B2 G&D Lec2: Infectious vaginitis Flashcards
Define vaginitis
inflammation of the vagina that can result in discharge, itching, and pain.
What are the common causes of vaginitis?
- Candidiasis
- Trichomoniasis
- Bacterial vaginosis
What is the pathophysiology of vaginitis?
• The use of antibiotics that inhibit the normal flora of the vagina, especially lactobacilli, predisposes to Candida vaginitis. Candida is a member of the normal flora of many women.
• The pathogenesis of bacterial vaginosis is uncertain, but it does not appear to be a sexually transmitted disease.
• Trichomoniasis, on the other hand, is a sexually transmitted disease.
Which organism cause Trichomoniasis?
Trichomonas Vaginalis
Mention morphology of T.vaginalis
- No cyst stage
- Trophozoite : active stage in the same time the infective stage
- Pear-shaped 10–30 μm in length and 5–10 μm in breadth with a short undulating membrane reaching up to the middle of the body.
- Has axostyle & flagella
*It has four anterior flagella and fifth running along the outer margin of the undulating membrane
- The trophoziote has a rapid jerky or twitching character of motility.
Which structure support the base of the anterior flagella ?
Costa ; a flexible rod
What is axostyle in T.vaginalis?
runs throughout the length of the body and projects posteriorly like a tail
Where is the habitat of female T.vaginalis?
It lives in vagina and cervix and may also be found in Bartholin’s glands, urethra, and urinary bladder.
Where is the habitat of male T.vaginalis?
It occurs mainly in the anterior urethra, but may also be found in the prostate.
How is Trophozoites divided?
By binary fission
Describe the life cycle of T.vaginalis
• Life cycle of T. vaginalis is completed in a single host, with a single stage “trophoziote”.
• There is no animal reservoir
• Trophozoites divide by binary fission.
• As cysts are not formed, the trophozite itself is the infective form.
How is T.vaginalis by trophozoite is transmitted?
Sexual transmission is the usual mode of infection and hence there is no need for a durable cyst form.
- trophozoite cannot survive outside and so infection has to be transmitted directly from person to- person.
- omites such as towels have been implicated in transmission.
- T€richomoniasis often coexists with other sexually transmitted diseases.
What is the incubation period of trophozoite in T.vaginalis?
10 days
Describe the pathogenesis of T.vaginalis
• It is an obligate parasite and cannot live without close association with the vaginal, urethral, or prostatic tissues.
• Parasite causes petechial hemorrhage ( strawberry mucosa)
and frothy discharge
• Intracellular edema and so called chickenlike epithelium, is the most characteristic feature of trichomoniasis.
Clinical features of Trichomonas Vaginalis
• Infection is often asymptomatic, particularly in males, although some may develop urethritis and prostatitis.
• In females, it may produce severe pruritic vaginitis with an offensive, yellowish and frothy discharge.
Which culture does T.vaginalis grow in?
Cysteine-peptone-liver-maltose (CPLM) medium
Which stain is used in fixation?
Giemsa stains
Describe the microscopic picture of T.vaginalis
• Vaginal or urethral discharge is examined microscopically in saline wet mount preparation for the trophoziotes with the characteristic shape, jerky and twitching motility.
• In males, trophozoites may be found in urine or prostatic secretions
When is culture performed for T.vaginalis?
Culture is recommended when direct microscopy is negative
Describe the properties of Gardnerella vaginalis
a facultative anaerobic gram-variable coccobacilli (short rods).
Structurally, it has a gram-positive cell wall but the wall is thin and tends to lose the purple color.
G.vaginalis is often found in association with which organism?
anaerobes such as Mobiluncus and together they cause the symptoms of this disease.
Is G.vaginalis sexually transmitted?
No
Mention the clinical findings of G.vaginalis
• Bacterial vaginosis is characterized by a malodorous, white or gray-colored vaginal discharge.
• The discharge has a characteristic “fishy” odor.
• Inflammatory changes are typically absent which is why it is called a “vaginosis” rather than a “vaginitis.”
• Mild itching may occur.
• Pregnant women with bacterial vaginosis have a higher incidence of preterm deliveries and, consequently, a higher incidence of morbidity and mortality occurs in their newborn children.
What is considered an important laboratory finding seen in a microscopic examination of the vaginal discharge in G.vaginalis?
Clue cells, which are vaginal epithelial cells covered with bacteria
What is the whiff test?
Used to diagnose G.vaginalis , often positive. Treating the vaginal discharge with 10% KOH (potassium hydroxide) and smelling a pungent, “fishy” odor.
• However, trichomoniasis, which can also cause a positive whiff test, must be ruled out before a diagnosis of bacterial vaginosis can be made.
