Cycle Menstruation

Cycle Menstruation

The menstrual cycle is a cycle of physiological changes that occurs in fertile females. Overt menstruation (where there is blood flow from the vagina) occurs primarily in humans and close evolutionary relatives such as chimpanzees.^[1] Females of other species of placental mammal undergo estrous cycles, in which the endometrium is completely reabsorbed by the animal (covert menstruation) at the end of its reproductive cycle. This article focuses on the human menstrual cycle. more detail

Placenta previa

Placenta previa is an obstetric complication that occurs in the second and third trimesters of pregnancy. It may cause serious morbidity and mortality to both the fetus and the mother. It is one of the leading causes of vaginal bleeding in the second and third trimesters.

Placenta previa is generally defined as the implantation of the placenta over or near the internal os of the cervix.

• Total placenta previa occurs when the internal cervical os is completely covered by the placenta.
• Partial placenta previa occurs when the internal os is partially covered by the placenta.
• Marginal placenta previa occurs when the placenta is at the margin of the internal os.
• Low-lying placenta previa occurs when the placenta is implanted in the lower uterine segment. In this variation, the edge of the placenta is near the internal os but does not reach it.

Pathophysiology

The exact etiology of placenta previa is unknown. The condition may be multifactorial and is postulated to be related to multiparity, multiple gestations, advanced maternal age, previous cesarean delivery, previous abortion, and possibly, smoking.

Unlike first trimester bleeding, second and third trimester bleeding is usually secondary to abnormal placental implantation. next

Abortion

The most common complication of pregnancy is spontaneous abortion, which is estimated to occur in 10-15% of pregnancies. Spontaneous abortion can be classified as threatened, inevitable, incomplete, complete, or missed. Spontaneous abortions can further be categorized as sporadic or recurrent (>3 occurrences). By definition, a complete abortion is the expulsion of all products of conception before the 20th week of gestation.

Pathophysiology

Pathophysiology of a spontaneous abortion may be suggested by the timing of miscarriage. Chromosomal defects commonly are seen in spontaneous abortions, especially those that occur during 4-8 weeks' gestation. Genetic etiologies are common in early first-trimester loss but may be seen throughout gestation. Trisomy chromosomes are the most common chromosomal anomaly. Insufficient or excessive hormonal levels usually result in spontaneous abortion before 10 weeks' gestation. Infectious, immunologic, and environmental factors generally are seen in first-trimester pregnancy loss. Anatomic factors usually are associated with second-trimester loss. Factor XIII deficiency and a complete or partial deficiency of fibrinogen are associated with recurrent spontaneous abortions. more

Ovarian Cysts

An ovarian cyst is a fluid-filled sac in an ovary. They can be present from the neonatal period to postmenopause. Most ovarian cysts occur during infancy and adolescence, which are hormonally active periods of development. Most are functional in nature and resolve with minimal treatment. However, ovarian cysts can herald an underlying malignant process or, possibly, distract the emergency clinician from a more dangerous condition, such as ectopic pregnancy, ovarian torsion, or appendicitis. When cysts are large, persistent, or painful, surgery may be required, sometimes resulting in removal of the ovary. With the more frequent use of ultrasonography in recent years, their diagnosis has become more common.

Pathophysiology

From fetal life through a woman's reproductive life, ovarian follicles undergo varying rates of maturation and involution under the guidance of the hypopituitary axis.

Multiple follicles are recruited every month during the proliferative phase of the menstrual cycle. However, only one follicle reaches maturity and produces estrogen, releasing a mature oocyte at mid cycle. The follicular cyst transforms into a corpus luteum following ovulation and produces progesterone until the beginning of the next cycle. In the absence of fertilization of the oocyte, it continues to atrophy.

Follicular dysgenesis occurs with hypothalamic-pituitary dysfunction or because of native anatomic defects in the reproductive system. When follicular development into a corpus luteum is arrested, a luteal ovarian cyst can result.

