Psychological and personality factors may be as important as, or more important than, pathological processes in the experience of pain, particularly in patients whose pain has a vague or uncertain source1-16. Patients with these vague and diffuse complaints of upper limb pain are commonly seen in hand surgery practices17,18. It can be difficult to make a specific diagnosis in the absence of objective findings, and therefore specific and effective treatment is elusive3,12,19,20. Patients with such idiopathic upper limb pain may have relatively maladaptive psychological factors and personality traits that contribute to disability related to somatic complaints3-5,7,8,10-12,15,16,20-23. We tested the hypothesis that patients who had pain with a discrete and easily identified cause would differ from patients who had vague, diffuse pain with no clear source (idiopathic pain) when evaluated with use of validated measures of several psychological factors, including pain anxiety, catastrophizing, a tendency for somatic complaints, body consciousness, and locus of control.
Materials and Methods
Our Human Research Committee approved a prospective protocol for the comparison of psychological factors in patients with discrete and idiopathic pain complaints. Following a single initial routine office evaluation in the practice of one of three hand surgeons (D.R., S.-G.P.L., or J.B.J.), patients were classified into one of the three groups on the basis of the clinical impression. The first group (the discrete pain cohort) included patients who had a single, discrete, identifiable cause of upper limb pain for which all of the symptoms and signs were consistent, with the treating physician being very confident about the diagnosis. The second group (the idiopathic pain cohort) included patients who had vague, diffuse complaints and inconsistent findings on examination, with the physician being very uncertain about the cause of the pain. The third group (the intermediate group) included patients who could not be assigned to either of the other two groups. Patients in the discrete pain and idiopathic pain cohorts rated the severity of their pain and completed the same battery of five psychological questionnaires. Patients in the intermediate group were excluded. Patients with previous operative treatment were also excluded. One hundred and seven patients (fifty-six with discrete pain and fifty-one with idiopathic pain) were enrolled in the study.
The present investigation focused on the initial impression of the treating physician. The distinction of patients into these three groups was based on the initial office visit alone, without regard to subsequent visits or diagnostic tests. Patients in the discrete pain group were those in whom the findings were specific enough for the physician to be extremely confident in the diagnosis on the basis of the interview and examination alone. Patients in the idiopathic pain group were those in whom the pain was so diffuse, vague, and/or extreme that there was no single pathological or anatomical process that could account for all of the symptoms or their severity. Patients with idiopathic pain were thought to have such noncharacteristic findings that no diagnostic tests would be able to explain the entire clinical presentation. Any patient who did not fit into either of these two extreme categories was considered intermediate and was excluded.
The diagnoses of the patients in the discrete pain cohort included trapeziometacarpal osteoarthritis (eleven patients), de Quervain tenosynovitis (thirteen), a single trigger digit (twenty-four), carpal tunnel syndrome (four), and lateral epicondylitis (four).
The discrete pain cohort included twenty-two men (39%) and thirty-four women, and the idiopathic pain cohort included fourteen men (27%) and thirty-seven women (p = 0.20). The average age (and standard deviation) was 55 ± 15 years (range, twenty-eight to eighty-two years) in the discrete pain cohort and 41 ± 15 years (range, twenty-two to eighty-six years) in the idiopathic pain cohort (p < 0.001).
In the discrete pain cohort, thirty-one patients worked full-time, five worked part-time, three were homemakers, fourteen were retired, one was unemployed but able to work, one was unemployed and unable to work, and one reported his work status as “other.” In the idiopathic pain cohort, thirty patients worked full-time, seven worked part-time, two were homemakers, five were retired, two were unemployed but able to work, two were unemployed and unable to work, and three reported their work status as “other.” There were no significant differences between the two groups with regard to employment status.
The idiopathic pain cohort had significantly more single individuals (nineteen compared with nine, p = 0.02), whereas the discrete pain cohort had significantly more married individuals (thirty-six compared with nineteen, p = 0.01). There was no significant difference between the discrete and idiopathic pain cohorts with regard to the number of patients living with a partner (three compared with six), the number of patients who were separated or divorced (six compared with four), or the number of patients who were widowed (two compared with three). The cohorts were comparable with respect to race. The discrete pain cohort included fifty individuals who described their race as white (not of Hispanic origin), two who described it as African-American, three who described it as Asian or Pacific Islander, and one who described it as American Indian or Alaskan Native. The idiopathic cohort included forty-seven individuals who described their race as white, two who described it as African-American, one who described it as Asian or Pacific Islander, and one who described it as Hispanic. The discrete and idiopathic cohorts also reported having similar levels of education (16.0 ± 3.0 years compared with 15.7 ± 2.9 years).
