Chapter 90. Common Pain Syndromes

1. Central sensitization is a cardinal element of chronic pain syndromes. Targeting factors contributing to this process is the cornerstone of managing chronic pain.

2. Chronic pain has a complex pathophysiology. Treatment should be multidisciplinary and aim for functional restoration.

3. Myofascial pain syndromes are characterized by the presence of trigger points, which have distinctive features that differentiate them from tender points.

4. Fibromyalgia is increasingly diagnosed. It is characterized by widespread pain and the presence of specific tender points. Multiple effective pharmacologic agents are now available.

5. Osteoarthritis (OA) is the most common joint disorder, is one of the most common chronic diseases in the elderly, and is a leading cause of disability. Certain measures may help prevent or slow the progression of OA. Conservative management options may delay or eliminate the need for surgery.

6. Tricyclic antidepressants, serotonin reuptake inhibitors, and antiepileptic drugs, especially calcium channel modulators, are considered good first-line options for treatment of most neuropathic pain syndromes.

7. Treatment of complex regional pain syndrome remains controversial but should start early and focus on mobility of the affected limb. Sympathetic blocks and multimodality analgesia help facilitate this. In advanced cases, more invasive options may be needed such as spinal cord stimulation or intrathecal analgesia.

8. Neck and back pain can be generated by a variety of different anatomic structures, which are targeted in the treatment plan. A careful history and physical examination along with imaging data will help reach the most specific pain generator, which should be targeted in the treatment plan instead of following a blind approach to target all potential generators.

9. Headache syndromes are numerous. The International Headache Society guidelines make the diagnosis of different headache syndromes easy and simple.

10. Tension and migraine headache are the most common primary headache. Preventative therapy is essential to their management.

Many pain conditions are encountered in clinical practice. This chapter provides a concise, practical, updated review of the most common pain syndromes. Along with the other chapters in this book on pain, a comprehensive review of pain is given.

Knowing the pathophysiology of chronic pain is essential for understanding the clinical features of different pain and the rationale of different treatment options used in the field. Chapter 89 covers this topic in detail. This chapter briefly summarizes the mechanisms of pain.

Pain sense starts by detecting noxious stimuli at the level of nociceptors, which are specialized receptors in the peripheral nervous system. An electrical signal is generated (transduction) and transmitted by the afferent fibers, A-δ fibers (slow, thin myelinated fibers), and C-fibers (the unmyelinated slowest fibers) of the spinal and cranial nerves. The first-order neurons of these fibers are located in the dorsal root ganglia or cranial nerve ganglia. Visceral afferent nociceptive fibers (A-δ and C) travel with sympathetic and parasympathetic fibers; their cell bodies also are found in the dorsal root ganglia. Muscles are also innervated by both A-δ and C-fibers. The pain signal then is transmitted to the sensory (second-order) neurons of ...