Fibromyalgia is a diffuse polyalgesic syndrome that has been evolving for at least 3 months and is associated with many other signs for which there is no unanimous pathophysiological hypothesis to date [9, 10].
In the present study, the frequency of fibromyalgia was 10.8%. This frequency seems to agree with the data in the literature suggesting a high prevalence of around 10–20% in rheumatology consultations [11]. This frequency is relatively higher than that found in general medical consultations (4 to 6%) and the general population (1 to 2%), as in France 1.4%, the USA 2%, Spain 2.4%, Italy 2.2%, Finland 0.75% and Denmark 0.66% [12]. These differences could probably be explained by the screening procedures, the diagnostic criteria used and the significant influence of secondary fibromyalgia cases in rheumatology consultations.
Women were twice as often affected as men, as has been shown in several studies throughout the world [13]. In the USA, fibromyalgia is 7 times more frequent in women (3.4%) than in men (0.5%), in Spain it is 20 times more frequent in women (4.2%) than in men (0.2%) and in Finland it is twice as important in women (0.98%) as in men (0.48%). This preponderance of women seems to be the result of several factors involving a supposed female susceptibility to pain, different psychological and socio-cultural experiences of pain, but also mechanisms of amplification and neurological inhibition of pain with a genetic or hormonal support [13, 14].
The mean age of the study population was 50.9 ± 12.4 years, results similar to the series of Girard in Switzerland [15], Aïni [16] in France and Guich in Morocco [17] with mean ages of 50 ± 9.8, 50.4 ± 6.9 and 57 ± 11.5 years respectively. 50.2% of the fibromyalgia patients were older than 50 years in the present study. In France, Jasson [18] found 65.7% of patients to be over 50 years of age. These data are in agreement with the literature which describes that fibromyalgia frequently appears in early or middle adulthood and its incidence tends to increase with age.
The diagnosis of fibromyalgia in the present study was made on the basis of the ACR 2010 criteria with a mean diagnostic score of 17.3 ± 3.6. This score includes a mean of 11.6 ± 2.9 for painful areas and 6.1 ± 1.7 for psychosomatic signs. The psychosomatic signs, including almost constant fatigue (93.7%), had been present for an average of 45.3 ± 22.9 months. They often arrived before the painful manifestations (24 ± 11.6 months), and led the patients to a long period of medical wandering with 5.2 ± 1.6 doctors consulted. These results are close to the series of Jasson [18] in France who found an average of 6 doctors consulted. It appears that in the majority of fibromyalgia patients, psychosomatic signs are present well before the onset of the diffuse polyalgesic syndrome characterizing the state period of the disease. In order to allow an early diagnosis, it would be necessary to institute a systematic search for these warning signs in all rheumatic patients with polyalgia who are refractory to the usual treatments [19–21].
Emotional stress was the triggering factor for fibromyalgia in 44.4% of cases, and its clinical manifestations were regressive in only 12.7% of cases. The basic psychological state of the patients was dominated by anxiety (41.3%). The aggravating factor was anxiety in 34.9% of the cases and the predominant factor of improvement was resting in calm (42.9%). Guich [17] in Morocco reported a feeling of injustice in 41.7% of the fibromyalgia patients in his series, whereas Alagnide [22] in Benin found the anxiety-depression syndrome to be the main etiological factor in 95% of the patients. All these data prove that there is a very important psychological component in this pathology, which sometimes explains the failure of isolated drug therapies. It is therefore necessary to have a multidisciplinary approach to the patients concerned, including psychological, medico-social and physical care [23–27].
Disability as the ultimate consequence of the negative evolution of fibromyalgia was found in 60.3% of cases. Jasson [18] in France and Alagnide [22] in Benin found a clear disruption of socio-professional life in 63% and 80% of patients. This disability associated with fibromyalgia is frequently reported in several studies and in the literature. It is often correlated with the importance of the painful areas and the duration of the symptoms [28–30]. In the present study, no factor was associated with the severity of the disease. This data should be considered with caution given the small sample size.
This series of clinical cases is the very first study which reports the frequency of fibromyalgia in the Congolese environment, its clinical characteristics and impact on rheumatic patients. Particular attention should be paid to it because fibromyalgia remains an under-diagnosed pathology in daily practice [31–33]. The present study showed a significant frequency of the disease using a current diagnostic tool with high sensitivity and specificity. However, the small sample size remains the major factor that can limit the extrapolation of the results of the present work, which require large-scale studies for their confirmation.