Patients in the idiopathic pain cohort had seen an average of 1.8 ± 1.7 doctors before presenting to one of us, whereas the discrete pain cohort had seen an average of 0.8 ± 0.7 doctors (p < 0.001). Nineteen patients had been offered disputable diagnoses, including carpal tunnel syndrome that was not verified by electrophysiological testing (seven patients), repetitive strain injury (five), tendonitis (four), fibromyalgia (three), and thoracic outlet syndrome (one), before presentation to us.
Psychiatric comorbidity (defined as a history of a psychiatric disorder or current use of psychiatric medication) was present in seven (12.5%) of the fifty-six patients in the discrete pain cohort and in fourteen (27.5%) of the fifty-one patients in the idiopathic pain cohort (p = 0.10).
Pain was assessed with use of 10-point Likert scales, with 1 point representing no pain and 10 points representing the worst pain ever experienced. Patients rated pain in several categories, including pain in general, worst pain, pain at rest, pain when lifting a heavy object, pain with repeated movements, and pain at night.
Pain Anxiety Symptoms Scale
The Pain Anxiety Symptoms Scale is a validated, forty-question inventory designed to assess anxiety about pain24. Its four ten-item subscales are reliable measures of differentiable aspects of pain anxiety: (1) cognitive anxiety, (2) fear of pain, (3) escape and avoidance, and (4) physiological anxiety. The cognitive-anxiety subscale evaluates symptoms such as the inability to concentrate and the frequency of unwanted thoughts when the patient is in pain. The fear-of-pain subscale measures the frequency of thoughts provoking fear and a profound dread of negative consequences when the patient is in pain. The escape-and-avoidance subscale rates the frequency of behaviors aimed at minimizing the severity and duration of pain. Finally, the physiological-anxiety subscale measures the patient's physical responses to pain, such as sweating or feeling dizzy. With use of a 6-point rating system (with 0 corresponding to “never” and 5 representing “always”), the possible score on each subscale ranges from 0 to 50 points. In addition, a combined total Pain Anxiety Symptoms Scale score (possible range, 0 to 200 points) has proved useful for the evaluation of generalized pain anxiety24. Based on a series of 180 patients with pain who were seen in a multidisciplinary setting, McCracken et al. reported a mean value (and standard deviation) of 26.02 ± 12.47 for the cognitive-anxiety subscale, 26.88 ± 9.88 for the escape-and-avoidance subscale, 18.70 ± 12.37 for the physiological-anxiety subscale, and 94.24 ± 39.16 for the total Pain Anxiety Symptoms Scale24.
Pain Catastrophizing Scale
The Pain Catastrophizing Scale was used to determine the extent to which the patients coped with their pain by catastrophizing (i.e., performing cognitive activities that exacerbate the fearful aspects of the pain experience)25. The Pain Catastrophizing Scale is a validated scale that measures three components of pain catastrophizing: rumination, magnification, and helplessness25,26. Rumination, the tendency to regurgitate thoughts about pain and to relive painful experiences, is measured with a four-question subscale. Magnification, the inclination to “make a mountain out of a molehill” or to believe that pain represents an undiagnosed serious or worsening problem, is measured with a three-question subscale. Finally, helplessness, an inability to mitigate pain symptoms or a submission to pain, is assessed with use of a six-question subscale. Questions are scored on a 5-point system, with 0 points corresponding to “not at all” and 4 points corresponding to “all of the time.” The possible scores range from 0 to 16 points on the rumination subscale, from 0 to 12 points on the magnification subscale, and from 0 to 24 points on the helplessness subscale. In addition, a combined total Pain Catastrophizing Scale score (possible range, 0 to 52) has proved to be effective for the assessment of generalized coping strategies25. Data have been published for two populations: a community sample of 215 individuals, and a pain clinic outpatient sample of sixty individuals26. The mean values (and standard deviations) for the community sample were 5.89 ± 4.15 points for rumination, 3.2 ± 2.45 points for magnification, 4.78 ± 4.67 points for helplessness, and 13.87 ± 10.11 points for the total Pain Catastrophizing Scale. The mean values for the pain clinic sample were appreciably higher: 9.02 ± 3.34 points for rumination, 4.58 ± 2.54 points for magnification, 8.65 ± 5.2 points for helplessness, and 22.25 ± 10.16 points for the total Pain Catastrophizing Scale.
