Medical brain notes 42

  ECTOPIC PREGNANCY   An  ectopic  or  extrauterine pregnancy  is one in which the blastocyst implants anywhere other than the endome-trial lining of the uterine cavity. As shown in Figure 13.1, 98% of ectopic pregnancies implant in the fallopian tube, with 80% occurring in the ampullary segment. Other locations include, but are not limited to, the ovary, cervix, and abdomen. In some form, they account for 1.3% to 2% of reported pregnancies in the United States.   In the past, ectopic pregnancy was life-threatening. Earlier diagnosis made possible by the new ability to detect the  β -subunit of human chorionic gonadotropin (hCG), combined with high-resolution transvaginal sonography (TVS), has reduced this threat. Nevertheless, ectopic pregnancies remain an important cause of morbidity and mortality in the United States. The incidence of ectopic pregnancy has increased consistent with the rise in chla-mydial infections.   Tubal Ectopic Pregna...

  PATHOPHYSIOLOGY AND RISK FACTORS   An appreciation of risk factors for ectopic pregnancy leads to a timely diagnosis with improved maternal survival and future reproductive potential.   Inflammation has been implicated in the role of tubal damage that predisposes to ectopic pregnancies. Inflam-matory processes, such as  salpingitis  and  salpingitis isth-mica nodosa,  may also play a role. Acute pathology, suchas  chlamydial infection,  causes intraluminal inflamma-tion and subsequent fibrin deposition with tubal scarring. Despite negative cultures, persistent chlamydial antigens can trigger a delayed hypersensitivity reaction with con-tinued scarring. Whereas endotoxin-producing  Neisseriagonorrhoeae  causes virulent pelvic inflammation with a rapidclinical onset, chlamydial inflammatory response is indo-lent and peaks at 7 to 14 days.   Although pregnancy after sterilization is rare, when it does occur, there is a substanti...

  SYMPTOMS   With the availability of early pregnancy testing, the ability to diagnose ectopic pregnancy before rupture—even before the onset of symptoms—is not unusual. The classic symp-toms associated with ectopic pregnancy are amenorrhea followed by vaginal bleeding and abdominal pain on the affected side. However, there is no constellation of symp-toms that are diagnostic. Other pregnancy discomforts, such as breast tenderness, nausea, and urinary frequency, may accompany more ominous findings. These include shoul-der pain worsened by inspiration, which is caused by phrenic nerve irritation from subdiaphragmatic blood, or vaso-motor disturbances such as vertigo and syncope from hem-orrhagic hypovolemia.   As long as placental hormones are produced, there is usually no vaginal bleeding. Irregular vaginal bleeding re-sults from the sloughing of the decidua from the endome-trial lining. Vaginal bleeding in patients with an ectopic gestation may range from little or none ...

  CLINICAL FINDINGS   Abdominal and pelvic findings are notoriously scant in many women before tubal rupture. Prior to rupture, the di-agnosis of an ectopic pregnancy is primarily based on labo-ratory and ultrasound findings. With rupture, however, nearly three-fourths of women will have marked tender-ness on both abdominal and pelvic examination, and pain is aggravated with cervical manipulation. A pelvic mass, in-cluding fullness posterolateral to the uterus, can be palpated in about 20% of women. Initially, the ectopic pregnancy may feel soft and elastic, whereas extensive hemorrhage produces a firmer consistency. Many times, discomfort pre-cludes palpation of the mass. Avoidance of pelvic examina-tions may actually help avert iatrogenic rupture.   Fever is not expected, although a mild elevation in temperature in response to intraperitoneal blood may occur. A temperature of 38 ° C may suggest an infectious cause to a patient’s symptoms. Abdominal distension and tender...

  DIFFERENTIAL DIAGNOSIS   Symptoms of ectopic pregnancy can mimic multiple entities. Early pregnancy complications (threatened, incomplete, or missed abortion), placental polyp, or hemorrhagic corpus luteal cyst are difficult to diagnose. Moreover, early bleed-ing occurs in about 20% of women with normal pregnan-cies. A number of nonpregnancy-related disorders, such as appendicitis and renal calculi, can mimic ectopic pregnancy.   The rapid and accurate diagnosis of ectopic pregnancy is imperative to reduce the risk of serious complications or death.  Up to half of the women who have died as a result of ec-topic pregnancy had a lag in treatment because of delayed or inaccurate diagnoses. Any sexually active woman in the reproductive age group who presents with pain, irregular bleeding, and/or amenorrhea should have ectopic preg-nancy as a part of the initial differential diagnosis.   DIAGNOSTIC PROCEDURES   TVS and serial serum  β -hCG measurements ar...

