A Process of Elimination


A diagnosis of Fibromyalgia frequently involves a process of elimination and is difficult to achieve in a timely manner. This is due to a number of reasons. There are no definitive tests for fibromyalgia. Fibromyalgia is an extremely individualistic syndrome and no two people experience the same symptoms and progression. Diagnosis typically relies heavily on a process of elimination to exclude other conditions that either co-occur with fibromyalgia or mimic it symptomatically.

 This article covers a number of conditions that are commonly associated with fibromyalgia, including chronic fatigue syndrome, irritable bowel syndrome, interstitial cystitis, and depression and anxiety, as well as several that can mimic fibromyalgia, such as Lyme disease, celiac disease, magnesium deficiency, hypothyroidism, and rheumatoid arthritis. For some patients, these conditions may be diagnosed along with fibromyalgia. For example, in many patients, the symptoms of chronic fatigue syndrome and fibromyalgia overlap to such a great extent that it can be difficult to differentiate one condition from the other. Therefore a single patient may, after careful examination and testing, be diagnosed with both chronic fatigue syndrome and fibromyalgia.

 Chronic Fatigue Syndrome

 Chronic, persistent fatigue is a hallmark symptom of fibromyalgia and occurs in up to 90% of fibromyalgia patients. It can be so severe as to impact an individual’s ability and desire to be active and engaged in life. Chronic fatigue syndrome (CFS) is a disorder that causes extreme fatigue that does not improve upon receiving rest. It shares a number of symptoms with fibromyalgia, including muscle pain, memory impairment, headaches, joint pain, sleep problems, and painful lymph nodes in the neck. In addition, it most commonly affects women, predominantly those in their 40s and 50s. CFS lasts for a long time and impairs one’s ability to carry out normal activities of daily living.

Because of the overlap of its symptoms with those of fibromyalgia, fibromyalgia and CFS are often mis-diagnosed as each other. Depending on the circumstances, CFS and fibromyalgia may also be diagnosed together in the same patient, either correctly or accidentally. According to Light et al. (2012) the incidence of fibromyalgia and chronic fatigue syndrome occurring together in the same patient varies depending on the diagnostic criteria used for each condition, however it generally ranges from as low as 21% to as high as 80% of all patients. Complicating the picture even further is the fact that many researchers continue to assert that fibromyalgia and CFS are the same condition and cite their overlapping symptoms, lack of a definitive cause for either condition, and the significant mental health components as supporting evidence (Brown and Jason, 2007).  The elimination of a CFS as a diagnosis is not possible as a tool to confirm or deny Fibromyalgia given the close but complicated relationship between the two disorders.

 Fibromyalgia and Interstitial Cystitis

Interstitial cystitis (IC) is a disease that results in frequent discomfort or pain in the bladder and the surrounding areas of the pelvis. Symptoms vary from person to person and may include mild discomfort, pressure, tenderness, or intense pain the bladder and pelvis. IC affects more women than men, including an estimated 3.3 million women in the U.S over the age of 18 and 1.6 million men. Individuals with fibromyalgia also frequently have interstitial cystitis. A 2011 study found an increased rate of fibromyalgia among women with IC (Peters et al., 2011), and a 2010 study found that patients who had IC were more likely to also have a diagnosis of fibromyalgia (17.7% compared to 2.6% of patients without IC) (Nickel et al., 2010). A diagnosis of IC is thus of little value relative to eliminating a possible co-morbid diagnosis of Fibromyalgia (provided the patient also has other Fibromyalgia symptoms), while conversely a diagnosis of Fibromyalgia would not rule out a possible IC diagnosis as well.

Fibromyalgia and Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a disorder of the bowel, or large intestine, which is characterized by severe abdominal pain and cramping, changes in bowel movements, and a variety of other symptoms. Most cases of IBS have an unknown cause, although some can result following an intestinal infection. There may also be neural (nerve) triggers. Similar to fibromyalgia, research has also shown that IBS can occur following a stressful life event, or may result from an impairment in the body’s ability to appropriately process pain. IBS is very common, affecting approximately one out of every six people in the U.S. It typically starts in the teens and early adulthood, and women are affected twice as often as men. It has been estimated that as many as two-thirds of all IBS patients have fibromyalgia, and a reported 70% of fibromyalgia patients also have IBS. These statistics differ greatly from the corresponding rates in the general population, where only 10%-15% of individuals are estimated to have IBS. It is unknown if the two conditions are related symptomatically or causally, or if their frequent co-occurrence is merely a coincidence.

 Fibromyalgia and Depression/Anxiety

Depression and anxiety are also highly associated with fibromyalgia. An estimated 30% of all fibromyalgia patients have major depression at the time they are diagnosed, and as many as 20% have generalized anxiety disorder. A number of causes have been suggested to explain why depression occurs in fibromyalgia patients. Researchers believe that low levels of brain chemicals known as neurotransmitters, which send signals to different parts of the brain in order to regulate mood, pain, and bodily functions, may be a primary cause. When levels of these neurotransmitters are low, an individual may feel depressed. Fibromyalgia-related disability is frequently associated with low levels of neurotransmitters, as is depression. Many antidepressant medications work by regulating the amount of serotonin in the brain. Having to deal with the chronic pain and tenderness associated with fibromyalgia may also play a role in the development of depression for fibromyalgia sufferers. Furthermore, the role of depression may also have a genetic link in fibromyalgia. Many individuals who have both depression and fibromyalgia also have a family history of depression.