Wahler Physical Symptom Inventory
The Wahler Physical Symptom Inventory is widely used to measure the frequency of somatic complaints and has been shown to have acceptable internal consistency and validity27. For the purposes of the present study, it was useful because its “score is based exclusively on somatic complaints without an admixture of emotional and mood symptoms such as worry, anxiety and depression.”27 To evaluate the occurrence and intensity of patient complaints of general physical symptoms, the Wahler Physical Symptom Inventory uses a forty-two-question format and a 6-point rating system, with 0 indicating that the patient experiences the symptom “almost never” and 5 indicating that the patient experiences the symptom “nearly every day.” The final Wahler Physical Symptom Inventory score, ranging from 0.0 to 5.0, is an average of individual responses. Wahler reported norms based on 111 male college students (0.56 ± 0.17), 134 female college students (0.66 ± 0.15), 236 male psychiatric outpatients (0.99 ± 0.56), and 317 female psychiatric outpatients (1.49 ± 0.69)27.
Body Consciousness Questionnaire
The Body Consciousness Questionnaire, a validated instrument demonstrating satisfactory test-retest reliability, has three subscales28. Of special interest to us was the 5-question Private Body Consciousness subscale, which assesses attention to internal physical sensations (e.g., dry mouth, hunger, and body temperature). Questions are rated on a 6-point scale, with 0 representing an “extremely uncharacteristic” quality and 5 representing an “extremely characteristic” quality. The Private Body Consciousness scores range from 0 to 25. Miller and Buss reported gender-specific societal norms based on 275 men (11.7 ± 3.0) and 353 women (12 ± 3.3)28.
Multidimensional Health Locus of Control Scale
Locus of control was measured with the Multidimensional Health Locus of Control Scale. This eighteen-item measure assesses the perception that the forces determining one's health are (1) primarily internal, (2) under the control of powerful others, or (3) a matter of chance29. Patients who score high on the “Internal Control” subscale demonstrate personal responsibility for their health. Those who score high on the “Powerful Others” subscale are likely to rely on others (e.g., their doctor) to control their health. Finally, those who score high on the “Chance” subscale are not likely to rely on their own actions or the actions of a doctor to cure their pain because they believe that their health is a matter of chance. The Multidimensional Health Locus of Control Scale is scored on a 6-point scale, with 1 representing “strongly disagree” and 6 representing “strongly agree.” Each dimension consists of six questions with scores ranging from 6 to 36 points. On the basis of data gathered from a normal population of individuals waiting at a metropolitan airport, Wallston et al. reported mean values (and standard deviations) of 25.1 ± 4.9 for the “Internal Control” subscale, 20.0 ± 5.2 for the “Powerful Others” subscale, and 15.6 ± 5.8 for the “Chance” subscale29.
A power analysis was performed on the basis of the Private Body Consciousness subscale of the Body Consciousness Questionnaire. Previous studies have suggested that the mean and the standard deviation of the Private Body Consciousness subscale for the general population are approximately 12 and 3 points, respectively28. To detect a cohort difference of one-fourth of a standard deviation—judged to be the smallest clinically important difference—at an alpha of 0.05 and a power of 80%, we estimated that a minimum of twenty-four patients would be needed in each cohort.
Commercial software was used for analysis (Statistical Package for the Social Sciences, Chicago, Illinois). Fisher's exact test was used to compare dichotomous variables. The Student t test and the Mann-Whitney test were used to compare continuous variables. A multiple stepwise logistic regression model using the backward elimination algorithm was used to account for potential confounding among the various psychological measures. Factors associated with differences between cohorts that were associated with a significance level of p ≤ 0.075 during univariate analysis were included as covariates in the model.
