and the Disability Dilemma:
new era in understanding a complex multidimensional pain syndrome
from: Bennett, R.M.
Fibromyalgia and the disability dilemma: new concepts in
understanding a complex multidimensional pain syndrome.
Published in Arthritis and
Volume 39: pages 1627-1634, 1996.
(FM) is a common syndrome of chronic pain that is increasingly seen in
rheumatology practice (1-6). According
to a recent epidemiology survey from Kansas, FM affects 2% of the total
population; 3.4% of all women and 0.5% of men (7). Most FM patients report that chronic pain and fatigue
adversely affect the quality of their life and negatively impact their
ability to be competitively employed (8-10).
The extent of reported disability in FM varies greatly from country
to country (11-14) probably reflecting differences in political
philosophies and socio-economic realities.
A recent survey of the work and disability status of 1,668 FM
patients from 7 centers in the USA reported that 25.3% had received
disability payments (14.8% were from Social Security Disability) (15).
Interestingly less than 25% of the SSD awards were specifically for
the diagnosis of FM. The
majority of patients who considered themselves disabled were
receiving disability payments. On
the other hand 66% of FM patients reported that they could work on all or
when asked assess disability issues in FM patients, have difficulty in
distinguishing between their FM patients who continue to work and the
patients who claim disability. It
seems that it is only the patient's self-perception of disability that
distinguish the able from the would-be disabled. There is often a mismatch
between what we find on clinical examination and the amount of alleged
dysfunction. Instinctively we
suspect that there is nothing really wrong with the patient FM
patients usually look normal. Thus
the problem must be in the psyche. Is
there some hidden agenda for these claims?
Is the patient getting some secondary gain for this behavior?
Maybe they are escaping the stresses of a boring job, receiving
more attention, getting an early pension or are they just bucking the
system? Such invidious
thoughts are not only the province of health care providers; family
members, co-workers and friends often harbor the same suspicions.
Are FM patients ever truly disabled and if so, what is the nature
of their impairment?
Pain cause Disability?
Most FM patients cite pain as a
major cause for disability. Chronic
widespread pain is a common finding (7,16).
The valid assessment of disability in chronic pain states is
notoriously difficult (17,18). The
problems that are encountered in assessing the chronic pain patient are
largely related to 4 issues: 1) pain is a purely subjective sensation which is usually
interpreted in an emotional context,
2) chronic pain cannot be fully understood in terms of the
classical model of disease that equates pathogenesis with tissue damage or
many non-sick people have persistent pain but are not
disabled, and 4) disability due to pain results from a complex interplay
between past experiences, education, income level, work related
self-esteem, motivation, psychological distress, fatigue, personal value
systems, ethno-cultural background and the availability of financial
are usually more confident of reliably assessing disability in patients
with rheumatoid arthritis and osteoarthritis; yet important determinants
of dysfunction in both of these diseases are psychosocial issues such as
coping style, symptom focus, anxiety and depression (19,20).
It is increasingly evident that dysfunction in chronic pain states
is poorly correlated with the severity of pain (18,21,22). Disabled pain patients usually link impaired functioning to
having persistent pain and cannot conceive of living a normal life as long
as they are in pain (23,24). Thus
they pursue a fruitless search for a cure which is never realized -- thus
rationalizing their continued disability.
In the process they not only remain dysfunctional, but also
over-utilize medical care and develop increasing personal distress.
Interestingly it is the belief that pain is the major cause
of disability, that seems to determine the actual degree of dysfunction,
rather than the absolute level of pain (25).
These psycho-social and behavioral issues are clearly relevant to
some FM patients seeking disability, but should not be generalized.
Each patient has to be thoughtfully evaluated according to their
unique set of circumstances.
Diagnosis of Fibromyalgia: Is
this the problem?
Fibromyalgia was not a frequent
diagnosis prior to 1980 and seldom a prominent topic in rheumatology
training programs. Some 15
years later FM is one of the commonest diagnoses made by rheumatologists. To some this is a cause for dismay: we have created a
monster and now it is up to us to make amends (26).
It has been suggested that the very act of giving patients a name
for their pain state legitimizes unproven pathophysiological theories in
ways that are counterproductive to effective management (27). In this view physicians are part of the problem.
Otherwise healthy individuals experience a string of transient
discomforts throughout their lifetime: headaches, back pain, post
exertional pain, fatigue, insomnia, stiffness, constipation, colds and
depression. At least one such
symptom occurs in any month (28). Some
individuals have an increased predilection to attribute such symptoms to
serious disease and repeatedly seek medical attention this is the
underlying basis of somatization (29).
