Vaginal Discharge
Differential Diagnosis
Common Diagnoses
- Excessive Normal Secretions
- Thrush
- Bacterial Vaginosis (BV)
- Trichomonal Vaginosis (TV)
- Cervicitis (Gonococcus, Chlamydia, Herpes)
Occasional Diagnoses
- Cervical Ectropion
- Cervical Polyp
- Lost Tampon, Ring Pessary or other Foreign Body
- IUCD
- Bartholinitis
- Salpingitis
Rare Diagnoses
- Vulvovaginal Neoplasia
- Cervical or Uterine Neoplasia
- Sloughing Intrauterine Fibroid
- Pyometra
- Pelvic Fistula
Ready Reckoner
Key distinguishing features of the most common diagnoses
| Normal | Thrush | BV | TV | Cervicitis | |
|---|---|---|---|---|---|
| Intense Itch | No | Yes | No | Possible | Possible |
| Offensive Smell | No | No | Yes | Yes | Possible |
| Vulval Soreness | No | Yes | No | Yes | Possible |
| Yellow/Green/Grey (Mucopurulent) Discharge | No | No | Yes | Yes | Yes |
| Inflamed Cervix | No | No | No | Yes | Yes |
Possible Investigations
Likely:High vaginal swab (HVS).
Possible:Endocervical swab, urethral swab, urine testing for Chlamydia, blood sugar or HbA1c.
Small Print:Other specialist investigations.
- Most GPs would confine themselves to the HVS, endocervical swab and urine test. Those with a special interest might undertake the microscopy themselves.
- HVS is simple and readily detects Candida, BV and TV.
- Wet saline microscopy shows clue cells in BV, motile trichomonads in TV.
- Gram stain of cervical or urethral exudate shows negatively staining diplococci in up to 85% of gonococcal infections.
- Endocervical swab for ELISA is the gold standard for detecting Chlamydia.
- DNA amplification testing of first-catch urine (not MSU) specimens for Chlamydia is noninvasive and relatively acceptable to patients.
- Blood sugar or HbA1c: To detect diabetes in severe or recurrent thrush.
- Specialist investigations might include D&C or hysteroscopy (for possible malignancy) and barium enema (for pelvic fistula).
Top Tips
- It is reasonable to diagnose and treat thrush empirically in a woman with classical symptoms who has had the problem before – many women successfully self-medicate and only attend to obtain their treatment free, via a prescription. But if in any doubt about the diagnosis, examine and investigate as appropriate.
- It is worth investing time with the patient suffering confirmed recurrent thrush – advice supplemented by written patient information may help minimise future problems.
- Make sure you have all the appropriate swabs (HVS, endocervical, urethral) to hand – you never know when you might need them.
- Excessive concern about normal secretions might mask a sexual problem or worry – enquire discreetly about this.
Red Flags
- Recurrent or florid thrush may be a presentation of undiagnosed diabetes mellitus. Ask about thirst, polyuria and tiredness and check a fasting glucose if any suspicion of underlying diabetes, or there is a positive family history of diabetes.
- Vaginal discharge is an uncommon symptom before puberty. Don’t forget the possibilities of abuse or a foreign body.
- Always conduct a full pelvic examination in the post-menopausal woman with vaginal discharge. Malignancy is one of the likeliest causes.
- A florid erosion is likely to be caused by chlamydial cervicitis – take a swab and treat appropriately.
- If you suspect a sexually transmitted disease, refer to the GUM clinic for full assessment and contact tracing. Refer urgently to the GUM clinic or duty gynaecologist if there are systemic flu-like symptoms and fever with pelvic pain and vaginal discharge.