Kacie Clark, BCCCP, PharmD
Emergency Medicine Clinical Pharmacy Specialist
Methodist Le Bonheur Healthcare
Memphis, Tennessee
Disclosure information not submitted.
Sterling Torian, PharmD, BCCCP, (she/her/hers)
Evening Critical Care Pharmacist
TriStar Centennial Medical Center
Nashville, Tennessee
Disclosure information not submitted.
Brett Patrick, MD, MD
Associate Professor
The University of Tennessee Health Science Center, United States
Disclosure information not submitted.
Title: Acute treatment of intracranial hemorrhage complicated by hemophilia A and emicizumab therapy
Introduction:
Emicizumab is indicated in hemophilia A patients with factor VIII inhibitors as prophylaxis. While bleeding frequency is reduced, emicizumab does not fully normalize the coagulation process and patients may still present with traumatic or spontaneous hemorrhage.
Description: A 62-year-old male, with a known past medical history of hemophilia A, presented to the emergency department with complaints of left upper and lower extremity weakness, paresthesia, facial droop, and altered speech. Imaging revealed acute intraparenchymal hemorrhage within the right basal ganglia associated with positive mass effect and a 6 mm midline shift. As laboratory blood samples were pending, it was discovered the patient was prescribed emicizumab with the last dose confirmed as one week prior. Emicizumab alters the readily available activated partial thromboplastin time (APTT) assay for coagulation studies, and the chromogenic assay appropriate for this situation would take several days to result. Without the ability to quickly obtain factor levels, the assumption of a 0% factor VIII level with a goal increase of 100% was made. To replace factor VIII, human antihemophilic factor 4000 units (50 units/kg of adjusted body weight) was administered. Hematology recommended empiric continuation of antihemophilic factor 4000 units every 12 hours due to the inability to assess factor levels in real time. Throughout the remainder of admission, the antihemophilic factor dose was empirically decreased based on the patient's improved clinical status and minimal hematoma expansion on follow-up CT. The patient was discharged 14 days later to an acute inpatient rehabilitation center.
Discussion: Early and appropriately dosed coagulation factor concentrate has been shown to have a protective effect on hemophiliac patients who experience intracranial hemorrhage. However, emicizumab interferes with the readily available assay for obtaining factor levels, and therefore, makes the determination of factor replacement dosing difficult. The assumption of an undetectable level for antihemophilic factor dosing, with subsequent doses based upon clinical status, may be an appropriate option for management of intracranial hemorrhage in hemophilia A patients on emicizumab therapy.