Factor V Inhibitor: Report of a Case, with Comments on a Possible Effect of Streptomycin

A 78-year-old woman developed, postoperatively, a spontaneous, transient factor V inhibitor. She is the third patient with this inhibitor that we have seen and the seventh patient reported in the English-language literature. She did not bleed severely, despite major surgery after discovery of the inhibitor. Because clinical bleeding in the other reported patients also was mild and the inhibitor disappeared spontaneously without specific therapy we believed that treatment should only be supportive. With specific antiserums, the inhibitor was characterized as a heterogeneous IgG antibody. The mechanism leading to its development is unknown, but a possible relation with the administration of streptomycin is discussed.