Question of the Week

Infective endocarditis has an estimated incidence of 1.5 – 3.3 cases per 1000 IV drug users per year.  The risk appears to be augmented when the injected substance is which drug of abuse?  Why?

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10 Responses

  1. Cocaine – it’s more thrombogenic as it causes an enhanced response of platelets to arachidonic acid.

  2. Staphylococcus Aureus, (Rosens pg. 1069-1070)

  3. heroin/speedball injection

  4. interesting – i think this has several good answers.
    1. according to an article from 1987, injection of cocaine causes vasospasm causing more skin damage, a larger portal for bacteria and repeated injections leading to more chances for badness

    2. according to another article from 1992…the higher incidence is caused by direct damage to the valves by talc that is cut into the cocaine

    either way – coke is bad and you will die a slow painful death

  5. Cocaine.

    The exact mechanism is unknown, but it’s thought that it causes endothelial damage that also predisposes the tissue to infection. There is also some association with the usage patterns with the cocaine vs other injection drugs that predispose to endocarditis.

    Regardless, if you’re injecting cocaine, bacterial endocarditis is one of the least of your concerns!

  6. Cocaine

    Vasospasm or increased number of injections

    Cocaine use and the risk for endocarditis in intravenous drug users.
    Chambers HF, Morris DL, Täuber MG, Modin G.
    Ann Intern Med. 1987 Jun;106(6):833-6.


  7. Cocaine is associated with and increased risk of infective endocarditis in IV drug users. In IV cocaine drug abusers’ endocarditis involves left-sided valves more often.

    Why? No one knows! Several sources verify this:

    1. The New England Journal: “The reason for this enhanced risk of endocarditis in cocaine users is unknown.”
    -Lange, RA et al. “Cardiovascular complications of cocaine use”. N Engl J Med 2001; 345:351-358

    2.The original report of this: “Logistic regression analysis showed cocaine use to be strongly associated with endocarditis. This special risk involving cocaine use has not been reported previously; the explanation for it may provide insight into the pathogenesis of endocarditis.”
    -Chambers, HF et al. “Cocaine Use and the Risk for Endocarditis in Intravenous Drug Users” Annals of Internal Medicine. June 1, 1987
    vol. 106 no. 6 833-836.

    “For unknown reasons, cocaine use has been observed as a greater independent risk factor for the development of endocarditis when compared with the use of other drugs”.
    -Kazimir, M et al. “Cardiomyopathy, Cocaine”. http://emedicine.medscape.com/article/152535-overview.

  8. I hate to cheat, but based on the varying estimates regarding the incidence of endocarditis, I think there are two answers: (1) the incidence tends to be lower in IV heroin because heroin base is non-water soluble and has to be “cooked” in order to get the liquid form – this heating potentially lowers the burden of bacteria the immune system has to deal with. (2) the incidence of cocaine associated endocarditis is higher because of the short duration of action requiring more frequent dosing.

  9. Cocaine

    From RA Lange 2001 NEJM Cardiovascular Complications of Cocaine Use
    “The elevation of the heart rate and systemic arterial pressure that accompanies cocaine use may induce valvular and vascular injury that predisposes users to bacterial invasion. The immunosuppressive effects of cocaine may increase the risk of infection. Alternatively, the manner in which cocaine is manufactured, as well as the adulterants that are often present in cocaine, may increase the risk of endocarditis.”

  10. Injection of Cocaine actually can augment more IE due to cocaines ability to induce vasospasms which damaging endothelium. making it easier for injected bacteria to attach.

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