Wednesday, October 23, 2019 11:13

Obstetrical Diseases

Tagged with:
Posted by on Wednesday, September 8, 2010, 3:02
This news item was posted in O, Obstetrical category and has 0 Comments so far.

Medical care of the obstetric or gynecologic patient reflects a growing interest in improving the quality of health care for females. Today, you must be able to assess, counsel, teach, and refer these patients, while weighing such relevant factors as the desire to have children, sexual adjustment problems, and self-image. Frequently, the situation is further complicated by the fact that multiple obstetric and gynecologic abnormalities often occur simultaneously. For example, a patient with dysmenorrhea may also have trichomonal vaginitis, dysuria, and unsuspected infertility. Her condition may be further complicated by associated urologic disorders, due to the proximity of the urinary and reproductive systems. This tendency to multiple and complex disorders is readily understandable upon review of the female genitalia’s anatomic structure. (See  External and internal female genitalia.)
External structures

Female genitalia include the following external structures, collectively known as the vulva: mons pubis (or mons veneris), labia majora, labia minora, clitoris, and the vestibule. The perineum is the external region between the vulva and the anus. The size, shape, and color of these structures — as well as pubic hair distribution and skin texture and pigmentation — vary greatly among individuals. Furthermore, these external structures undergo distinct changes during the life cycle.

Obstetrical Diseases
Obstetrical Diseases

The mons pubis is the pad of fat over the symphysis pubis (pubic bone), which is usually covered by the base of the inverted triangular patch of pubic hair that grows over the vulva after puberty.

The labia majora are the two thick, longitudinal folds of fatty tissue that extend from the mons pubis to the posterior aspect of the perineum. The labia majora protect the perineum and contain large sebaceous glands that help maintain lubrication. Virtually absent in the young child, their development is a characteristic sign of puberty’s onset. The skin of the more prominent parts of the labia majora is pigmented and darkens after puberty.

The labia minora are the two thin, longitudinal folds of skin that border the vestibule. Firmer than the labia majora, they extend from the clitoris to the fourchette.

The clitoris is the small, protuberant organ located just beneath the arch of the mons pubis. The clitoris contains erectile tissue, venous cavernous spaces, and specialized sensory corpuscles that are stimulated during coitus.

The vestibule is the oval space bordered by the clitoris, labia minora, and fourchette. The urethral meatus is located in the anterior portion of the vestibule; the vaginal meatus, in the posterior portion. The hymen is the elastic membrane that partially obstructs the vaginal meatus in virgins.

Several glands lubricate the vestibule. Skene’s glands open on both sides of the urethral meatus; Bartholin’s glands, on both sides of the vaginal meatus.

The fourchette is the posterior junction of the labia majora and labia minora. The perineum, which includes the underlying muscles and fascia, is the external surface of the floor of the pelvis, extending from the fourchette to the anus.
Internal structures

The following internal structures are included in the female genitalia: vagina, cervix, uterus, fallopian tubes (or oviducts), and ovaries.

The vagina occupies the space between the bladder and the rectum. A muscular, membranous tube that’s approximately 3″(7.5 cm) long, the vagina connects the uterus and the vestibule of the external genitalia. It serves as a passageway for sperm to the fallopian tubes, for the discharge of menstrual fluid, and for childbirth.

The cervix, or neck of the uterus, protrudes at least ¾”(2 cm) into the proximal end of the vagina. A rounded, conical structure, the cervix joins the uterus and the vagina at a 45- to 90-degree angle.

The uterus is the hollow, pear-shaped organ in which the conceptus grows during pregnancy. The part of the uterus above the junction of the fallopian tubes is called the fundus; the part below this junction is called the corpus. The junction of the corpus and cervix forms the lower uterine segment.

The thick uterine wall consists of mucosal, muscular, and serous layers. The inner mucosal lining — the endometrium — undergoes cyclic changes to facilitate and maintain pregnancy.

The smooth muscular middle layer — the myometrium — interlaces the uterine and ovarian arteries and veins that circulate blood through the uterus. During pregnancy, this vascular system expands dramatically. After abortion or childbirth, the myometrium contracts to constrict the vasculature and control blood loss.

