Transcript of VPS Podcast 5 - Vulvodynia: a podcast lecture by David Nunns

Slide 11 (07:59) Vulvodynia – an overdiagnosis?

I think it’s important to cover the skin problems before moving on to vulvodynia because sometimes a diagnosis of vulvodynia can be given to a patient and a subtle skin problem can be overlooked. This paper was published in 2008 by Bowen et al from an American clinic where vulval biopsy was carried out on most of the patients attending the clinic who had vulval pain. They found that in 61% of women who were diagnosed by the referring clinician with vulvodynia, there was a clinically relevant skin problem, and this was often eczema, lichen sclerosus or irritant dermatitis. So I think it’s very important before a diagnosis of vulvodynia is given to do a proper assessment of the patient with a full history and examination.

Slide 12 (08:56) Vulvodynia

Vulvodynia is the term that we use to describe women who experience vulval pain in the absence of any skin disease or infection. These are not women who’ve got fissuring, or with lichen sclerosus, these are not women who’ve got evidence of vaginal infections. This is essentially a problem of the nerve endings, the nociceptors in the skin. This can produce an unprovoked pain picture, or a provoked pain picture, and in our up to date classification on this slide, we are going to want to try to identify where the patient feels pain. Is it clitoral pain, one-sided pain, or is it localised to the vestibule area? The term we used to use, ‘vestibulitis’, has now been replaced with a term called ‘vestibulodynia’, where there is pain on touch localised to the vestibule. Dynia means ‘burning’, and allodynia is the phenomenon when light touch produces a pain sensation.

Slide 13 (10:03) A spectrum of problems

I think there are good and bad things about having a diagnosis of vulvodynia. No doubt for the patient, this is a good thing, because it gives the woman a diagnosis, it allows her to focus perhaps on an appropriate treatment strategy related to the pain, and it would encourage doctors not to prescribe repeat antifungals to any women who’ve got chronic vulval pain. The disadvantages, however, of having a diagnosis of vulvodynia, are that you have a wide spectrum of pain perception in the women that we see, so that we have in one extreme, one woman with constant pain who is unable to move because of a vulval pain, perhaps needing strong pain relief. At the other extreme, you might get a woman who has a variable, even minimal amount of pain on touch in the vestibule, and this might just be during intercourse, but it is something that she can self-manage, and doesn’t require any medical intervention for. In the middle, you’ve got a wide variety of women who are coming towards health professionals wanting treatment for a pain problem. What I think may be happening is that when we see patients as doctors with vulvodynia, we give the diagnosis too soon, and launch into a treatment strategy, without really appreciating what is the individual impact on the woman of the pain. I think this is very important, because it’s that individual experience of pain that’s going to determine what sort of strategy you give to the patient for pain relief.

Slide 14 (12:02) Why does it develop?

We’re still not clear as to the cause of vulvodynia. We know that there is no subtle underlying infection in these patients; there is no hidden skin disease on biopsies, and there’s no evidence of a back problem that might be referring pain to the vulva, which is why we don’t do as a matter of routine vulval biopsies and MRI scans on patients who present with pain. What we do see in the histories of these women very regularly is a story of recurrent attacks of vulvovaginal thrush or cystitis-type problems. What we also know on biopsies taken from women with vulvodynia is that there is an increased number of nerve endings in the skin. So, the question is: does a past history of inflammation of the vulva lead to a chronic pain problem as seen in vulvodynia?

Slide 15 (13:12) Why does it develop? (continued)

There seems to be evidence now that a history of inflammation through recurrent thrush can lead to the problem of vulvodynia, at least in experimental animal studies. This is a study published in September 2011 and it involved giving mice recurrent attacks of vulvovaginal thrush, and treating them with Diflucan and antifungal. The aim of the experiment was to try and show whether an allodynia response or a vulvodynia-type picture would develop in mice with repeated attacks of thrush. The assessment of the mice to the recurrent attacks of thrush in terms of pain was using small monofilament von Frey fibres, which are used on the vulvas and, as a control, on the hind feet of mice, to try and demonstrate a response to pain by gentle pressure. What they found was that when the mice had two attacks of thrush treated by Diflucan, there was no allodynia response after these two infections subsided, but after a third attack of thrush and treatment, 40% of the mice continued with a sustained allodynia response.

In addition, in another experiment, there was a prolonged attack of thrush without treatment in the mice, which produced a sustained allodynia response in the mice. This suggests that recurrent attacks of thrush despite treatment can produce sustained changes in nerve ending function, i.e. allodynia. When the histology of the vulva was looked at, there was no evidence of inflammation, so this pain that was experienced was not related to inflammation, but they did find that there was an increase in nerve endings, i.e. a proliferation of nerve fibres in the skin.

When they tried to look at the allodynia response in another experiment in the mice by producing a similar reaction to the fungus and assessing the allodynia response, it was very variable and the question really is this: are there genetic reasons amongst the different mice to account for the variable response to allodynia? These are unknown questions, but it certainly seems from this study that inflammation is linked to producing an allodynia-type chronic pain problem that we see in vulvodynia in humans.