GC119 Vaginal Discharge Obstetric And Gynaecological Infections
Vaginal discharge resulting from obstetric and gynaecological infections encompasses abnormal genital tract secretions caused by pathogens such as Candida, bacterial vaginosis organisms, Trichomonas, Chlamydia, or Neisseria gonorrhoeae during pregnancy or in the gynaecological setting, requiring prompt identification and treatment to prevent complications.
Vaginal Discharge: Obstetric & Gynaecological Infections
This GC 119 lecture by Dr M Cheng (O&G, QMH) is one of the most directly examinable O&G lectures in the General Clerkship. It sits at the intersection of gynaecology (vaginal discharge, PID), obstetrics (maternal-fetal infection, GBS screening), and microbiology (STIs, specimen collection, antibiotic choice). The deck covers:
- Natural vaginal defence mechanisms and what breaks them down
- Non-infectious vs infectious causes of vaginal discharge
- Six core infections in detail: Candidiasis, GBS, Bacterial Vaginosis, Trichomoniasis, Chlamydia, Gonorrhoea
- Pelvic Inflammatory Disease (PID) — diagnosis, management, complications
- General approach to STIs — screening, partner tracing, pregnancy considerations
Learning Objectives (directly from lecture) [1]
- Common causes of maternal infection and the effects on fetus
- Evaluate the screening of congenital infection in obstetric patients
- Describe the management of pelvic inflammatory disease
- Recognize the physical signs of pelvic inflammatory disease
High Yield: PID management (outpatient vs inpatient antibiotics), GBS intrapartum antibiotic prophylaxis indications, BV Amsel's criteria, and the complications of Chlamydia/Gonorrhoea (especially subfertility statistics) are repeatedly examined in MCQs, SAQs, and mini-cases. [1][3]
Understanding defence mechanisms is essential because every predisposing factor you learn for genital infection works by breaking one of these barriers.
Natural defence mechanisms [1]:
- Apposition of labia & vaginal walls — physical barrier preventing entry
- Stratified squamous epithelium — inherently resistant to infection (multi-layered, keratinised surface)
- Vaginal microbiome, especially lactobacilli — produce lactic acid and hydrogen peroxide, competitively exclude pathogens
- Vaginal acidity (pH 3.5–4.5) — most pathogenic bacteria cannot survive in this pH
Factors That Compromise Defence [1]
| Factor | Mechanism |
|---|---|
| Menstrual cycle | Secretions become alkaline around menses → ↑ pH → pathogens can survive |
| Pregnancy & puerperium | ↑ pH; ↑ estrogen → ↑ glycogen in vaginal epithelium → promotes Candida; trauma at delivery breaches barriers; lochia is alkaline |
| Broad-spectrum antibiotics | Kill lactobacilli → ↑ pH → overgrowth of Candida/anaerobes |
| Immunosuppression | Reduced local and systemic immune clearance |
| Diabetes mellitus | ↑ glycogen, impaired neutrophil function |
| IUCD | Foreign body, acts as a wick for ascending infection |
Why is pregnancy a double hit?
Pregnancy raises vaginal pH and increases glycogen content simultaneously. The pH rise allows bacteria to colonise, while the excess glycogen feeds Candida. Post-delivery, the alkaline lochia and cervical/vaginal trauma create perfect conditions for ascending infection. This is why GBS screening and intrapartum antibiotic prophylaxis exist.
