Sexually Transmitted Infections

Question 1

List the 4 routes of transmission for STIs

Answer 1

Oral-genital contact
Vaginal intercourse
Anal intercourse
Anilingus

Question 2

List 5 STIs that can be spread by oral-genital contact

Answer 2

Chlamydia
Gonorrhoea
HSV
Syphilis
HPV

Question 3

List 5 STIs that can be spread by anilingus

Answer 3

Amoeba
Cryptosporidia
Giardia
Shigella
HAV

Question 4

What type of bacteria is N. gonorrhoeae?

Answer 4

Gram negative diplococci

Question 5

What kind of cells does N. gonorrhoeae colonise?

Answer 5

Columnar epithelium

Question 6

What is the incubation period of N. gonorrhoeae?

Answer 6

2-7 days (relatively short)

Question 7

What are the symptoms of gonorrhoea in males?

Answer 7

Urethritis with a thick, creamy urethral discharge (can block the urethra and cause pain)
May be asymptomatic (10%)

Question 8

What are the symptoms of gonorrhoea in females?

Answer 8

Mostly asymptomatic (80%)
Causes cervicitis

Question 9

What are the symptoms of gonorrhoea transmitted via the oral-genital route?

Answer 9

May have pharyngitis and lymphadenopathy

May be asymptomatic

Question 10

What is the hypothesised reason for increasing rates of antibiotic resistance in N. gonorrhoeae?

Answer 10

Many other members of Neisseria colonise mucous membranes of the body (including the throat) as normal flora; these organisms can all exchange genes, including those encoding for antibiotic resistance

Question 11

In what % of untreated cases does disseminated gonorrhoea occur?

Answer 11

0.5-3%

Question 12

What are the symptoms of disseminated gonorrhoea?

Answer 12

Arthritis
Maculopapular rash
Meningitis
Endocarditis
Epididymitis
Peri-hepatitis (Fitz-Hugh-Curtis syndrome)

Question 13

What is Fitz-Hugh-Curtis syndrome?

Answer 13

A peri-hepatitis caused by the ascension of N. gonorrhoeae up the female genital tract, into the abdominal cavity via the ovaries, where it causes infection of the liver capsule and produces “violin-string adhesions”

Question 14

What increases the risk of gonorrhoea dissemination?

Answer 14

Risk increases post menses

Question 15

What are the 2 possible complications of gonorrhoea?

Answer 15

Dissemination

PID

Question 16

What are the possible consequences of untreated PID?

Answer 16

Tubal scarring

Infertility (10-20%)

Question 17

What are some possible abnormal findings in PID?

Answer 17

Pain on bimanual palpation of the cervix

Fluid, abscesses on imaging

Question 18

What is the characteristic presentation of neonatal gonococcal opthalmia?

Answer 18

Gross purulent conjunctivitis in first week of life

Mild disease indistinguishable from other causes

Question 19

What are the possible consequences of untreated neonatal gonococcal opthalmia?

Answer 19

Perforation and blindness in days 2-5

Question 20

What is the treatment for neonatal gonococcal opthalmia?

Answer 20

Cefotaxime 50mg/kg IV, 8-hourly for 7 days
Regular irrigation of eyes
Treatment of mother and sexual contacts

Question 21

What diagnostic specimens may be required for gonorrhoea screening?

Answer 21

Cervical swab into charcoal transport
Male urethral swabs
Urine (first void, ~10mL)
Other specimens: conjunctiva, pharynx, skin lesions, anal, CSF, blood, synovial fluid

Question 22

What kind of media are used for laboratory investigations into gonorrhoea?

Answer 22

Non-selective (chocolate blood agar in CO2) used for CSF, joint fluid aspirate
Selective (Thayer-Martin agar) used for swabs taken from an area with normal flora
Culture for antibiotic sensitivities

Question 23

What makes up Thayer-Martin agar? What does each agent do?

Answer 23

Colistin: inhibits growth of Gram negatives
Vancomycin: inhibits growth of Gram positives
Nystatin: anti-fungal

Question 24

What samples are required for nucleic acid amplification tests (NAAT) for gonorrhoea?

Answer 24

Genital (cervical or vaginal) swabs

First void urine

Question 25

In what % of cases of gonorrhoea is there co-infection with chlamydia?

Answer 25

50%

Question 26

What is the advantage with using NAAT to diagnose gonorrhoea?

Answer 26

Less invasive samples (patient can self-collect)

Combined chlamydia and neisseria detection

Question 27

Approximately what % of N. gonorrhoeae display antibiotic resistance to ceftriaxone? How is this overcome?

Answer 27

~30%

Higher doses of ceftriaxone (previously 125mg, now 500mg)

Question 28

How is gonorrhoea treated?

Answer 28

Ceftriaxone 500mg IM/IV and azithromycin 1g oral
OR ciprofloxacin 500mg oral (if sensitive)
OR amoxicillin 3g + probenecid 1g oral in endemic areas (sensitivity has been retained)