The outer serous layer — the parietal peritoneum — covers all of the fundus, part of the corpus, but none of the cervix. This incompleteness allows surgical entry into the uterus without incision of the peritoneum, thereby reducing the risk of peritonitis.

The fallopian tubes extend from the sides of the fundus and terminate near the ovaries. Through ciliary and muscular action, these small tubes (3¼”to 5½”[8 to 14 cm] long) carry ova from the ovaries to the uterus and facilitate the movement of sperm from the uterus toward the ovaries. Fertilization of the ovum normally occurs in a fallopian tube. The same ciliary and muscular action helps move a zygote (fertilized ovum) down to the uterus, where it implants in the blood-rich inner uterine lining, the endometrium.

The ovaries are two almond-shaped organs, one on either side of the fundus, that are situated behind and below the fallopian tubes. The ovaries produce ova and two primary hormones — estrogen and progesterone — in addition to small amounts of androgen. These hormones, in turn, produce and maintain secondary sex characteristics, prepare the uterus for pregnancy, and stimulate mammary gland development.

The ovaries are connected to the uterus by the utero-ovarian ligament and are divided into two parts: the cortex, which contains primordial and graafian follicles in various stages of development, and the medulla, which consists primarily of vasculature and loose connective tissue.

A normal female is born with at least 400,000 primordial follicles in her ovaries. At puberty, these ova precursors become graafian follicles, in response to the effects of pituitary gonadotropic hormones — follicle-stimulating hormone (FSH) and luteinizing hormone (LH). In the life cycle of a female, however, less than 500 ova eventually mature and develop the potential for fertilization.
The menstrual cycle

Maturation of the hypothalamus and the resultant increase in hormone levels initiate puberty. In the young girl, breast development — the first sign of puberty — is followed by the appearance of pubic and axillary hair and the characteristic adolescent growth spurt. The reproductive system begins to undergo a series of hormone-induced changes that result in menarche, onset of menstruation (or menses). In North American females, menarche usually occurs at about age 13 but may occur between ages 9 and 18. Menstrual periods initially are irregular and anovulatory, but after a year or so, they become more regular. (See Menstrual cycle.)

The menstrual cycle consists of three different phases: menstrual, proliferative (estrogen-dominated), and secretory (progesterone-dominated). These phases correspond to the phases of ovarian function. The menstrual and proliferative phases correspond to the follicular ovarian phase; the secretory phase corresponds to the luteal ovarian phase.

The menstrual phase begins with day 1 of menstruation. During this phase, low estrogen and progesterone levels stimulate the hypothalamus to secrete gonadotropin-releasing hormone (Gn-RH). This substance, in turn, stimulates pituitary secretion of FSH and LH. When the FSH level rises, LH output increases.

The proliferative (follicular) phase lasts from cycle day 6 to day 14. During this phase, LH and FSH act on the ovarian follicle, causing estrogen secretion, which in turn stimulates the buildup of the endometrium. Late in this phase, estrogen levels peak, FSH secretion declines, and LH secretion increases, surging at midcycle (around day 14). Then estrogen production decreases, the follicle matures, and ovulation occurs.

During the secretory phase, FSH and LH levels drop. Estrogen levels decline initially, then increase along with progesterone levels as the corpus luteum begins functioning. During this phase, the endometrium responds to progesterone stimulation by becoming thick and secretory in preparation for implantation of a fertilized ovum. About 10 to 12 days after ovulation, the corpus luteum begins to diminish, as do estrogen and progesterone levels, until hormone levels are insufficient to sustain the endometrium in a fully developed secretory state. Then the endometrial lining is shed (menses). Subsequently decreasing estrogen and progesterone levels stimulate the hypothalamus to produce Gn-RH, which in turn begins the cycle again.