"Medicalization" is the provision of a chronic
medical diagnosis to a minor transient discomfort and its resulting
treatment. Gurus of
chronic pain research have averred that Western medicines increasing
proclivity for medicalization is one of the causes for the current
epidemic of chronic pain. While
maintaining that the patient has "real" pain, they minimize any
pathophysiological explanations by maintaining that chronic pain states
reflect the overwhelming stress engendered by the individuals failure to
cope with the demands of industrialized society (22). The
general experience with FM patients does not fit the somatization concept.
A formal diagnosis of somatization can only be made in 14% to 23%
of FM patients (30,31). Whereas
lifetime psychiatric disorders are more prevalent in FM patients than FM
non-patients, they are not intrinsically related to the pathophysiology of
the FM syndrome. However they
do seem to partly determine who becomes a patient with FM (31).
Furthermore psychological distress in FM patients appears to be
mainly a result of symptom severity (31,32).
Most studies have reported that FM symptomatology is remarkably
persistent and pervasive over many years (12,33,34), despite many patients
being reassured that this is not a crippling condition.
Furthermore, providing a diagnosis and engaging the patient in a
program of cognitive restructuring and aerobic conditioning has been shown
to result in long term improvement (30).
If FM turns out to be primarily a behavioral disorder
rheumatologists have done society a disfavor.
If the behavioral aspect of FM is largely secondary to persistent pain
and fatigue, then pain guru's have pursued a narrow minded and self
do fibromyalgia patients hurt?
It is difficult to rationalize
decisions regarding disability in FM patients without having a conceptual
framework as to symptom generation. The cardinal symptom of FM is
widespread body pain (35). The
cardinal finding is the presence of focal areas of hyperalgesia,
the tender points (35). Tender
points imply that the patient has a local area of reduced pain threshold
suggesting a focal pathology (36).
In general tender points occur at muscle tendon junctions, a site
where mechanical forces are most likely to cause micro-injuries (37).
Many, but not all FM patients, have tender skin and a overall
reduction in pain threshold (38). These
latter observations suggest that some FM patients have a generalized
pain amplification state. There
has been a recent plethora of experimental studies apposite to the
pathophysiological basis of central pain states.
As the confident assessment of disability is aided by an
understanding of relevant pathophysiology, a synopsis of this scientific
evidence is now given.
is now apparent that there is no global defect of muscle in FM
patients (39), but there are several clinical observations that indicate
the focal muscle origin of pain.
(1) Most patients cite muscle as the source of their discomfort.
(2) FM patients experience increased pain during repetitive
muscular activity -- which improves on cessation.
Interestingly, there is a rebound of pain 24-48 hours after
unaccustomed activity -- as seen in normal individuals. (3). Fibromyalgia
patients are tender over focal areas of muscle, usually at
musculotendinous junctions (35,40). (4)
There is an improvement of pain after these locations are injected with
local anesthetics (41). Indeed,
the very act of injection provides evidence for a focal muscle pathology.
The muscle adjacent to the tender points is relatively unresponsive
to needling, whereas there is a sudden increase in pain when the tender
point is needled (42). 5).
Bengtsson et al. performed sequential epidural installations of saline,
fentanyl, naloxone and lidocaine in FM patients (43).
The saline had no effect, the fentanyl caused a significant
improvement (which was partly reversed by naloxone) and lidocaine totally
abolished both pain and tender points.
These results are not compatible with the notion that FM pain is solely
central in origin. It is more
likely that peripheral nociceptive input is required to maintain a state
of central pain sensitization -- as envisaged in the concept of
neuroplasticity (see below). What
is the nature of this continuing nociceptive input?
Elert et al. made the interesting observation that fibromyalgia
patients were less able to relax their muscles in the short pauses between
isokinetic muscle contractions and had increased muscle fatiguability
compared to healthy controls (44). These
observations may be relevant to continuing nociceptive input on the basis
of impaired central coordination of muscle activity predisposing to
mechanical muscle damage -- as envisaged by Edwards (45).
objective demonstration that FM patients have a generalized increase in
pain sensitivity was provided by Gibson et al (46).
They reported an increased nociceptive evoked EEG somatosensory
response in 10 FM patients compared to 10 matched controls following CO2
laser stimulation of the skin. Arroyo and Cohen, using the technique of electrocutaneous
stimulation, found that the upper limbs of FM patients could be
characterized as regions of secondary hyperalgesia (47). Primary hyperalgesia is the normal perception of pain from
nociceptor stimulation in an injured tissue.
Secondary hyperalgesia refers to pain elicited from uninjured
tissues (48). This results in
normally non-noxious impulses (e.g. light touch) being perceived as
painful; the elegant experiments of Torebjork et al have convincingly
demonstrated this phenomenon in humans (49).
