Subtypes of Provoked Vestibulodynia: A Prospective Study to Evaluate a Diagnostic Algorithm in Regard to Different Treatment Modalities

Background Provoked vestibulodynia (PVD) is the term describing a syndrome of provoked, localized allodynia of the vestibule of the vulva, not explained by another condition, and lasting more than 3 months. PVD is not a defined disease but rather a symptom. It is thought that PVD represent a group of distinct disorders that have been classified together because they produce pain in the same anatomic location. Causes of these disorders include hormonal imbalance, mainly caused by hormonal contraception, nerve fiber proliferation in the vestibular mucosa and hypertonic pelvic floor dysfunction. PVD may appear with sexual debut or first attempts to insert a tampon (primary PVD) or can be a new onset of pain with activities that did not previously illicit pain (secondary PVD).

Studies found that different factors such as genetic, inflammatory mediators, recurrent vaginitis, allergy and trauma may be involved in the development of PVD. A high percentage of patients with vulvar pain report an antecedent history of vulvovaginal candida infection, although it is unknown if this represents a true increase in incidence or a misdiagnosis. It has been suggested that repeated vulvovaginal infections are a triggering event for some women leading to chronic vulvar pain. This observation has led to hypothesis that in patients with neurogenic vulnerability, an initiating event or series of events may lead to chronic vulvar pain.

Treatment of vulvodynia is generally predicated on a trial and error basis, because the pathogenesis is not defined. The result is that many forms of therapeutic interventions have been used, yet the evidence remains largely inconclusive, the response rate varies between 40-85%, and many women do not respond to any of the treatments. Unfavorable outcomes to therapy can be explained by grouping patients with different conditions under one diagnosis, and then studying an intervention that might only help one subset of the conditions. This can lead to an apparent lack of effect, due to dilution of the patient subpopulations.

A different approach to diagnosis and treatment of PVD was suggested by Dr. Andrew Goldstein. He classifies PVD into groups, based on history and examination findings:

1. Hormonally mediated PVD - The pain began while taking hormonal contraceptive or other medications that affect hormones, after removal of ovaries, breastfeeding or menopause. Typically, patients have a low calculated free testosterone and complain of dryness and decreased libido. The entire vestibule is tender and vestibular mucosa is often dry and thin. Treatment includes stopping hormonal contraception and application of topical estradiol with testosterone to the vestibule.
2. Hypertonic pelvic muscle dysfunction - In this subgroup, pelvic floor (PF) muscles become tight and tender. Patients often have other symptoms suggesting hypertonicity (urinary frequency, urgency and hesitancy, constipation, hemorrhoids and anal fissures), and predisposing factors, such as musculoskeletal disorders or anxiety may coexist. Typically, the pain is much worse at 4-8 o'clock position of the vestibule with minimal or no pain in the upper vestibule. Treatment includes PF physiotherapy, with an optional addition of muscle relaxants (valium suppositories and Botulinum toxin injections).
3. Neuroproliferative PVD- In this condition, women have an increased number of nociceptors in the vestibular mucosa. This group is further subdivided into congenital and acquired forms. In the congenital subgroup, vestibular pain has always been present, and there may be sensitivity to palpation of the belly button (which is an evidence of a congenital neuronal hyperplasia within the tissue derived from the urogenital sinus). With acquired neuroproliferative PVD, the pain may begin after a severe allergic reaction or vaginitis. There is tenderness of the entire vestibule. Treatments include topical anaesthetics, antidepressants, antiseizure drugs, capsaicin cream and vulvar vestibulectomy.