  MANAGEMENT   Management may be either surgical or medical, depending on a variety of factors. Surgery may be minimal or extensive, depending on the gestational age of the pregnancy and other factors. Due to the inherent risks of each, medical therapy is preferred over surgery in appropriate patients.   Medical Management  Methotrexate is the medical treat-ment usually used as an alternative to surgical therapy. Methotrexate is a folic acid antagonist that competi-tively inhibits the binding of dihydrofolic acid to dihydro-folate reductase, which in turn reduces the amount of active intracellular metabolite, folinic acid.   The best candidate for medical therapy is the woman who is asymptomatic, motivated, and who has resources to be compliant with follow-up. Relative and absolute contraindications for medical management are listed in Box 13.1.   Factors that can be assessed in predicting the success of medical therapy include initial  β -hCG level, s...

  OVARIAN PREGNANCY   Ectopic implantation of the fertilized egg in the ovary is rare. The recent increased incidence is likely due to im-proved imaging modalities. Risk factors are similar to those for tubal pregnancies. Diagnosis is based on the classical  sonographic description of a cyst with a wide echogenic outer ring on or within the ovary.   INTERSTITIAL PREGNANCY   Also termed  cornual pregnancy,  interstitial pregnancies implant in the proximal tubal segment that lies within the muscular uterine wall. Swelling lateral to the insertion of the round ligament is the characteristic anatomic finding. A pregnancy that implants in the cornual segment of the tube tends to present several weeks later in pregnancy, be-cause the muscular cornu of the uterus is better able to expand and accommodate an enlarging pregnancy. As a result, rupture of a cornual ( isthmic ) pregnancy typically occurs between the eighth and sixteenth gestational weeks, and is of...

  SPONTANEOUS ABORTION   Abortion  is the expulsion of the fetus prior to 20 weeks ofgestation.  Spontaneous abortion  (miscarriage) occurs in the absence of intervention. An incidence of recognized spontaneous abortion of 15% to 25% is commonly cited, with approximately 80% occurring during the first 12 weeks of pregnancy. Approximately 50% of early spontaneous abortions are attributed to chromosomal abnormalities, most of which are trisomy.   Compared with first-trimester abortions, second-trimester abortions are less likely to be caused by chromo-somal abnormalities and more likely to be caused by ma-ternal systemic disease, abnormal placentation, or other anatomic considerations. This difference is clinically signif-icant, because these conditions often can be treated and re-current abortions can thereby potentially be prevented.

  Etiology   INFECTIOUS FACTORS   Infections are an uncommon cause of early spontaneous abortion.  Chlamydia trachomatis  and  Listeria monocytogenes  have been associated with spontaneous abortion. Sero-logical evidence supports a role for  Mycoplasma hominis  and  Ureaplasma urealyticum  in abortions. Finally, abortion is independently associated with serological evidence of syphilis, human immunodeficiency virus (HIV)-1 infection, and with vaginal colonization with group B streptococci.   ENDOCRINE FACTORS   Thyroid autoantibodies are associated with an increased incidence of spontaneous abortion, even in the absence of clinical hypothyroidism. In women with type 1 diabetes, the degree of metabolic control in early pregnancy is asso-ciated with an increased risk of spontaneous abortion and major congenital malformation.     ENVIRONMENTAL FACTORS   The abortion risk increases in a linear fashion with the n...

  Classification and Differential Diagnosis of Spontaneous Abortions   Because the differential diagnosis of bleeding in the first trimester of pregnancy includes a wide range of possibili-ties, such as ectopic pregnancy, hydatidiform mole, cervi-cal polyps, cervicitis, and neoplasm, the patient should be examined whenever there is bleeding in early pregnancy.     TYPES OF SPONTANEOUS ABORTION   Threatened abortion  is characterized by bleeding in thefirst trimester without loss of fluid or tissue. About half of women with a threatened abortion proceed to spontaneous abortion. Those who carry to viability a pregnancy compli-cated by threatened abortion are at greater risk for preterm delivery and an infant of low birth weight. There does not, however, appear to be a higher incidence of congenital malformations in these newborns. Some patients describe bleeding at the time of their expected menses, sometimes referred to as  implantation bleeding,  ...