Rudimentary horn pregnancy mimicking an acute abdomen in the emergency department.

Dear Editor,

Congenital uterine anomalies are relatively rare, but the true incidence and prevalence are not known since many women are asymptomatic. A unicornuate uterus is a rare Mullerian duct malformation results from the defective fusion of the malformed duct with the contra-lateral duct which appears in about 1/1,000 women and causes many obstetric and gynecologic complications.[1] Rudimentary horn is not connected to the uterine cavity in 80-90% of the cases. A rudimentary horn can occur with a functional endometrial cavity or small solid lump without functional endometrium.[2] We report a case of rudimentary horn pregnancy who presented in the second trimester.

A 29-year-old female, gravida 3 para 2 at 16 weeks of gestation was admitted to the emergency department (ED) with complaints of abdominal pain, nausea and dysurie for the past 1-day. Her history revealed that previous pregnancies were continued and resulted in liveborn vaginal deliveries at full term. On examination, the patient's vital signs were normal and defense and rebound was negative. Urine test had been 28 HPF leukocyte, 8 HPF erythrocyte. Patient that assessed by the obstetrician was discharged with a diagnosis of urinary tract infection. After about 7 h, patient admitted to another hospital with severe abdominal pain, and she was referred to our hospital with the diagnosis of perforated appendicitis. The patient's vital signs were in the normal ranges. Her physical examination showed abdominal sensitivity, defense and rebound tenderness consistent with an acute abdomen. A transabdominal ultrasound evaluation showed an ectopic gestational sac (black arrows) and the fetus (black star) with positive fetal heart activity [Figure 1].

Figure 1

A transabdominal ultrasound evaluation showed an ectopic gestational sac (black arrows) and a fetus (black star)

An emergency exploratory laparotomy revealed a ruptured right rudimentary intact sac lying free in the peritonel cavitiy. In laparotomy, there was a rupture of right rudimentary intact sac lying free in the peritoneal cavity with a hemoperitoneum of about 3 L. Fetus weighed about 300 g [Figure 2].

Figure 2

Fetus removed with laparotomy

Rudimentary horn pregnancy is a rare entity that cannot be diagnosed always and carries a high risk of maternal and perinatal mortality. Rupture is the most common and mortal complication of rudimentary horn pregnancy (80%). This complication usually occurs in the first and second trimester (85%) and infrequently in the third trimester (20%).[3] Rudimentary horn pregnancy has often been misdiagnosed as ectopic pregnancy, appendicitis, intestinal perforation.

Especially in the EDs, physicians have to take into consideration this life-threatening complication of pregnancy in the patients that admitted for recurrent abdominal pain.[45] The clinical diagnosis of rudimentary horn pregnancy can be challenging and various surgical conditions, which are commonly misdiagnosed as acute abdomen. To avoid missing this diagnosis, a high index of clinical suspicion and a careful history and further imaging tests are necessary.