Patients with idiopathic pain had more extreme complaints about pain than patients with discrete pain did (Table I). Patients with idiopathic pain had significantly more pain with repeated movements (mean score [and standard deviation], 6.8 ± 2.6 compared with 5.2 ± 2.8; p = 0.01) and pain at rest (4.1 ± 2.6 compared with 3.0 ± 2.4; p = 0.02) than patients with discrete pain did. The differences between the two groups with regard to pain at night (4.9 ± 2.8 compared with 3.9 ± 2.8; p = 0.06) and pain in general (5.3 ± 2.4 compared with 4.4 ± 2.5; p = 0.10) showed trends toward significance. Patients in both groups had similar scores for the severity of pain when lifting a heavy object (5.9 ± 2.8 compared with 5.4 ± 3.2; p = 0.34) and for the severity of the worst pain (7.3 ± 2.1 compared with 6.3 ± 2.7; p = 0.48).
Patients with idiopathic pain had greater anxiety about their pain than did those with discrete pain (Table II). According to the Pain Anxiety Symptoms Scale, patients with idiopathic pain had significantly greater cognitive anxiety (21.7 ± 10.1 compared with 16.8 ± 8.7; p = 0.008) and had nearly significantly greater fear of pain (14.4 ± 8.1 compared with 11.8 ± 6.8; p = 0.07) and overall pain anxiety (69.2 ± 29.0 compared with 59.3 ± 25.9; p = 0.07) than did those with discrete pain. The differences between the groups with regard to physiological anxiety (11.1 ± 8.4 compared with 9.8 ± 8.2, p = 0.43) and pain-escaping behavior (22.2 ± 7.5 compared with 21.0 ± 8.7; p = 0.47) were not significant.
Patients with idiopathic pain had less-adaptive personality traits than did those with discrete pain (Table III). Patients with idiopathic pain demonstrated significantly greater helplessness than did patients with discrete pain (8.2 ± 5.5 compared with 5.1 ± 4.6; p = 0.002). Patients with idiopathic pain also had significantly higher scores on the pain-magnification subscale (4.5 ± 3.3 compared with 2.8 ± 2.7; p = 0.007) and the total combined Pain Catastrophizing Scale (20.4 ± 11.7 compared with 14.0 ± 11.3, p = 0.005). The difference between the groups with regard to the rumination subscale score was nearly significant (7.7 ± 4.5 compared with 6.1 ± 4.9, p = 0.08). There was nearly a significant difference between the patients with idiopathic pain and those with discrete pain in terms of somatic complaining as measured with the Wahler Physical Symptom Inventory (1.11 ± 0.56 compared with 0.93 ± 0.49; p = 0.07).
There was no significant difference between the idiopathic pain cohort and the discrete pain cohort with regard to the average score on the Private Body Consciousness subscale (14.1 ± 5.0 compared with 14.7 ± 5.8; p = 0.55). With regard to the Multidimensional Health Locus of Control Scale, the idiopathic pain cohort scored higher on the “Internal Control” subscale (25.1 ± 4.8 compared with 23.8 ± 4.5; p = 0.17) and the “Chance” subscale (16.4 ± 4.9 compared with 14.9 ± 4.8, p = 0.11), whereas the discrete pain cohort scored higher on the “Powerful Others” subscale (17.9 ± 5.4 compared with 16.0 ± 5.8; p = 0.08). All of these differences failed to reach significance.
Eight covariates met the criteria for inclusion in the logistic regression model: the overall Pain Anxiety Symptoms Scale score, the cognitive-anxiety subscale score, the fear-of-pain subscale score, the combined total Pain Catastrophizing Scale score, the Pain Catastrophizing Scale magnification score, the Pain Catastrophizing Scale rumination score, the Pain Catastrophizing Scale helplessness score, and the Wahler Physical Symptom Inventory score. The regression model identified the total Pain Catastrophizing Scale score as the sole predictor of the cohort to which a patient would belong (p = 0.008). This model was used to determine a patient's probability of belonging to each cohort. A total Pain Catastrophizing Scale score of 0 corresponded with a 25% probability that the patient would be in the idiopathic pain cohort, a score of 10 corresponded with a 40% probability, a score of 20 corresponded with a 50% probability, a score of 30 corresponded with a 65% probability, and a score of 40 corresponded with a 75% probability.
