Medical brain notes 42

  AMENORRHEA   Amenorrhea  (the  absence  of  menstruation)  and A  abnormal uterine bleeding are the most commongynecologic disorders of reproductive-age women. Amenorrhea and abnormal uterine bleeding are discussed as separate topics. However, the pathophysiol-ogy underlying amenorrhea and abnormal uterine bleeding  is often the same.   If a young woman has never menstruated by age 13 with-out secondary sexual development or by age 15 with sec-ondary sexual development, she is classified as having  primary amenorrhea.  If a menstruating woman has notmenstruated for 3 to 6 months or for the duration of three typical menstrual cycles for the patient with oligomenor-rhea, she is classified as having  secondary amenorrhea.  The designation of primary or secondary amenorrhea has no bearing on the severity of the underlying disorder or on the prognosis for restoring cyclic ovulation. Terms often confused with these includ...

  Causes of Amenorrhea   When endocrine function along the hypothalamic– pituitary–ovarian axis is disrupted or an abnormality devel-ops in the genital outflow tract (obstruction of the uterus, cervix, or vagina or scarring of the endometrium), menstru-ation ceases. Causes of amenorrhea are divided into those arising from (1) pregnancy, (2) hypothalamic–pituitary dys-function, (3) ovarian dysfunction, and (4) alteration of the genital outflow tract.   PREGNANCY Because pregnancy is the most common cause of amenorrhea, it is essential to exclude pregnancy in the evaluation of amenorrhea. A history of breast fullness, weight gain, and nausea suggest the diagnosis of pregnancy, which is confirmed by a positive human chorionic gonadotropin (hCG) assay. It is important to rule out pregnancy to allay the patient’s anxiety and to avoid unnecessary testing. Also, some treatments for other causes of amenorrhea can be harmful to an ongoing pregnancy. Lastly, the diag-nosis of ectop...

  Treatment of Amenorrhea   The first step is to establish a cause for the amenorrhea. The progesterone “challenge test” is commonly used to deter-mine whether or not the patient has adequate estrogen, a competent endometrium, and a patent outflow tract. An injection of 100 mg of progesterone in oil or a 5-day to 14-day course of oral medroxyprogesterone acetate or micronized progesterone is expected to induce proges-terone withdrawal bleeding within a few days after com-pleting the oral course. If bleeding does occur, the patient is likely to be anovulatory or oligo-ovulatory. If withdrawal bleeding does not occur, the patient may be hypoestro-genic or have an anatomic condition such as Asherman syndrome or outflow tract obstruction.   Hyperprolactinemia associated with some pituitary adeno-mas (or other medical conditions) results in amenorrhea and  galactorrhea  (a milky discharge from the breast). Approxi-mately 80% of all pituitary tumors secrete prolactin,...

  ABNORMAL UTERINE BLEEDING   Failure to ovulate results in either amenorrhea or irregu-lar uterine bleeding. Irregular bleeding that is unrelated to anatomic lesions of the uterus is referred to as  anovula-tory uterine bleeding.  It is most likely to occur in asso-ciation with anovulation as found in polycystic ovarian disease, exogenous obesity, or adrenal hyperplasia.   Women with hypothalamic amenorrhea (hypothalamic– pituitary dysfunction) and no genital tract obstruction are in a state of estrogen deficiency.  Estrogen is inadequate to stimulategrowth and development of the endometrium. Therefore, there is inadequate endometrium for uterine bleeding to occur.  In contrast, women with oligo-ovulation and anovulationwith abnormal uterine bleeding have constant, noncyclic blood estrogen concentrations that stimulate growth and development of the endometrium.  Without the predictable effect of ovulation,progesterone-induced changes do not occur...