Osteonecrosis (ON), or avascular necrosis of bone, has been related to decreased blood flow to the bone. Many local and systemic factors have been implicated in the pathogenesis of ON, involving corticosteroid therapy, systemic lupus erythematosus (SLE), hemoglobinopathies, alcohol abuse, Caisson disease, Gaucher disease, and hypercoagulability states. We describe the case of a previously healthy young male with no history of corticosteroid therapy, who developed ON initially on the femoral head, and later on the humeral head with high levels of anticardiolipin antibodies (aCL), beta-2-glycoprotein 1 antibodies and positive lupus anticoagulant. The association between primary antiphospholipid syndrome (PAPS) and ON is controversial and few cases without other risk factors have been described. A review of ON pathogenesis and its relation with thrombotic microangiopathy because of PAPS is presented.

In 2014, the chikungunya virus reached Colombia for the first time, resulting in a nationwide epidemic. The objective of this study was to describe the demographics and clinical characteristics of suspected chikungunya cases. Chikungunya infection was confirmed by enzyme-linked immunosorbent assay and 548 patients where included in the study. Of these patients, 295 were positive for antibodies against chikungunya (53.8%), and 27.6% (151/295) were symptomatic for chikungunya infection, with a symptomatic:asymptomatic ratio of 1.04:1. Factors associated with infection included low income and low socio-economic strata (odds ratio [OR]: 1.8; 95% confidence interval [CI]: 1.0–3.2, p = 0.003 and OR: 2.1; CI: 1.3–3.4, p = 0.002, respectively). Confirmed symptomatic cases were associated with symmetric arthritis (OR: 11.7; CI: 6.0–23.0, p < 0.001) of ankles (OR: 8.5; CI: 3.5–20.9, p < 0.001), hands (OR: 8.5; CI: 3.5–20.9, p < 0.001), feet (OR: 6.5; CI: 2.8–15.3, p < 0.001), and wrists (OR: 17.3; CI: 2.3–130.5, p < 0.001). Our study showed that poverty is associated with chikungunya infection. Public health strategies to prevent and control chikungunya should focus on poorer communities that are more vulnerable to infection. The rate of asymptomatic infections among confirmed cases was 48.8%. However, those with symptoms displayed a characteristic rheumatic clinical picture, which could help differentiate chikungunya infection from other endemic viral diseases.