No dental antibiotic prophylaxis for VP shunts.

During a routine clinic follow-up, a patient with an indwelling ventriculo-peritoneal shunt enquires whether prophylactic antibiotics are necessary prior to routine dental hygiene work. He produces a letter from his dentist enquiring the same.

Dr Max Nathan of Morriston Hospital, Swansea, UK has had this happen … has it happened to you? And what did you do?

(I think it raises some interesting questions – how much do we need to worry vs how much do we need to know about ‘something’ before we act? If you already advise to take, what would it take to stop you? If you advise to avoid, how much data would you need to change your mind?)

[Edit – 27 March 2008]

Since first posting,  in February, the BNF committee has produced new guidance highlighting the ineffectiveness of antibacterial prophylaxis for preventing bacterial endocarditis. This accords with the findings of Dr Nathan and colleagues.

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  • iwacogne

    I’ve not come across this question before, although I can understand why it has been asked. However, I wonder if things have got a little muddled with this dentist…

    – we know that if you brush your teeth you get a bacteraemia, moreso if you do more aggressive stuff to teeth
    – we know that if you’ve got turbulent flow or artificial devices in your heart that there can be patches where bacteria find it easier to settle
    – we know, therefore, that you need antibiotics to prevent bacterial endocarditis in this situation.

    However, with a VP shunt, what is the proposed mechanism? (I could understand a little more if it were a VA shunt, but I haven’t seen one of those in years.) It would make more sense if we were talking about a portacath or something indwelling in the bloodstream – Bob, you use those all the time, do you advise bacterial prophylaxis?

    Do VP shunts get infected by haematogenous spread? Well, I guess so, although it would be hard to prove precisely the route of each infection.

    So, the interesting thing I’d like to see answered is: is there a plausible mechanism for increased infection rate, and if there is, what’s the risk? And how does that compare to the (admittedly trivial) risk of a dose of antibiotics.

  • bphillips

    Ian – there is a feeling that you can get haematogenous spread of bugs into/onto VP shunts (though exactly how they did this – I can’t imagine your average Staphlococcus answering such a question – I’m unsure about). Somewhere around 10-15% of shunts get infected mostly in the first year of placement; I don’t know what proportion have an ‘identified source’.

    I have never considered antibiotic prophylaxis for someone with a Port-a-cath pre-dentistry. I must ask a dentist next time I see one.

    Now, back to the VP shunts: I agree that the core question has to be “How does the risk of prophylactic antibiotics compare with the risk of post-procedural shunt infection?”.

    (Out of interest – anyone know what the risk of endocarditis is for a simple VSD without prophylaxis, for example? Would give us a baseline on which to build any assessment of VP shunt prophylaxis.)

  • Jayne Harrison

    I have been asked the same question this week about ABC for extraction and/or for orthodontic treatment. What is the opinion/guidance now? jayne Harrison, consultant orthodontist

  • Undergoing treatments in my opinion really needs a lot of work not only on the actual treatment but on information gathering itself because patients need to understand what treatment they will be undergoing, the advantages and disadvantages so that in they don’t like the outcome of the treatment they can always cancel it.