If we can treat it before symptoms what different after symptoms start showing?
In: 11
With rabies specifically it has to do with when rabies shows symptoms.
Rabies shows symptoms once it’s in the brain, we don’t have a good way to put medicine into the brain in any meaningful quantity.
[removed]
The blood brain barrier let’s almost nothing in, including medication. But rabies can cross the blood brain barrier. Even if you injected medication into the spine or brain it would still be too late.
Rabies is only symptomatic once it reaches CNS – and once it does, it’s set in your nerve cells and there’s no therapy that can do all of these: a) cross the blood-brain barrier, b)deactivate the virus and c)not kill you in the process.
Rabies virus doesn’t do anything until it reaches your brain. It travels along nerves from the site of a dog bite or bat bite and works its way up. You only show symptoms when it messes with the neurons in your brain. Unfortunately, modern medicine has not discovered any suitable curative drug that can attentuate and reverse all the damage rabies does. The best we can do is vaccinate you and give you antibodies after a suspected rabid dog/bat bite and hope that the immune system kills off 100% of the rabies virus before it travels to the brain.
The difference is where the virus is at the time.
The blood vessels in your brain have a special lining called the blood-brain barrier. It’s there to protect your brain by blocking almost anything from leaving the blood stream and entering the brain except very specific small things like oxygen and water, which the brain needs. As a result, it is VERY hard to get any medicine into the brain itself, since the blood-brain barrier blocks nearly everything. But, **the rabies virus can cross the blood-brain barrier, and it’s only once the brain is infected that symptoms begin.**
So when you get bitten by a rabid animal, the rabies virus is at the wound site, then in the tissue around the wound site, then in the blood near there. At that point, there are no symptoms. It can be treated then, because the antiviral medicine can be injected at the wound site and into the blood stream and reach where the rabies is and kill it.
If left untreated, the rabies virus crosses the barrier into your brain and begins attacking it. That’s what causes the symptoms. But by then it’s too late, because the antiviral medicines can’t cross the blood-brain barrier to where the rabies is living at that point.
For diseases in general, treating before symptoms often means that the disease hasn’t progressed that much. If someone is showing symptoms, whatever is going on has set in and is having a more severe effect. For rabies, there are a bunch of symptoms that can result in death outside the disease itself, mainly hydrophobia and difficulty swallowing. Those symptoms make it harder to keep the patient alive while being treated independently of how hard they are to treat.
Latest Answers