Always consider these before jumping to infection:
| Cause | Key Features |
|---|---|
| Physiological | Clear/white, non-offensive, varies with cycle (↑ mid-cycle due to estrogen), no pruritus |
| Cervical ectropion | Columnar epithelium visible on ectocervix, mucoid discharge, common with OCP/pregnancy |
| Foreign bodies | Retained tampon/condom → offensive discharge ± bleeding |
| Vulval dermatitis | Contact irritant or allergic → itch, erythema, discharge secondary to excoriation |
| Benign and malignant tumours | Cervical/endometrial polyp, cervical/endometrial carcinoma → blood-stained/watery discharge |
Key history elements:
- Timing of discharge (onset, relation to cycle)
- Smell (fishy = BV/Trichomoniasis; none/yeasty = Candida)
- Associated symptoms: abdominal pain, fever, pruritus, dyspareunia, dysuria, intermenstrual bleeding
- Contraception (IUCD → PID risk; OCP → Candida risk)
- Past health (diabetes, immunosuppression)
- Previous obstetric history
- Cervical smear status
- Physical examination including speculum and bimanual
Goals of Assessment [1]
- Differentiate physiological vs pathological discharge
- Initiate investigation and treatment
- Prevent recurrence
Part 4: Non-Sexually Transmitted Infections
4A. Candidiasis [1]
Organism: Candida albicans — Gram-positive, yeast-like fungus
| Feature | Detail |
|---|---|
| Prevalence in pregnant women | 10–16% symptomatic; 30–40% asymptomatic colonisation |
| Prevalence in healthy young women | 20–25% |
| Recurrence rate | < 5% |
| NOT a sexually transmitted disease | Important: do not refer partner unless symptomatic |
- Vulvovaginitis: pruritus vulvae, soreness
- Thick, white or yellow, cheesy discharge
- Erythema of vulva & vagina
- May cause skin fissure
- Pregnancy (↑ glycogen)
- Diabetes mellitus
- Immunosuppression
- Oral contraceptive pills
- Broad-spectrum antibiotics
- Clinical features (often sufficient for uncomplicated cases)
- Vaginal swab from vaginal fornix for microscopic exam ± culture
- Wet mount: pseudohyphae surrounded by vaginal epithelial cells
- Culture more important if complicated — severe symptoms, pregnancy, recurrent, non-albicans, abnormal host
- Asymptomatic: NO treatment needed
- Genital hygiene (clean & dry, avoid irritants, loose cotton clothing)
- Antifungal agents: topical or oral — clotrimazole, econazole, miconazole
- Example: clotrimazole pessary 200 mg for 3 nights
- Vaginal route for pregnant women (oral azoles are teratogenic in first trimester)
- Maintenance therapy for recurrent candidiasis (weekly oral fluconazole for 6 months)
- Keep genital area clean and dry
- Use vulval moisturisers as soap substitute
- Avoid tight-fitting synthetic clothing
- Avoid local irritants e.g. perfumed products
- Colonisation is NOT associated with low birth weight or premature delivery
- Only treat if symptomatic
- Use vaginal (not oral) antifungals
4B. Group B Streptococcus (GBS) [1]
This is THE obstetric screening topic. Expect MCQs on indications for intrapartum antibiotic prophylaxis (IAP).
Organism: Streptococcus agalactiae — Gram-positive cocci
- GI tract is the primary reservoir
- Vaginal colonisation: 6–30% of pregnant women
- Not a STD
- UTI
- PROM / PPROM
- Preterm labour
- Chorioamnionitis
- Post-partum endometritis
- Neonatal GBS colonisation via vertical (during delivery) or horizontal (postnatal contact) transmission
- 1 in 100–200 babies of GBS-colonised mothers will develop signs/symptoms of infection
- ~1/1000 births in HK
| Type | Timing | Transmission | Manifestations | Mortality |
|---|---|---|---|---|
| Early-onset | < 7 days | Vertical | Septicaemia, pneumonia, respiratory failure | 5–10% |
| Late-onset | 7 days – 3 months | Vertical/Horizontal | Meningitis, pneumonia | Lower |
Universal GBS screening started in HK since January 2012
- Low vaginal AND rectal swab at 35–37 weeks
- Screening NOT required if:
- Intrapartum antibiotic prophylaxis already indicated (e.g. GBS bacteriuria this pregnancy, previous baby with invasive GBS)
- Planned caesarean section (no labour, no membrane rupture → no vertical transmission)
The lecture mentions screening criteria referencing the Wilson & Jungner principles [1]:
- Important problem ✓
- Natural history understood ✓
- Recognisable latent/early state ✓
- Acceptable & effective treatment ✓
- Facilities available ✓
- Cost-effective ✓
Give IAP if ANY of the following:
- Previous baby with invasive neonatal GBS disease
- GBS bacteriuria in current pregnancy
- Positive GBS screening (unless elective CS)
- Gestation < 37 weeks (except if negative screening result)
