Genitourinary problems associated with menopause

Drug Store News, Jan 22, 1990 by William J. Bologna

Genitourinary problems associated with menopause

Jan. 22, 1990, lesson 679-401-90-01

Goal: To provide pharmacists with practical knowledge of the pathophysiology and contemporary treatment of vaginal dryness and menopause-linked urinary incontinence.

Objectives: After completing this lesson, the pharmacist should be able to: 1. Describe the pathophysiology of vaginal dryness. 2. Describe the role of estrogen and progesterone in the production of vaginal fluids and maturation of the vaginal mucosa. 3. Describe the role of hormones in maintaining the normal vaginal ecology. 4. Describe the role of lactobacilli and the acid environment they create in preventing vaginal infections. 5. Describe the common vaginal infections and appropriate therapy. 6. Discuss the advantages and disadvantages of using oral and transdermal estrogen replacement therapy (ERT), topical estrogen creams, and nonhormonal methods of preventing vaginal dryness.

The vaginal wall is composed of three layers: the tunica externa (adventitia), the muscularis, and the mucosa. The tunica externa, the outer coat, is made up of dense connective tissue with many coarse elastic fibers. The muscularis makes up the bulk of the vaginal wall and mainly consists of smooth muscle and dense connective tissue. The muscle bundles are primarily arranged longitudinally, with a smaller inner portion of circular fibers. The mucosa is composed of an epithelium (outer layer of cells) with a basement membrane and a lamina propria. The lamina propria is a dense, thin layer of connective tissue with an interlacing network of elastic fibers.

The epithelium, the outermost layer, lies above the basement membrane and consists of stratified squamous epithelium subdivided into four parts: basal, parabasal, intermediate, and superficial layers. The hormonal milieu determines the relative proportion of each of the three outer layers.

The vagina begins as a potential cavity, with the walls in apposition in women who have not had children. With the tearing and stretching of childbirth or the loss of vaginal support that occurs at menopause, a persistent cavity is created. In women who have not had children, the vaginal epithelium contains numerous rugae (ridges). These rugae are lost after multiple childbirth and at menopause, resulting in the smooth and shiny appearance of the postmenopausal vagina.

Physiology

The vaginal mucosa, the lining of the vagina, must be lubricated in order to provide adequate protective moisture day to day. Mucosa is really a misnomer, since the vaginal lining does not contain mucus-producing glands to lubricate the tissue except for the Bartholin's and Skene's glands, which are located near the vaginal opening.

Vaginal secretions, including those needed for lubrication during sexual arousal, arise predominantly from fluid that flows through the vaginal wall (transudation), cervical mucus, and cells that are sloughed off the vaginal mucosa.

Cervical mucus is an important contributor to vaginal secretion. It is primarily (90 percent to 95 percent) water in addition to both low-molecular-weight components such as inorganic and organic salts, and high-molecular-weight components such as mucin and proteins. The most distinctive constituent of cervical mucus is the glycoprotein called mucin. Mucus, which contains mucin, is a naturally occurring bioadhesive; it can adhere to a variety of molecules and binds firmly to the cell surface of vaginal epithelial cells. Mucus protects the underlying surface by acting as a barrier.

The mean quantity of vaginal secretion produced by women of reproductive age is approximately 1 to 3 grams/day. Sexual stimulation increases the production of vaginal fluid as a result of increased vascularity. (Blood vessels dilate and, as a result, more blood flows into the area.) This increase in fluid production during sexual arousal is important to avoid undue friction during intercourse.

The physiologic role

of estrogen

The vagina remains remarkably sensitive to estrogen throughout its lifetime. Receptors for estrogen have been demonstrated within the vaginal tissue, with the highest concentration found in the basal and parabasal cells. The quantity of these receptors is independent of the woman's age or menopausal status. Thus, the changes seen in the postmenopausal woman can be attributed, for the most part, to the lack of hormonal support of the vagina rather than to the loss of the capacity to respond.

The outer portion of the vaginal mucosa is composed of four epithelial cell types, three of which are regularly exfoliated (sloughed off): parabasal cells, intermediate cells, and superficial cells. Basal cells are only exfoliated after extensive trauma or radiation exposure.

The parabasal cell is the most immature of the three regularly exfoliated cell types. Its presence in the vaginal discharge usually means a low level of estrogen stimulation. The superficial cell is the most mature; its presence indicates that there is normal estrogen stimulation. In women who have adequate levels of estrogen, the superficial cells are located on the surface of the vaginal mucosa and the intermediate cells are just below them.