Modelado electro-mecánico

approximately half of all reports of STDs. The recom-mended treatment is either a single oral dose of azithromycin or a 7-day course of oral doxycycline, not a 14-day course of doxycycline (choice C). A 7-day course of oral ofloxacin, not a 14-day course of ofloxacin (choice D), is an alternative regimen. To pre-vent reinfection of the patient, guidelines state that it is necessary to treat all partners within 60 days of infec-tious signs and symptoms or positive probe.

A single intramuscular dose of benzathine penicillin G (choice A) is the treatment for primary syphilis, as long as there is no ocular or central nervous system disease.

If there is ocular or central nervous system disease, 10 to 14 days of intravenous penicillin is indicated.

Metronidazole (choice E) is the treatment for bacterial vaginosis and trichomoniasis.

44. The correct answer is E. Trisomy 21, or Down syn-drome, is the most common chromosomal abnormality among term births, occurring in approximately 1 in 700 live births. The main risk factor is maternal age greater than 35 years. As women age, they should be advised that the risk for genetic fetal abnormalities (choice B) does increase. Children with Down syndrome (caused 95% of the time by trisomy 21) classically have broad-bridged noses, flattened facies, upward slanted palpebral fissures, epicanthal folds, a protruding tongue, and a webbed neck, among other findings.

An abnormality or absence of the X chromosome (choice A) is a common cause of Turner syndrome, classically 45,XO. These patients have primary amenor-rhea, sterility, and sparse pubic-axillary hair. Typical physical findings include webbing of the neck, a low hairline, low-set ears, micrognathia, a “shield chest,”

and in newborns, lymphedema of the feet or hands.

Unlike Down syndrome, this condition is not closely associated with increased maternal age.

An additional X chromosome (choice C) causes Klinefelter syndrome, classically with the genotype 47,XXY. These patients have mental retardation and psychosocial and learning problems. Patients may pre-sent in adolescence with delayed puberty. Physical examination reveals a lanky, tall, slim, and underweight patient, perhaps with gynecomastia and sparse facial hair. Unlike Down syndrome, this condition is not closely associated with increased maternal age.

The risk for sudden infant death syndrome (choice D) does not increase with maternal age. Indeed, the women most at risk for having a child with SIDS are young mothers (younger than age 20 years) and those who smoke.

45. The correct answer is E. Congenital varicella syndrome is characterized by “zigzag” skin lesions, which appear as scars and are referred to as “cicatricial” in the medical literature. These babies also can have microophthalmia, cataracts, chorioretinitis, extremity hypoplasia, and motor and sensory defects.

Congenital cytomegalovirus (choice A) babies have petechiae, meningoencephalitis, hepatosplenomegaly, jaundice, and thrombocytopenia.

Congenital herpes simplex virus (choice B) is marked by pneumonia, meningoencephalitis, petechiae, mental retardation, and jaundice.

The triad of congenital rubella syndrome (choice C) is

Fetuses exposed to Toxoplasma (choice D) in utero can have symmetric IUGR and nonimmune fetal hydrops on ultrasound. These babies will also have micro-cephaly and diffuse intracranial calcifications.

46. The correct answer is A. This patient most likely has a complete hydatidiform mole. This condition of one of many that are grouped under the heading of gestational trophoblastic disease. Gestational trophoblastic disease is divided into hydatidiform mole and gestational tro-phoblastic tumors, which can be either metastatic or nonmetastatic. Patients with a complete hydatidiform mole usually present with complaints of vaginal bleed-ing; have size greater than dates; have no fetal parts on ultrasound and possibly a “snowstorm” pattern, signify-ing hydropic chorionic villi; and have an hCG level that is abnormally elevated. The treatment is to evacuate the mole with a dilation and curettage and then to follow-up closely with the patient (by checking hCG titers) to detect persistent trophoblastic proliferation or malig-nant change. If the hCG titers falls to an undetectable level appropriately, then no chemotherapy is necessary.

To treat this patient with dilation and curettage, then methotrexate (choice B), or dilation and curettage, then combination chemotherapy (choice C), would not be correct in this case. Dilation and curettage followed by methotrexate would be appropriate for the patient with a gestational trophoblastic tumor with nonmetastatic or low-risk metastatic disease. Dilation and curettage followed by combination chemotherapy is appropriate for the patient with a high-risk trophoblastic tumor.