The pathophysiological basis for this phenomenon is an activation
of NMDA (N-methyl D-aspartate)
receptors (50). Synergism
between substance P and NMDA receptors play a major role in the
perpetuation of secondary hyperalgesia (51). A recent study from Sweden has provided some evidence that
secondary hyperalgesia may be relevant to pain in FM patients -- Sorensen
et al reported that
intravenous ketamine (an NMDA receptor antagonist) attenuates pain and
pain threshold, as well as improving muscle endurance in FM patients (52).
The finding of increased cerebrospinal fluid levels of substance-P
in FM patients is consonant with the notion that secondary hyperalgesia is
relevant to understanding FM pain (53).
possibility that pain related functional CNS changes can be demonstrated
by imaging techniques has been pursued by Mountz et al (54).
They reported that FM patients, characterized by low pain
thresholds, had a decreased regional cerebral flow compared to healthy
controls The decreased perfusion was particularly prominent in the
thalamic and caudate nuclei (structures involved in the processing of
nociceptive stimuli). A
similar finding has been reported in patients with chronic neuropathic
pain, using O-15 positron emission tomography (55).
term given to functional changes within the CNS is "neuroplasticity".
The classical example of neuroplasticity is the phenomenon of phantom limb
following an amputation. Neuroplasticity
refers to a re-wiring of the synaptic connections which, if prolonged, can
result in a pain state in the absence of peripheral input.
An increased understanding of this phenomenon has been instrumental
in providing a new conceptual framework for understanding chronic pain
Fibromyalgia is more than a muscle pain syndrome (56).
The central pain sensitization state, as outlined above, would
account for the symptom magnification that is seen in the fibromyalgia associated
conditions of irritable bowel syndrome, skin tenderness, headaches,
restless legs syndrome, irritable bladder and premenstrual tension
syndrome. The continued
barrage of noxious impulse from these associated
conditions could be perpetuating factors for the maintenance of the
neuroplastic changes -- resulting in the chronicity of fibromyalgia
multi-dimensional features of fibromyalgia can be explained by persistent
pain causing a variable chronic stress response which drives several
feedback loops that amplify and perpetuate the chronic pain state
(57,58)-- see figure 1. Some of these feedback loops have been identified:
altered behavior (e.g. deconditioning (59)), depression (32), high
levels of psychological distress (31), sleep disturbance (60) and
hypothalamic-pituitary dysfunction (61,62).
Secondary hyperalgesia and stress feedback loops probably account
for the prominent "somatization" of some FM patients.
is the cause of disability in fibromyalgia patients?
The World Health Organization
defines disability as a limitation of function that compromises an
individual's ability to perform an activity within the range appropriate
considered normal (63). Disability
is the result of an impairment. There is seldom a good linear relationship
between impairment and disability this is particularly true in chronic
pain states. Impairment is
defined as the anatomical/physiological loss or a psychological impediment
that results in disability. Impairment
relates to disorders of function at the organ level (e.g. a left sided
hemiplegia -an anatomic problem, epilepsy
a physiologic problem, schizophrenia
a psychological problem). Disability
is an integrated concept that views impairment in a multidimensional
context; to wit: age, sex, educational level, psychological profile, past
attainments, job satisfaction, motivation, re-training prospects, social
support systems, economic consequences and the potential for being
competitive in the workforce. Work
disability, which is the subject of this review, is the inability or
diminished potential for engaging in full time gainful employment.
The problems that FM patients cite as being instrumental in their
disability are: difficulty in sustaining repetitive motor tasks (due to
both increasing pain and fatigue), reduced physical efficiency (as they
take longer to accomplish tasks), loss of mental sharpness, fear of poor
performance, difficulty in conforming to usual working hours (FM patients
describe a diurnal variation in energy level and alertness that is
different from healthy individuals, citing a "window of
opportunity" for constructive work that typically extends from about
10 am to 2 p.m.(64)), prolonged sitting or standing and workplace
stressors (coldness, excessive noise, rigid time/performance expectations)
(9,65). The net result of
these problems may make an individual non-competitive in the work force
due to erratic performance and frequent absences; these issues are
themselves a potent cause for increased stress.
There are a few studies that have documented functional impairment
in FM patients. Cathey et al. used a computerized workstation to physically
stress shoulders, cervical/thoracic/lumbar spine, wrists and elbows in a
simulated work environment (66). FM
patients (#28) were compared to RA patients (#26) and healthy controls
(#11). As expected RA
patients had a limited work capacity and could only perform 59% of the
work done by healthy controls. However
FM patients were equally impaired and were only able to perform 62% of the
healthy control workload. There
was a strong correlation between objective performance and the HAQ
disability index (67). FM
patients decreased their rate of performance or stopped the test mainly
due to increasing pain. Hidding
et al. compared self report measures of disability with a blinded
evaluation of observed disability (by grading a videotape of 9
selected activities) in patients with RA, AS and FM (68).
