

The key question should really be not so much what causes these conditions, since virtually anything can cause it, but what's the core physiological reason behind its development? For example, if the remote control failed because the batteries died, you'd tell me that the reason the remote control really failed is because there was no source of energy left for it to work off of. Similarly, there's a deeper reason for why meningitis and encephalitis occur. It actually has less to do with a microbe that may cause it and more to do with your immune system. That's right; it's your own body's defense mechanisms that are mainly responsible for this condition.

What happens is basically as follows. Let's say some bacteria enter your body and travel to the brain or meninges. The bacteria may actually be quite harmless. Some of them aren't harmless, and release all sorts of nasty toxins, but others do not. However, our immune system doesn't care if they're harmless or not. It just doesn't want the foreign bacteria there in the first place.

In order to get rid of the foreign invaders, the immune system's cells, which are like little soldiers designed to kill the bacteria, release all sorts of chemicals that not only destroy the bacteria but also your own body's cells and tissues. Essentially, you can liken this to a war with a lot of collateral damage where innocent civilians, or your body's cells, get hurt in the process of your army trying to kill off the bad guy.

The Signs and Symptoms of Meningitis and Encephalitis

As the battle inside your skull rages on, you'll begin to experience the signs and symptoms associated with the inflammation of your brain and meninges. In the case of encephalitis, this includes:

  • Confusion
  • Headache
  • Fever
  • Seizure
  • Paralysis
  • Increased intracranial pressure due to edema, or swelling of the brain
  • And, in severe cases, even death

Meningitis has some very similar signs as well, but may also have 'a feeling of a stiff neck.'

Diagnosing Meningitis and Encephalitis

Since all of those signs and symptoms are all indicators of a problem, it's important to get a diagnosis established as soon as possible. I mean, if the remote control wasn't working correctly, you'd have to figure out if you needed to change the batteries, what kind of batteries you need, or if the problem isn't even with the remote control to begin with. Very similarly, we need to figure out if those signs are a result of meningitis or encephalitis, both, or something else.

To do this, we can do all sorts of tests. For example, we can take a sample of the protective fluid that surrounds the brain and spinal cord, called cerebrospinal fluid, through a procedure known as a spinal or lumbar tap. Under normal conditions, this fluid shouldn't have many immune system cells, called white blood cells, shouldn't have lots of protein, or bacteria in it. If we see a lot of white blood cells, lots of protein, bacteria, or a combination of these, then we can safely assume an infectious cause of encephalitis or meningitis is occurring.

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