Bacterial STIs Flashcards
Types of bacterial and protozoa STIs
Neisseria gonorrhoea
Chlamydia trachomatis
Mycoplasma genitalium
Treponema pallidum
Ureaplasma urealyticum
Haemophilus ducreyl
Pathophysiology of neisseria gonorrhoea
Gram negative intracellular diplococcus, infects mucus membranes and can disseminate
Symptoms of neisseria gonorrhoea
Dysuria, discharge from urethra or vagina, proctitis, pharyngitis, conjunctivitis
Complications of neisseria gonorrhoea
Can ascend to cause PID, epididymitis and can disseminate, fetal loss, conjunctivitis, Bartholins abscess, perihepatiic, appendicitis, worse and more common in women
How is neisseria gonorrhoea diagnosed
Nucleic acid test from urine/swabs
Difficulties in diagnosis of gonorrhoea
Culture only grows 1/3 but this allows resistance testing. Microscopy can be used for immediate diagnosis but needs lots of organism (urethritis valuable)
Pathophysiology of chlamydia trachomatis
Small intracellular bacteria not seen by light microscopy
Symptoms of chlamydia trachomatis
Dsyuria, discharge, acute illness milder than in neisseria gonorrhoea, inflamed genital tract
Diagnosis of chlamydia trachomatis
NAATs from urine or swabs as it is very difficult to grow
Complications of chlamydia trachomatis
SARA, PID, epididymitis, some strains cause LGV, endometritis, salpingitis, infertility, ectopic pregnancy, adhesions, Fitz-Hugh Curtis syndrome, conjunctivitis, arthirits
Pathophysiology of mycoplasma genitalium
Low grade pathogen very difficult to culture
Pathophysiology of treponema pallidum
Spirochaete bacteria seen on dark field microscopy. Causes syphilis.
How is treponema pallidum diagnosed
PCR from early lesions or serology
Populations at risk of treponema pallidum
Homosexual men especially if HIV positive
Sexual contact with person from endemic area
Pregnancy or tissue donation
Symptoms of treponema pallidum
Ulcers, rashes and problems associated with syphilis
Pathophysiology of trichomonas vaginalis (TV)
Flagellated protozoan parasite
Symptoms of TV in women
Vaginal discharge
Vulval itching
Dysuria
Offensive odour
Signs of TV in males
Affect urethra, supreputial sac and lesions of penis
What can TV increase the risk of
Problems in pregnancy and risk of HIV
What bowel diseases are primarily in MSM
Giardia, Shigella, Entamoeba
Bacterias that can cause urethritis
Chlamydia, mycoplasma, gonorrhoea, trichomonas
Where is TV most commonly found in women
Vagina, urethra, paraurethral glands
Signs of TV in women
None in 10% women
Vaginal discharge which can be profuse and frothy yellow (>30%) or thin and scanty
Symptoms of TV in men
15-50% asymptomatic
Discharge
Dysuria
Irritation of urethra
Urinary frequency
Complications of TV
Vaginitis or salpingitis due to concurrent infections, in men rarely causes balanoposhitis or penile ulceration
Diagnosis of TV in females
NAAT from swab of posterior fornix, wet mount microscopy, acrinidine orange
Diagnosis of TV in males
Male urethral culture, acridine orange, NAAT
Treatment of TV
Metronidazole 2g oral dose or 400-500mg twice daily for 5-7 days
Tinidazole 2g orally in single dose
Do not take alcohol for duration of treatment and 48 hours afterwards
Partners should complete treatment before sexual intercourse
What is the spontaneous cure rate of TV
20-25%
What can you do if there is no response to TV treatment
If not responded to first treatment then repeat course once more
How to diagnose the cause of urethritis
Symptoms, signs, urine and microscopy (evidence of polymorphs in urethral discharge)
Causes of urethritis %
5% gonococcal
45% chlamydial
50% non chlamydia non gonococcal - most commonly mycoplasma
Incubation time of chlamydial infection
7-21 days
% of asymptomatic males with chlamydia
50%
% of asymptomatic females with chlamydia
70-80%
What is Reiter’s syndrome
Complication of chlamydia causing arthritis
What is Fitz-Hugh Curtis Syndrome
Complication of chlamydia which affects the liver giving an acute cholecystitis presentation
% of women who get PID from chlamydia
10-30% of women with untreated chlamydia
What percentage of PID is caused by chlamydia
60%
What percentage of ectopic pregnancies are caused by chlamydia
60%
Diagnosis of chlamydia
First catch urine, 15ml needed. Self taken vulvovaginal swab, cervical, urethral, rectal and pharyngeal swabs also taken. Then NAAT test
Is chlamydia visible under microscope
No
Is gonorrhoea visible under microscope
Yes
When is chlamydia retested for
After 4 weeks
Treatment of chlamydia
Erythromycin 100mg BD for 7 days or azithromycin 1g STAT then 500mg OD for 2 days
How is non gonococcal non chlamydia urethritis treated (NSU)
Diagnosis of exclusion as not seen on microscopy but many due to mycoplasma genitalium
Treatment of mycoplasma genitalium
Prime wit doxycycline 100mg BD for 1 week then extend to azithromycin 1g STAT then 500mg OD for 2 days
What is the main concern for treating mycoplasma
There is resistance starting against azithromycin (50%) so now having to use quinolones but these have bad side effects
Incubation period for mycoplasma genitalium
Longer than chalymdia (>21 days)
How contagious is gonorrhoea
Very - one contact from male to female can have 60-80% transmission, female to male is 20%
Incubation period for gonorrhoea
5-8 days
Specific symptoms of gonorrhoea in males
80% profuse purulent discharge, 50% dysuria, asymptomatic in 10%
Specific symptoms of gonorrhoea in females
50-70% asymptomatic, mucupurulent discharge <50%, pelvic pain <5%
Other sites that gonorrhoea can infect
Pharynx - asymptomatic in 90%. Mild pharayngitis.
Rectum - asymptomatic in 90%. Can cause purulent rectal discharge
Symptoms of disseminated gonococcal infection
Rare <1%, fever, rash, arthritis, tendonitis
Treatment of gonorrhoea
3rd generation cephalosporin such as ceftriaxone 1g IM - but check local guidelines
When should a test of cure be done for gonorrhoea
2 weeks
When should gonorrhoea be treated empirically
Only treat if sex in past 2 weeks with symptoms otherwise tests as needed - could be another STI due to short incubation period
