Fibromyalgia: An Environmental Scan
Table of Contents
4.1.2 Outline of Specific Chronic Pain Disorders
There are numerous chronic pain syndromes and the majority fall into the following categories (See Appendix E for a list of pain conditions). For illustrative purposes, three CPD: Myofascial Pain Syndrome (MPS), Neuropathic Pain (NP) and Chronic Headaches (CH) will be discussed in general to provide a macro-level orientation to different types of chronic pain. This is followed by a specific in-depth review of fibromyalgia in Section 3.3.
- Myofascial Pain Syndrome
- Neuropathic Pain
- Chronic Headaches
Myofascial Pain Syndrome (MPS)
Myofascial pain syndrome (MPS) involves the skeletal muscles and specifically the connective tissue that covers the muscle. Specific to MPS is the presentation of referred pain, pain that occurs somewhere else in the body when particular trigger points have applied pressure. Such trigger points are nodules or taut bands of muscle that can often be felt through the skin. The pain of trigger points is associated with pain in the neck or jaw, lower back, pelvic region along with the legs and arms. The most frequently occurring symptoms are aching pain within the muscles that can either persist or get worse over time, muscle and joint stiffness, feeling of tension within specific muscles and pain interfering with restorative sleep. Most individuals with MPS can trace the origin to either an injury or an overuse of the muscles at some point. MPS often affects adults between 35 and 50 and women are more likely to develop MPS compared to men.
Specifically, myofascial pain syndrome (MPS) may be confused with fibromyalgia and often co-occurs and although MPS is very common among individuals with fibromyalgia; it is not clear if one in fact causes the other. The patient history in conjunction with the physical examination will allow the clinician to determine whether a patient has fibromyalgia, myofascial pain syndrome, or both. MPS is associated with pain from trigger points within certain muscles. Overall, the definitive differentiation between myofascial pain syndrome and fibromyalgia is made by physical examination. In some cases, MPS is treated with medication whereas other cases require a combination of physical therapy, trigger point injections and or massage therapy.
Neuropathic Pain (NP)
Neuropathic pain (NP) or nerve pain results from damage to the nervous system, including peripheral nerves, spinal cord and certain central nervous system (CNS) regions. Nearly half of all NP pain occurrences follow a trauma, inflammation or infection. NP is caused by some alteration in the structure within the nervous system versus non-neuropathic pain, which is generally associated with lesions as opposed to changes in structure. Specific examples of neuropathic pain include trigeminal neuralgia (TGN) and shingles. The clinical symptoms of neuropathic pain include spontaneous pain, allodynia (i.e., pain due to a stimulus that does not normally produce pain, such as soft touch), and hyperalgesia (i.e., an exaggerated response to a stimulus that is normally somewhat painful). The pain may be experienced in the local region of the nerve or in different places on both sides of the body (i.e., bilaterally). NP pain is described as burning, shooting, stabbing, piercing, and a feeling of electric shock (Gatchel et al. 2007).
A specific example of NP is a condition known as trigeminal neuralgia (TGN), a debilitating pain in the face that commonly starts without reason and begins on one side. The pain is excruciating and described as an electric shock. The onset of TGN is most frequent among older adults but does not exclusively affect the older population. TGN may flare up at any time and triggers are numerous: chewing, touch, temperature, showering or even stepping outside in the wind. The pain may pass very quickly or last several minutes. As in most chronic pain disorders, treatment focuses on reducing symptoms and may involve prescribed anticonvulsants such as gabapentin. Trigeminal neuralgia is one of many syndromes associated with compression in the neurovascular system. An artery in the brain is compressing a cranial nerve. In situations where pharmacological agents do not provide sufficient pain relief, individuals with TGN can undergo surgery and have micorvascular decompression of the artery and the trigeminal nerve. Research has demonstrated that a vast majority of surgical patients report positive improvement in pain along with the disappearance of pain in many cases (Monstad, 2009).
Chronic headaches may be further classified as chronic migraine, cluster, trauma, tension and analgesic overuse types of headaches. Classifications are largely based on location and duration. The duration of chronic head pain is an important diagnostic factor and headaches lasting more than 2 hours are most common among cluster, migraine and tension headaches. Additionally, the rate of recurrence, the severity and whether or not it is on one side of the body or both are all important characteristics when making a diagnosis. The causes of headaches are numerous and include other conditions such as glaucoma, temporomandibular joint dysfunction or trigeminal neuralgia. Additionally, some lifestyle factors play a role in trigger headaches such as alcohol, smoking and for some people certain foods such as chocolate. Finally, particular psychological causes such as depression, increased stress levels and sleep disturbances are associated with headaches. In most cases, chronic headaches are treated with oral analgesics. However, if an individual experiences severe recurring episodes, a preventative pharmacological agent along with modifying certain lifestyle factors may be necessary (Schürks, Diener, and Goadsby 2008)(Marcus 2009)(May 2005).