What is Tetanus? Immunizations?
On a recent long weekend, a friend was out mowing the lawn. She stepped on an old nail that penetrated her foot. After cleaning the wound, she wondered about the urgency of getting a tetanus shot because it was over 10 years since the last one. Is one really needed? How long can you wait? What is ‘tetanus’ anyway?
What Is Tetanus?
Tetanus is a nervous system disorder characterized by muscle spasms (almost everyone has heard of ‘lock jaw.’) A bacteria, Clostridium tetani (a cousin of Clostridium perfringens that causes gas gangrene) produces a toxin in injured tissue. C. tetani is found world-wide, in the soil and in the gut. It cannot be eliminated and therefore the problems it causes must be controlled – ideally through prevention.
In resource-rich countries where almost everyone is vaccinated as infants, tetanus is very rare (in the USA 0.10 cases/million people.) In resource-poor countries, there are over 1 million cases/year – 1/3 to ½ of them die.
While working/teaching in Borneo for a year and Tanzania for multiple months, I saw 5-6 patients with tetanus. Some were in the ICU, on a ventilator, heavily sedated for weeks. Trust me, you DO NOT want to get tetanus.
- tetani ‘likes’ the following conditions:
- A penetrating injury
- Coinfection with other bacteria (commonly our own skin bacteria)
- Tissue with a poor blood and oxygen supply (note people with diabetes are higher risk)
- An object still in the wound (glass, metal, splinter, fabric, dirt, etc.)
- Open, dirty wounds
Once in the wound, C. Tetani produces a neurotoxin that specifically destroys a key part of the nervous system. Here is an example: as you read this, your eyes are moving from left to right. For that to occur smoothly, the muscles on the right side of each eyeball need to gently contract while those on the left side must gently relax. There is a finely balanced mix of muscle activation and inhibition. The C. tetani toxin destroys the inhibitory neurons in the brain stem and spinal cord, so in this example, the signal to read from left to right results in an extreme contraction to the right, spasm, and pain. The same occurs in the whole body – head, arm, leg, abdominal movements result in extreme spasms and are VERY painful because consciousness is not affected. ‘Lock jaw’ is often an early sign because the jaw muscles are small but powerful.
In addition, other parts of the nervous system can go haywire resulting in uncontrolled sweating, heart rate, blood pressure changes, problems swallowing, etc.
The incubation period is about 8 days but can be 3-21 days. Once treated, it takes four – six weeks for the damaged neurons to be replaced. It is common for patients with tetanus to require prolonged ICU treatment and suffer secondary complications of prolonged hospital stays.
How is Tetanus Prevented?
In resource-rich countries, virtually all children are immunized with three specifically timed injections. That results in immune system antibodies that last for 10 years. A booster is required every ten years. However, in the case of a ‘tetanus prone’ wound, as described above, a booster should be given (after proper wound management) every five years. This is because there may not be enough antibodies to neutralize the toxin.
Get Immunized BEFORE You Go To Work or Play
Considering all the nasty stuff above, why does PRAXES not include tetanus boosters in their medical kits? Tetanus immunization vials must be refrigerated at 2-8 degrees C at all times. If frozen or warmed, it becomes unreliable. It is virtually impossible to ensure the ‘cold chain’ from supplier, transportation to your site, and storage on ships or work sites until it is needed.
Therefore, EVERYONE who is planning to be in a remote setting for work or play should strongly consider ensuring they have adequate, up-to-date tetanus prevention.
It would be ideal to have simple company policies in place that keep essential immunization records for employees including tetanus, influenza (for workers living in close quarters) and others such as pneumonia and shingles.
Back to my friend’s story: she ended up going to the local Emergency Department, the only option available, waited almost six hours, and got her tetanus immunization. What options would she have if she was 200 NM offshore?
John Ross MD FRCPC – Medical Director, PRAXES Medical Group
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