Differential Diagnosis for the Patient
The patient presents with diffuse abdominal pain, a rigid abdomen, and hemodynamic instability. The following differential diagnoses are considered:
- Single most likely diagnosis
- Ruptured ovarian cyst or hemorrhagic ovarian cyst: The patient's history of recent deep venous thrombosis and anticoagulant use increases the risk of bleeding. The sudden onset of pain, radiation to the right shoulder (Kehr's sign), and hemodynamic instability suggest a hemorrhagic event. The patient's low hematocrit (26%) and symptoms support this diagnosis.
- Other Likely diagnoses
- Ruptured ectopic pregnancy: Although the patient's β-hCG is <5 mIU/mL, a ruptured ectopic pregnancy cannot be entirely ruled out, especially if the patient has irregular menstrual cycles or the test is not sensitive enough. However, the patient's last menstrual period was 3 weeks ago, making this less likely.
- Appendicitis: The patient's initial pain in the right lower abdomen could suggest appendicitis, but the diffuse nature of the pain, radiation to the shoulder, and hemodynamic instability are not typical for appendicitis.
- Intestinal obstruction or ischemia: The patient's abdominal tenderness, guarding, and rebound could suggest an intestinal obstruction or ischemia, but the sudden onset and radiation to the shoulder are not typical for these conditions.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Ruptured abdominal aortic aneurysm: Although the patient is relatively young, a ruptured abdominal aortic aneurysm can occur in anyone and is a life-threatening condition that requires immediate attention.
- Pulmonary embolism: The patient's history of deep venous thrombosis and anticoagulant use increases the risk of pulmonary embolism, which can cause abdominal pain and hemodynamic instability.
- Splenetic rupture: Although the patient has no history of trauma, a splenic rupture can occur spontaneously, especially in patients with underlying conditions that affect the spleen.
- Rare diagnoses
- Hemorrhagic pancreatitis: The patient's abdominal pain and hemodynamic instability could suggest pancreatitis, but the lack of typical risk factors (e.g., gallstones, alcohol use) and the absence of elevated pancreatic enzymes make this diagnosis less likely.
- Ruptured hepatic adenoma: The patient's history of oral contraceptive use increases the risk of hepatic adenoma, but the lack of typical symptoms (e.g., liver mass, abnormal liver function tests) makes this diagnosis less likely.