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

NormalThrushBVTVCervicitis
Intense ItchNoYesNoPossiblePossible
Offensive SmellNoNoYesYesPossible
Vulval SorenessNoYesNoYesPossible
Yellow/Green/Grey (Mucopurulent) DischargeNoNoYesYesYes
Inflamed CervixNoNoNoYesYes

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.
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