As many as one-third of irritable bowel syndrome (IBS) patients have described extra intestinal symptoms such as rashes, tension headaches, and muscle pains. Research has shown that as many as 60% of IBS patients also have fibromyalgia syndrome (FMS). Conversely, as many as 70% of FMS patients have reported experiencing symptoms of IBS. Could there be a common cause for both conditions?
FibromyalgiaFMS is a disorder of the musculoskeletal system that is associated with symptoms of general muscle aches, stiffness, overall fatigue, and poor sleeping habits (see Fibromyalgia Symptoms Checklist for a complete list of fibromyalgia symptoms). Symptoms can vary in both severity and duration; the pain may be dull or knife-like, linger persistently, or be intermittent. Like IBS, FMS is a functional disorder, and therefore tests to find the origins of the pain often come back negative (see Table below for the diagnostic criteria for FMS). Approximately 3.4% of women, and 5% of men suffer from FMS.
The IBS-FMS ConnectionGiven the co-existence of IBS and FM in so many patients, it is reasonable to consider a connection. Even though IBS affects the gastrointestinal tract and FMS the musculoskeletal system, there are similarities that the two conditions share. Neither condition can be explained by organic disease; they are considered functional disorders. Both occur frequently in women and the onset may be during a stressful event in life. Cognitive behavior therapy and certain types of prescription drugs are effective in both.
Research has been suggested that people with IBS or FMS respond to pain differently than other persons. However, IBS patients have an altered response to visceral (intestinal) pain, while persons with FMS have an altered response to somatic (skin and muscle) pain. Not surprisingly, further studies have shown that people with both conditions have an altered response to both types of pain. Additionally, persons with severe IBS were more likely to have FMS than those with less acute symptoms.
Although researchers suggest a common mechanism for both disorders, its origins are still unknown. Relatively speaking, the medical community has only just recognized IBS and FMS as legitimate disorders and not psychosomatic problems. Therefore, research on either condition is still in its infancy, and studies connecting the two are rare. However, there is hope, as researchers are taking new interest in discovering why IBS and FMS seem to be connected.
Diagnosing FibromyalgiaIn 1990, criteria for the diagnosis of fibromyalgia were established by the American College of Rheumatology.(3) These are:
- A history of widespread pain, which is identified by pain being present:
- In the left side of the body.
- In the right side of the body.
- Above the waist.
- Below the waist.
- Cervical spine.
- Anterior chest.
- Thoracic spine.
- Low back (lower segment).
- Pain must also be present in 11 of 18 pre-defined sites on the body when palpated (touched) by a physician.
- 1-2:The base of the skull, right and left sides (occiput: bilateral, at the suboccipital muscle insertions).
- 3-4: The lower neck, right and left sides (low cervical: bilateral, at the anterior aspects of the intertransverse spaces at C5-C7).
- 5-6: The midpoint between the neck and shoulder, right and left sides (trapezius: bilateral, at the midpoint of the upper border).
- 7-8: Muscles over the shoulder blades, right and left sides (supraspinatus: bilateral, at origins, above the scapula spine near the medial border).
- 9-10: The upper edge of the breastbone, right and left sides (second rib: bilateral, at he second costochondral junctions, just lateral to the junctions on upper surfaces).
- 11-12: Two centimeters towards the wrist from either elbow (lateral epicondyle: bilateral, 2 cm distal to the epicondyles).
- 13-14: The outer buttock muscles, right and left sides (gluteal: bilateral, in upper outer quadrants of buttocks in anterior fold of muscle).
- 15-16: Upper buttock muscle where the buttocks meet the back, right and left sides (greater trochanter: bilateral, posterior to the trochanteric prominence).
- 17-18: Just inside and above either kneecap (knee: bilateral, at the medial fat pad proximal to the joint line).
Veale D, Kavanagh G, Fielding JF, Fitzgerald O. Primary fibromyalgia and the irritable bowel syndrome. Br J Rheumatol. 1991;30:220-222.
Lubrano E, Iovino P, Tremolaterra F, et al. Fibromyalgia in patients with irritable bowel syndrome. An association with the severity of the intestinal disorder. Int J Colorectal Dis. 2001;16:211-215.
Wolfe F, Smythe HA, Yunus MB, et al. The American College of Rheumatology 1990 Criteria for the Classification of Fibromyalgia. Report of the Multicenter Criteria Committee. Arthritis Rheum. 1990;33:160-172.