Background Hypermobility represents the excessive mobility of the joints. Joint hypermobility syndrome (JHS) is defined as the musculoskeletal symptoms in individuals with hypermobility in the absence of any systemic rheumatic disease, and the incidence in the general population is about 0.5%. A biochemical or structural disorder affecting collagen synthesis is assumed as an underlying mechanism in hypermobility syndrome. In animal studies, bilirubin has been shown to reduce fibrosis induced by bleomycin. In these studies, it is suggested that bilirubin leads to hypermobility by affecting the structure or function of collagen. In addition, our observation in clinical practice is that hypermobility and acrocyanosis is more common in patients with indirect hyperbilirubinemia.
Objectives This study aimed to evaluate the frequency of hypermobility and acrocyanosis in patients with indirect hyperbilirubinemia.
Methods The study recruited 120 consecutive patients with indirect hyperbilirubinemia examined in gastroenterology outpatient clinics of a university hospital and 107 healthy individuals as a control group with normal bilirubin levels. Patients were examined for the presence of hypermobility and acrocyanosis. Hypermobility was determined by using Beighton scoring (Score, 0–9). To conclude whether the JHS was present, Brighton criteria were used. Acrocyanosis was identified by history and compatible physical examination.
Results The mean age of the patients and the control group enrolled in the study were 33.4 ± 12.9 and 36.2 ± 11.2 years, respectively (p=0.09). 100 of the patients (83%) and 78 (73%) of the control group of were males (p=0.075). The average indirect bilirubin levels of the study and control groups were 1.44 ± 0.66 mg/dL and 0.37 ± 0.18 mg/dl, respectively. By Beighton scoring, 23 patients (19.2%) in the study group and 3 (2.8%) individuals in the control group had joint hypermobility. The difference between groups was statistically significant (p<0.001). 4 patients in the study group and 1 individual in the control group had JHS, and the difference was not statistically significant (p=0.220). In 35 (29.2%) of study patients and 12 (11.2%) individuals in the control group had acrocyanosis. The difference between groups was statistically significant (p=0.001). Joint hypermobility did not have any significant relationship with the presence of acrocyanosis (p=0.441).
Conclusions According to the results of our study, joint hypermobility and acrocyanosis is more frequent in patients with indirect hyperbilirubinemia compared to controls. This finding suggests that bilirubin has a role in both diseased. It should be determined whether they share a common or difference pathogenic pathway.
Beighton P, Solomon L, Soskolne CL. Articular mobility in an African population. Ann Rheum Dis. 1973;32(5):413–8.
Disclosure of Interest None declared