In this lesson, we will discuss a well-known condition called tetanus. You will learn about the bacteria, toxins, and symptoms associated with this deadly disease.
Death by Puncture Wound
Not too long ago, I heard of an elderly man who was working barefoot in the garden. He was doing this and that and all of a sudden stepped on a nail. He took a look down at his heel and noticed that the nail did, in fact, penetrate a little bit into his foot, but it wasn’t that painful, and he didn’t think too much of it.A few days later, he felt like he was getting sick but again, didn’t think much of it.
Later, he felt as if his muscles were stiffening up, but as many men seem to do, he still refused to see the doctor. In the end, the man ended up dying because he was infected with a deadly microbe that was introduced into his body through the puncture wound he suffered.
Infected with Tetanus
The man ended up dying due to a condition known as tetanus, a potentially deadly bacterial disease that causes lockjaw, trouble swallowing, muscle spasms, and in severe cases, respiratory failure. The Gram-positive, anaerobic, drumstick-shaped bacteria that causes tetanus is known as Clostridium tetani. Finally, the scientists named something after the disease it causes! That one should be easy to remember without a metaphor.This bacterium is anaerobic, meaning it doesn’t need oxygen for growth, and it has a very thick cell wall, which is why it’s called Gram-positive.
It is found in many places, including feces, dust, and the soil that was almost certainly on the nail that penetrated into the man’s flesh. Once this bacterium gains entry into a person, the fun starts, so to speak. However, you might be surprised to learn that the bacterium itself doesn’t cause much of an invasive infection that triggers the immune system. It’s what the bacterium releases, as opposed to the bacterium itself, that is the cause of all of your troubles.
Tetanospasmin and the A-B Toxin
That’s because this bacterium releases something called tetanospasmin, which is a neurotoxin that is sometimes known as the A-B toxin.
This toxin is so utterly powerful that 1mg can kill over 10 million mice. The way this toxin functions isn’t too difficult to understand.Excitatory nerves that stimulate your muscles to contract do so at a place called the neuromuscular junction. Here, the nerves release a substance, called acetylcholine, that binds to a receptor on the muscle cells. This causes the muscle to contract.
You can think of the excitatory nerve as a striker for a soccer team – the ball is a molecule of acetylcholine, the receptor is a goal, and the muscle is the crowd in the stadium. As soon as the attacker scores a goal the crowd yells and jumps up and down, and fans tightly hug one another in celebration. All of these actions depend on the excitatory nerves stimulating our muscles to do all of these things.There are, however, other nerves, called inhibitory nerves, that stop the excitatory nerves at the neuromuscular junction from releasing too much acetylcholine.
These inhibitory nerves are the ones that are inactivated by the A-B toxin I mentioned before. If the inhibitory nerves are inactivated, the nerves that stimulate our muscles to contract never stop signaling. This indefinite signaling causes our muscles to undergo continuous spasms and rigidity, leading to things like lockjaw and opisthotonos, which is a condition where the person hyper-extends their entire spinal column.In this case, it’s basically like our striker scoring a goal over and over again, non-stop. Our crowd would be constantly yelling, jumping up and down, and giving each other a very tight hug to the point where the person being hugged can’t breathe.
This is because in even more serious cases, tetanus causes the muscles of respiration, such as the diaphragm, to tighten up so much that they can no longer function. This causes respiratory paralysis and therefore, death.
Treatment and Prevention
The best way to avoid all of this mayhem is to get a tetanus vaccine from your doctor. However, this isn’t an ordinary vaccine, as it doesn’t contain the bacterium that causes this disease. Remember, I told you before that the bacterium isn’t our biggest concern; it’s the toxin it releases. Hence, the tetanus vaccine, called a tetanus toxoid, is actually a collection of inactivated toxins, not bacteria. Individuals who are affected with tetanus will also need to be hospitalized, given drugs such as antibiotics, and may need to be placed on critical life support in very serious cases.
In order to avoid all of these treatments, a simple vaccine can help prevent tetanus, a potentially deadly bacterial disease that causes lockjaw, trouble swallowing, muscle spasms, and in severe cases, respiratory failure. The Gram-positive, anaerobic, drumstick-shaped bacteria that causes tetanus is known as Clostridium tetani. However, as I mentioned before, the bacterium itself isn’t the main problem, it’s what it releases that causes an individual to die if left untreated. This death-inducing substance is called tetanospasmin. Tetanospasmin is a potent neurotoxin that is sometimes known as the A-B toxin. Besides many other signs and symptoms, one famous problem the A-B toxin may cause is known as opisthotonos, and it’s a condition where the person hyper-extends their entire spinal column.
After watching this lesson, you should be able to:
- Describe the symptoms of tetanus
- Name the bacteria that causes tetanus and know where it is found
- Recall the neurotoxin that the bacteria releases and understand how the actions of this toxin lead to the symptoms of tetanus
- Explain how the tetanus vaccine is different from other vaccines
- Summarize the treatment for tetanus