177High Subjectivity
Given the fact that the symptoms of FMS are numerous and very subjective, and that
there are no objective measures of disease evolution, such as biomarkers, the fol-
low- up of FMS patients is complex. The following are the most typical symptoms
present in FMS and a brief description of how they appear in the clinic.
Pain , as already noted, is a major symptom in FMS. It is typically widespread—
whole body aches—and causes signifi cant reduction in quality of life. It is often
described as chronic and both “electrical” and “tingling,” as it is often accompanied
by paresthesia [ 20 ]. Notwithstanding, pain varies widely in intensity and quality
from one patient to another.
Fatigue is another landmark in FMS. It can be physical (i.e., lack of energy,
physical exhaustion), emotional (i.e., lack of motivation), or cognitive (inability to
think or concentrate). Fatigue impacts on virtually any aspect of living, such as the
ability to work, meet family needs, or engage in social activities [ 21 ]. Patients
describe fatigue as “an inescapable or overwhelming feeling of deep physical tired-
ness,” “weakness in the muscles,” “an uncontrollable, unpredictable constant state
of never being rested,” “a ghastly sensation of being totally drained of every fi ber of
energy,” “not proportional to effort exerted,” “not relieved by rest,” and as “an invis-
ible foe that creeps upon (them) unannounced and without warning” [ 22 ].
Sleep. The FMS impact on slee p was defi ned in OMERACT (Outcome Measures
in Rheumatology Clinical Trials) as diffi culty falling asleep and staying asleep, and
getting unrefreshing sleep [ 23 ]. More than 70 % of patients with FMS complain of
poor sleep quality and associate this with feeling tired and diffi culty in performing
physical activity [ 24 ].
Cognitive impairment. Cognitive diffi culties —specifi cally, longer reaction
times, short-term memory defi cits, and attention problems—are 2.5 times more
prevalent in patients with FMS than with any other rheumatic condition. It has been
estimated that 76.4–82.5 % of persons with FMS in a rheumatology practice may
complain of cognitive diffi culties [ 25 , 26 ]. More than half of the persons with FMS
report “mental confusion,” now termed as “fi brofog,” which in some cases may be
more worrisome than pain [ 27 ]. Patients describe this state as “looking at life as
through a haze” [ 27 ]. Patients with FMS have limited working and long-term mem-
ory, and this limitation is independent of, or on top of, anxiety or depression [ 28 ,
29 ]. Consequences of this limitation are a decline in attention and in executive func-
tion [ 25 ].
Gender Issues
FMS is believed to be a disease of women; however, the new classifi cation has
brought up a high prevalence in men as well [ 30 ]. Several studies have analyzed the
differences of the syndrome between men and women. Apparently, men have lower
7 PROMs for Fibromyalgia