Diagnostic Criteria for Trigger Points

In this section you may learn how to include the diagnosis of pain, due to trigger points (TrPs), in a differential diagnosis. Inclusion of this common pain generator and appropriate intervention can make a tremendous difference in the lives of your patients.

While this section is designed to give some insight to the diagnosis of trigger points and myofascial pain syndrome it is important to realize there is no substitute for practical, 'hands on' education. There is only one educational program which focuses on musculoskeletal pain and trigger points for physicians in the country and is called, "The Janet Travell Seminar Series" and is presented by Bob Gerwin MD, Jan Dommerholt PT, among others.

To diagnose trigger points in your patient, you must complete a comprehensive medical history to determine the pain generator. Many times TrPs go unrecognized because they look like other conditions, such as but not limited to: bursitis, appendicitis, tendonitis, epicondylitis, subacromial bursitis, tennis elbow, tension headache, and thoracic outlet syndrome. The reason muscles can mimick so many different disorders is because they can refer pain and tenderness to distal regions of the body that overlay these areas. Other symptoms TrPs may cause are radiculopathy due to nerve entrapment as the nerve passes through hypertonic areas of muscle, proprioceptive disturbances, and tinnitus.

After the medical history, a clinician should look for any perpetuating factors (PF's), which allow TrPs to activate and persist. PF's are divided into three (3) groups: mechanical, nutritional, and systemic. Lifestyle examination of the patient is needed to determine any mechanical factors. There are blood tests which may be ordered to determine if nutritional and systemic factors are present. Detailed examples of PF's and testing available on the perpetuating factors page.

Physical examination for TrPs usually includes the following:

Documentation of the patient's pain on a body map.
Patient rating of pain on some type of pain scale (usually 1-10).
Neurologic exam (if indicated).
Orthopedic exam (if indicated).
Postural exam to determine apperent abnormalities in form.
Range of Motion (ROM) exam of suspected muscle(s) to determine if the muscle is shortened, which is a characteristic of TrPs.
Palpation of the suspected muscle (generally palpation is done by stroking perpendicular to the direction of the muscle fibers) to look for TrPs and taut bands within the muscle as well as a local twitch response (LTR).
Patient feedback to determine if referred pain is present while the muscle is being palpated. Patient's pain level should NOT be taken above a 5-6 on their pain scale while palpating.

A 2007 review of diagnostic criteria used in studies of trigger points concluded that

there is as yet limited consensus on case definition in respect of MTrP pain syndrome. Further research is needed to test the reliability and validity of diagnostic criteria. Until reliable diagnostic criteria have been established, there is a need for greater transparency in research papers on how a case of MTrP pain syndrome is defined, and claims for effective interventions in treating the condition should be viewed with caution.[1]

Despite this report, there are 3 diagnostic criteria which seem to be a common denominator to assertain the presence of trigger points.

Presence of a tender nodule in a taught band of muscle.
Local twitch response (LTR)
Compression of the trigger point will cause its referred pain to appear or increase in pain intensity.

Resources

Variability of criteria used to diagnose myofascial trigger point pain syndrome--evidence from a review of the literature. The Clinical journal of pain. Retrieved on 2008-01-25.