Prekallikrein and high molecular weight kininogen deficiency in Oman: a challenging diagnosis in mucosal bleeding

Abstract

Background: Prekallikrein (PK) and high molecular weight kininogen (HMWK) are contact factors that are involved in the intrinsic pathway of the coagulation cascade. Deficiency of PK or HMWK are known to be associated with prolonged a PTT, but no clinical bleeding. However, rare cases of PK deficiency have been reported to be associated with mucosal bleeding. Objective: To report on epidemiological and clinical characteristics of Omani patients with PK and HMWK deficiency, focusing on one symptomatic case. Patients and methods: We reviewed the files of Omani patients who had persistently prolonged a PTT that proved to be secondary to PK or HMWK deficiency over a period of ten years. Results: Eight cases (three with PK, five with HMWK deficiency) were identified. All but one case were asymptomatic. A thirteen year-old female with Hashimoto thyroiditis who presented with easy bruising, severe prepubertal vaginal bleeding and recurrent hematemesis proved to have prekallikrein deficiency. Acquired vWD, coagulation factors deficiency, lupus anticoagulant, platelet dysfunction were ruled out. No local cause of bleeding could be identified even after four endoscopic examinations, Meckel’s diverticulum scintigraphy and CT angiography of the abdomen. Conclusion: PK and HMWK are underestimated in Oman. Most cases were incidentally detected. They significantly impact medical costs, related to extensive laboratory testing and undue delay in planned surgical procedures. Some cases with clinical bleeding impose a diagnostic challenge.