The observers reported similar levels of disability in all 3
Cognitive dysfunction is a self perceived cause of impairment in
many FM patients. Sletvold et al. employed a comprehensive series of
neuropsychological tests to evaluate information processing in FM (#25),
major depression (#22) and healthy controls (#18) (69). Both FM and major depression patients processed information
less effectively than controls. The
defects included purely mental tasks as well as psychomotor performance.
The results were not explainable by a subset of FM patients having
FM patients may be told that
they are "just out of sorts" and should get on with their lives
(70). This advice is based on
the concept that a major component of the FM dilemma is perceived
helplessness and poor pain coping mechanisms.
Nicassio et al. analyzed the factor structure of the Coping
Strategies Questionnaire(CSQ) with several measures of pain outcome (pain
behavior, pain reporting, depressive symptoms and quality of well-being)
in 122 FM patients (71). There
was strong correlation between high levels of passive coping (e.g.
perceived ability to control pain and absence of catastrophizing)
and low levels in pain outcomes as is also seen in patients with RA.
Quite unexpectedly high levels of active coping (e.g.
ignoring pain in the accomplishment of goals) was associated high
levels in pain outcomes this is the opposite of what is found in RA.
It was surmised that these findings reflect a fundamental
difference between RA and FM. The
results indicate that "active coping in FM may unwittingly exacerbate
muscular and other physiological mechanisms that contribute to FM
pain" (71). Though FM
patients do need to "get on with their lives", such flip-advice
is not a constructive substitute for management advice based on a careful
analysis of each patients dysfunctional profile.
can Disability be assessed in Fibromyalgia patients?
Let me start by stating a
truism: gainful employment is a powerful force in fulfilling one's
obligations to society, maintaining self esteem and achieving financial
security. It should be the
aim of rheumatologists to minimize disability in FM patients (72).
In utopia no one with FM will seek disability. However in real life we are all faced with disability forms
which ask for defensible opinions.
are 3 excellent reviews that expertly pinpoint the dilemma faced by
physicians as well as FM patients involved in the process of disability
evaluation (52,73,74). Hadler
has provided eloquent essays on the role of the diagnostic process and
disability evaluation as a prescription for reinforcement of illness
behavior (75,76). These
concepts are clearly relevant to some FM patients but such
generalizations are seldom constructive when considering the complexities
of the human dilemma.
are no validated instruments for assessing disability in FM patients.
The most useful practical resource is the American Medical
Association Guides to the Evaluation of Permanent Impairment (77).
Chapter 15 provides a balanced approach to assessing impairment in
patients with chronic pain states. As
an overview to the problem it states: (1) pain evaluation does not lend
itself to strict laboratory standards of accuracy;
(2) the evaluation of chronic pain cannot be made on the basis of
the degree of tissue damage the classical medical model;
(3) pain evaluation requires a thorough understanding of a
multi-faceted biopsychosocial model of disease (78);
(4) the physicians judgment of impairment represents a blend of the
art and science of medicine, and judgment must be characterized not so
much by scientific accuracy as by procedural regularity.
It acknowledges that physicians are often uncomfortable in
evaluating chronic pain states, but notes that they regularly make
decisions on the basis of probabilities backed up by experience and stated
in terms of reasonable medical probability.
uniform approach to gathering data on which to base judgments of
reasonable medical probability is required.
Goldenberg et al. have recently provided a model to assess the
severity and impact of FM (79). Out
of 15 factors analyzed they found the following to be significantly
associated with severity and impaired functional status: pain level,
self-assessed disability, psychological distress, pending litigation,
educational level, helplessness and poor coping strategies.
A suggested flowchart for the assessment of disability in FM is
provided in figure 2. It is
recommended that patients have an independent psychological evaluation and
occupational therapy evaluation (where available), and that assessors use
validated questionnaires that have proven useful in evaluating FM.
Such instruments include: the Health Assessment Questionnaire (HAQ)
(67), the Fibromyalgia Impact
Questionnaire (FIQ) (80), the Coping Strategies Questionnaire (CSQ) (81),
the Beck Depression Inventory (82,83) and the Quality of Life Scale (84).
evaluation in FM patients can only be made in terms of the biopsychosocial
model of disease (78) and stated in terms of reasonable probability. Some
physicians will feel always uncomfortable in the assessment of chronic
pain (85), others will not have acquired the broad knowledge base
necessary for understanding the biopsychosocial concept of disease. It is preferable that both groups excuse themselves from the
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