Case Presentation: A 93-year-old female with a history of stroke, hypertension, moderate aortic stenosis (AS) and peripheral vascular disease presented with four days of right lower extremity pain. She had recently been seen in vascular clinic for difficulty walking and associated pain, which was attributed to chronic venous insufficiency. In the emergency department, examination revealed ecchymosis overlying the right lateral thigh without any reported trauma and a systolic murmur but was otherwise unremarkable. She was admitted for further evaluation. Laboratory studies revealed a hemoglobin of 8.7 g/dL (baseline 11-12 g/dL), a PTT >200 seconds, and an INR of 1.3. CT imaging demonstrated edema in the right thigh along the course of the vastus lateralis muscle, with a rim-enhancing suprapatellar joint effusion. Hematology was consulted, and the patient received desmopressin and prothrombin complex concentrate. The following day, she developed a second hematoma on her right arm, attributed to compression from a blood pressure cuff. Additional labs revealed normal von Willebrand factor activity and antigen levels, mixing studies which failed to correct the PTT, and low factor VIII activity, leading to a diagnosis of acquired hemophilia A (AHA). Additionally, a repeat echocardiogram showed progression of moderate aortic stenosis to severe AS. The patient was started on corticosteroids and repeat factor VIII levels are pending to evaluate treatment response.
Discussion: AHA is a rare but serious bleeding disorder caused by the development of autoantibodies against factor VIII. A typical presentation involves an elderly patient with spontaneous hematomas, particularly in the muscles, with the hallmark laboratory finding of prolonged PTT that does not correct with mixing studies. In this case, the patient presented with nonspecific pain and swelling of the right lower extremity, symptoms that were initially attributed to chronic venous insufficiency until laboratory studies pointed to an acquired coagulopathy. Unique to this case was the identification of suprapatellar hemarthrosis on CT imaging, a finding more commonly associated with congenital hemophilia; however, classic muscular hematomas were also present. AHA management typically includes hemostatic therapy for acute bleeding and immunosuppressive therapy, steroids in this case, to address the underlying autoimmunity. While most cases of AHA are idiopathic, the condition may also occur postpartum or in association with underlying malignancy. Thus the patient underwent additional testing with flow cytometry which showed no evidence of malignancy or lymphoproliferative disorders, which should be ruled out in cases of AHA. Coagulopathy can also occur in severe AS due to mechanical stress on red blood cells and platelet dysfunction, leading to bleeding. However, there are no known cases of AHA secondary to AS.
Conclusions: AHA should be considered in elderly patients presenting with nonspecific or unexplained bleeding, particularly in the presence of significant hematoma formation. Early diagnosis and treatment are critical, and management involves immunosuppressive therapy and monitoring of factor VIII levels and PTT to assess response. This diagnosis should be suspected in patients without a history of trauma or an inherited bleeding disorder. Although rare, keeping AHA on the differential in this patient population can dictate life-saving treatment.