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What is Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)?

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Until the COVID-19 pandemic began and people started experiencing Long COVID symptoms, many people had never heard of myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS). However, ME/CFS is not a new condition. ME/CFS is a serious, complex, and chronic systemic disease that can have a profoundly negative impact on the lives of sufferers as well as their families. It was first identified and given the name ‘myalgic encephalomyelitis’ by Dr. Melvin Ramsay in 1955 after an outbreak of the condition at the Royal Free Hospital in the United Kingdom. The first description and classification of ME/CFS in the United States came from the CDC in 1988.

But ME/CFS has a much longer history. In fact, historians and those who lived through the Spanish flu in 1918-1919 describe symptoms similar to ME/CFS in those who recovered from the initial viral infection.

The subsequent history of ME/CFS has been fraught.  Due to its high prevalence in women and perhaps due in part to the fact that some recover from the same virus that disables others, there was confusion around what caused or contributed to ME/CFS, and a great deal of stigma around its sufferers.

What is ME/CFS?

ME/CFS is a serious and chronic neurological disease that affects every body system, with notable symptoms in the immune system, nervous system, and endocrine system. This chronic condition causes a wide variety of different symptoms, with the most common being profound fatigue not generally relieved by rest, post-exertional malaise (PEM), and cognitive impairment. While the exact cause of ME/CFS is unknown, over 80% of cases stem from a previous infection, such as the Epstein-Barr Virus, SARS, SARS-CoV-2, or enterovirus. Fungal infections and bacterial infections may also trigger ME/CFS.  In fact, according to the NIH, 1 out of 10 people who develop certain infections go on to develop ME/CFS. Other potential triggers can be extreme physical stress (major surgery, a significant injury), emotional challenges (loss of a loved one), and immune system changes.

ME/CFS affects over 20 million people worldwide, including 1-2.5 million Americans.  Estimates show that 90% of cases of ME/CFS are undiagnosed. ME/CFS is a debilitating disease that leaves up to 70% of patients unable to work and 25% of patients homebound or bedbound. Less than 5% of adults who develop ME/CFS ever return to their pre-illness level of functioning in their lifetime, though many can experience some improvements in function over the years.

While anyone can get ME/CFS, it is more common in women, and the peak ages of onset of the illness are 10-19 years old and 30-39 years old.  The highest number of people currently living with ME/CFS are between the ages of 40-60. Caucasians are more frequently diagnosed with ME/CFS, but this is suspected to be due to greater access to healthcare providers knowledgeable in ME/CFS rather than a true difference in the prevalence of the disease across races or ethnicities.

What Causes ME/CFS?

While there is an established connection between infections, stressors, and the development of ME/CFS, there is still so much that researchers and physicians do not understand when it comes to ME/CFS. They do know, however, that it is a neurological disease that affects all body systems.

The same chemical in the body can affect multiple different cell types in different ways, and different cell types can produce the same chemical signals. Unfortunately, this has made it difficult for researchers to pinpoint which system dysfunction may be the primary driver behind ME/CFS.

Potential Causes of ME/CFS

  • Immune system
    Studies have most reliably shown reduced natural killer (NK) cell function. Some studies show abnormal cytokine levels. Others show an altered ability of the immune system to respond to specific infections like EBV. Still others show autoimmune markers or elevated markers of mast cell activation.
  • Nervous system
    Reduced blood flow to the brain upon upright positioning has been demonstrated in ME/CFS. Autonomic dysfunction is found in >30% of ME/CFS patients. Small fiber neuropathy in ~30% while some studies have demonstrated reduced white and gray matter in the brain and possible neuroinflammation.
  • Cardiovascular/circulatory system
    Cardiovascular manifestations may be secondary to nervous or immune system dysregulation, but invasive CPET testing demonstrates that a significant portion of ME/CFS patients have poor blood return to the heart with upright positioning and exercise, poor oxygen extraction from the blood with upright exercise, and overall low blood volume.
  • Endocrine system
    Some studies demonstrate HPA Axis dysregulation with blunted ACTH and cortisol responses, lower levels of T3 thyroid hormone, and low growth hormone (GH) levels.
  • Metabolic and mitochondrial dysfunction
    Several studies demonstrate cellular reliance on amino acids (from protein) as a primary energy source and decreased ability to utilize more efficient energy sources like glucose, fatty acids, and ketones. Others have found higher levels of oxidative stress markers.
  • Infectious disease
    Re-activation of latent herpes viruses like EBV, the persistence of viruses in specific tissues (like coxsackieviruses in the GI tract or heart), chronic low-level or undiagnosed infection with vector-borne infections (like Lyme, Bartonella, etc.), translocation of intestinal flora into the bloodstream (leaky gut) leading to increased levels of IL-1, TNF alpha, neopterin, and elastase that can contribute to common symptoms seen in ME/CFS.
  • Musculoskeletal & connective tissue
    Some studies demonstrate an unusually high prevalence of tethered cord syndrome, spinal instabilities, Chiari malformation, and connective tissue disorders in ME/CFS patients.

