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USMLE® Step 1 style questions USMLE

1 questions

A 28-year-old woman, gravida 1 para 1, presents to the emergency department with complaints of lower abdominal pain and foul-smelling vaginal discharge. She gave birth to a healthy female newborn 2 days ago. Vaginal delivery was converted into emergency cesarean section due to obstructed labor, and the placenta was removed manually. Past medical history is significant for pre-gestational diabetes mellitus type II as well as Neisseria gonorrhoeae cervicitis when the patient was 19, for which she was treated appropriately. Temperature is 101.4°F (38.5 °C), pulse is 100/minute, respirations are 19/minute, and blood pressure is 100/60 mmHg. BMI is 33 kg/m2. On physical examination, there is mild peri-incisional tenderness, minimal discharge at the surgical site, and no erythema or edema around the incision site. Foul-smelling greenish-yellow lochia is observed in the vaginal vault. Bimanual examination shows cervical motion and uterine tenderness. Complete blood profile shows hemoglobin of 12 g/dL and leukocyte count of 18,000/mm3. Which of the following is the most likely diagnosis?  

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Content Reviewers:

Rishi Desai, MD, MPH


Sam Gillespie, BSc

Endometritis is an inflammation of the endometrium, which is the inner lining of the uterus.

It is usually caused by an infection of the endometrium from bacteria that normally live in the female lower genital tract, but it could also be caused by bacteria from outside the body.

The female reproductive system is divided into upper and lower genital tracts.

The upper genital tract consists of the uterus, ovaries, and fallopian tubes.

The lower genital tract in turn consists of the cervix, vagina and the external genitals, which includes the labia and the clitoris.

Now, The uterus consists of 3 layers, an outer thin layer called the perimetrium or the serosa, a middle smooth muscle layer called the myometrium, and the innermost layer, the endometrium.

The endometrium has two layers, an inner functional layer made up mainly of glands and supporting connective tissue, called stroma, and an outer thin basal layer which regenerates the overlying functional layer after each menstrual cycle.

Alright, normally, there are many species of bacteria living in the female’s lower genital tract, and this is called the normal flora.

These include Ureaplasma urealyticum, Peptostreptococcus and group B Streptococcus.

Under normal conditions, these bacteria live there happily without causing any harm, however, if they reach the upper genital tract, they can cause an infection like endometritis if they make it to the uterus.

Endometritis is a common problem during pregnancy because bacteria can easily reach the uterus during childbirth.

Okay, so normally the fetus is surrounded by membranes and amniotic fluid, and the uterus’s opening is sealed by a mucous plug.

This mucus plug has antimicrobial properties, preventing bacteria from reaching the uterus. Typically, during vaginal delivery, the mucus plug is shed, the cervix widens, and the membranes around the fetus rupture, so the baby can be delivered.

However, bacteria in the lower genital tract can take advantage of this, and sneak through the opening up to the uterus, causing endometritis.

To make matters worse, under certain conditions, bacteria can have even more time to reach the endometrium.

This can occur when there’s prolonged labor, and premature rupture of membranes, where the membranes around the fetus have ruptured before the onset of labor.

In addition, if the amniotic fluid or the membranes around the fetus become infected, a condition known as chorioamnionitis, the infection can spread to the nearby endometrium causing it to be infected as well.

In addition, people who give birth by cesarean section are even more likely to have endometritis after childbirth.

This is because cesarean section makes it easier for the bacteria in the lower genital tract to reach the endometrium, and even bacteria from outside the body can make their way in.

Endometritis can also occur when placental or fetal tissues are not completely removed from the uterus after delivery or abortion.

These tissues provide a good environment for bacteria to grow and cause an infection in the uterus.

Now, apart from childbirth, there are other factors that makes it easier for bacteria from the lower genital tract to reach the endometrium, even in non-pregnant females.

This can occur during hysteroscopy, where the inside of the uterus is viewed using a camera inserted through the vagina, and when there’s an intrauterine contraceptive device, which has a thread that reaches down to the cervix or the vagina.

When these devices are inserted into the uterus, they might introduce forign bacteria accidentally.

Finally, endometritis can be caused by outside bacteria such as Chlamydia trachomatis or Neisseria gonorrhoeae, which are sexually transmitted infections.

Also, some cases of endometritis can occur in a female with tuberculosis, in which Mycobacterium tuberculosis spreads from the lungs into the blood and travels to other organs such as the uterus.

Alright, endometritis can be acute or chronic. People with acute endometritis, can present with fever, abnormal uterine bleeding, lower abdominal pain, dysuria, which is painful urination, or dyspareunia, which means pain during sexual intercourse.

When endometritis occurs after childbirth, the lochia, which is the normal vaginal discharge after giving birth, can become purulent, meaning yellowish, and foul smelling.


Endometritis refers to inflammation of the endometrium, the inner lining of the uterus. It is usually caused by normal flora of the genital tract if the endometrium is breached, but can also be caused by sexually transmitted infections, such as Chlamydia trachomatis and Neisseria gonorrhoeae infections.

Common symptoms are fever, pain in the pelvis or lower abdomen, abnormal vaginal discharge, and painful sexual intercourse. Procedures which can lacerate the endometrium such as childbirth, abortion, surgery on the uterus or other pelvic organs, and insertion of an intrauterine contraceptive device (IUD), all increase a chance of having endometritis.

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