Trichomonas vaginalis Flashcards
What type of organism is trichomonas vaginalis?
Flagellated protozoon
Where in women is T vaginalis infection found?
Vagina
Urethra
Paraurethral glands
Where in men is T vaginalis infection found?
Urethra
Subpreputial sac
Lesions of the penis
What are the symptoms of T vaginalis infection in women? (7)
Asymptomatic Vaginal discharge Vulval itching Dysuria Offensive odour Lower abdominal pain Vulval ulceration
How often is T vaginalis asymptomatic in women?
10-50%
What are the symptoms of T vaginalis infection in men? (4)
Urethral discharge
Dysuria
Urethral irritation
Urinary frequency
What is the most common presentation of T vaginalis in men?
Urethral discharge
Dysuria
What is the classic description of vaginal discharge in T vaginalis infection?
Frothy yellow discharge
How common is frothy yellow discharge in T vaginalis infection?
10-30%
What is the pathognomonic appearance of the cervix in T vaginalis infection? How common is it?
Strawberry cervix
2%
How often is vaginal discharge the presenting complaint in T vaginalis infection?
70%
How often will a man be asymptomatic of T vaginalis infection?
77%
What impact may T vaginalis infection have on a pregnancy?
Preterm delivery
Low birth weight
What impact may T vaginalis infection have on a woman postpartum?
Predispose to maternal postpartum SEPSIS
When should women have testing for T vaginalis?
Vaginal discharge
Vulvitis
Evidence of vulvitis or vaginitis on examination
When should men have testing for T vaginalis?
TV contacts
Persistent urethritis
What is the preferred specimen for T vaginalis in women?
Swab of posterior fornix during speculum
What specimen is required for T vaginalis in men?
Urethral swab OR
first void urine
How sensitive is testing for T vaginalis in men?
60-80% with urethral or FVU culture
Sampling both sites significantly increases diagnostic rate
Microscopy - T vaginalis - describe the steps?
Wet preparation slide - vaginal discharge
Low magnification 100x - scan slide
Higher magnification 400x - confirm morphology of trichomonads and visualise flagella
When should a wet preparation microscopy slide be read following sampling?
within 10 minutes
Why should a wet preparation slide be read within 10 minutes for investigation of T vaginalis?
Trichomonads quickly LOSE MOTILITY and more DIFFICULT to IDENTIFY
What is the sensitivity of microscopy for T vaginalis?
45-60%
In what setting are false positive results more likely when performing Trichomonad Rapid Test for T vaginalis infection?
In populations with a LOW PREVALENCE of disease
What is the ‘gold standard’ for T vaginalis testing?
nucleic acid amplification tests (NAATs)
If testing for T vaginalis what other testing should take place?
screening for co-existent STIs
What antibiotic class can be used to treat T vaginalis?
almost any NITROIMIDAZOLE drug (Cochrane review)
How effective is a nitroimidazole at treating T vaginalis?
> 90% cure rate
Why is a single high dose nitroimidazole not as acceptable as a longer lower dose for T vaginalis?
associated with more frequent SIDE EFFECTS
What are the regimen options for T vaginalis treatment? (3)
Metronidazole 2 g orally in a single dose
Metronidazole 400–500 mg twice daily for 5–7 days
Tinidazole 2g orally in a single dose
Can metronidazole be used in pregnancy?
Yes however some clinicians may avoid in first trimester
What should be avoided if prescribing metronidazole to a breast feeding woman?
HIGH DOSE metronidazole or
discontinue breast feeding 12-24 hours to reduce infant exposure
Which regimen may not be as effective for treatment of TV in HIV-positive women?
Single high dose metronidazole
What should patients avoid whilst taking metronidazole? Why?
alcohol - duration of treatment and 48 h after
Disulfiram-like reaction - nausea, vomiting, flushing, dizziness, throbbing headache, chest and abdominal discomfort
In the event of persistent or recurrent TV what should you do?
Check:
COMPLIANCE and exclude vomiting of metronidazole . Sexual history for possibility of RE-INFECTION and ask
if partner(s) have been treated
What are the benefits of tinidazole vs metronidazole for TV?
longer serum half-life
good tissue penetration
a better side-effect profile
lower levels of resistance
When should tinidazole be used for TV infection?
when infections have not responded to metronidazole
Why should metronidazole 400mg twice daily for 7 days be the first line therapy for non-response to first course treatment of TV?
in those who failed to respond to a first course of treatment, 40% responded to a repeat course
If a person fails treatment with standard therapy metronidazole what are the options for TV infection?
HIGHER DOSE
metronidazole or tinidazole 2gram FIVE-SEVEN days
Metronidazole 800mg 3 times daily for 7 days
In those who have failed repeat treatment with standard therapy metronidazole for TV, what percentage respond to a higher dose?
70%
In those who had failed other treatments, 92% and 90%
responded to a VERY HIGH DOSE course of tinidazole - what is this regimen?
Tinidazole 1 g twice or three times daily for 14 days
Tinidazole 2 g twice daily for 14 days
(intravaginal tinidazole 500 mg twice daily for 14 days can be added to oral therapy)
How far back should contact tracing be for TV?
current and previous partners within 4 weeks of presentation
If a male contact of TV has urethritis on screening, what should first line treatment be?
treat for TV
repeat urethral smear before considering treatment of NGU
