last authored: July 2010, Kim Colangelo
last reviewed:
A change in vaginal discharge is a frequent presenting complaint. Normal (physiologic) discharge is clear or white and odourless. If smeared on a slide it will show epithelial cells that slough off on a continuous basis and lactobacilli that are part of the normal vaginal flora. The normal vaginal pH is 3.8-4.2. Physiologic discharge can increase at various reproductive stages, particularly those that increase estrogen such as pregnancy, oral contraceptive pill use, polycystic ovarian syndrome and premenarchal.
Vulvovaginitis
can be stratified into prepubertal, reproductive, and postmenopausal
ages as the most likely diagnosis varies with each age. Vaginosis is
different from vaginitis in that there is no
inflammatory reaction, however there is overlap in symptoms between the
two conditions.
The three most common causes of discharge of an infectious etiology are bacterial vaginosis, candidiasis, and trichomoniasis.
A 30yo female presents to her family doctor's office with a 3 day history of a white vaginal discharge. Her main concern is that the discharge smells unpleasant. There is no pruritis, rash, or dysuria. She is otherwise healthy. Gynecological history reveals a past chlamydial infection for which she was treated.
The main organisms of bacterial vaginosis include:
The main risk factors for BV include:
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There are three possible species for candidiasis:
Candidiasis risk factors:
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Trichomoniasis is caused by Trichomonas vaginalis, which is a flagellated protozoan.
Trichomonas is considered a sexually transmitted infection thus it can be passed between partners.
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"Clue cells" suggesting bacterial vaginosis
used with permission, Per Grinsted
Hydrogen peroxide producing lactobacilli are normally the predominant organism in the vaginal flora. When these decline, the pH rises (become more alkaline) and anaerobes proliferate. The anaerobes produce enzymes that break down substances into amines that have a foul smell; this, combined with the normal cells of the vagina sloughing off more during bacterial vaginosis, results in the discharge that is characteristic.
If Gardnerella vaginalis is the causative organism it can cling to the epithelial cells sloughing off and create the "clue cells" that are part of the diagnostic criteria.
Candidiasis is a fungal infection. The source may be the perianal area that gains access to the vagina or it may normally be present in the woman and because of altered host factors (such as douching) become symptomatic.
Trichomonas is considered a sexually transmitted infection. Trichomonas has adherence factors that allow it to adhere to the cervicovaginal epithelium and passed between partners.
All three infectious causes may be asymptomatic but seen on cultures.
Condition |
Bacterial vaginosis |
Candidiasis |
Trichomoniasis |
Discharge |
grey, thin, watery, foul smelling, copious |
white, "cottage-cheese" |
yellow-green, foul smelling, copious |
Other symptoms |
discharge is typically the only symptom |
pruritis, dysuria, dyspareunia |
pruritis, dysuria, dyspareunia, burning |
Physical Exam |
copious discharge with no inflammatory reaction |
satellite vulvar erythema swollen, inflamed vulva |
strawberry cervix diffuse vulvar erythema |
Bacterial Vaginosis is diagnosed when at least 3 of the following 4 are present (Amsel criteria):
A vaginal culture is not necessary for diagnosing BV or candidiasis; clinical signs and symptoms alone are sufficient. If a swab is taken for the wet mount or pH it should be taken from high in the vaginal canal to avoid contamination with organisms of the skin. The swab can then be applied to a wet mount for the whiff amine test or to look for clue cells, or to litmus paper to check the pH.
Bacterial Vaginosis |
Candidiasis |
Trichomoniasis |
|
KOH |
fishy odour produced |
cells remain intact but no odour is produced |
can be odour producing |
pH |
greatly increased |
normal |
increased |
wet mount
|
clue cells (epithelial cells covered with bacteria) |
can see budding yeast and hyphae |
oscillating protozoan numerous WBC's and inflammatory cells |
gram stain
|
switch from gram positive rods to gram negative rods or curved bacteria |
gram positive yeast with buds |
large, gram negative protozoan |
The differential includes:
Bacterial Vaginosis
Candidiasis
Trichomoniasis
BV
and trichomoniasis are associated with a higher risk of sexually
transmitted infections such as HIV, HSV, gonorrhea, and chlamydia. They
are also associated with a higher risk of preterm birth and other
obstetric complications in affected pregnant
women and postoperative vaginal cellulitis in women undergoing pelvic
surgery. BV has a high recurrence rate, maintenance antimicrobial
therapy has been investigated. The use of condoms or abstinence has
been associated with lower recurrence rates.
Vaginal candidiasis is not associated with adverse pregnancy outcomes.
authors: Kim Colangelo, 2010
reviewers: