Although this middle-aged and IVDU woman had been under antiretroviral treatment and presented three events of DVT (2008, 2009, and 2010), thromboprophylaxis was not done. Her diagnosis of recurrent DVT was characterized by clinical data and comparative imaging studies by USS, and a full anticoagulation schedule was utilized with success. Complications related with IVDU may affect veins, arteries, and lymphatic vessels, including ischemia and pseudoaneurism due to intraarterial injection, vasculitis, artery dissection, arterial-venous fistulae, compartment syndrome, DVT, thromboflebitis, soft-tissue infections, bacteraemia, and sepsis.[
2–
4,
6]
Recently, low serum levels of the C and S proteins and high levels of homocysteine were reported by Basavanagowdappa
et al. in a 27-year-old Indian male with HIV infection and normal CD4.[
7] Although the involved mechanisms are not entirely clear, HIV is an independent risk factor for venous thrombosis. The prothrombotic state observed in HIV-infected patients has been associated with antiphospholipid antibodies, aspartyl protease, endothelial and platelet activation, low levels of C and S proteins, and lupus anticoagulant.[
5–
7] In spite of controversies, the highly active antiretroviral therapy and protease inhibitors may cause thromboembolic events.[
5] The risk of thrombosis can increase in patients with AIDS due to systemic inflammatory response and comorbidities such as immobility, infections, and malignancies.[
4–
7] Cooke and Fletcher reviewed the data about DVT among 109 patients in England; 33 of the IVDU group and 76 of the non-IVDU group (median ages were 29 and 51 years, respectively).[
1] Although the exact rate of recurrences could not be monitored, the recurrent DVTs were more frequent in patients from the IVDU group. One possible explanation was the shorter duration of anticoagulation to avoid hemorrhagic events in this group of patients.[
2] Irish
et al. reviewed data from the United Kingdom Department of Health about skin, soft tissue, and vascular complications among drug users and found a conspicuous increase in hospitalization. They emphasized the role of injections in femoral vessels (groin injecting), which may cause superficial phlebitis, DVT, and arterial pseudoaneurisms in lower limbs.[
3] Similar phenomena were observed in the patient here reported. Saber
et al. reviewed data of 45 patients in New York with HIV/AIDS and DVTs in the lower limbs and found recurrent episodes of thrombosis in 26.7% of the cases. The patient's mean age was 43 years and 55.5% of the DVTs had caused femoral or iliofemoral obstructions.[
8] The authors concluded that HIV/AIDS constitutes a main risk factor for DVTs in lower limbs, and this condition occurs near 10 times more often than in general population.[
8]