- Maternal fever > 38°C
- PROM for > 18 hours
- Screening results not yet available at leaking/onset of labour
2025 MCQ Stem – Directly Tested!
Question 75 of the 2025 Fourth Summative MCQ describes a woman at 38 weeks with ROM, positive for "beta-haemolytic Gram-positive cocci" at 35 weeks, no drug allergy. The answer is B. Give intravenous benzylpenicillin after checking drug allergy record. This is pure GBS IAP — recognise the organism description and know the first-line drug. [3]
- First line: Penicillin G (benzylpenicillin) IV
- If allergic:
- Cefazolin (if not at high risk of anaphylaxis)
- Clindamycin
- Erythromycin
- Vancomycin
Important limitation: IAP reduces early-onset GBS but does NOT always prevent late-onset GBS infection. Babies may acquire GBS from contacts postnatally. [1]
4C. Bacterial Vaginosis (BV) [1]
Commonest cause of vaginal discharge in reproductive-aged women
| Feature | Detail |
|---|---|
| Organisms | Mainly anaerobes: Gardnerella vaginalis, Prevotella sp., Mycoplasma hominis, Mobiluncus sp. |
| Mechanism | Replace lactobacilli → pH rises to ~7 |
| Prevalence (UK data) | 5% asymptomatic students; ~12% pregnant women; 30% women undergoing TOP |
| Risk factors | Black ethnicity, IUCD, smokers |
| NOT exclusively STI | Can occur in sexually active AND inactive women |
- 50% asymptomatic
- Offensive, fishy-smelling vaginal discharge
- Thin, white, homogeneous discharge coating vaginal wall/vestibule
- NOT usually associated with vulvovaginitis (no itch/soreness — key differentiator from Candida)
1. Thin, white, homogeneous discharge 2. Clue cells on microscopy (epithelial cells studded with bacteria) 3. pH of vaginal fluid > 4.5 4. Release of fishy odour on adding alkali — 10% KOH ("whiff test")
| Candida | BV |
|---|---|
| Thick, cheesy | Thin, homogeneous |
| Pruritus, soreness | Fishy smell, no itch |
| pH normal (< 4.5) | pH > 4.5 |
| Pseudohyphae on wet mount | Clue cells on wet mount |
- PID (though no evidence treating asymptomatic women prevents PID)
- Post-TOP endometritis
- Late miscarriage
- Preterm labour
- PPROM
- Postpartum endometritis
- Vaginal cuff cellulitis and abscess after vaginal hysterectomy
- Advise against vaginal douching, shower gels, antiseptic bath agents
- Treat: symptomatic women, those undergoing surgery, pregnant women
- Oral metronidazole 400 mg BD for 5–7 days or 2 g single dose
- Alternatives: intravaginal metronidazole gel or clindamycin cream
- ? Role of screening in pregnant women (uncertain benefit)
BV Treatment Pearl
Students often confuse BV treatment with Trichomoniasis treatment — both use metronidazole. The difference: BV is not an STI so you do NOT need to treat the partner or screen for other STIs. Trichomoniasis IS an STI, so you must screen and treat the partner.
Part 5: Sexually Transmitted Infections
Top 5 STI diagnoses in social hygiene clinics:
- Non-gonococcal urethritis / Non-specific genital infection (5840)
- Genital warts (2007)
- Gonorrhoea (1593)
- Syphilis (1116)
- Herpes genitalis (751)
5A. Trichomoniasis [1]
Organism: Trichomonas vaginalis — flagellated protozoa Sexually transmitted
| Feature | Detail |
|---|---|
| Risk factors | Smokers, Afro-Caribbean/African race, lower educational level, unsafe sex, multiple partners |
- Pruritus
- Vaginitis, dyspareunia, soreness
- Foul smell, frothy, yellowish-green discharge
- Post-coital bleeding in pregnant women
- Strawberry cervix (punctate haemorrhages on cervix — pathognomonic but seen in < 5%)
- May be associated with preterm birth and low birth weight
| Method | Sensitivity |
|---|---|
| High vaginal swab wet mount & microscopy | 51–65% |
| Culture | 75–96% (up to 7 days) |
| Rapid antigen test | 82–95% |
| NAAT | 90–100% |
| PCR | 95–100% |
| At QMH: high vaginal swab for microscopy and culture | — |
- Specimens must be examined within 10 minutes to observe motile parasites on wet mount
- Metronidazole: oral single dose 2 g OR 400 mg BD for 5–7 days
- Screen for other STDs
- Screen and treat partner
- Test of cure: only if symptomatic after treatment or if symptoms recur
5B. Chlamydia [1]
Organism: Chlamydia trachomatis — obligate intracellular parasite Sexually transmitted
| Feature | Detail |
|---|---|
| Risk factors | Young age, multiple sexual partners, unsafe sex, low socioeconomic class, history of STD/PID |
| Prevalence | 1–30% |
| Incubation | 7–21 days |
