7
Microbiology, inflammation, and Viral infections
Fig. 7.66
Candida
infection.
(A) LBGS (Papanicolaou x HP). (B) Budding yeast forms in
C andida
infection. These occur commonly among asymptomatic
women. Vaginopancervical smear (Papanicolaou x HP).
Fig. 7.67 "Polydust"
background in
C andida
infection. Vaginopancervical
smear (Papanicolaou x MP).
Key features of
C a n d id a
infection
• Infection may be asymptomatic,
• Polydust and herringbone patterns are useful diagnos-
tically;
• Only yeast forms may occur; and
• Cellular changes may resemble epithelial atypia.
Parasitic infections
Trichomonas vaginalis
Trichomonas vaginalis
is a protozoan and is the most common
parasitic organism in cervicovaginal specimens. It is one of
the four species (
Trichomonas tenax, Trichomonas hominis, Tri-
chomonas fecalis,
and
T. vaginalis)
and is the only pathogen for
human beings. The most common infection occurs in the lower
female genital tract, although nongenital infections including
neonatal pneumonia, perinephric abscess, cutaneous lesion,
and alimentary tract infection all have been documented, as has
been human prostatic disease. Host factors such as endocervical
glands and mucus, various immunoglobulins, the complement
system and leukocytes, macrophages, and the polymicrobial
vaginal environment are some of the important contributing
factors for clinical symptoms.
Clinical disease is often described as occurring in acute,
chronic, and latent phases. Nearly 50% of the women who
have this infection harbor this parasite in the latent phase and
are asymptomatic. During the symptomatic phase, the organ-
isms occur in the vagina and occasionally in the secretions of
the Skene and Bartholin glands. In approximately 10-20% of
the women, lower urinary tract infection may occur and present
as dysuria and urethral discharge. The organism may be recov-
ered from clean-catch urine specimens. It has also been recov-
ered from purulent tubal material. The precise role, if any, of
T. vaginalis
infection in the development of PID, although
documented, is controversial.
The incubation period of
T. vaginalis
infection is between
4 and 28 days. A foamy vaginal discharge occurs in 10-25%
of patients. It may be malodorous, copious, frothy, and green-
ish-yellow. Vulvar vaginitis and symptoms of PID including
inguinal lymphadenopathy may occur. "Strawberry vagina" with
reddening of the mucosa and small, punctate hemorrhagic spots
is typical. The strawberry cervix, although classic, is seen in less
than 5% of infected patients.
The disease may exacerbate in the latent phase during or
immediately following the menstrual period. Clinical disease is
more common during pregnancy. Frost observed
Trichomonas
in
19% of pregnant women.10 The effect of
Trichomonas
infection
on the newborn infant and postpartum endometrial infection is
documented but not universally accepted.
Cytomorphologic Features
Although a number of techniques such as dark field, hanging
drop and wet mount preparations, and PAS, Romanowsky, and
immunoenzymatic staining methods can observe the organism,
excellent morphologic details are seen using wet fixation and
Papanicolaou stained vaginal smears. "Routine" vaginopancer-
vical smears are most valuable diagnostically. Because the organ-
isms occur in the vagina, vaginal pool material or secretions
from the posterior fornix are more sensitive. Vaginal douching in
the preceding 24 hours, dilution of the secretions by menstrual
blood, inflammation with cellular obscuring, marked cytolytic
123
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