Common Symptoms of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Common symptoms seen with myalgic encephalomyelitis/chronic fatigue syndrome can include, but are not limited to, the following:

  • Post-exertional malaise (an unusual response to physical or cognitive effort)
  • Extreme fatigue
  • Confusion and cognitive impairment
  • Non-restorative sleep or reversed diurnal rhythm (sleepy during the day, wakeful at night)
  • Dizziness and lightheadedness
  • Orthostatic Intolerance – abnormal response to being upright, causing dizziness, fainting, or other symptoms that resolve when sitting or lying down.
  • Elevated heart rate (tachycardia)
  • Lymph node tenderness
  • Headaches of new origin
  • Muscle pain
  • Joint pain
  • Sensitivities to light, sounds, or chemicals
  • Inability to regulate body temperature
  • Extreme thirst and frequent/excessive urination
  • Gastrointestinal issues

Diagnostic Criteria for ME/CFS

Because there is no single, diagnostic biomarker for myalgic encephalomyelitis/chronic fatigue syndrome, and medical education on the condition is sparse, diagnoses can be challenging to access. Physicians often begin by ruling out other potential underlying conditions before looking at ME/CFS. With that in mind, a diagnosis of ME/CFS requires a patient to meet certain conditions. These include:

Three Mandatory ME/CFS Symptoms

  • Post-exertional malaise (unusual symptoms after physical or cognitive effort)
  • Unrefreshing sleep
  • A substantial reduction in the ability to engage in pre-illness levels of occupational, educational, social, or personal activities that persist for more than 6 months and is accompanied by fatigue not alleviated by rest.

One of the Two Following Must Also Be Present

  • Cognitive Impairment
  • Orthostatic Intolerance

Treatment Options for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

There is no cure for myalgic encephalomyelitis/chronic fatigue syndrome and no FDA-approved treatments. However, there are treatment options available to help ease and manage symptoms, as well as improve quality of life. Treatments are very individualized as each patient experiences different symptoms and severity. There are a variety of different medications and lifestyle changes and strategies that can help reduce the symptoms associated with ME/CFS.

Pacing for Post-Exertional Malaise (PEM)

Post-exertional malaise (PEM) is the worsening of symptoms following mental or physical exertion. This can include things like a simple walk or trying to complete homework. After performing these activities, people with ME/CFS can experience worsening symptoms a few hours to several days later.

Pacing is an adaptive strategy that helps you reduce the risk of PEM while still managing to remain as active as possible. Pacing involves learning where your PEM threshold is and changing your activities with this threshold in mind. Some techniques that help with pacing include:

  • Prioritize — Prioritize your daily activities, putting the most important activities first and eliminating non-essential activities.
  • Minimize — Minimize your activity throughout the day. Break larger activities into smaller segments and make changes as necessary. For example, a stool in the kitchen to use while you cook can help get you off your feet and reduce physical exertion.
  • Stop and rest — If you feel dizzy, experience shortness of breath, an increased heart rate, or any of your individual triggers, stop and rest immediately.
  • Schedule rest times — Take time throughout the day to rest, even if you are feeling good. This allows you to recoup and build up energy for your next activity.
  • Learn to recognize mental and emotional triggers — Learn your mental and emotional triggers and work to eliminate or reduce them. For example, if watching the news causes stress, give yourself one time a day when you check the daily news and avoid it the rest of the day.
  • Do NOT push yourself — No matter how good you feel, do not push yourself past your known limit. It is very common for people who feel well to take advantage and do more than they normally can. Unfortunately, this typically leads to a PEM crash a few days later.


Unfortunately, there are no FDA-approved medications designed to treat myalgic encephalomyelitis/chronic fatigue syndrome. However, medications are used to treat symptoms such as orthostatic intolerance, pain, sleep issues, and anxiety and depression. Current clinical trials are underway testing a drug’s efficacy for ME/CFS. Ampligen has already been endorsed and used in other countries. However, it does not yet have FDA approval in the United States. Clinical trials are also looking at Ampligen for the treatment of fatigue-like symptoms seen in Long COVID patients.

Mental Health Care

Living with ME/CFS or any chronic complex and disabling disease is a challenge to good mental health and may lead to secondary anxiety and depression. It is not uncommon for patients to feel anger, grief, and a loss of self after they get sick. Mental health counseling can be very beneficial to help reduce these potential emotional triggers that can also lead to PEM. If therapies alone do not work, medications may also be considered.

Diet and Nutrition

Diet and proper nutrition play an important role in everyday health and this is especially true for people with ME/CFS. Working with a nutritionist can help you find a diet that works well for you. Some things to consider are eating smaller, more frequent meals (eating large meals can often be a trigger for PEM), keeping healthy snacks on hand throughout the day, drinking plenty of water, and finding out what works best for you. Oftentimes allergies to foods may develop, so avoiding these foods becomes necessary as well. In addition, consider talking with your physician about potential dietary supplements, especially if your food choices are often limited.

The Connection Between ME/CFS and Long COVID

When the SARS-CoV-2 virus began spreading rapidly around the world, many ME/CFS researchers and physicians knew what was coming. As we have seen with many other viral outbreaks, the presence of viral-associated illness and subsequent ME/CFS symptoms and diagnosis is common. And COVID is no different. However, what is different is the worldwide spread of this virus, the number of positive patients, and the percentage of patients that are displaying signs and symptoms of viral-associated illness (Long COVID) and then an eventual diagnosis of ME/CFS.

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