What is the pathophysiology of vaginitis?

Updated: Dec 04, 2018
  • Author: Hetal B Gor, MD, FACOG; Chief Editor: Michel E Rivlin, MD  more...
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A complex and intricate balance of microorganisms maintains the normal vaginal flora. Important organisms include lactobacilli, corynebacteria, and yeast. Aerobic and anaerobic bacteria can be cultured from the vagina of prepubertal girls, pubertal adolescents, and adult women. A number of factors can change the composition of the vaginal flora, including the following:

  • Age

  • Sexual activity (or abuse)

  • Hormonal status

  • Hygiene

  • Immunologic status

  • Underlying skin diseases

The normal postmenarchal and premenopausal vaginal pH is 3.8-4.2. At this pH, growth of pathogenic organisms usually is inhibited. Disturbance of the normal vaginal pH can alter the vaginal flora, leading to overgrowth of pathogens. Factors that alter the vaginal environment include feminine hygiene products, contraceptives, vaginal medications, antibiotics, sexually transmitted diseases (STDs), sexual intercourse, and stress.

The overgrowth of normally present bacteria, infecting bacteria, or viruses can cause symptoms of vaginitis. Chemical irritation also can be a significant factor. Atrophic vaginitis is associated with hypoestrogenism, and symptoms include dyspareunia, dryness, pruritus, and abnormal bleeding. A state of decreased estrogen can result in an altered risk of infection.

Based on data from 11 countries, Kenyon and Colebunders found evidence that the risk of bacterial vaginosis is increased in women whose male sexual partner is concurrently having sexual relations with other partners. [1]

The age of the patient affects the anatomy and physiology of the vagina. Prepubertal children have a more alkaline vaginal pH than do pubertal and postpubertal adolescents and women. The vaginal mucosa is squamous epithelium, vaginal mucous glands are absent, the normal vaginal flora is similar to that of postmenopausal women (eg, gram-positive cocci and anaerobic gram-negatives are more common), and the labia are thin with a thin hymen.

Pubertal and postpubertal adolescents and women have a more acidic vaginal pH, a stratified squamous vaginal mucosa, vaginal mucous glands, a normal vaginal flora dominated by lactobacilli, thick labia, and hypertrophied hymens and vaginal walls. Loss of vaginal lactobacilli appears to be the primary factor in the changes leading to bacterial vaginosis. Recurrences of vaginitis are associated with a failure to establish a healthy vaginal microflora dominated by lactobacilli.

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