QUESTION 12

 A 20-year-old woman comes to the emergency department due to vaginal bleeding and right lower quadrant pain that began 3 days

ago. She describes the bleeding as heavier than a period, and she passed vaginal clots 3 hours prior to presentation. Her menarche

was at age 13 and she has often gone months without a menstrual period The patient's last period began approximately 7 weeks

ago. She is sexually active and uses the withdrawal method for contraception. Her temperature is 37.2 C (98 9 F), blood pressure is

120/74 mm Hg, and pulse is 80/min. Examination shows mild right lower quadrant tenderness, but no rebound or guarding. There is

no active vaginal bleeding and the cervical os is closed. Laboratory results are as follows

Hemoglobin

13-hCG

Blood type

Rh factor

11 g/dl

1000 IU/L

AB

positive

A transvaginal ultrasound reveals no intrauterine or extrauterine pregnancy Which of the following is the best next step in

management of this patient?

O A Administer anti-D immune globulin

O B. Administer methotrexate

O C. Perform abdominal ultrasound

0 D. Perform laparoscopy

E. Provide reassurance and observation

0 F. Repeat serum 13-hCG in 2 days

This patient has a positive pregnancy test but no evidence off an intrauterine or extrauterine pregnancy The differential includes an

early viable intrauterine pregnancy, ectopic pregnancy, or nonviable intrauterine pregnancy (completed abortion) Serial 13-hCG

levels should be ordered when the initial transvaginal ultrasound (TVUS) is indeterminate. 13-hCG should generally increase every 2

days in viable pregnancies but rise at a slower rate in ectopic and nonviable intrauterine pregnancies An intrauterine pregnancy

should be seen with TVUS at a 13-hCG of 1500-2000 IU/L. Serum 13-hCG levels would not be needed if initial TVUS detected an

intrauterine pregnancy or if a gestational sac with yolk sac was clearly identified in an ectopic location.

The patient is currently hemodynamically stable with a nonsurgical abdomen. Because an intrauterine pregnancy would not likely be

visible at a 13-hCG of 1000 IU/L, this patient's levels should be remeasured in 2 days. Once 13-hCG is >1500 IU/L, a TVUS should be

repeated

(Choice A) Administration of anti-0 immune globulin prevenits Rh sensitization in an Rh-negative pregnant woman by an Rh-positive

fetus. Anti-0 immune globulin is given to an Rh-negative patient any time fetal blood may enter maternal circulation (eg, antepartum

bleeding, spontaneous or induced abortion, abdominal trauma). This patient is Rh-positive

(Choice B) Methotrexate may be used for the medical management of a non-ruptured ectopic pregnancy. However, the diagnosis

must be confirmed first as it is still possible that this patient has a viable intrauterine pregnancy

(Choice C) Abdominal ultrasound is much less sensitive in detecting an early pregnancy and would not be useful if a TVUS did not

reveal a gestational sac.

(Choice D) Although laparoscopy is the gold standard for the diagnosis of an ectopic pregnancy, it is rarely required for diagnosis as

a pregnancy test and TVUS are usually sufficient. Laparoscopy should be performed if the patient is hemodynamically unstable

(suggesting an impending or ongoing ruptured ectopic mass) or when medical treatment {methotrexate) fails.

(Choice E) Reassurance and observation are not recommended until the location of the pregnancy is determined to be intrauterine.

Educational objective

An intrauterine pregnancy should be seen with transvaginal ultrasound at serum 13-hCG levels of 1500-2000 IU/L. If the level is <1500

IU/L, serum 13-hCG should be repeated in 2 days