6Role of central sensitization in symptoms beyond muscle pain, and the evaluation of a patient with widespread pain
Section snippets
Fatigue
Fatigue is common in FMS, occurring in 80–90% of the patients, and may be a more prominent symptom than pain in some patients. A patient typically complains that ‘I am always tired’. Other words used by the patients for fatigue are exhaustion, a lack of energy, and a feeling of generalized weakness.3 It is usually worse in the morning. In one cross-sectional study with a subset who kept a diary of symptoms prospectively for a week, fatigue correlated with depression and poor sleep quality, and
Non-restorative sleep
Poor sleep as a symptom is common in FMS, occurring in about 70–75% of cases.3 However, morning fatigue may be a better indicator of non-restorative sleep, and is present in about 75–80%.3 Sleep problems in FMS include difficulty in falling asleep, with tossing and turning, light sleep, frequent awakening, and morning fatigue.
Several factors may contribute to poor sleep, including pain from any cause, associated restless legs syndrome, neuritis, reflux esophagitis, frequent micturition at
Paresthesia and swollen feeling
Both the above symptoms occur in about 50–60% of patients with FMS, usually in the extremities.3 The subjective swelling is described both in the joints and diffusely in the soft tissues. These symptoms can be quite prominent in some patients. The swollen feeling can be confused with arthritis, and numbness and tingling with a neurological disease such as neuritis. However, there is neither objective swelling in the joints nor any abnormal neurological signs. Sometimes, however, a generalized
Conditions associated with FMS: central sensitivity syndromes
It has been suggested that fibromyalgia and overlapping conditions (e.g. irritable bowel syndrome, chronic fatigue syndrome, headaches and restless legs syndrome among others) form a spectrum of central sensitivity syndromes (CSS)1, *2, 18, a term first used in 2000.18 These CSS are mutually associated1, *2, 18, 19 and bound by a common pathophysiological mechanism of CS, as has been reviewed.1, *2, 18, 20 The Yunus criteria for CSS consist of (a) evidence for association of a condition with a
Psychological/psychiatric symptoms
Anxiety, depression, and mental stress are present in many, but not all, patients with WSP or FMS.50 These symptoms, as well as coping difficulties and maladaptive belief about pain and other symptoms, are also common.51 The relationship between depression, mental stress and anxiety, and FMS/WSP is bidirectional.2 These psychological or psychiatric symptoms may antedate and probably play a causative role in the onset of musculoskeletal and non-musculoskeletal symptoms, or follow the development
Cognitive symptoms
These symptoms may be present in about 60% of patients.3 Validated neuropsychological testing has shown that patients with FMS have problems with memory, information processing and attention.*3, 54 These findings were present even after adjusting data for age, depression, poor sleep, medications and education.55 Neuroimaging studies have shown a pattern of increased neural recruitment during a cognitive task.54
Other symptoms
Dizziness or vertigo occurs in nearly 60% of patients. The cause of this common symptom is unknown, but no structural pathology is usually found. Dry mouth and eyes in the absence of medications or Sjogren's syndrome, tinnitus, and Raynaud's-like symptoms are described by some patients (Table 1). These symptoms may be due to an enhanced sensory perception related to CS, with or without concomitant emotional factors. These and other symptoms of FMS have been previously reviewed.3 They are also
Comments on CS and non-musculoskeletal symptoms in WSP/FMS
Besides demonstration of CS in the human pain laboratory, as discussed above, a good number of neuroimaging and other forms of brain studies (not described here) have also supported the presence of CS in several CSS conditions.1, *2 Research on CS in CSS disorders in general is somewhat in its infancy at present, although evidence of CS is rather convincing in several of them – e.g. FMS, regional soft-tissue pain syndrome/myofascial pain, IBS, tension-type headache, migraine and TMD – based on
Significance
What is the significance of CS and the CSS concept from a practical point of view? This question has been adequately answered elsewhere.1, *2, 18 Among others, CSS conditions taken together are the most common reasons for which a patient seeks medical help for their suffering. Widespread pain and fibromyalgia are among the most frequent problems seen in a rheumatology practice, unless a biased rheumatologist chooses not to see such patients. Thus physician education is important for proper
Evaluation of a patient for widespread pain
There are numerous causes of chronic widespread pain with structural pathology (the so-called organic diseases), e.g. various forms of polyarthritis, connective tissue diseases (CTDs), polymyalgia rheumatica, vasculitis, sarcoidosis, chronic viral diseases (hepatitis, human immunodeficiency virus), malignancy and metabolic diseases (such as hypothyroidism). It is noteworthy that poly-dermatomyositis only rarely presents with muscle pain, the major symptom being muscle weakness. Diagnoses of
Summary
WSP/FMS have many other symptoms besides pain, which include symptoms of an associated CSS condition. These symptoms are likely to be mediated by CS and other neurological mechanisms, as well as endocrine aberrations, psychosocial factors, genetics, trauma, poor sleep, and other unknown mechanisms. While there is evidence for CS in WSP/FMS and several other CSS, more studies are necessary. Patients presenting with WSP should be carefully evaluated by proper history and physical examination as
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