Atlas of pathophysiology, 2 Edition

Part II - Disorders

Genital Diseases

Dysfunctional Uterine Bleeding

Dysfunctional uterine bleeding refers to endometrial bleeding without recognizable organic lesions. It's the indication for almost 25% of gynecologic surgical procedures. The prognosis varies with the cause. Correction of hormonal imbalance or structural abnormality yields a good prognosis.

Age Alert

Approximately 20% of dysfunctional uterine bleeding cases occur in adolescents and 40% in women over age 40.

Causes

·   Polycystic ovarian syndrome

·   Obesity—enzymes in peripheral adipose tissue convert the androgen androstenedione to estrogens

·   Immaturity of the hypothalamic-pituitary-ovarian mechanism (postpubertal teenagers)

·   Anovulation (women in their late 30s or early 40s)

·   Hormone-producing ovarian tumor

·   Endometriosis

·   Sexual assault

·   Trauma

·   Pelvic inflammatory disease

·   Coagulopathy

Pathophysiology

Irregular bleeding is associated with hormonal imbalance and absence of ovulation (anovulation). When progesterone secretion is absent but estrogen secretion continues, the endometrium proliferates and become hypervascular. When ovulation doesn't occur, the endometrium randomly breaks down, and exposed vascular channels cause prolonged and excessive bleeding. In the absence of adequate progesterone levels, the usual endometrial control mechanisms are missing, such as vasoconstrictive rhythmicity, tight coiling of spiral vessels, and orderly collapse, and stasis doesn't occur. Unopposed estrogen induces a progression of endometrial responses beginning with proliferation, hyperplasia, and adenomatous hyperplasia; over a course of years, unopposed estrogen may lead to atypia and carcinoma.

Signs and symptoms

·   Metrorrhagia—episodes of vaginal bleeding between menses

·   Hypermenorrhea—heavy or prolonged menses, longer than 8 days

·   Chronic polymenorrhea (menstrual cycle less than 18 days) or oligomenorrhea (infrequent menses)

·   Fatigue due to anemia

·   Oligomenorrhea and infertility due to anovulation

Diagnostic test results

·   Laboratory studies reveal decreased progesterone levels.

·   Complete blood count test reveals anemia if excessive bleeding is present.

·   Coagulation profile detects prolonged bleeding times in the presence of a coagulation disorder.

·   Thyroid studies detect abnormal thyroid hormone levels.

·   Dilation and curettage and endometrial biopsy detect endometrial hyperplasia or carcinoma.

Treatment

·   High-dose estrogen-progestogen combination therapy (oral contraceptives) to control endometrial growth and reestablish a normal cyclic pattern of menstruation (usually given four times daily for 5 to 7 days even though bleeding usually stops in 12 to 24 hours; drug choice and dosage determined by patient's age and cause of bleeding); maintenance therapy with lower dose combination oral contraceptives

·   Progestogen therapy—alternative in many women, especially those susceptible to adverse effects of estrogen such as thrombophlebitis

·   I.V. estrogen followed by progesterone or combination oral contraceptives if the patient is young (more likely to be anovulatory) and severely anemic (if oral drug therapy is ineffective)

·   Iron replacement or transfusions of packed cells or whole blood, as indicated, due to anemia caused by recurrent bleeding

·   Dilatation and curettage

·   Endometrial oblation

·   Hysterectomy

P.311

DYSFUNCTIONAL UTERINE BLEEDING

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