Two functional ovarian cysts may develop: follicular cysts (ie, graafian follicular cysts) occur in the first 2 weeks of the cycle, and corpus luteal cysts occur in the later half of the cycle. The rupture of the follicular cyst can lead to sharp, severe, unilateral pain of mittelschmerz (occurring mid cycle), and it is experienced by approximately 25% of menstruating women. Similarly, failure of corpus luteum degeneration leads to a luteal cyst formation. These cysts may become inflamed or spontaneously hemorrhage, producing symptoms during the later half of the menstrual cycle.

Carcinomatous processes of the ovary, both primary and metastatic, frequently are complicated by cystic degeneration. The formation of inclusions of the ovary's germinal epithelium may lead to cystic development.

Endometriomas are cysts filled with blood from the ectopic endometrium.

Endometriosis

Endometriosis is the presence of endometrial-like tissue outside the uterine cavity, which induces a chronic inflammatory reaction. It can occur in various pelvic sites such as on the ovaries, fallopian tubes, vagina, cervix, or uterosacral ligaments or in the rectovaginal septum. It can also occur in distant sites including laparotomy scars, pleura, lung, diaphragm, kidney, spleen, gallbladder, nasal mucosa, spinal canal, stomach, and breast.

This condition is often associated with pelvic pain and infertility, but it is most often asymptomatic. It is a frequently encountered gynecologic disorder in the emergency department (ED) as well as in the outpatient setting. Because it is enigmatic, endometriosis can present as a diagnostic and therapeutic challenge for emergency physicians in their approach to the female patient with pelvic pain.
Pathophysiology
The exact cause and pathogenesis of endometriosis is unclear. Several theories exist that attempt to explain this disease though none have been entirely proven.

Previous theories suggest that endometriosis results from the transport of viable endometrial cells through retrograde menstruation. Cells flow backwards through the fallopian tubes and deposit on the pelvic organs where they seed and grow. A population of cells reside in the endometrium, which retain stem cell properties. It may be these properties that allow these cells to survive in ectopic locations.

Retrograde menstruation is a common physiologic event. Diagnostic laparoscopy during the perimenstrual period has shown that as many as 90% of women with patent fallopian tubes have bloody peritoneal fluid. Since most women do not have endometriosis, perhaps immunologic or hormonal dysfunction leaves some women predisposed.

Recent research has suggested involvement of the immune system in the pathogenesis of endometriosis. Women with this disorder appear to exhibit increased humoral immune responsiveness and macrophage activation while showing diminished cell-mediated immunity with decreased T-cell and natural killer cell responsiveness.

Transtubal dissemination is the most common route, although other routes have been observed. These include lymphatic and vascular channels. This may explain how endometrial tissue can be found at distant locations in the body.

Metaplasia, or the changing from one normal type of tissue to another normal type of tissue, is another theory. The endometrium and the peritoneum are derivatives of the same coelomic wall epithelium. Peritoneal mesothelium has been postulated to retain its embryologic ability to transform into reproductive tissue. Such transformation may occur spontaneously, or it may be facilitated by exposure to chronic irritation by retrograde menstrual fluid.

Another theory states that remnant mullerian cells may remain in the pelvic tissues during development of the mullerian system. Under situations of estrogen stimulation, they may be induced to differentiate into functioning endometrial glands and stroma.

Finally, iatrogenic deposition of endometrial tissue has been found in some cases following gynecologic procedures and cesarean sections.

Some women may have a genetic predisposition to endometriosis. Studies have shown that first-degree relatives of women with this disease are more likely to develop it as well. The search for an endometriosis gene is currently underway.

Many theories exist as to why endometriosis occurs, and it is likely a combination of these factors that cause and determine severity of disease.

