Cytolytic Vaginosis

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Diagnosis and reasoning

This young lady has presented with an abnormal vaginal discharge for 3 months. The causes of vaginal discharge can be broadly classified into vaginitis, cervicitis, and neoplasms of the genital tract. While the above share many signs and symptoms, there are often characteristic clinical features which can help determine which of these is more likely. Thus, in this patient, the presence of vulvovaginal itching and dyspareunia along with the examination findings of a erythematous vaginal mucosa are most suggestive of vaginitis. The absence of a purulent exudate from the cervical os, or contact bleeding from cervix make cervicitis clinically less likely. Cervical cancer is the main neoplastic condition giving rise to vaginal discharge; while there are no obvious gross lesions to suggest this diagnosis, it should be noted that (in the early stages) examination findings can be normal; thus a pap smear is always advisable in these patients. Around 90% of cases of vaginitis are due to either trichomoniasis, bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC); recent studies have also identified cytolytic vaginosis and lactobacillosis as causative etiologies in around 5% of patients. The odorless discharge, presence of itching and acidic vaginal PH make bacterial vaginosis clinically less likely; the absence of clue cells upon microscopy, and negative whiff test provide further negative evidence. The discharge of trichomoniasis is typically yellow, green or grey, with a strong odor; in addition, the wet mount show no evidence of trichomonads, excluding this diagnosis. The presence of thick whitish discharge and vulvovaginal itching favors a clinical diagnosis of vulvovaginal candidiasis (VVC). Surprisingly enough though, no hyphae are seen in the wet mount; this instead shows the presence of a large number of intermediate epithelial cells with copious amounts of lactobacilli. This favors a diagnosis of either cytolytic vaginosis or lactobacillosis. However, note the presence of cytoplasmic debris (such as bare and naked nuclei); this is most suggestive of cytolytic vaginosis. In lactobacillosis, cytoplasmic debris are absent, while the lactobacilli appear as long, segmented chains (also known as leptothrix) and are usually less abundant. The worsening of symptoms around two weeks prior to menstruation is another characteristic in favor of cytolytic vaginosis. The management of cytolytic vaginosis is based on reducing the number of lactobacilli by increasing the vaginal pH; douching with Sodium Bicarbonate (NaHCO3) twice weekly for two weeks is typically employed. Discontinuation of tampon use is important, as the resulting menstrual flow will help increase the vaginal pH. Antimycotic treatment is not necessary here; as cytolytic vaginosis is not a sexually transmitted infection (STI), her partner need not be screened.


Cytolytic vaginosis, which was previously known as lactobacillus overgrowth syndrome or Doderlein's cytolysis, is an important cause of vaginal discharge, particularly in women who are otherwise healthy. To understand the pathogenesis of the condition, one needs to appreciate that Lactobacilli are a key component of the normal vaginal flora in healthy women of reproductive age. They help maintain an acidic vaginal pH (4.0-4.5), and also reduce overgrowth of E. coli, Candida spp., Gardnerella vaginalis and Mobilincus spp, via the production of hydrogen peroxide (H2O2). However, overgrowth may occur in some of these women; the abundant lactobacilli then damage the vaginal intermediate epithelium, causing lysis of those cells. The underlying etiology for the overgrowth is still unknown; however, patients with diabetes mellitus have an increased incidence, as Lactobacilli are more abundant in women with high serum glucose levels. Interestingly, lactobacilli levels have been observed to increase during the luteal phase; this explains why many of these patients experience an increase in symptoms during this time. While the true incidence is still unknown, cytolytic vaginosis is believed to account for around 1% to 5% of all vulvovaginal complaints. Unfortunately, the condition is often missed, as the symptoms and signs are suggestive of vulvovaginal candidiasis (VVC); thus, patients self-diagnose themselves inaccurately and medicate themselves with over-the-counter (OTC) antimycotics. As mentioned earlier, the symptoms of cytolytic vaginosis mimic those of VVC; thus, many of these patients present with a lengthy history, possibly due to previous misdiagnosis. They typically complain of a thick, odorless, white vaginal discharge and intense pruritus; dysuria and dyspareunia along with a sensation of vulvar burning or discomfort may also be present. Note that the symptoms of cytolytic vaginosis characteristically cyclical; they tend to increase in severity during the luteal phase with a peak shortly before the menstruation. The physical examination may reveal an erythymatous and edematous vaginal tissue; the cervix, uterus, and adnexa typically appear normal. The investigations required for diagnosis are relatively simple; these include microscopic examination, vaginal pH measurement, and any other investigations necessary to rule out the other differentials. Microscopy of a saline wet mount typically reveals a large number of intermediate epithelial cells, copious amounts of lactobacilli of varying lengths, and cytoplasmic debris (including bare or naked nuclei). Leukocytes are sparse or generally absent. Note that, some lactobacilli may adhere to the fragmented epithelial cells; this can be mistaken for the “clue cells” of bacterial vaginosis. The vaginal pH is typically acidic with a range of 3.5-4.5. In many patients, the diagnosis of cytolytic vaginosis can be challenging, due to the high degree of similarity to VVC. Thus, the following diagnostic criteria have been suggested: - Strong clinical suspicion of cytolytic vaginosis. - Absence of Trichomonas, Gardnerella or Candida on a wet smear. - An increase in the number of Lactobacilli. - A paucity of white blood cells. - Evidence of cytolysis. - The presence of a characteristic discharge. - A vaginal pH between 3.5-4.5. The key goal of management is to restore the vaginal equilibrium; this is achieved by increasing the vaginal pH in order to reduce the number of lactobacilli. In many women using tampons, the vaginal pH can be sufficiently raised merely by discontinuing tampon use and thus restoring menstrual flow. The other main modality of management involves douching with a sodium bicarbonate (baking soda) solution, by using a sodium bicarbonate suppository vaginally, or via sodium bicarbonate in a sitz bath. This is typically performed twice weekly for 2 to 3 weeks. Note that if symptoms persist beyond 2 to 3 weeks of treatment, re-evaluation is warranted. Patient education is also an important aspect of management; this includes informing them about the condition, and providing instructions on basic vulvovaginal care (i.e. using cotton undergarments, and avoiding the use of soap to cleanse the genital area).

Take home messages

  1. Cytolytic vaginosis is often misdiagnosed as vulvovaginal candidiasis, due to the similar clinical presentation.
  2. The management revolves around restoring the vaginal equilibrium by raising the pH.
  3. In women using tampons, discontinuation is often sufficient to raise the vaginal pH; Sodium Bicarbonate douching is the other main modality of treatment.

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