Classification & Diagnosis
Vaginal Muscle Spasm
In her 1547 treatise on 'The Diseases of Women', Trotula of Salerno is thought to have provided the earliest description of what we today call vaginismus: 'a tightening of the vulva so that even a woman who has been seduced may appear a virgin'. Much later, Huguier gave the first medical description of the syndrome; however, it appears that Sims first coined the term 'vaginismus' in 1862 while addressing the Obstetrical Society of London. Sims described vaginismus as 'an involuntary spasmodic closure of the mouth of the vagina, attended with such excessive supersensitiveness as to form a complete barrier to coition'. To date, the involuntary muscle spasm remains the core element of the definition of vaginismus suggested by the American College of Obstetrics and Gynecology (ACOG) and by the Diagnostic and Statistical Manual of Mental Disorders-IV-TR (DSM-IV-TR).[1,16] The International Classification of Diseases (ICD)-10 categorizes vaginismus either as a 'pain disorder' or as a 'sexual dysfunction comprised of a spasm of the pelvic floor muscles that surround the vagina, causing the occlusion of the vaginal opening with penile entry being either impossible or painful'.
This 150-year consensus concerning the definition of vaginismus is striking given the lack of empirical findings validating the vaginal muscle spasm criterion. In fact, Reissing et al. (n = 87) found that although vaginismic women demonstrated a greater frequency of vaginal muscle spasm while undergoing a gynecological examination than did age, relationship and parity matched healthy controls or women suffering from dyspareunia associated with provoked vestibulodynia (PVD), only 28% of the vaginismus group actually displayed a vaginal muscle spasm. Moreover, only 24% reported experiencing spasms with attempted intercourse. Even more puzzling was the finding that two independent gynecologists agreed only 4% of the time on the diagnosis of vaginismus. These findings call into question the primary diagnostic criterion of vaginismus.
Another method of evaluating the validity of the vaginal muscle spasm criterion is via the electrical recording of muscle activity, which can be done through surface electromyography (sEMG) or needle electromyography. Recent sEMG and needle EMG studies have investigated the activity of the pelvic floor muscles in women diagnosed with vaginismus. Reissing et al. found that women with vaginismus displayed lower pelvic floor muscle strength and greater vaginal/pelvic muscle tone compared with matched controls but no significant differences at all between the vaginismus and PVD group.[18,19] Shafik and El-Sibai (n = 14) also demonstrated through needle EMG, a higher EMG activity at rest and on induction of the vaginismus reflex in the levator ani, puborectalis and bulbocavernosus muscles in women with vaginismus compared with age-matched controls. Consistent with the findings above, Frasson et al. (n = 30) found significant needle EMG basal and reactive hyperexcitability in primary lifelong vaginismus and in women with PVD accompanied by vaginismus as compared with controls. On the other hand, three well-controlled sEMG (ranging from 29 to 224) studies did not confirm a significant difference in ability to contract and relax the pelvic floor muscles between women with and without vaginismus.[22–24]
These contradictory results may be partially explained by the lack of an operationalized definition of the term 'muscle spasm' as well as the lack of consensus regarding which muscles are involved in vaginismus. Some authors refer to broad groups of muscles such as the muscles of the outer third of the vagina, the pelvic muscles or the circumvaginal and perivaginal muscles,[25–29] while others refer to more specific ones, such as the bulbocavernosus, the levator ani and puboccoccygeus.[30,31] None of these studies indicate how they concluded which muscles are involved. The term spasm itself is also controversial as there is no agreement on whether spasm refers to an involuntary muscle cramp, a defensive mechanism or a hypertonicity of the pelvic floor muscles.
