What is the most common diagnosis for a patient presenting with severe unilateral abdominal pain, dizziness, nausea/vomiting, signs of shock, vaginal bleeding, cervical motion tenderness, adnexal mass, and ultrasound showing the absence of gestational sac?

The clinical presentation described aligns with a ruptured ectopic pregnancy. This condition occurs when a fertilized egg implants outside the uterus, typically in a fallopian tube. The severe unilateral abdominal pain is due to the stretching and rupture of the tube, which can lead to internal bleeding. Dizziness and signs of shock indicate significant blood loss, which is common when a ruptured ectopic pregnancy occurs. The presence of vaginal bleeding, cervical motion tenderness, and an adnexal mass all suggest a gynecological issue, and specifically, these signs are characteristic of an ectopic pregnancy rather than other conditions.

The absence of a gestational sac on ultrasound further supports this diagnosis. In cases of a viable intrauterine pregnancy, a gestational sac would generally be visible at this stage. The combination of these symptoms and findings makes a ruptured ectopic pregnancy the most likely diagnosis compared to other conditions such as ovarian torsion, pelvic inflammatory disease, or appendicitis. Ovarian torsion might present with similar abdominal pain but would not typically cause significant vaginal bleeding or the absence of a gestational sac. Pelvic inflammatory disease often has more diffuse pelvic pain and additional signs of infection. Appendicitis typically presents with right lower quadrant pain and does not