A patient is admitted to the local hospital with a pulmonary embolus. He was unconscious when admitted to the emergency department. Ultrasound revealed a large clot in the patient's saphenous vein. Thrombolytic therapy is administered, and eventually the patient's condition stabilizes. Laboratory tests are performed at hospital admission; their results follow: PT: 15.5 sec
INR: 2.85
APTT: 76 sec
Protein C antigen: 14%
Protein C functional activity: 18%
Molecular studies: FV-R506Q present
Based on this information, what is the most probable diagnosis for this patient?

Question

Quizplus · Accepted Answer

The patient's laboratory results suggest a possible diagnosis of activated protein C resistance (APCR), which is commonly caused by factor V Leiden (FV-R506Q) mutation. The decreased protein C antigen and functional activity levels also suggest a coexisting protein C deficiency. PS deficiency is less likely given the patient's laboratory results. HC-II deficiency is not mentioned and cannot be inferred based on the information provided. Therefore, option C, APCR and PC deficiency, is the most probable diagnosis for this patient.

A Patient Is Admitted to the Local Hospital with a Pulmonary