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Overlapping and Related Conditions

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By Bruce Campbell

Do you have just ME/CFS or fibromyalgia, or is there something more going on? If you are like the majority of people with either condition, you live with more than one medical problem.

Research suggests that about two thirds of people diagnosed with ME/CFS also meet the diagnostic criteria for fibromyalgia, and vice versa.

Often the diagnosis made first depends on which medical specialist is consulted. A primary care physician might spot ME/CFS, while a rheumatologist may be more likely to diagnose fibromyalgia.

In addition, people with ME/CFS and fibromyalgia often experience one or more additional medical problems, which are frequently called overlapping or related conditions.

Overlapping medical conditions
are ones that share symptoms and diagnostic criteria in common with ME/CFS and fibromyalgia. Related conditions are medical problems that often occur along with ME/CFS and FM.

Having multiple medical conditions complicates life and increases suffering, but successful treatment of other problems may ease the overall symptom level of people with ME/CFS and fibromyalgia. Sometimes, a patient is eventually understood to have one of the other conditions rather than ME/CFS or fibromyalgia.

Here are eight of the more common medical issues faced by people who have ME/CFS and fibromyalgia, along with common treatments for them.  


Orthostatic Intolerance (NMH and POTS)

Orthostatic Intolerance (OI) is a condition of sudden decrease in blood pressure that causes light-headedness, nausea and sometimes fainting. It is very common in people with ME/CFS, so common that the expert panel of the Institute of Medicine, in their 2015 report, included it as one of the proposed diagnostic criteria for the condition. 

OI occurs when the usual mechanisms for maintaining blood pressure fail. Normally, when a person stands, blood pressure is increased to keep blood flowing to the head. In people with OI, this process is reversed and blood pressure falls. Dizziness or fainting can also be caused by the release of adrenaline.

Treatments include increasing blood volume through the consumption of more fluids and salt, wearing support hose, avoiding long periods of standing, and using medications like Florinef.

The two most common forms of OI are Neurally Mediated Hypotension (NMH) and postural orthostatic tachycardia syndrome (POTS), which causes a rapid increase in heart rate when a patient stands up.

Irritable Bowel Syndrome (IBS)

A majority of ME/CFS and fibromyalgia patients suffer from irritable bowel syndrome (IBS), a digestive-system disorder characterized by abdominal pain, cramping and bloating, constipation, diarrhea or alternating constipation and diarrhea.

IBS often occurs together with ME/CFS and fibromyalgia, because all three involve problems in the autonomic nervous system. IBS is a chronic condition with intermittent symptoms. Symptoms can often be managed with lifestyle changes that may include the reduction of stress and elimination of foods that aggravate symptoms.

Sometimes medications are used. These include stool softeners or laxatives for constipation, anti-diarrheal agents like loperamide, low-dose antidepressants used as pain relievers, and sometimes antibiotics to treat bacterial overgrowth.

Multiple Chemical Sensitivity

A majority of fibromyalgia and ME/CFS patients experience allergic reactions to various substances. Sensitivities to mold, dust mites and grasses are common.

Patients also react to perfumes, scented products, cigarette smoke, household chemicals, car exhaust and diesel fumes, glues, inks and dyes. (Because many patients are chemically sensitive, most ME/CFS and FM support groups ask people to come to in-person meetings "fragrance free.")

The range of reactions varies greatly among patients, from mild annoyance to serious threat. Symptoms include headaches, dizziness, faintness, nausea, breathing difficulties, and irritation of the eyes, mouth and throat.

Those with more severe reactions may be housebound. The most useful coping strategy is avoidance, which includes eliminating offending substances from the home and limiting exposure to them while outside the house.

Myofascial Pain Syndrome (MPS)

Many fibromyalgia patients also experience Myofascial Pain Syndrome (MPS), a pain condition localized in trigger points (specific locations in muscles or fascia), often in the neck or shoulders.

