Chapter 106: Vaginal discharge

INTRODUCTION

Vaginal discharge is a common complaint seen by family physicians, yet it is often difficult to solve, especially if it is recurrent or persistent. Women may complain of an increase in the amount of discharge, a change in the consistency or colour and the presence of an offensive odour. It is important to make a proper diagnosis, to differentiate between normal (physiological) and pathological discharge and to be aware of the considerable variation in secretion of vaginal fluid.

This variation extends to different age groups, with microbial causes less likely in prepubertal girls and the elderly, who more often present with dermatoses and symptoms related to reduced vaginal oestrogen.

The differential diagnoses should include consideration of normal discharge, vaginal candidiasis, bacterial vaginosis (BV), STIs, foreign body, vulval dermatoses, atrophic vaginitis and genital tract malignancy.

A DIAGNOSTIC APPROACH

A summary of the diagnostic strategy model is presented in TABLE 106.1.

Probability diagnosis

The most common causes of vaginal discharge are physiological discharge, vulovaginal candidiasis and bacterial vaginosis.

Physiological discharge

Normal physiological discharge is usually milky-white or clear mucoid and originates from a combination of the following sources:

• cervical mucus (secretions from cervical glands)

• vaginal secretion (transudate through vaginal mucosa)

• vaginal squamous epithelial cells (desquamation)

• cervical columnar epithelial cells

• resident commensal bacteria

The predominant bacterial flora are lactobacilli, which produce lactic acid from glucose derived from the epithelial cells. The lactic acid keeps the vaginal pH acidic (<4.7). Other commensal bacteria include staphylococci, diphtheroids and streptococci.

With physiological discharge there is usually no odour or pruritus.

In addition, the egg-white discharge accompanying ovulation may be noted. Normal discharge usually shows on underwear by the end of the day. Clear or white, it oxidises to a yellow or brown on contact with air. It is ...