- 75% asymptomatic — this is why it's so dangerous
- Increased vaginal discharge
- Dyspareunia
- Intermenstrual bleeding
- Abdominal pain
- Dysuria
Gynaecological:
- PID
- Chronic pelvic pain
- Increased risk of ectopic pregnancy
- Subfertility
- Fitz-Hugh-Curtis Syndrome (perihepatitis — "violin string" perihepatic adhesions)
- Reiter's Syndrome — urethritis, conjunctivitis, arthritis
Pregnancy-related:
- Preterm labour, PPROM, low birth weight, post-partum endometritis
Neonatal:
- Conjunctivitis (5–12 days after birth)
- Pneumonitis (2–3 weeks after birth)
Fitz-Hugh-Curtis Syndrome
This is perihepatitis — inflammation of Glisson's capsule. It causes RUQ pain mimicking cholecystitis or liver disease. At laparoscopy, you see "violin string" perihepatic adhesions. It can be caused by BOTH Chlamydia and Gonorrhoea, but is more classically associated with Chlamydia in exams. [1][2]
- Endocervical swab and/or first-void urine
- PCR and ligase chain reaction (most sensitive)
- ELISA (monoclonal Chlamydia-specific antibodies) — less sensitive, possible false positives
- Culture (expensive, McCoy cell line) — gold standard but impractical
- At QMH: endocervical swab for immunofluorescence and culture
- Doxycycline 100 mg BD for 7 days OR Azithromycin 1 g single dose
- In pregnancy: azithromycin, erythromycin, or amoxicillin (doxycycline is contraindicated — tetracyclines cause fetal tooth discolouration and bone growth inhibition)
- Screen for other STDs
- Contact tracing and treatment
- Test of cure: NOT routinely recommended for uncomplicated infection, but RECOMMENDED in pregnancy
5C. Gonorrhoea [1]
Organism: Neisseria gonorrhoeae — kidney/bean-shaped, Gram-negative diplococci Affects: genitourinary tract, rectum, pharynx, eyes Sexually transmitted
| Feature | Detail |
|---|---|
| Incubation | ~10 days |
- 30–60% asymptomatic
- Dysuria, frequency
- Increased vaginal discharge, yellow-green
- Vaginal pruritus, burning
- Post-coital bleeding
- Vaginal erythema
- Vulval swelling/pain → Bartholin's abscess
Gynaecological: PID, ↑ ectopic pregnancy risk, subfertility, chronic pelvic pain Systemic: arthritis, conjunctivitis, pharyngitis, proctitis, urethritis, endocarditis, meningitis, disseminated gonococcal infection (rare)
Pregnancy-related: miscarriage, premature labour, PPROM, chorioamnionitis, SGA, stillbirth, post-partum endometritis and pelvic sepsis
Neonatal: Ophthalmia neonatorum (purulent conjunctivitis in first few days of life) — a notifiable condition; in contrast, Chlamydia conjunctivitis presents at 5–12 days [1][2]
- Endocervical, urethral, anal, pharyngeal swabs (triple swabs if risk factors [4])
- Gram stain: diplococci on microscopy
- Culture: Thayer-Martin medium or Martin-Lewis medium
- PCR for DNA (expensive)
- At QMH: endocervical swab for culture
- Ceftriaxone 500 mg IM + Azithromycin 1 g orally (dual therapy to cover co-infection with Chlamydia and reduce resistance emergence)
- Resistant strains: quinolone
- Screen for other STDs
- Contact tracing
- Test of cure: RECOMMENDED IN ALL CASES (because of increasing antibiotic resistance)
| Feature | Candida | BV | Trichomoniasis | Chlamydia | Gonorrhoea |
|---|---|---|---|---|---|
| Organism | C. albicans (fungus) | Gardnerella + anaerobes | T. vaginalis (protozoa) | C. trachomatis (obligate intracellular) | N. gonorrhoeae (Gram -ve diplococci) |
| STI? | No | No | Yes | Yes | Yes |
| Discharge | Thick, white, cheesy | Thin, white, homogeneous, fishy | Frothy, yellowish-green, foul | Mucopurulent or subtle | Yellow-green, purulent |
| Itch | Yes (pruritus vulvae) | No | Yes | ± | ± |
| pH | Normal (< 4.5) | > 4.5 | > 4.5 | — | — |
| Diagnosis | Pseudohyphae on wet mount | Amsel's criteria / clue cells | Motile flagellates on wet mount; culture | PCR / endocervical swab | Gram stain diplococci; culture on Thayer-Martin |
| Specimen | HVS from fornix | HVS | HVS | Endocervical swab / urine | Endocervical swab |
| Treatment | Clotrimazole pessary (vaginal in pregnancy) | Metronidazole PO | Metronidazole PO | Doxycycline or azithromycin | Ceftriaxone IM + azithromycin PO |
| Partner Rx? | No | No | Yes | Yes | Yes |
| Test of cure? | No | No | Only if persistent Sx | In pregnancy only | All cases |
Part 6: Pelvic Inflammatory Disease (PID) [1]
This is the highest-yield clinical management topic in this lecture. The 2024 Fourth Summative MCQ Q89 directly tested PID management [3].