Ultrasonography

Pelvic sonography may be viewed as a form or extension of the physical examination. In transabdominal scanning, a full bladder is used to displace bowel gas and serve as an acoustic window to allow a large viewing field of the pelvis. Endovaginal imaging is the preferred technique for emergency physicians because a full bladder is not necessary. Filling the bladder delays the examination.
Clinical
History

Clinical indications for pelvic sonography include the following:

* Evaluation of vaginal bleeding in early pregnancy
o This indication is well outlined in Pregnancy, Ectopic.
o Subchorionic hemorrhage (implantation bleeding) is a common cause of spotting.
o Endovaginal scanning uses a high-frequency transducer and enables optimal imaging of organs close to the probe, including the endometrium, myometrium, cul-de-sac, and ovaries, which can be seen in detail.
* Evaluation of pelvic pain
o Ultrasonography can be used to evaluate pelvic pain, a common complaint of patients presenting to the ED, and entities such as ovarian cysts, tubo-ovarian abscesses, uterine fibroids, or even an infected pelvic kidney.
o In a female patient who is obese, pelvic ultrasonography can simplify a difficult physical examination.
* Evaluation of a pelvic mass
o Pelvic ultrasonography can be used to determine the etiology of a pelvic mass.
o Compared with endovaginal ultrasonography, transabdominal ultrasonography uses a lower frequency and can penetrate farther, with a large field of view. Thus, fibroids, ovaries, or cysts located high in the pelvis may be out of the focal range of an endovaginal probe. In addition, pelvic kidneys can be visualized.
* Evaluation of pelvic infection
o Tubo-ovarian abscesses are difficult to diagnose at physical examination.
o A normal fallopian tube may not be visualized at endovaginal ultrasonography; however, a fluid- or pus-filled tube can be identified.
o Pelvic inflammatory disease can be identified at ultrasonography.
* Localization of an intrauterine device or foreign body
o Ultrasonography can aid in the localization or detection of an intrauterine device or foreign body.
o An intrauterine device produces a characteristic acoustic artifact (shadow), which is helpful to the physician sonographer.
* Evaluation of trauma
o Views of the pelvis are used at ultrasonographic examination to evaluate for free fluid or clotted blood, which can be present in the pouch of Douglas (cul-de-sac).
o Views of the pelvis obtained before insertion of a Foley catheter are helpful.
* Evaluation of abnormal uterine bleeding in the premenopausal patient as well as the postpartum and postabortion patient

Pregnancy, Preeclampsia

Preeclampsia is a disorder of widespread vascular endothelial malfunction and vasospasm that occurs after 20 weeks' gestation. It is clinically defined by hypertension and proteinuria.

Preeclampsia is part of a spectrum of disorders that includes gestational hypertension, severe preeclampsia, and eclampsia. Although each of these disorders can appear in isolation, they are thought of as progressive manifestations of a single process and are believed to share a common etiology.

The diagnostic criteria for preeclampsia focus on measurement of elevated blood pressure and proteinuria that develop after 20 weeks' gestation. Consensus is lacking among the various national and international organizations about the values that define the disorder, but a reasonable limit in a woman who was normotensive prior to 20 weeks' gestation is a systolic blood pressure (BP) greater than 140 mm Hg and a diastolic BP greater than 90 mm Hg on 2 successive measurements 4-6 hours apart. Preeclampsia in a patient with preexisting essential hypertension is diagnosed if systolic BP has increased by 30 mm Hg or if diastolic BP has increased by 15 mm Hg.

Proteinuria is defined as 300 mg or more of protein in a 24-hour urine sample. In the emergency department, a urine protein-to-creatinine ratio of 0.19 or greater is somewhat predictive of significant proteinuria (negative predictive value [NPV], 87%).¹ Serial confirmations 6 hours apart increase the predictive value. Although more convenient, a urine dipstick value of 1+ or more (30 mg/dL) is not reliable.

For the purposes of guiding management, a distinction can be made between mild preeclampsia and severe preeclampsia.

Diagnostic criteria for severe preeclampsia include at least one of the following:

• Systolic BP greater than 160 mm Hg or diastolic BP greater than 110 mm Hg on 2 occasions 6 hours apart with the patient at bed rest
• Proteinuria greater than 5000 mg in a 24-hour collection or more than 3+ on 2 random urine samples collected at least 4 hours apart
• Oliguria with less than 500 mL per 24 hours
• Persistent maternal headache or visual disturbance
• Pulmonary edema or cyanosis
• Concerning abdominal pain
• Impaired liver function test findings
• Thrombocytopenia
• Oligohydramnios, decreased fetal growth, or placental abruption

Eclampsia is defined as seizures in a patient with preeclampsia.