In the nonpregnant female, LH controls the secretions of the corpus luteum; in the pregnant female, human chorionic gonadotropin (hCG) controls them. At the end of the secretory phase, the uterine lining is ready to receive and nourish a zygote. If fertilization doesn’t occur, increasing estrogen and progesterone levels decrease LH and FSH production. Because LH is necessary to maintain the corpus luteum, a decrease in LH production causes the corpus luteum to atrophy and stop secreting estrogen and progesterone. The thickened uterine lining then begins to slough off, and menstruation begins again.

If fertilization and pregnancy do occur, the endometrium grows even thicker. After implantation of the zygote (about 5 or 6 days after fertilization), the endometrium becomes the decidua. Chorionic villi produce hCG soon after implantation, stimulating the corpus luteum to continue secreting estrogen and progesterone, which prevents further ovulation and menstruation.

HCG continues to stimulate the corpus luteum until the placenta — the vascular organ that develops to transport materials to and from the fetus — forms and starts producing its own estrogen and progesterone. After the placenta takes over hormonal production, secretions of the corpus luteum are no longer needed to maintain the pregnancy, and the corpus luteum gradually decreases its function and begins to degenerate.

Cell multiplication and differentiation begin in the zygote at the moment of conception. By about 17 days after conception, the placenta has established circulation to what is now an embryo (the term used for the conceptus between the 2nd and 7th weeks of pregnancy). By the end of the embryonic stage, fetal structures are formed. Further development now consists primarily of growth and maturation of already formed structures. From this point until birth, the conceptus is called a fetus.
First trimester

Normal pregnancies last an average of 280 days. Although pregnancies vary in duration, they’re conveniently divided into three trimesters.

During the first trimester, a female usually experiences physical changes, such as amenorrhea, urinary frequency, nausea and vomiting (more severe in the morning or when the stomach is empty), breast swelling and tenderness, fatigue, increased vaginal secretions, and constipation.

Within 7 to 10 days after conception, pregnancy tests, which detect hCG in the urine and serum, are usually positive. A pelvic examination at this stage can yield various findings, such as Hegar’s sign (cervical and uterine softening), Chadwick’s sign (a bluish coloration of the vagina and cervix resulting from increased venous circulation), and enlargement of the uterus. A pelvic examination will help estimate gestational age but vaginal sonography is more accurate.

The first trimester is a critical time during pregnancy. Rapid cell differentiation makes the developing embryo or fetus highly susceptible to the teratogenetic effects of viruses, alcohol, cigarettes, caffeine, and other drugs.
Second trimester

From the 13th to the 28th week of pregnancy, uterine and fetal size increase substantially, causing weight gain, a thickening waistline, abdominal enlargement and, possibly, reddish streaks as abdominal skin stretches (striation). In addition, pigment changes may cause skin alterations, such as linea nigra, melasma (mask of pregnancy), and a darkening of the areolae of the nipples.

Other physical changes may include diaphoresis, increased salivation, indigestion, continuing constipation, hemorrhoids, nosebleeds, and some dependent edema. The breasts become larger and heavier, and approximately 19 weeks after the last menstrual period, they may secrete colostrum. By about the 18th to the 20th week of pregnancy, the fetus is large enough for the mother to feel it move (quickening).
Third trimester

During this period, the mother feels Braxton Hicks contractions — sporadic episodes of painless uterine tightening — which help strengthen uterine muscles in preparation for labor. Increasing uterine size may displace pelvic and intestinal structures, causing indigestion, protrusion of the umbilicus, shortness of breath, and insomnia. The mother may experience backaches because she walks with a swaybacked posture to counteract her frontal weight. By lying down, she can help minimize the development of varicose veins, hemorrhoids, and ankle edema.
Labor and delivery

About 2 to 4 weeks before birth, lighten-ing — the descent of the fetal head into the pelvis — shifts the uterine position. This relieves pressure on the diaphragm and enables the mother to breathe more easily.

Onset of labor characteristically produces low back pain and passage of a small amount of bloody “show.” A brownish or blood-tinged plug of cervical mucus may be passed up to 2 weeks before labor. As labor progresses, the cervix becomes soft, then effaces and dilates; the amniotic membranes may rupture spontaneously, causing a gush or leakage of amniotic fluid. Uterine contractions become increasingly regular, frequent, intense, and long.

