Brain Changes Identified in Those Living with Long-Term Lyme Disease

January 12, 2023

Summary: Each year, about half a million people are affected by Lyme disease. It is a bacterial infection caused by a tick bite. Though the infection can be treated with prolonged antibiotic therapy, but some people develop post-treatment Lyme disease (PTLD). PTLD is a poorly understood condition causing symptoms like body aches, fatigue, sleep disorders, cognitive issues, and more. A new study has identified that PTLD occurs due to changes in the white matter in the frontal lobe.

Investigators at Johns Hopkins University have found that chronic or post-treatment Lyme disease may cause some permanent brain changes. This may explain why some people living with chronic Lyme disease continue to experience symptoms like poor memory, brain fog, and other cognitive issues. Researchers think that understanding these changes in the brain due to chronic Lyme disease would also help understand covid related brain issues, multiple sclerosis, fibromyalgia, chronic fatigue syndrome, and other ailments causing cognitive problems. Hence, a well tailored lyme disease prevention and chronic pain treatment is required. 

Lyme disease is caused by a bacterial infection propagated through a tick bite. Early signs of lyme disease include  ticks, rash, fatigue, body aches, fever, and some flu-like symptoms. Since it is a bacterial infection, the condition is treated with great success with antibiotics. 

However, effects of Lyme disease remain undiagnosed in many cases, as its diagnosis is quite challenging. In many instances, it is diagnosed relatively late. In many cases, antibiotics may eradicate the infection, but they fail to provide complete relief. 

It seems that Lyme disease may cause some permanent brain changes in about 20% of the cases, which is significant. This 20% of people develop a so-called chronic Lyme disease or post-treatment Lyme disease (PTLD). PTLD causes vague kind of symptoms like cognitive issues, depression, fatigue, body aches, sleep difficulties, and more. However, in most cases of PTLD, laboratory tests appear relatively normal. Thus, science has struggled to explain the pathogenesis of PTLD. Hence, it is among the difficult-to-treat conditions.

In the new study, researchers conducted brain scans of those living with PTLD. In the study, they enrolled 12 patients and also 12 control subjects. For this purpose, they carried out functional MRI (fMRI), which can help visualize the activity level of various brain regions. It also allows visualization of the blood flow to different brain parts in real-time.

The researchers have published their findings in the journal PLOS ONE. They found that many cognitive difficulties in those living with PTLD are due to changes in the white matter in the brain. This results in slow processing and movement of the information. Further, the study found significant changes in the activity level in the frontal lobe, a brain area associated with memory and recalling. These changes were expected as those living with PTLD have longer recalling periods and suffer from memory issues.

However, when researchers compared the brain scans with those not affected by Lyme disease, they did not find any unusual activity in the frontal lobe region. 

Investigators wanted to confirm their findings, and thus they used another kind of brain imaging called diffusion tensor imaging (DTI) in all those living with PTLD and without it. Again, they found a more significant water movement within brain tissues in those living with PTLD. Thus, this test also confirmed unusual brain activity in the frontal lobe in those living with PTLD.

Researchers think this increased brain activity was due to higher activity of the immune system in the white matter of that part of the brain. This may explain why those living with PTLD have cognitive issues.

Here it is worth noticing that these findings have many implications. Such poorly understood cognitive issues are found in many other disorders like fibromyalgia and multiple sclerosis. Thus, researchers say similar experiments can be done in patients with these disorders, too. The study can help create reliable biomarkers for these disease conditions.

Finally, it is also worth noticing that CDC statistics show that each year about half a million people suffer from the effects of Lyme disease in the US, and these numbers are increasing. Hence, in the last few decades, the incidence of PTLD has increased multiple times. However, despite this increase, no reliable tests can help diagnose PTLD reliably. Hence, this research can not only contribute to creating reliable diagnostic tests for the condition but also help in better chronic pain treatment.

By Gurpreet Singh Padda, MD, MBA, MHP