What is chronic fatigue syndrome?
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complicated illness characterized by at least six months of extreme fatigue that is not relieved by rest, and a group of additional symptoms that also are constant for at least six months. In many people with chronic fatigue syndrome, the disorder begins suddenly, often following a flulike infection or an episode of physical or psychological trauma, such as surgery, a traumatic accident or the death of a loved one. In other cases, chronic fatigue syndrome develops gradually. The illness lasts for many months or years, and only a small percentage of people recover full health.
Many people feel tired a lot of the time, and many seek help from their doctors. Most people who experience chronic (long-lasting) fatigue are not suffering from chronic fatigue syndrome. Depression and overwork are much more common causes of chronic fatigue.
The exact cause of chronic fatigue syndrome remains a mystery. The illness can follow a number of common infectious illnesses, such as Lyme disease or infectious mononucleosis, but not all cases are tied to infections. Testing has found that people with chronic fatigue syndrome have abnormalities in the brain, particularly in the hypothalamus (a part of the brain that regulates hormones and vital functions) and the pituitary gland.
Testing also has found that patients have abnormalities in the part of the nervous system called the autonomic nervous system, which controls blood pressure, heart rate, body temperature and other vital body functions. For example, many patients with chronic fatigue syndrome have an unusually high heart rate and low blood pressure when they have been standing for a while.
Several parts of the immune system remain activated for long periods in people with chronic fatigue syndrome. There is growing evidence that some patients with chronic fatigue syndrome have an autoimmune condition: their immune system is attacking particular tissues in the body.
Patients with chronic fatigue syndrome have defects in the ability of cells in their bodies to make energy. Some studies indicate that certain genes are built differently, and that the activity of genes in white blood cells is different, in patients with chronic fatigue syndrome.
Many different tests of the brain, and of the autonomic nervous system, reveal abnormalities that are not seen in healthy people of the same age, or in people with other conditions that can cause fatigue, such as depression.
Many of the abnormalities of the immune system, energy metabolism, and the nervous system seem to come and go. Furthermore, not all of the abnormalities affect every patient with chronic fatigue syndrome.
In the United States, federal health authorities estimate that chronic fatigue syndrome affects 1 to 8 of every 1,000 Americans older than age 18. Women are affected about three times as often as men. Although the illness is most common in people 25 to 45 years old, chronic fatigue syndrome can attack people of all age groups, including children. The condition also is found in people of all racial, ethnic and economic backgrounds. It appears to be more common in African-Americans and Latinos, and in people in lower socioeconomic groups. It appears to be less common in Asian-Americans. Studies from the U.S. Centers for Disease Control and Prevention (CDC) and other research groups estimate that the United States loses as much as $25 billion each year in reduced productivity and medical expenses due to chronic fatigue syndrome.
Although most cases of chronic fatigue syndrome do not occur during epidemics, at least 30 outbreaks of chronic fatigue syndrome have been reported, during which many people in the same area suddenly developed the illness at the same time. However, health experts have failed to identify a cause for their chronic fatigue syndrome symptoms.
Many people infected with the SARS Co-V2 virus that causes COVID-19 have developed long-lasting symptoms, including symptoms consistent with ME/CFS.
Symptoms of chronic fatigue syndrome
The most prominent symptom of ME/CFS is an unexplained feeling of fatigue, which is not relieved by rest. However, many other medical conditions cause marked fatigue.
To better identify people with ME/CFS, diagnostic criteria should include these four types of symptoms:
- A substantial reduction or impairment in the ability to engage in pre-illness levels of occupational, educational, social or personal activities for longer than 6 months
- Post-exertional malaise (PEM), which is a worsening of symptoms following physical, mental, or emotional exertion that would not have caused a problem before the illness. PEM can last a couple days to more than a week following the bout of exertion.
- Unrefreshing sleep that leaves not feeling better or perhaps even feeling worse after a full night’s sleep and no other reason for poor sleep quality.
- One or both of these neurological symptoms:
- Cognitive impairment, such as problems with thinking, memory, attention, organization skills, and information processing. These symptoms are often made worse after physical exertion, prolonged standing, or mental tasks.
