Symptoms

Primary Symptoms

Also called “core” symptoms, these occur in most patients with ME/CFS. The three primary symptoms required for diagnosis are:

• Greatly lowered ability to do activities that were usual before the illness. This drop in activity level occurs along with fatigue and must last six months or longer. People with ME/CFS have fatigue that is very different from just being tired. The fatigue of ME/CFS:
  • Can be severe.
  • Is not a result of unusually difficult activity.
  • Is not relieved by sleep or rest.
  • Was not a problem before becoming ill (not life-long).
• Worsening of ME/CFS symptoms after physical or mental activity that would not have caused a problem before illness. This is known as post-exertional malaise (PEM). People with ME/CFS often describe this experience as a “crash,” “relapse,” or “collapse.” It may take days, weeks, or longer to recover from a crash. Sometimes patients may be house-bound or even completely bed-bound during crashes. People with ME/CFS may not be able to predict what will cause a crash or how long it will last. As examples:

• Attending a child’s school event may leave someone house-bound for a couple of days and not able to do needed tasks, like laundry.
• Shopping at the grocery store may cause a physical crash that requires a nap in the car before driving home or a call for a ride home.
• Taking a shower may leave someone with severe ME/CFS bed-bound and unable to do anything for days.

• Sleep problems. People with ME/CFS may not feel better or less tired, even after a full night of sleep. Some people with ME/CFS may have problems falling asleep or staying asleep.

In addition to these core symptoms, one of the following two symptoms is required for diagnosis:

• Problems with thinking and memory. Most people with ME/CFS have trouble thinking quickly, remembering things, and paying attention to details. Patients often say they have “brain fog” to describe this problem because they feel “stuck in a fog” and not able to think clearly.
• Worsening of symptoms while standing or sitting upright. This is called orthostatic intolerance. People with ME/CFS may be lightheaded, dizzy, weak, or faint while standing or sitting up. They may have vision changes like blurring or seeing spots.

Other Common Symptoms

Many but not all people with ME/CFS have other symptoms.

Pain is very common in people with ME/CFS. The type of pain, where it occurs, and how bad it is varies a lot. The pain people with ME/CFS feel is not caused by an injury. The most common types of pain in ME/CFS are:

• Muscle pain and aches
• Joint pain without swelling or redness
• Headaches, either new or worsening

Some people with ME/CFS may also have:

• Tender lymph nodes in the neck or armpits
• A sore throat that happens often
• Digestive issues, like irritable bowel syndrome
• Chills and night sweats
• Allergies and sensitivities to foods, odors, chemicals, or noise

Disclaimer: This website is for informational purposes only. The information provided on this website is not intended to be a substitute for professional medical advice, diagnosis, or treatment.