Silent uterine rupture: Resident's dilemma and lessons learnt.

A 36-year-old female with G7P6L6 at 36 weeks of gestation presented with complaints of vague pain abdomen and decreased perception of fetal movement since morning, accompanied by an episode of minimal bleeding per vaginum. There was no history of trauma and no prior antenatal checkups or investigations were done. On examination, she had mild pallor, pulse was 86/min and blood pressure was 110/70 mm of Hg. Her abdominal examination revealed 36 weeks sized uterus with maintained contour, absent fetal heart sound, no tenderness, and without superficial palpable fetal parts. A per speculum examination was done suspecting the possibility of placenta previa, which revealed no active bleeding. An emergency ultrasonography reported intrauterine fetal demise and placenta completely covering os. Her investigations showed: hemoglobin 8.8 gm/dl, hematocrit 30%, and normal coagulation profile and platelet count. The patient was diagnosed as type 4 placenta previa with intrauterine fetal demise and posted for cesarean section. It came as a bolt from the blue when intact amniotic sac with fetus en-caul was found extruded into the abdominal cavity through a fundal uterine rupture [Figure 1]. Sonographic features interpreted as placenta previa covering the os was in fact the contracted and empty uterus. The overlying fetus en-caul was creating a tamponade effect at site of rupture, thereby preventing hemorrhage and no signs of peritonism. These features led to a diagnostic dilemma as the patient was hemodynamically stable and uterine contour seemed to be maintained due to fetus en-caul and no free fluid in abdomen was detected on ultrasound. The patient underwent peripartum hysterectomy and was discharged on her 12th postoperative day.

Figure 1

Clinical photograph showing intact amniotic sac (horizontal black arrow) and placenta (tilted black arrow) which were extruded through the ruptured uterus into the abdominal cavity

When rupture uterus presents classically with hemodynamic instability, abdominal pain, and vaginal bleeding, the suspicion is prompt; however, if it presents atypically masquerading the telltale signs, diagnosis is often missed.[12] In present case, the only point favoring the diagnosis of rupture was patient's grand-multiparity. Other features like mild bleeding per vaginum before the onset of labor pointed more towards placenta previa. Ultrasonography had wrongly interpreted the fetus en-caul overlying the contracted uterus as central placenta previa. A similar case of misdiagnosing rupture uterus as placenta previa on ultrasound has been reported from Kangra, India.[3] The absence of peritoneal signs due to extrusion of product of pregnancy with intact amniotic sac along with insignificant bleeding into the abdominal cavity or vaginally results in this diagnostic dilemma.[4]

The unusual aspect of our case was rupture at the uterine fundus. Fundus is the thickest part of uterine musculature and usually does not give way spontaneously, unless associated with fundal placenta accreta or percreta, prior surgery or fundal pressure applied during delivery. Spontaneous rupture at the fundus before the onset of labor was the unique feature of the present case which also explained the hemodynamic stability of the patient as no major vessels were severed and only contracted myometrium was present at that site [Figure 2]. Massive hemorrhage is seen when major blood vessels are damaged: the uterine arteries being along the lateral walls are torn more commonly when the lower segment ruptures extending laterally. Also, in the present case, a tamponade effect exerted by the intact sac over the ruptured yet contracted uterus minimized blood loss.

Figure 2

Clinical photograph showing the rupture site at fundus (black arrow) with contracted myometrium and no major vessels severed

To conclude, when a patient presents with antepartum hemorrhage the common diagnoses that arise in our mind are placenta previa or abruptio placentae. The present case highlights that a diagnosis of silent rupture uterus should also be kept in mind.

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