Diagnosing Fibromyalgia Plus Symptoms, Comorbid Disorders and Disease Mimics

Diagnosing Fibromyalgia Plus Symptoms, Comorbid Disorders and Disease Mimics


Fibromyalgia (FM), like chronic fatigue syndrome, has been plagued with diagnostic issues largely because no biological test has been validated for the disease. Diagnosing fibromyalgia requires ruling out other diseases that might be causing your symptoms and carefully assessing your symptoms. It can take several years to get a diagnosis.

The 1990 American College of Rheumatology criteria required chronic widespread pain (CWP) for >3months, and the presence of at least 11 out of 18 specified tender points.

2010 American Rheumatology Preliminary Diagnostic Criteria - By 2010 the tender point requirement - long criticized - was dropped in favor of requiring the presence of widespread pain and a symptom severity scale. The new criteria have been criticized for not requiring a physical exam but seem to have stuck. They've been modified several times.
  1. Widespread pain index (WPI) > or= 7; symptom severity scale >or =5; or WPI 3-6 and SS scale > or = 9.
  2. Symptoms have been present at a similar level for at least 3 months.
  3. The patient does not have a disorder that would otherwise explain the pain.
Modified 2010 Criteria - The symptom severity scale was replaced with a three question survey.

2016 Criteria - the modified 2010 criteria were slightly revised in 2016 to prevent people with regional pain syndromes from being misclassified as having fibromyalgia.
  1. Widespread pain index (WPI) and symptom severity score (SSS) • WPI ≥ 7 and SSS ≥ 5 OR WPI 4-6 and SSS ≥ 9
  2. Generalized pain: pain in 4/5 regions
  3. Symptoms present ≥ 3 months
At each modification the percentage of women relative to men with the disease has dropped significantly from 14:1 to 5:1 to 2:1.

To put it more simply. The Mayo Clinic states that in order to be diagnosed with FM you must experience
  • Widespread pain lasting at least three months
  • Presence of other symptoms such as fatigue, waking up tired and trouble thinking
  • No other underlying condition that might be causing the symptoms


Core Symptoms

Fibromyalgia’s core characteristic is widespread pain that can occur in a variety of flavors. Some of the terms used to describe the kinds of pain encountered include burning, stabbing, throbbing, radiating and aching. The pain is often worse in the morning and can be severe enough to significantly limit a person’s ability to work and socialize.

When even the touch of a piece of cloth or similar substance registers as painful allodynia is present. Nerve associated pain such as numbness, tingling and burning is also commonly found.

It's important to note that fibromyalgia, in contrast to other pain disorders, also produces a core suite of non-pain symptoms which usually include fatigue, post-exertional malaise, sleep problems (unrefreshing sleep, insomnia) and cognitive problems (e.g “fibrofog” – difficulty concentrating, poor short-term memory, slowed information processing, problems multi-tasking).

Other Symptoms

Other symptoms commonly found can include morning stiffness and pain, back pain, joint pain, numbness, muscle spasms, rashes, dizziness, sensitivity to lights, odors and noises, gut cramping and bloating, muscle weakness, restless legs, myoclonic twitches, cold (and sometimes bluish) hands, pelvic pain, tinnitus and poor coordination.

A survey from the National Fibromyalgia Association found the following symptoms in FM. (Taken from the Fibrocenter).


In Their Own Words

For a particularly vivid display of the rich assemblage of symptoms that can be experienced in fibromyalgia check out:

Comorbid Disorders

Fibromyalgia often co-occurs with other disorders such as irritable bowel syndrome, myofascial pain syndrome, headaches and/or migraine, restless leg syndrome, jaw pain (temporomandibular joint syndrome (TMJ)), small fiber neuropathy, interstitial cystitis, Raynaud's phenomenon, vaginal pain, endometriosis, chiari malformation, anxiety or depression.

Secondary Fibromyalgia

People with a chronic pain condition such as rheumatoid arthritis (RA) or osteoarthritis (OA) are at increased risk of developing "secondary" (as opposed to primary) fibromyalgia as well. People with FM, on the other hand, are not at increased risk of developing RA or OA.

Fibromyalgia Mimics

Because FM can cause so many symptoms it's not surprising to see it being misdiagnosed as another disease or vice versa. (Several are from Dr. Martinez-Lavin's book "When Stress Becomes Real")
  • Systemic rheumatic and autoimmune diseases - rheumatoid arthritis, Sjogren's syndrome, lupus and polymyalgia rheumatica can initially present in similar ways to FM.
  • Nerve Trunk Compression , chiari malformation, spinal stenosis - structural problems in the upper spine and neck can produce similar symptoms
  • Thyroid Issues - problems with this master gland can cause multiform symptoms
  • Adrenal gland dysfunction - can cause fatigue and other symptoms
  • Neurological disorders such as multiple sclerosis and myasthenia gravis. The numbness numbness, tingling and other neurological symptoms can mimic those found in multiple sclerosis and myasthenia gravis.
  • Chronic infections - chronic hepatitis virus infection
  • Gluten intolerance, food sensitivities
  • Mental health problems. Depression and anxiety can cause fatigue, increased pain sensitivity and cognitive issues.

The Fibromyalgia Mimics – When Your Pain is Not Due to FM
I'm in Pain - Do I Have Fibromyalgia?
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