Labor is usually divided into four stages:

❑ Stage I, the longest stage, lasts from onset of regular contractions until full cervical dilation (4″[10 cm]). Average duration of this stage is about 12 hours for a primigravida and 6 hours for a multigravida.

❑ Stage II lasts from full cervical dilation until delivery of the infant — about 1 to 3 hours for a primigravida, 30 to 60 minutes for a multigravida.

❑ Stage III, the time between delivery and expulsion of the placenta, usually lasts several minutes (duration varies widely) but may last up to 30 minutes.

❑ Stage IV is a period of recovery during which homeostasis is re-established. This final stage lasts 1 to 4 hours after the placenta is expelled.
Sources of pathology

In no other body part do so many interrelated physiologic functions occur so close together as in the area of the female reproductive tract. Besides the internal genitalia, the female pelvis contains the organs of the urinary and the GI systems (bladder, ureters, urethra, sigmoid colon, and rectum). The reproductive tract and its surrounding area are thus the site of urination, defecation, menstruation, ovulation, copulation, impregnation, and parturition. It’s easy to understand how an abnormality in one pelvic organ can readily induce abnormality in another.

When conducting a pelvic examination, therefore, you must consider all possible sources of pathology. Remember that some serious abnormalities of the pelvic organs can be asymptomatic. Remember, too, that some abnormal findings in the pelvic area may result from pathologic changes in other organ systems, such as the upper urinary and GI tracts, the endocrine glands, and the neuromusculoskeletal system. Pain symptoms are often associated with the menstrual cycle; therefore, in many common diseases of the female reproductive tract, such pain follows a cyclic pattern. A patient with pelvic inflammatory disease, for example, may complain of increasing premenstrual pain that’s relieved by onset of menstruation.
Pelvic examination

A pelvic examination and a thorough patient history are essential for any patient with symptoms related to the reproductive tract or adjacent body systems. Document any history of pregnancy, miscarriage, and abortion. Ask the patient if she has experienced any recent changes in her urinary habits or menstrual cycle. If she practices birth control, find out what method she uses and whether she has experienced any adverse effects.

Then prepare the patient for the pelvic examination as follows:

❑ Ask the patient if she has douched within the last 24 hours. Explain that douching washes away cells or organisms that the examination is designed to evaluate.

❑ Check weight and blood pressure.

❑ For the patient’s comfort, instruct her to empty her bladder before the examination. Provide a urine specimen container if needed.

❑ To help the patient relax, which is essential for a thorough pelvic examination, explain what the examination entails and why it’s necessary.

❑ If the patient is scheduled for a Papanicolaou (Pap) test, inform her that another smear may have to be taken later if there are abnormal findings with the first test. Reassure her that this is done to confirm the first test’s results. If she has never had a Pap test before, tell her it may be uncomfortable.

❑ After the Pap test, a bimanual examination is performed to assess the size and location of the ovaries and uterus.

❑ After the examination, offer the patient premoistened tissues to clean the vulva.
Other diagnostic tests

Diagnostic measures for gynecologic disorders also include the following tests, which can be performed in the physician’s office:

❑ wet smear to examine vaginal secretions for specific organisms, such as Trichomonas vaginalis and Candida albicans, or to evaluate semen specimens collected in connection with rape or infertility cases

❑ endometrial biopsy to assess hormonal secretions of the corpus luteum, to determine whether normal ovulation is occurring, and to check for neoplasia

❑ dilatation and curettage with hysteroscopy to evaluate atypical bleeding and to detect carcinoma.

Laparoscopy, used to evaluate infertility, dysmenorrhea, and pelvic pain, and as a means of sterilization, is usually performed in a health care facility while the patient is under anesthesia. Increasingly, however, it’s being performed as a less invasive procedure under conscious sedation in an office setting using microlaparoscopic technique.

Obstetrical Diseases
Obstetrical Diseases

Random Diseases

You can leave a response, or trackback from your own site.

No Responses to “Obstetrical Diseases”

Leave a Reply