In addition to the lack of agreement regarding the term muscle spasm and the muscles involved in vaginismus, there is no empirically standardized diagnostic protocol for vaginal muscle spasm. Although Masters and Johnson claimed that a pelvic exam was necessary to diagnose vaginismus, researchers and clinicians have frequently relied on self report of difficulties with vaginal penetration.[2,32] The lack of a standardized diagnostic protocol is not a trivial problem since studies concerning vaginismus may well include highly diverse samples. The fact that studies using the vaginal muscle spasm DSM-IV-TR definition of vaginismus failed to find a vaginal spasm suggests that vaginal muscle spasm is not a reliable diagnosis and as a result diverse patient populations might have been included.[21–24]
Even though vaginismus is classified as a sexual pain disorder in the DSM-IV-TR, pain is not mentioned in the diagnostic criteria. Other definitions of vaginismus such as those published by the ACOG, the International Association for the Study of Pain (IASP), the WHO and Lamont do mention pain in their definitions.[17,33,34] However, no description of the pain characteristics, such as location, quality, intensity and duration are provided. There is also a lack of information regarding whether the pain is a cause or consequence of the vaginal muscle spasm. While most clinical reports and research concerning vaginismus do not make reference to the pain element in vaginismus, some authors believe that pain is one of its core components.[10,18,36–40] In fact, several studies have found that a large percentage of women suffering from vaginismus experience pain with attempted vaginal penetration.[18,25,35,37,40–43] The pain experienced by women with vaginismus has been found to be very similar to the pain reported by women with PVD.[18,40,42]
According to the DSM-IV-TR, vaginismus can be classified as either lifelong (primary) or acquired (secondary). It has often been suggested that PVD may result in acquired vaginismus.[31,34,44] Although lifelong and acquired vaginismus are generally considered to differ in their etiology and response to treatment, there are no empirical data validating these claims.
Differential Diagnosis of Vaginismus from Dyspareunia
According to the DSM-IV-TR, there are two mutually exclusive sexual pain disorders: vaginismus and dyspareunia. Dyspareunia is defined as 'recurrent genital pain associated with sexual intercourse'. PVD is reported to be the most frequent subtype of dyspareunia in premenopausal women with a prevalence of 7% in the general population.[45,46] Women with PVD typically experience a severe, sharp, burning pain upon vestibular touch or attempted vaginal entry.[45,47,48] It is diagnosed through the cotton-swab test, which consists of the application of a cotton swab to various areas of the vulvar vestibule and surrounding tissue.
Despite the fact that vaginismus and dyspareunia associated with PVD have been portrayed as two distinct clinical entities, they have many overlapping characteristics, such as the elevated vulvar pain and vaginal/pelvic muscle tone.[18,42] In fact, a number of studies have demonstrated that a large percentage (range between 42 and 100%) of women with vaginismus also meet the criteria for PVD.[18,24,41,42] This may explain, in part, why health practitioners (i.e., gynecologists, physical therapists and psychologists) show significant difficulties reliably differentiating vaginismus from PVD. It should be noted, however, that PVD is characterized superficial dyspareunia. The pain of deeper dyspareunia is usually easily differentiable from that associated with vaginismus. Women with vaginismus, however, were found to display significantly higher levels of emotional distress while undergoing a gynecological examination and to avoid significantly more sexual and nonsexual vaginal penetration attempts as compared with women with PVD.[18,37,42]
Clinical reports have long suggested that fear plays an important role in vaginismus.[3,16,47–50] Only a few studies have investigated this further.[50–53] For example, fear of pain was the primary reason reported by women with vaginismus for their abstinence as well as the core motive underlying their avoidance of sexual intercourse.[18,53] Moreover, a large percentage (range between 74 and 88%) of women with vaginismus report significant fear of pain during coitus.[50,53] Women suffering from vaginismus share a number of characteristics with individuals suffering from a 'specific phobia'. Specific phobias are defined as 'marked and persistent fear that is excessive or unreasonable, cued by the presence or anticipation of a specific object or situation'. Individuals with a specific phobia will experience feelings of anxiety, fear or panic upon encountering the feared object or situation. As a result, they will tend to actively avoid direct contact with the phobic stimulus. Women with vaginismus report fear of vaginal penetration and associated pain and display high levels of emotional distress during vaginal penetration situations, such as during gynecological examinations.[18,50] Women with vaginismus also tend to avoid situations involving vaginal penetration (i.e., gynecological examination, tampon insertion and sexual intercourse).
It still remains unknown, however, whether vaginismic women avoid these particular situations in order to diminish their anxiety level similar to individuals suffering from a specific phobia, or in response to their pain experience, or both. Nonetheless, the avoidance of vaginal penetration cannot be solely explained by the experience of pain since women with dyspareunia, who also experience severe pain during vaginal penetration, have not been shown to avoid vaginal penetration situations as much as women suffering from vaginismus.[18,42] Although fear appears to be a promising factor that characterizes women with vaginismus, the existing empirical studies lack appropriate control groups, standardized instruments to measure fear and appropriate statistical analysis.[50–53]
Women's Health. 2010;6(5):705-719. © 2010
Future Medicine Ltd.