- Orthostatic intolerance, which is a worsening of symptoms upon assuming and maintaining upright posture. This can include lightheadedness, fainting, increased fatigue, cognitive worsening, headaches, or nausea with standing and often some relief with lying down.
Many people with ME/CFS also experience additional symptoms, including:
- Muscle pain
- Pain in the joints without swelling or redness
- Headaches of a new type, pattern, or severity
- Swollen or tender lymph nodes in the neck or armpit
- A sore throat that is frequent or recurring
- Sensitivity to light and sound
- Allergies or sensitivities to foods, odors, chemicals, or medications
Diagnosing chronic fatigue syndrome
Although there is a lot of evidence that chronic fatigue syndrome is caused by a physical problem involving the immune system, energy metabolism and the nervous system, there is no laboratory test or procedure to confirm the diagnosis. Today, the diagnosis of ME/CFS is based on the presence of the four major symptoms noted above.
Your doctor will also want to consider other possible reasons for your symptoms, such as:
- Hypothyroidism (underactive thyroid gland)
- Adrenal insufficiency (underactive adrenal gland)
- Heart disorders
- Sleep apnea or narcolepsy
- Side effects of medications
- Chronic hepatitis
- Kidney disease
Your doctor will examine you and likely order some basic blood tests, such as a red blood cell count (hematocrit), white blood cell count and differential white blood cell count, thyroid, kidney and liver tests. Additional, more specialized testing may be needed, including testing of your autonomic nervous system.
Expected duration of chronic fatigue syndrome
To be diagnosed as ME/CFS, symptoms must last for at least six months. Unfortunately, in many people, symptoms persist for years. Symptoms tend to be worse in the first one to two years, and level of functioning gradually improving over time. However, only a small percentage of people recover to full health.
Preventing chronic fatigue syndrome
There are no specific actions a person can take to prevent ME/CFS.
Treating chronic fatigue syndrome
There is no FDA proven treatment for ME/CFS. However, clinician acknowledgement of the patient’s condition as ME/CFS and symptom guided approaches can improve quality of life.
In general, doctors use a combination of the following:
- Lifestyle changes. Patients are often initially encouraged to slow down, minimize physical exertion and try to avoid psychological stress. They learn to save their energy for essential activities at home or work and to cut back on less-important activities.
- Pacing of physical activities. Patients must first recognize the level of physical exertion that will trigger post-exertional malaise (PEM) symptoms and avoid reaching that level. With the help of a physical therapist or personal trainer experienced with ME/CFS, they then can begin an exercise program. But it must be paced to avoid PEM symptoms. Once there is comfort with what activities can be done and for how long, a program to help prevent deconditioning can be constructed.
- Pacing of cognitive activities. Similar to the goals for physical pacing, patients need to initially try to avoid stressful, intense or prolonged mental tasks, especially those with tight deadlines. Adaptations to work or school obligations are often required.
- Addressing symptoms related to orthostatic intolerance. Staying well hydrated, adding salt, wearing compression stockings, and avoiding prolonged standing can help prevent lightheadedness and extreme fatigue.
- Improving sleep quality. This starts with sleep hygiene. Your doctor may suggest low dose trazadone or a tricyclic antidepressant before bed.
- Treating existing pain. Aspirin, acetaminophen (Tylenol) or nonsteroidal anti-inflammatory drugs (NSAIDs) are used to treat headaches, muscle pain and joint pain. Antidepressant medications also may help to reduce chronic pain.
When to call a professional
Call your doctor if you have symptoms of chronic fatigue syndrome, especially if extreme fatigue prevents you from fully participating in activities at home, work or school.
People with ME/CFS usually experience their most severe symptoms in the first one to two years of illness. After that time, a small number of people recover totally, and a smaller number become totally incapacitated. For most people, there is gradual improvement, although they usually do not achieve the level of activity they were capable of before becoming ill. Recovery tends to be less likely among people who:
- Have symptoms for a longer time
- Have other chronic medical conditions
- Are older than 40 when symptoms start
- Have multiple physical symptoms
Centers for Disease Control and Prevention (CDC)
Medline Plus, from the National Institutes of Health/National Library of Medicine
International Association for Chronic Fatigue Syndrome/Myalgic Encephalomyelitis