Summary: In Lyme disease, pain, inflammation, and fatigue persist long after the infection has been wiped out. Researchers have tried to learn why this pain lasts, and why most common painkillers fail. Now a new study has found one of the root causes of chronic pain due to Lyme disease. The pain seems to come from too much activity of fibroblast growth factor receptors (FGFRs). So drugs that block these receptors can help calm inflammation in the nerves, brain, and spinal cord. That can help ease chronic pain in Lyme disease patients.
The bacterium Borrelia burgdorferi causes Lyme disease. It spreads through tick bites. Since it is a bacterial infection, killing it with antibiotics is not hard. Yet Lyme disease keeps hurting people even after the germ is gone.
Lyme disease causes pain, fatigue, and mental distress. These can last for months and even years after the first infection is treated. This happens because the germ leaves specific changes in the brain, spinal cord, and nerves.
Chronic pain differs from acute pain in more than how long it lasts. Chronic pain is hard to treat because it keeps going after the disease that caused it is treated. So, unlike acute pain, chronic pain also requires undoing the body changes left behind by the illness or infection.
There are many painkillers, but they only block the chemicals that cause pain. They dull the feeling, but they cannot fully relieve chronic pain. Full relief means undoing the body changes that drive chronic pain.
This is where new biologics shine. These drugs try to undo body changes, reset pain switches in the body, and calm inflammation. That way they aim for lasting relief from chronic pain. The new study, published in the Frontiers in Immunology found that fibroblast growth factor receptor inhibitors (FGFRIs) could be quite helpful for Lyme disease-related chronic pain (1).
Why does Lyme disease pain continue after antibiotics?
Past studies showed that higher activity of fibroblast growth factor receptors (FGFRs) is one of the major drivers of pain and inflammation in Lyme disease. This rise happens in response to Borrelia burgdorferi infection. Researchers also noticed something odd. Even dead B. burgdorferi can push up FGFRs in brain and nerve cells. That explains why antibiotics can wipe out the infection while the pain goes on.
Here is the strange part. Studies show that dead B. burgdorferi was an even more potent stimulator of FGFRs. So antibiotic treatment can even make the pain and inflammation from this germ worse. Many cells make these FGFRs, including brain support cells called astrocytes. Once bacterial toxins push their output up, it stays high even after the infection is treated. This explains why people with Lyme disease keep hurting long after the infection is treated and the germ is gone.
Next, researchers tested FGFR inhibitors. They found these drugs can significantly reduce inflammation and the cell death it causes. So this new class of trial drugs can help control chronic pain in Lyme patients. They might also ease other symptoms like fatigue and mood problems.
But they also found some hurdles. Two different kinds of FGFRIs were needed to manage Lyme disease pain. That is because one type of biologic works better on damage in the nerves of the body. The other works better on pain in the brain and spinal cord (CNS).
Is there a new treatment for Lyme disease chronic pain?
Researchers have found a new way to control pain, inflammation, and fatigue in Lyme disease patients. They also learned why the pain and inflammation last so long after the germ is fully gone from the body.
Of course, many hurdles remain before these treatments reach the clinic. Still, these new studies show how chronic pain is different. And they give hope to people living with chronic pain.
Frequently asked questions
How long does pain last after Lyme disease is treated?
For some people, months and even years. Pain, fatigue and mental distress can go on long after antibiotics clear the infection. That is because Borrelia burgdorferi leaves behind changes in the brain, spinal cord, and nerves. Those changes do not undo themselves when the germ is gone. That is why this pain acts like chronic pain, not the pain of an active infection.
Do antibiotics cure Lyme disease?
Antibiotics clear the infection, and that part is not hard. They do not always clear the symptoms. Even dead Borrelia burgdorferi drives up fibroblast growth factor receptor (FGFR) activity in brain and nerve cells. Dead bacteria were an even stronger trigger than live ones. Once that activity rises, it stays high after the infection is gone. So the pain and inflammation go on.
Why don’t regular painkillers work for Lyme disease pain?
Common painkillers only block the chemicals that make the pain signal. They can dull the feeling, but they do not undo the nerve changes that keep chronic pain going. Lasting relief means undoing those changes. That is the goal of newer biologics that reset pain switches in the body and calm inflammation.
Can nerve damage from Lyme disease be reversed?
That is exactly what researchers are working toward. In the Frontiers in Immunology study, FGFR inhibitors significantly reduced inflammation and the cell death it causes in nerve tissue. Two different kinds were needed. One works better on the nerves of the body, the other on the brain and spinal cord. These drugs are still experimental, and hurdles remain before they reach the clinic.
References
1. Parthasarathy G. Fibroblast growth factor receptor inhibitors mitigate the neuropathogenicity of Borrelia burgdorferi or its remnants ex vivo. Front Immunol [Internet]. 2024 Apr 4 [cited 2024 May 1];15. Available from: https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2024.1327416/full
Dr. Gurpreet Singh Padda, MD, MBA, MHP