Pelvic infection — infection of the uterus, fallopian tubes, adjacent parametria & overlying peritoneum. Does NOT include vulval or vaginal infection.
- Ascending from lower genital tract — MOST COMMON
- From nearby organs (e.g. acute appendicitis)
- Haematological route
| Category | Organisms |
|---|---|
| STI-related | Chlamydia trachomatis, Neisseria gonorrhoeae |
| Aerobes | Streptococci, staphylococci, coliforms, H. influenzae |
| Anaerobes | Peptococci, streptopeptococci, Clostridium species, Bacteroides |
| Others | Mycoplasma hominis, Ureaplasma urealyticum, TB, Actinomyces |
Note: Actinomyces is associated with prolonged IUCD use — always consider this in a woman with PID and long-standing IUCD.
- Risky sexual behaviour
- Post-abortal
- Puerperium
- Following surgery
- IUCD insertion
- Abdominal pain
- Fever
- Vaginal discharge/bleeding
- Urinary symptoms
- GI symptoms
- Predisposing factors
- Previous PID history
Key examination findings:
- Fever
- BP, pulse (haemodynamic status)
- Abdomen: signs of peritonitis
- Vagina: hot, discharge
- Cervical excitation tenderness ← the most classic and important sign
- Uterine & adnexal tenderness
- Adnexal mass (tubo-ovarian complex/abscess)
Sexually active women experiencing pelvic or lower abdominal pain, in the absence of other cause, with either cervical motion OR uterine OR adnexal tenderness
This is a clinical diagnosis — you don't need lab confirmation to start treatment. The threshold for treatment should be LOW because untreated PID has devastating consequences.
- Ectopic pregnancy (always do pregnancy test!)
- Ovarian cyst complication (torsion, rupture)
- Urinary tract infection
- Acute appendicitis
| Investigation | Purpose |
|---|---|
| CBP | Leucocytosis |
| ESR, CRP | Inflammatory markers |
| Endocervical swabs | Gonococcus, Chlamydia, culture |
| High vaginal swabs | Trichomoniasis (STD screening), culture |
| VDRL | Syphilis screening |
| HIV-Ab | HIV screening |
| Pregnancy test | Exclude ectopic |
| USG pelvis | Tubo-ovarian abscess/collection |
| MSU | Exclude UTI |
| Cervical smear | If not up to date |
Critical Exam Point
ALWAYS do a pregnancy test in any reproductive-age woman with lower abdominal pain. The number one differential for PID is ectopic pregnancy. Missing this is a fatal error — literally and in exams.
Management [1]
Single dose IM Ceftriaxone 1000 mg + oral Doxycycline 100 mg BD + oral Metronidazole 400 mg BD for 14 days
Why this triple combination?
