Review Question - QID 104657

This patient is presenting with lupus (given her renal insufficiency, arthralgias, and malar rash) in the setting of multiple pregnancy losses suggesting a diagnosis of antiphospholipid syndrome. Antiphospholipid syndrome will cause prolongation of the PTT and lends itself to a hypercoagulable state.

Lupus anticoagulant is an immunoglobulin that binds to phospholipids and proteins associated with the cell membrane. This binding interferes with phospholipids that induce in vitro coagulation during the PTT laboratory test. The term lupus anticoagulant is actually a misnomer since the protein is associated with a thrombophilic state and can present with recurrent arterial or venous thromboses or spontaneous abortions in women. PT, bleeding time, platelet count, and D-dimer are normal, while the PTT is prolonged. PT tests the function of factors I, II, V, VII, and X (the extrinsic pathway), while PTT tests the function of all factors except VII and XIII (the intrinsic pathway). Patients with antiphospholipid syndrome who have a history of thromboses require anticoagulation with appropriate medications including heparin, enoxaparin, aspirin, warfarin, and novel anticoagulants such as rivaroxaban.

Figure A shows the classic malar rash seen in lupus.

Incorrect Answers:
Answer 1: Isolated PT elevation is rare; however, the PT/INR is monitored to determine if a patient is therapeutic on warfarin with most conditions having a goal INR of 2.0-3.0.

Answer 2: Increased PT and PTT could be seen in liver disease where the liver is unable to synthesize clotting factors.

Answers 3-4: Increased PT and PTT, decreased platelets and increased PT, PTT, and D-dimer could be seen in disseminated intravascular coagulation which presents with consumption of everything needed for coagulation, hemolysis/schistocytes, and diffuse bleeding.

Bullet Summary:
Antiphospholipid syndrome presents with repeat thromboses and an elevated PTT.