According to the University of Maryland Medical Center, 10 percent to 30 percent of all doctor's office visits are due to symptoms that resemble those of fibromyalgia, including fatigue, malaise and widespread muscle pain. Fibromyalgia may accompany other conditions, so a diagnosis of another disorder does not necessarily rule out fibromyalgia. It is not clear whether these conditions cause fibromyalgia, are risk factors for the disorder, have causes in common with fibromyalgia, or have no relationship to it.
No laboratory or X-ray test can diagnose fibromyalgia. Diagnosis is based on medical history, self-reported symptoms and an examination of tender points, according to the National Fibromyalgia Association.
Chronic Fatigue Syndrome
The symptoms of chronic fatigue syndrome and fibromyalgia are very similar, except that the muscle pain of chronic fatigue syndrome is less prominent that of fibromyalgia. Both conditions are diagnosed on the basis of medical history and self-reported symptoms, and their treatment is almost identical.
Myofascial Pain Syndrome
Myofascial pain syndrome can be confused with fibromyalgia and may also accompany it. Unlike fibromyalgia, myofascial pain tends to occur in "trigger points" rather than "tender points," and typically there is no widespread, generalized pain. Trigger-point pain occurs in tight muscles, and the muscle may twitch when presses.
Major Depression
An estimated 50 percent to 70 percent of fibromyalgia have a history of depression, but only 18 percent to 36 percent have major depression, according to the University of Maryland Medical Center. Fibromyalgia patients often experience temporary depression related to the condition. Major depression, on the other hand, can last for months, and does not typically include physical symptoms.
Chronic Headache
Chronic primary headaches, such as migraines, are common in fibromyalgia patients. Chronic migraine sufferers who do not benefit from the usual therapies may also have fibromyalgia.
Stress-Related Disorders
Certain stress-related disorders commonly occur with fibromyalgia and have overlapping symptoms. These disorders include exposure to chemical and environmental toxins, irritable bowel syndrome, temporal mandibular joint disorders, multiple sclerosis, and osteoarthritis.
Autoimmune Diseases
The symptoms of rheumatoid arthritis, systemic lupus erythematosus, and Sjogren syndrome can be confused with fibromyalgia, especially if the condition develops slowly.
Lyme Disease
According to the University of Maryland Medical Center, as many as 15 percent to 50 percent of patients referred to clinics for Lyme disease---a bacterial disease transmitted by ticks--actually have fibromyalgia. Blood tests for Lyme disease can assist with the diagnosis, although sometimes the organism cannot be identified.
Drug and Alcohol Dependency
Starting, stopping or changing medications--prescription and over-the-counter medications and caffeine--may cause fatigue. Drug and alcohol dependency can also cause chronic fatigue.
Polymyalgia Rheumatica
Polymyalgia rheumatica causes pain and stiffness, particularly in older women. Tender points are present but primarily are located in the hip or shoulder areas. Patients may also experience fever, fatigue and weight loss.