- Ceftriaxone: covers Neisseria gonorrhoeae
- Doxycycline: covers Chlamydia trachomatis and other aerobes
- Metronidazole: covers anaerobes
Alternatives:
- Oral Ofloxacin 400 mg BD + Metronidazole 400 mg BD for 14 days (note: quinolone side effects on tendons/nerves)
- Oral Moxifloxacin 400 mg daily for 14 days (best microbiological activity against M. genitalium)
- IM Ceftriaxone 1000 mg + oral Azithromycin 1 g/week for 2 weeks
Admit if:
- Surgical emergency cannot be excluded
- Clinically severe disease
- Tubo-ovarian abscess
- PID in pregnancy
- Lack of response to oral therapy
- Intolerance to oral therapy
Recommended:
- IV Ceftriaxone 2 g daily + oral Doxycycline 100 mg Q12H → then step down to oral Doxycycline 100 mg BD + Metronidazole 400 mg BD for total 14 days
- IV Cefoxitin 1–2 g Q6H
- IV Augmentin + Doxycycline
Alternative:
- IV Clindamycin 900 mg TDS + IV Gentamicin (2 mg/kg loading → 1.5 mg/kg TDS, or 7 mg/kg daily) → then oral Clindamycin 450 mg QID or Doxycycline + Metronidazole to complete 14 days
IV antibiotics continued until 24 hours after clinical improvement, then switch to oral
2024 MCQ Q89 — PID Management
Scenario: 23F, lower abdominal pain, fever, 3 sexual partners, foul-smelling discharge, cervical excitation present. The answer is A. Give single dose IM ceftriaxone, followed by oral doxycycline and metronidazole — this is the standard OUTPATIENT PID regimen. Note: the question says "admitted to gynaecology ward" but the answer corresponds to the recommended outpatient regimen (which can be initiated on the ward for mild PID). Option D (IV ceftriaxone) would be for severe/inpatient indications. [3]
Whether to remove IUD is controversial
- Balance against risk of pregnancy if unprotected intercourse in preceding 7 days
- If no clinical improvement within 48–72 hours of treatment → consider removing the IUD
- Image-guided drainage / laparoscopy / laparotomy — for tubo-ovarian abscess not responding to antibiotics
Complications of PID [1]
- Tubo-ovarian abscess
- Septic shock
| Complication | Details |
|---|---|
| Recurrent PID | 1/4 may have further episode |
| Fitz-Hugh-Curtis syndrome | Perihepatic adhesions |
| Chronic pelvic pain (dysmenorrhoea, dyspareunia) | 15–20% |
| Ectopic pregnancy | Due to tubal damage |
| Subfertility (tubal obstruction) | ~20% overall; 1 episode → 13%; 2 episodes → 36%; 3 episodes → 75% |
The subfertility statistics are classic exam content. Memorise: 13% → 36% → 75% with 1, 2, 3 episodes respectively. [1]
- Education — avoid risky sexual behaviour
- Contraception — barrier methods
- Prompt diagnosis and treatment
- Contact tracing and treatment
The "S.S.T.P.S.S.C." approach:
- Sensitive — non-judgmental approach
- Screen for other STIs (HIV, VDRL)
- Treatment — appropriate for the organism
- Partner(s) referral & treatment
- Special consideration during pregnancy
- Safer sex education
- Cervical smear — ensure up to date
- Counselling on possible sequelae
This list is directly from the final slide and is a perfect framework for SAQ answers about STI management. [1]
| Organism | Test of Cure? |
|---|---|
| Candida | No |
| GBS | No (prophylaxis-based) |
| BV | No |
| Trichomoniasis | Only if symptomatic after treatment or if symptoms recur |
| Chlamydia | Not routine; RECOMMENDED in pregnancy |
| Gonorrhoea | RECOMMENDED IN ALL CASES |
The pattern: Gonorrhoea always needs test of cure (antibiotic resistance concern). Chlamydia needs it only in pregnancy. Trichomoniasis only if persistent symptoms.
