Warfarin-induced skin necrosis in HIV-1-infected patients with tuberculosis and venous thrombosis

• Published in: South African medical journal Vol. 100; no. 6; pp. 372 - 377
• Main Authors: BHAIJEE, F, WAINWRIGHT, H, MEINTJES, G, WILKINSON, R. J, TODD, G, DE VRIES, E, PEPPER, D. J
• Format: Journal Article
• Language: English
• Published: Rondebosch Health and Medical Publishing Group 01-06-2010; Health & Medical Publishing Group
• Subjects: Acinetobacter; Adult; Anticoagulants - adverse effects; Bacterial diseases; Biological and medical sciences; Care and treatment; Comorbidity; Complications and side effects; Dosage and administration; Escherichia coli; Female; General aspects; HIV Infections - epidemiology; HIV patients; Human bacterial diseases; Human immunodeficiency virus 1; Human viral diseases; Humans; Infectious diseases; Klebsiella pneumoniae; Medical sciences; Mycobacterium; Necrosis; Necrosis - chemically induced; Retrospective Studies; Risk factors; Skin - drug effects; Skin - pathology; Staphylococcus aureus; Tuberculosis; Tuberculosis - epidemiology; Tuberculosis and atypical mycobacterial infections; Tuberculosis, Pulmonary - epidemiology; Venous thrombosis; Venous Thrombosis - epidemiology; Viral diseases; Viral diseases of the lymphoid tissue and the blood. Aids; Warfarin; Warfarin - adverse effects; South Africa; Immunopathology; Warfarin; Cardiovascular disease; AIDS; Anticoagulant; Mycobacterial infection; Immune deficiency; Venous disease; Necrosis; Infection; Vascular disease; Tuberculosis; Viral disease; Bacteriosis; Tropical medicine; Skin; Venous thrombosis
• ISSN: 0256-9574; 2078-5135
• DOI: 10.7196/SAMJ.3565

At the turn of the century, only 300 cases of warfarin-induced skin necrosis (WISN) had been reported. WISN is a rare but potentially fatal complication of warfarin therapy. There are no published reports of WISN occurring in patients with HIV-1 infection or tuberculosis (TB).
We retrospectively reviewed cases of WISN presenting from April 2005 to July 2008 at a referral hospital in Cape Town, South Africa.
Six cases of WISN occurred in 973 patients receiving warfarin therapy for venous thrombosis (0.62%, 95% CI 0.25 - 1.37%). All 6 cases occurred in HIV-1-infected women (median age 30 years, range 27 - 42) with microbiologically confirmed TB and venous thrombosis. All were profoundly immunosuppressed (median CD4+ count at TB diagnosis 49 cells/microl, interquartile range 23 - 170). Of the 3 patients receiving combination antiretroviral therapy, 2 had TB-IRIS (immune reconstitution inflammatory syndrome). The median interval from initiation of antituberculosis treatment to venous thrombosis was 37 days (range 0 - 150). The median duration of parallel heparin and warfarin therapy was 2 days (range 1 - 6). WISN manifested 6 days (range 4 - 8) after initiation of warfarin therapy. The international normalised ratio (INR) at WISN onset was supra-therapeutic, median 6.2 (range 3.8 - 6.6). Sites of WISN included breasts, buttocks and thighs. Four of 6 WISN sites were secondarily infected with drug-resistant nosocomial bacteria (methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter, extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae) 17 - 37 days after WISN onset. In 4 patients, the median interval from WISN onset to death was 43 days (range 25 - 45). One of the 2 patients who survived underwent bilateral mastectomies and extensive skin grafting at a specialist centre.
This is one of the largest case series of WISN. We report a novel clinical entity: WISN in HIV-1 infected patients with TB and venous thrombosis. The occurrence of 6 WISN cases in a 40-month period may be attributed to (i) hypercoagulability, secondary to HIV-1 and TB: (ii) short concurrent heparin and warfarin therapy; and (iii) high loading doses of warfarin. Active prevention and appropriate management of WISN are likely to improve the dire morbidity and mortality of this unusual condition.