Fibromyalgia syndrome (FMS) is a diagnosis given to many patients who complain of diffuse pain. The diagnosis is made when someone has pain in the upper and lower body, right and left-sided pain, and pain close to the spine.
Originally, Fibromyalgia Syndrome diagnosis was based on two criteria: 1. That patients had widespread pain, and 2. Physical examination revealed tenderness at 11 or more of 18 specific tender points (http://bit.ly/1cybXTj).
Most patients received the diagnosis of Fibromyalgia Syndrome from their primary care physician. Studies revealed that patients were being diagnosed with fibromyalgia without meeting the full criteria. In fact, in one study, as many as 66% of the patients were incorrectly diagnosed with Fibromyalgia Syndrome (http://bit.ly/17O66Ea).
Since it was found that many physicians were making the diagnosis without actually physically examining the patient, new criteria were created to assist physicians in diagnosing fibromyalgia – however, these criteria are not meant to replace the old criteria made in 1990 but are an alternative means to make the diagnosis. The new criteria are based on two scales: Widespread Pain Index (WPI) and Symptom Severity Scale (SSS).
WPI is a number between 0 and 19, which reflects the prevalence of the following symptoms:
- right shoulder girdle pain
- left shoulder girdle pain
- right upper arm pain
- left upper arm pain
- right lower arm pain
- left lower arm pain
- left hip pain (in the buttock or trochanter)
- right hip pain (in the buttock or trochanter)
- left upper leg pain
- right upper leg pain
- left lower leg pain
- right lower leg pain
- left jaw pain
- right jaw pain
- chest pain
- abdominal pain
- upper back pain
- lower back pain
- neck pain
The SSS is a score between 0 and 12, which reflects the severity and number of symptoms, including the following:
- waking unrefreshed
- cognitive symptoms
A patient is diagnosed with fibromyalgia when they fulfill the following 3 criteria:
- A widespread pain index of ≥7 and a symptom severity scale of ≥5 OR a widespread pain index of 3-6 and a symptom severity scale of ≥9
- Symptoms present at a similar level for at least 3 months
- No other disorder to explain the pain
Patients have complained of widespread, diffuse pain without an obvious cause throughout history. It has been a challenge to understand the source of pain. Until recently, it was thought that patients' pain originated in tender muscles, but currently the theoretical model is based on dysfunction in the central nervous system (CNS). Patients with FMS are found to have oversensitivity in the nerves that respond to heat and pressure, and the treatment has focused on drugs that can diminish the sensitivity. Patients with FMS therefore are frequently prescribed anticonvulsants such as pregabalin (Lyrica) and gabapentin (Neurontin) or serotonin/norepinephrine reuptake inhibitors (SNRIs) like duloxetine (Cymbalta) and venlafaxine (Effexor). These drugs suppress activity in the neurons transmitting pain-related signals in the CNS and can decrease the pain in FMS.
CNS dysfunction is thought to be related to a variety of signs and symptoms frequently seen in patients diagnosed with FMS such as depression, diarrhea, dizziness, dry eyes, dry mouth, shortness of breath, hearing difficulties, headache, hives/welts, trouble thinking, oral ulcers, muscle pain, muscle weakness, nausea, nervousness, numbness/tingling, pain in upper abdomen, sun sensitivity, chest pain, easy bruising, heartburn, rash, Raynaud's phenomenon, seizures, loss/change in taste, ringing in ears, blurred vision, vomiting, pain/cramps in abdomen, hair loss, loss of appetite, wheezing, constipation, fever, itching, insomnia, and fatigue/tiredness ( http://bit.ly/19MUowp).
Patients diagnosed with a painful condition, such as osteoarthritis and myofascial trigger points, may also be diagnosed with fibromyalgia. For these patients, treating peripheral pain generators may decrease or eliminate their widespread pain and hyperalgesia (increased sensitivity to pain). One published study took a group of patients who had osteoarthritis in their hip and were also diagnosed with fibromyalgia. The patients that were treated with a hip replacement had a significant decrease or elimination of their widespread pain (http://1.usa.gov/1hZzME6).
One explanation for this decrease in FMS pain is related to central sensitization. Central sensitization is the phenomenon of increased sensitivity of the central nervous system to all stimuli because of tissue damage somewhere in the periphery. When the threshold for pain decreases, stimuli that normally only produce a pressure sensation or mild discomfort would now produce pain. If the peripheral tissue damage is treated, the threshold for excitation of the nerves can return to a more normal level and the widespread pain can decrease, as shown in the example of the hip replacement patients.