This article is part of a series presented by the ALS Therapy Development Institute (ALS TDI) comparing the similarities and differences between ALS and other commonly associated diseases. For further reading, see our past articles on ALS vs Huntington’s Disease vs Spinal Muscular AtrophyALS vs PLSALS vs Frontotemporal Dementia, and ALS vs MS vs Parkinson’s Disease.

Diagnosing a potential case of amyotrophic lateral sclerosis (ALS) is often a long and difficult process. An important part of this process is to rule out other potential conditions by looking for signs of diseases that share similar symptoms with ALS. Often, one of the conditions that doctors and clinicians will test for is Lyme disease. While the two diseases are very different, some symptoms of Lyme correspond with those of ALS, particularly in its early stages.

What is Lyme disease?

Lyme disease is a common infection caused by the bacterium Borrelia burgdorferi and rarely, Borrelia mayonii. It is spread to humans through the bites of certain species of ticks. A Lyme disease infection can often, but not always, be initially identified by a rash around the site of the bite. Common symptoms include fatigue, fever, joint aches, neck stiffness, and headaches. Most cases of Lyme disease can be successfully treated with antibiotics if they are caught early.

If left untreated, the infection can spread to other parts of the body, including the heart, joints, and nervous system. This can lead to a variety of ongoing health issues, including severe headaches, arthritis, inflammation of the brain and spinal cord, irregular heartbeat, and facial palsy (the weakening of muscles in the face, which can cause a “drooping” appearance on one or both sides). While most people who receive treatment in the first few weeks after infection make a full recovery, in rare cases symptoms may also persist in a condition known as Post-Treatment Lyme Disease Syndrome (PTLDS).

Colloquially, the symptoms of both PLTDS and untreated Lyme disease are often referred to as “chronic Lyme disease.” The reasons why some people experience these extended symptoms, especially in cases of PTLDS, are poorly understood. However, in many cases, people have reported experiencing ongoing pain, fatigue, and cognitive issues for months or even years.

ALS Symptoms versus Lyme Symptoms

ALS and Lyme are very different diseases. ALS is a neurogenerative condition whose causes are poorly understood – but thought to be potentially related to a variety of genetic and environmental factors. Lyme disease, on the other hand, is well-known to be caused by a bacterial infection.

However, Lyme disease can affect the central nervous system, muscles, and joints, especially when left untreated, causing symptoms that correspond to some of the early signs of ALS.

Weakness, fasciculations (twitching), muscle atrophy, and facial palsy are all symptoms that can be present in both Lyme disease and early ALS.

ALS Diagnosis versus Lyme Diagnosis

Even to a trained medical professional, these two diseases can appear remarkably similar. In some cases, an initial diagnosis of Lyme may later be found to be ALS, and vice versa.  While diagnosing ALS is a long and complicated process, most experts agree that a Lyme disease infection can be identified using a variety of blood tests, even months or years after infection. In some cases, a cerebral spinal fluid test may also be conducted for people with symptoms suggesting that a Lyme disease infection could be affecting their central nervous system. Most ALS clinics can test their patients for Lyme disease, particularly if they are from areas where the disease is common.

ALS Prognosis versus Lyme Prognosis

While symptoms may present similarly initially, the prognosis for these diseases is very different. Once diagnosed, most cases of Lyme Disease can resolve or can be treated in a few weeks using antibiotics, although in some rare cases, symptoms may continue for months or years. Currently, there are no effective treatments to cure, stop or reverse ALS, and the life expectancy following diagnosis is 3-5 years. Researchers at the ALS Therapy Development Institute (ALS TDI) and around the world are working to develop treatments that can change the prognosis of this disease.

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