To treat this patient with dilation and curettage, then radiation therapy (choice D) would not be correct. This management scheme is not used to treat patients with hydatidiform mole or gestational trophoblastic tumors.

Hysterectomy (choice E) can be used in the treatment of hydatidiform mole. However, this patient is an 18-year-old woman and likely desires future fertility; therefore, hysterectomy would not be the most appropriate man-agement strategy.

47. The correct answer is C. Cervical cytology screening (i.e. the Pap smear) is largely responsible for the tremen-dous decrease in the incidence and mortality from cer-vical cancer that occurred in the late twentieth century.

The issue of when to begin screening is an important one because of the high costs and benefits associated with the screening program. It is difficult to determine the exact, correct time to begin cervical cytology

screen-and the opportunity to intervene earlier. The disadvan-tage of earlier screening is the increased anxiety that women would experience from starting the screening earlier. Earlier screening also has the disadvantage of generating increased morbidity and expense from earlier and more frequent intervention. Current recommenda-tions from the American College of Obstetrics and Gynecology are that screening begins at age 21, or 3 years after the onset of sexual activity.

To recommend that this patient begin having cervical cytology screening at age 12, or with menarche (choice A), would be incorrect. Starting screening this early would lead to a significant increase in anxiety for patients and parents. Furthermore, given the natural history of infection with human papillomavirus (the causative organism for cervical neoplasia,) screening this early would not be necessary.

To recommend screening at age 18, or with the onset of sexual activity (choice B), was the standard of care for screening for many years. However, improved under-standing of the human papillomavirus and the impact of cervical cytology screening programs has led to the change in recommendation to age 21, or 3 years after the initiation of sexual intercourse.

To recommend screening at age 30, or 10 years after the onset of sexual activity (choice D), would not be correct.

Cervical neoplasia can develop within 3 years after initi-ation of sexual activity, so to wait 10 years would be too long. Furthermore, women from age 20 to 30 are at very high risk, so to wait until age 30 would also be too late.

To state that pap tests will not be necessary in this patient (choice E) is incorrect. As stated above, the Pap test has proven itself over many years to reduce the inci-dence and mortality from cervical cancer. This patient should begin having cervical cytology screening at age 21, or 3 years after the onset of sexual activity.

48. The correct answer is C. It is essential to use the post-partum visit to counsel the patient regarding family planning, birth spacing, and contraceptive methods.

This is an ideal time, with the recent pregnancy fresh in the woman’s mind, to set up a contraceptive plan in order to prevent an unintended pregnancy. This patient would like to start on birth control but has a few issues that must be considered. First, she is breast-feeding. In women who are breast-feeding, it is recommended that progestin-only contraceptives be used. Estrogen-containing contraceptives have been shown to reduce the quality and quantity of breast milk and to reduce the rate and duration of breast-feeding. Therefore, of the above choices, only the medroxyprogesterone acetate injectable suspension (Depo-Provera) is a

progestin-only form of contraception and should be used in this patient. Second, this patient has a recent history of gon-orrhea. Because of this, the intrauterine device (IUD) would be contraindicated and this patient should be thoroughly counseled that the medroxyprogesterone acetate injectable suspension will not protect her from sexually transmitted disease and that she must also use a barrier form of contraception.

The combined oral contraceptive pill (choice A) has been used successfully by women for decades to prevent pregnancy and for other medical indications. However, as noted above, estrogen-progestin containing pills have been shown to adversely affect breast milk and feeding and are not recommended in breast-feeding women.

The contraceptive vaginal ring (choice B) is a relatively new addition to the contraceptive options for women.

However, it is also estrogen-progestin containing and, therefore, should not be used in this lactating woman.

The monthly contraceptive injection (choice D) is similar to medroxyprogesterone acetate in that it is an injection.

However, Lunelle is also an estrogen-progestin containing contraceptive and should not, therefore, be used in this breast-feeding patient.

Transdermal contraception (choice E) is another recent addition to the contraceptive options for women. It too, however, is an estrogen-progestin form of contraception and, therefore, would not be recommended for this patient until she had completed breast-feeding.