For more information, see Medscape’s Pregnancy Resource Center.

For a related CME activities, see CME - Hypertension in Pregnancy: Emerging Risk Factor for Cardiovascular Disease, CME/CE – Folic Acid in Early Second Trimester May Reduce Risk of Preeclampsia, and CME – Antioxidants May Not Reduce Risk for Preeclampsia.

Pathophysiology

The mechanism by which preeclampsia occurs is not certain, and the diagnosis may represent a diversity of pathophysiologies that proceed to a common final pathway. The inciting event is believed to be placental hypoperfusion, which may result because the uteroplacental spiral arterioles are abnormally formed, leaving them highly sensitive to vasoconstriction. Both maternal and paternal factors have been implicated in the development of preeclampsia.

Placental hypoperfusion leads by an unclear pathway to the release of systemic vasoactive compounds that cause an exaggerated inflammatory response, vasoconstriction, endothelial damage, capillary leak, hypercoagulability, and platelet dysfunction, all of which contribute to organ dysfunction and the various clinical features of the disease.

Preeclampsia is a state of high systemic vascular resistance with normal or relatively low intravascular volume.

Frequency

United States

Preeclampsia occurs in approximately 5% of all pregnancies. The incidence of preeclampsia is 23.6 cases per 1,000 deliveries in the United States.

International

The global incidence of preeclampsia has been estimated at 5-14% of all pregnancies.

Mortality/Morbidity

Preeclampsia is the third leading pregnancy-related cause of death, after hemorrhage and embolism. Preeclampsia is the cause in an estimated 790 maternal deaths per 100,000 live births.

Morbidity and mortality is related to systemic endothelial dysfunction; vasospasm and small-vessel thrombosis leading to tissue and organ ischemia; CNS events such as seizures, strokes, and hemorrhage; acute tubular necrosis; coagulopathies; and placental abruption in the mother.

Hemolysis, elevated liver enzyme levels, and low platelets (HELLP) syndrome may be an outcome of severe preeclampsia, although some authors believe it to have an unrelated etiology.

In the fetus, ischemic encephalopathy, growth retardation, and the various sequelae of premature birth can occur.

Race

The frequency of mortality differs among race and ethnicity, with African Americans having a worse mortality rate than white women.

Age

Preeclampsia occurs more frequently in women at the extremes of reproductive age.

• Younger women (<20>
• Older women (>35 y) have a markedly increased risk.

Clinical

History

Mild-to-moderate preeclampsia may be asymptomatic. Many cases are detected through routine prenatal screening. Patients with severe preeclampsia display end-organ effects and may complain of the following:

• CNS
  • Headache
  • Visual disturbances - Blurred, scintillating scotomata
  • Altered mental status
  • Blindness - May be cortical or retinal
• Dyspnea
• Edema: This exists in many pregnant women but sudden increase in edema or facial edema is more concerning for preeclampsia. The edema of preeclampsia occurs by a distinct mechanism that is similar to that of angioneurotic edema.
• Epigastric or right upper quadrant (RUQ) abdominal pain: Hepatic involvement occurs in 10% of women with severe preeclampsia.
• Weakness or malaise: This may be evidence of hemolytic anemia.

Physical

Findings on physical examination may include the following:

• Increased BP compared with the patient's baseline or greater than 140/90 mm Hg
• Altered mental status
• Decreased vision
• Papilledema
• Epigastric or RUQ abdominal tenderness
• Peripheral edema: Edema can be normal in pregnancy, but a sudden increase in edema or swelling of the face is more suggestive of preeclampsia.
• Hyperreflexia or clonus
• Seizures
• Focal neurologic deficit

Causes

• Pregnancy-associated risk factors
  • Chromosomal abnormalities
  • Hydatidiform mole
  • Multifetal pregnancy
  • Oocyte donation or donor insemination
  • Urinary tract infection
• Maternal-specific risk factors
  • Extremes of age
  • Black race
  • Family history of preeclampsia
  • Nulliparity
  • Preeclampsia in a previous pregnancy
  • Diabetes
  • Obesity
  • Chronic hypertension
  • Renal disease
  • Periodontal disease²