A Case of Severe Prekallikrein Deficiency Manifesting as Isolated Activated Partial Thromboplastin Time (aPTT) Prolongation.

We present the case of a 54-year-old female who was admitted to the medicine service for a left foot ulcer with cellulitis requiring hallux amputation. Pre-surgical laboratory findings were significant for an isolated elevation in activated partial thromboplastin time (aPTT). Hematology was consulted for evaluation of prolonged aPTT prior to surgery given potential for bleeding risk. Further laboratory studies obtained were significant for normal factor levels, negative hypercoagulable workup, normal kininogen activity, and severe prekallikrein deficiency. The patient was pre-operatively given one unit of fresh frozen plasma (FFP). She had minimal blood loss during her procedure with no additional blood products required post intervention. Because patients with prekallikrein deficiency have preserved auto-activation of factor XII, they rarely manifest with increased bleeding risk or thrombotic risk. Thus, presurgical optimization of patients with severe prekallikrein deficiency should be standardized to limit delay of care. Our review suggests that routine prophylactic administration of blood products for pre-operative management of this condition is not indicated but may be considered if the patient is at high risk of hemorrhage or clinical deterioration. Thrombotic risk should also be considered in these patients.