MPS is usually treated with medication, massage, rest, heat and cold and the injection of local anesthetics into the trigger points. The latter, often called "spray and stretch," is often accompanied by the stretching of the muscle involved.

Since myofascial pain may be aggravated by stress, repetitive motion and poor body mechanics, it can also be treated with lifestyle adjustments, such as relaxation, avoidance of repetitive motion and improved body mechanics.


ME/CFS and fibromyalgia patients frequently experience depression, which can be of two types, situational and biochemical. Situational or reactive depression is a response to a particular set of circumstances, in this case the disruptions and uncertainties created by long-term illness.

Situational depression lends itself to self-management strategies such as those discussed in elsewhere on this site. Some patients are also helped by professional counseling. One effective approach is cognitive therapy.

Patients may also experience a second type of depression. Prolonged stress can alter the biochemistry in the body, creating biochemical depression. Self-management strategies may also be useful for this type of depression, but treatment normally includes medication as well.

If you are deeply depressed about your illness, for example if you have thought seriously about killing yourself, get professional help. For resources, see the article Killing Me Softly: FM/CFS & Suicide.

Food Issues: Yeast Infections, Celiac Disease & Lactose Intolerance

About one third of ME/CFS and fibromyalgia patients are sensitive to foods and experience gastrointestinal symptoms (heartburn, gas, nausea, diarrhea and constipation), as well as other symptoms, such as headaches, muscle pain, changes in pulse and fatigue.

While symptoms may be due in part to ME/CFS or FM, they may also be caused by yeast infections, like candida; celiac disease, which causes a strong allergic reaction to wheat and other grains; or lactose intolerance, which is the inability to digest the sugar in milk.

There are two major treatments for food allergies: avoidance and the rotation diet. If foods produce strong reactions, such as diarrhea, nausea, headaches or hives, the normal treatment is to eliminate them from the diet entirely.

Often, the elimination of just a few foods can improve symptoms dramatically. Alternatively, a food may be tolerated if it is eaten only occasionally (the rotation diet).

Sleep Apnea

Apnea, meaning absence of breathing, occurs when a person's airway becomes blocked during sleep. An episode can last from a few seconds to a few minutes. The person then awakens, gasps for air and falls asleep again.

This can occur many times a night, leaving the person exhausted in the morning. Sleep apnea intensifies the nonrestorative sleep usually experienced by people with ME/CFS and fibromyalgia.

Apnea is a treatable condition. A common remedy is use of a CPAP (continuous positive airway pressure) machine to keep the airway open. The patient wears a mask through which a compressor delivers a continuous stream of air, keeping the airway open. Other treatments are also used for this condition. If you suspect you have this problem, consult a sleep specialist.

Restless Legs Syndrome (RLS)

Restless legs syndrome involves "twitchy limbs," strong unpleasant sensations in the leg muscles that create an urge to move. The problem is often at its worst at night, making good sleep difficult.

Self-management techniques that may help include reducing consumption of caffeine and other stimulants, establishing a regular sleep pattern, doing exercise that involves the legs, distracting yourself through immersion in absorbing activities, using hot or cold baths or showers, and taking supplements to counteract deficiencies in iron, folate and magnesium.

Several categories of medications may also help, including sedatives, drugs affecting dopamine, pain relievers and anticonvulsants. Drugs that are often prescribed are the pills Requip and Mirapex, and the patch Neupro.

Other Related Conditions

Besides the conditions just described, other medical problems often occur together with Chronic Fatigue Syndrome and fibromyalgia. Among people who take our self-help course, the following conditions, listed alphabetically, are common in addition to those mentioned earlier:

  • Arthritis 
  • Asthma
  • Back and spinal problems,
  • GERD (gastroesophageal reflux disease)
  • Thyroid problems

In Conclusion

The twin bottom lines:

  • For people with ME/CFS and fibromyalgia, having multiple medical problems is common.
  • By treating other conditions, you may be able to moderate your overall symptom level.