49. The correct answer is C. Patients with type 1 diabetes, like this patient, are known to have a substantially increased risk for developing preeclampsia during their pregnancy. This risk also depends on which class of dia-betes a patient has. For example, a patient with class B diabetes has an approximately 10 to 15% chance of developing preeclampsia during pregnancy. A patient with class C or D diabetes has a 20 to 25% risk. This patient would be classified as having class F diabetes because of her nephropathy. Studies have demonstrated that patients with class F diabetes have a 30 to 50% risk for developing preeclampsia during the pregnancy. This patient, therefore, should be monitored carefully throughout the pregnancy, with special attention to the signs and symptoms of preeclampsia.

Caudal regression syndrome (choice A) is a congenital anomaly that is strongly associated with the offspring of diabetic mothers. Although it is strongly associated, the absolute risk for a diabetic mother having a child with caudal regression syndrome is small.

Placenta previa (choice B) is not a commonly recog-nized complication of diabetic pregnancies.

Shoulder dystocia (choice D) is a risk for infants of dia-betic mothers. Diadia-betic mothers tend to have offspring who are larger than are the offspring of mothers with nor-mal glucose tolerance. Furthermore, infants of diabetic mothers tend to be larger in the chest and shoulders, which places them at increased risk for shoulder dystocia.

Although infants of diabetic mothers are at increased risk for shoulder dystocia, however, this complication is not nearly as likely as is the development of preeclampsia in this woman with class F diabetes.

Pregnant patients with diabetes are much more likely to experience a stillbirth (choice E) than are their nondia-betic counterparts. Again, however, stillbirth is still a relatively rare occurrence, even in diabetic women, and not nearly as common as is the development of preeclampsia in a class F diabetic.

50. The correct answer is B. In the differential diagnosis, two entities should be considered: either pregnancy-related bleeding or dysfunctional uterine bleeding. A pregnancy test is critical in establishing a diagnosis. On the basis of her reproductive history (regular menses and uncomplicated pregnancies) and physical exami-nation (at the upper limits of a normal-sized uterus, adnexal fullness, positive culdocentesis), the evidence points to the likelihood of a tubal ectopic pregnancy.

The method of tubal sterilization influences the chance for ectopic pregnancy. In a patient who becomes preg-nant after sterilization, electrocoagulation is associated with a 50% chance of ectopic pregnancy, whereas rings, clips, or tubal resection are associated with about 10%

incidence of ectopic pregnancy. Laparoscopic proce-dures are associated with an increased risk of ectopic pregnancy compared with open procedures.

Dysfunctional uterine bleeding (choice A) is not a diagnosis but a symptom. Some authorities consider dysfunctional uterine bleeding as a descriptor of anovulation. Causes of abnormal uterine bleeding include anovulation, hematologic disorders, and neo-plasias of the cervix or endometrium. None of these conditions is supported by the patient’s history.

Menorrhagia, ovarian cyst formation, and pelvic pain characterize the post-tubal ligation syndrome (choice C) in the absence of pelvic pathology, except for a his-tory of tubal ligation. Possible explanations for it include foci of endosalpingiosis, adhesions at the site of tubal ligation, congestion of pelvic veins, torsion of the adnexa lateral to the point of ligation, hydrosalpinx

congestion. This patient’s findings are not characteristic of this syndrome. The existence of the post-tubal liga-tion syndrome is subject to controversy.

Involution of a normal corpus luteum is usually pain-less. When rupture of the corpus luteum occurs (choice D), it is during the involutional process in the luteal phase of the menstrual cycle. Amenorrhea associated with pelvic pain, uterine bleeding, and a tender adnex-al mass are typicadnex-al of this phenomenon. Bleeding may be significant, and the patient may be at risk for hypo-volemic shock. Findings would include orthostatic changes, abdominal distention, decreased bowel sounds, and significant voluntary guarding to abdomi-nal palpation. This syndrome should be considered in patients who present with typical symptoms and who are on anticoagulants. This patient is asymptomatic and did not have a period of amenorrhea; therefore, it is not likely that she has a ruptured corpus luteum.

The majority of follicle cysts is asymptomatic and is dis-covered during a routine pelvic examination. Only rarely is there significant intraperitoneal hemorrhage associated with follicle cyst rupture (choice E).

Menstrual irregularities and abnormal uterine bleeding may be associated with follicular cysts. Large cysts may cause aching, pelvic pain, and dyspareunia. This syn-drome should also be considered in patients who pre-sent with typical symptoms but are on anticoagulants.

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