 Lyme Disease

Lyme disease is a bacterial infection that is transmitted by the bite of infected blacklegged ticks. Lyme disease progresses through three stages. Stage one is characterized by flu-like symptoms such as fever, chills, headache, lightheadedness, muscle pain, stiff neck, and itching. A rash or red spot at the site of the tick bite may also be visible. If diagnosed in the early stages, Lyme disease can usually be effectively treated with antibiotics. If left untreated, Lyme disease can progress and cause more serious and widespread complications. Stage two symptoms include weakness or paralysis in the facial muscles, muscle pain or swelling in the large joints, and heart palpitations. Stage three symptoms include abnormal muscle movements, muscle weakness, numbness and tingling, and difficulty speaking. Lyme disease shares obvious symptoms with fibromyalgia, along with certain forms of arthritis and other conditions, therefore it may need to be considered as a possible diagnosis among individuals who have the possibility of being exposed to disease-carrying ticks.  While Lyme disease is itself difficult to diagnose, there are tests that at least offer some possibility of a definitive Lyme diagnosis.  Patients who live in geographic areas where Lyme is prevalent may be well served to try and eliminate this possibility before accepting a diagnosis of Fibromyalgia.

Celiac Disease

Celiac disease is a digestive disease that results from consumption of the protein known as gluten. Gluten is frequently found in breads, pastas, pizza, and a number of other foods that contain wheat, barley, and rye. When individuals who have celiac disease eat foods that contain gluten, they experience an immune reaction in their small intestine, which results in damage to the inner surface of the intestine and impairs their body’s ability to absorb nutrients. As a result, individuals with celiac disease experience abdominal pain and diarrhea, and eventually various vitamin deficiencies. Despite these characteristic symptoms, celiac disease can also manifest in uncharacteristic ways, and often without any gastrointestinal symptoms at all. Some people may experience depression, joint pain, muscle cramps, osteoporosis, and tingling in the legs and feet. This uncharacteristic presentation of celiac disease can mimic other conditions, such as fibromyalgia and irritable bowel syndrome, thus leading to confusion surrounding a proper diagnosis.  Testing a gluten free diet can be instrumental to differentiating a diagnosis of celiac’s from Fibromyalgia, though both conditions do frequently co-exist.

Magnesium Deficiency

The signs and symptoms associated with magnesium deficiency may also overlap those associated with fibromyalgia. Magnesium, a mineral, is essential to the functioning of almost every organ in the body. It also plays a key role in the transmission of nerve signals, in particular the signals that cause muscles to contract and relax. Symptoms of magnesium deficiency include loss of appetite, vomiting, nausea, and behavioral changes, as well as abnormal levels of calcium and potassium. When magnesium, calcium, and potassium levels are not optimal, they can impair the function of the body’s central nervous system. Due to its role in muscle function and nerve conduction, magnesium may be involved in the development of fibromyalgia. Some research suggests that individuals with fibromyalgia also suffer from decreased magnesium levels. However, to further complicate diagnostic process, prolonged magnesium deficiency can result in anxiety, restless leg syndrome, muscle spasms and weakness, all of which are symptoms that overlap with fibromyalgia. Given that a magnesium deficiency can be relatively easily treated, those suspecting Fibromyalgia may be well served to begin supplementing their magnesium intake. If this successfully resolves symptoms, Fibromyalgia may not be present at all but rather the patient suffers from a much simpler magnesium deficiency.


Hypothyroidism is a disorder of the thyroid gland that is characterized by low levels of thyroid hormone and can be diagnosed by performing blood tests to measure blood levels of thyroid hormone. Symptoms associated with hypothyroidism are similar to those of fibromyalgia and include depression, widespread muscle pain, muscle stiffness, cognitive impairment, cold sensitivity, and sleep disturbances. As many as 15% of patients with hypothyroidism also have fibromyalgia, and many fibromyalgia patients have under-functioning thyroid glands. Given that Hypothyroidism can be tested for,  the elimination of this as a possible diagnosis can be of use in moving toward a diagnosis of Fibromyalgia.

Rheumatoid Arthritis

Rheumatoid arthritis is a chronic disease that results in inflammation of the joints and surrounding tissues on both sides of the body. It can also affect various organ systems within the body. The cause of rheumatoid arthritis is not known, but it is classified as an auto-immune disease, meaning that it results when the body’s immune system incorrectly views healthy tissue as foreign and attacks it. Like fibromyalgia, rheumatoid arthritis most commonly affects middle aged women, and the presenting symptoms generally include minor joint pain, stiffness, and fatigue. Morning stiffness is also common, and range of motion may become limited over time. Numbness, tingling, and burning sensations in the hands and feet may also be signs of rheumatoid arthritis. Although there is no specific lab test to definitively determine if an individual has rheumatoid arthritis, several blood tests are helpful – rheumatoid factor test and anti-CCP antibody test. These can be useful in possibly eliminating Fibromyalgia as a diagnosis through a confirmed diagnosis of rheumatoid arthritis.



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