Kalil. 35 years old female presents with Bilateral deep vein thrombosis in legs. There is past history of recurrent fetal loss and one attack of pulmonary embolism. Screening tests of coagulation reveal a prolonged APPT. Likely diagnosis is:
**Core Concept**
The patient's presentation of bilateral deep vein thrombosis (DVT), recurrent fetal loss, and a history of pulmonary embolism suggests a coagulopathy. The prolonged activated partial thromboplastin time (APPT) indicates a problem with the intrinsic coagulation pathway. This patient's symptoms and lab results point towards a disorder of the coagulation cascade.
**Why the Correct Answer is Right**
The patient's symptoms and lab results are consistent with Antithrombin III deficiency, a condition characterized by a deficiency of the anticoagulant protein antithrombin III. This protein normally inhibits the coagulation cascade by inactivating thrombin and other clotting factors. A deficiency in antithrombin III leads to an increased risk of thrombosis, including DVT and pulmonary embolism. The prolonged APPT is consistent with a defect in the intrinsic coagulation pathway, which involves the antithrombin III pathway.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the patient's presentation, as Factor V Leiden mutation is associated with an increased risk of thrombosis, but it typically presents with a normal or prolonged prothrombin time (PT), not a prolonged APPT.
**Option B:** Protein C deficiency is another cause of thrombophilia, but it typically presents with a normal or slightly prolonged APPT, not a significantly prolonged APPT as seen in this patient.
**Option C:** This option is not relevant to the patient's presentation, as Factor VIII deficiency (Hemophilia A) typically presents with a prolonged PT, not a prolonged APPT.
**Clinical Pearl / High-Yield Fact**
Antithrombin III deficiency is a rare coagulopathy that increases the risk of thrombosis, and it is often associated with a history of recurrent fetal loss and thrombotic events.
**Correct Answer:** D.