Part 9: Integration with Other Lectures
- Endocervical/urethral discharge → swab with transport medium
- For Chlamydia/Gonorrhoea: small swab with flexible wire for scraping if discharge scanty
- Both detectable by PCR (rapid) and culture (slower)
- In males: first-stream urine is good for PCR
- Triple swabs (cervical + anal + throat) in homosexual patients or those with exposure history
- Gram stain: clue cells = BV; high WBC = vaginitis/cervicitis
- PID as a cause of RLQ pain — differentials include appendicitis, ectopic pregnancy, ovarian cyst complications
- Cervical excitation tenderness is the hallmark
- Clinical assessment framework: chief complaint, sexual behaviour, risk behaviours (chemsex), past STI testing, menstrual/contraceptive/obstetric history, partner history
- Ophthalmia neonatorum: any conjunctivitis in first 28 days
- Gonococcal → first few days; Chlamydial → 5–12 days
- Management: topical/systemic antibiotics + paediatrician referral + maternal STD screening
Likely Exam Questions
-
A 35-week pregnant woman is found positive on GBS screening. She goes into spontaneous labour at 39 weeks. What is the most appropriate action? → IV benzylpenicillin (IAP indicated: positive screening + in labour)
-
A woman presents with thin, white, fishy-smelling discharge. pH 5.5. Clue cells on microscopy. What is the diagnosis? → Bacterial vaginosis (3/4 Amsel's criteria met)
-
Which vaginal infection requires test of cure in ALL cases? → Gonorrhoea
-
A woman with PID has had 2 previous episodes. What is her approximate risk of subfertility? → 36%
-
List the indications for intrapartum antibiotic prophylaxis for GBS. (7 marks — 1 per indication) → Previous invasive neonatal GBS; GBS bacteriuria this pregnancy; positive screening; gestation < 37 weeks (if not negative screen); maternal fever > 38°C; PROM > 18 hours; screening results unavailable at labour onset
-
Describe the outpatient management of PID. (5 marks) → IM Ceftriaxone 1000 mg single dose + oral Doxycycline 100 mg BD for 14 days + oral Metronidazole 400 mg BD for 14 days. Screen for other STDs. Contact tracing.
-
List the Amsel's criteria for diagnosing bacterial vaginosis. (4 marks) → Thin white homogeneous discharge; clue cells on microscopy; vaginal pH > 4.5; positive whiff test with 10% KOH. Need 3 out of 4.
- A 24-year-old woman with lower abdominal pain, fever, and cervical excitation tenderness. Pregnancy test negative. List the key investigations. (6 marks) → CBP, ESR/CRP, endocervical swabs (GC, CT, culture), HVS (TV, culture), pregnancy test, VDRL, HIV-Ab, ± USG pelvis
High Yield Summary
Core infections to know: Candidiasis (NOT STI; cheesy discharge; treat with topical azoles, vaginal route in pregnancy), GBS (screen at 35–37 weeks; IAP with IV penicillin G if indicated), BV (commonest cause of discharge; Amsel's criteria 3/4; metronidazole; NOT STI), Trichomoniasis (flagellated protozoa; frothy yellow-green discharge; strawberry cervix; metronidazole + treat partner), Chlamydia (75% asymptomatic; obligate intracellular; doxycycline/azithromycin; complications = PID, Fitz-Hugh-Curtis, Reiter's; neonatal conjunctivitis at 5–12 days), Gonorrhoea (Gram-negative diplococci; ceftriaxone + azithromycin; test of cure in ALL cases; ophthalmia neonatorum in first few days).
PID: Ascending infection; clinical diagnosis = sexually active + lower abdominal pain + cervical motion/uterine/adnexal tenderness; ALWAYS exclude ectopic pregnancy; outpatient = IM ceftriaxone + PO doxycycline + PO metronidazole x14d; admit if severe/abscess/pregnancy/failed oral Rx; subfertility risk escalates: 13% → 36% → 75% with 1, 2, 3 episodes.
GBS IAP: 7 indications (previous invasive GBS, GBS bacteriuria, positive screen, < 37 weeks, fever > 38°C, PROM > 18h, results unavailable). Drug = IV penicillin G. Does NOT prevent late-onset GBS.
Approach to STI: Be sensitive; screen for other STIs including HIV/VDRL; treat; trace and treat partners; pregnancy considerations; safer sex education; cervical smear; counsel on sequelae.
Active Recall - Vaginal Discharge & O&G Infections
[1] Lecture slides: GC 119. Vaginal discharge obstetric and gynaecological infections.pdf (all pages) [2] Senior notes: MBBS Final MB (Medicine) (Felix PY Lai).pdf (p.1049–1054) — Chlamydia and Gonorrhoea sections [3] Past papers: 2024 Fourth Summative MCQ.pdf (Q89); 2025 Fourth Summative MCQ.pdf (Q75) [4] Lecture slides: GC 101. Diagnosis of infections [Handouts].pdf (p.2, p.7 — genital tract specimen collection) [5] Lecture slides: GC 195. Lower and diffuse abdominal pain RLQ problems; pelvic inflammatory disease; peritonitis and abdominal emergencies.pdf [6] Lecture slides: Dermatology STD Teaching by Dr KM Ho 2.pdf (p.1, p.13) [7] Senior notes: Ryan Ho Opthalmology.pdf (p.125 — ophthalmia neonatorum)
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