Many patients have complaints of pain that are diffuse, vague, and nonspecific3,20. These patients represent diagnostic and treatment dilemmas. While patients and surgeons crave a specific diagnosis, such a diagnosis may affect employment, insurance, and lawsuits and may lead to operative procedures or other potentially harmful treatments. When patients complain of diffuse pain that is associated with few objective findings, doctors should be honest with themselves and with their patients and refer to such pain as idiopathic19 or nonspecific20.
The present investigation demonstrated several differences in the psychological characteristics of patients with idiopathic, as compared with discrete, pain. Patients with idiopathic arm pain reported their pain as more severe; exhibited higher levels of cognitive anxiety and fear of pain; demonstrated more helplessness, magnification, and overall catastrophic coping mechanisms for dealing with pain; and showed a tendency for increased somatic complaining. The tendency to react to pain by perceiving progressively worse and worse outcomes related to a specific worry (catastrophizing) was the strongest single factor in our investigation. Catastrophizing is commonly associated with pain disorders and is related to anxiety and neuroticism, but is somewhat independent of depression22. It is notable that the patients with discrete pain had substantially greater somatic complaints compared with college students and demonstrated scores resembling those of psychiatric outpatients27.
The term idiopathic implies no judgment on the proportion of pain that is physical (organic) and the proportion that is psychological (functional)19. While both purely physical and purely psychogenic pain are observed, the experience of pain usually reflects the interaction of physical and psychological factors2. While it might be suggested that idiopathic arm pain may be a somatic representation of psychological distress (that is, it may be psychosomatic) or may represent a heightened sensitivity to bodily sensations, the major factor in the present study of idiopathic arm pain was the poor coping mechanisms of the patients. Regardless of the source of the pain, these patients struggled to adapt to and manage their pain.
Syndromes and terms that are invented by physicians who are trying to understand these problems (e.g., repetitive strain injury23, fibromyalgia30,31, etc.) are often provocative and misleading and have limited scientific support. Such terms may affect a patient's perception of his or her illness, often in a negative way (e.g., “My pain means that I am injuring myself”). These terms also may imply an understanding of etiology when such an understanding is, in reality, very poor. For example, use of the term fibromyalgia to refer to chronic multifocal idiopathic pain suggests some relationship to muscles or fibrous tissues, while the true source of the pain remains unknown. Diagnoses and terms may be influential in other aspects of a patient's life, such as work, insurance, and legal issues. Finally, diagnoses usually are linked to treatment. For instance, a patient who has been diagnosed with carpal tunnel syndrome eventually may request carpal tunnel release. In the absence of true compression of the median nerve at the carpal tunnel, such operative intervention can only do harm32.
The treatment of idiopathic arm pain can be very frustrating for both the patient and the doctor. Although it may be impossible to definitively diagnose and specifically treat vague, diffuse, idiopathic pain in the upper extremity, the physician can help patients to manage their symptoms through reassurance and support3,19. Because the diagnosis is elusive and specific treatments are unavailable, it is important to place the focus of management on adapting to and coping with the pain. Physicians should be aware that psychological factors limiting appropriate coping mechanisms may be the primary reason that the patient is seeking help. History has documented the power of “medical suggestion”—that is, the concept that physicians can create illnesses and encourage illness behavior by the way that they react to their patients2,3,12,14. Individuals who primarily demonstrate anxiety and maladaptive coping mechanisms when in pain may respond to relaxation training and cognitive behavioral therapy33-37. Cognitive behavioral therapy may be beneficial for teaching patients the difference between discomfort and pain and for demonstrating that they have the ability to control their response to both external and internal stimuli. Unfortunately, it is difficult to offer these facets of treatment without patients taking offense and thinking that the surgeon is belittling their complaints (e.g., “You think it's all in my head”). Nonetheless, an honest assessment of the uncertainty of the diagnosis and the influence of psychological factors may help the patient's primary care physician and other physicians to address these issues. ▪
In support of their research or preparation of this manuscript, one or more of the authors received grants or outside funding from the AO Foundation. None of the authors received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.
Investigation performed at the Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston, Massachusetts
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