Heparin-like effect resistant to protamine in a child with haemorrhagic shock. Do we need heparinase?

Acquired haemophilia A: Italian Consensus Recommendations on diagnosis, general management and treatment of bleeding

BACKGROUND

Acquired haemophilia A (AHA) is a rare bleeding disorder due to autoantibodies to coagulation factor VIII that may be secondary to autoimmune diseases, cancer, drugs, pregnancy, infections, or be idiopathic. Recurrent bleeding, often severe, mostly in muscles and soft tissues, and isolated prolonged activated partial thromboplastin time (aPTT), in the absence of personal and family history of bleeding, are typical features that should raise the suspicion of AHA. Poor awareness of the disease results in diagnostic delays and inappropriate treatment.

MATERIALS AND METHODS

The Italian Association of Haemophilia Centres (AICE) developed consensus recommendations in cooperation with the Italian Society on Thrombosis and Haemostasis (SISET). The document was shared with scientific societies of specialist physicians, laboratory professionals and pharmacists to spread knowledge about AHA and promote appropriate diagnosis/treatment.

RESULTS

Ready availability of the aPTT mixing test is crucial, although diagnostic confirmation and optimal management require prompt referral of patients to specialised centres with rapidly available diagnostic and therapeutic facilities. If immediate referral is unfeasible, treatment must be undertaken early, under guidance of specialised centres or based on shared protocols. Recommendations about diagnosis, general management and, in bleeding patients, haemostatic therapy using bypassing agents or replacement treatment, including the recently available recombinant porcine factor VIII, are provided, considering the different clinical settings and laboratory facilities.

DISCUSSION

This consensus document aims to improve the overall healthcare pathways for AHA, harmonise the management and therapeutic approaches to newly diagnosed patients and reduce the still relevant complications and mortality in this setting.

Structural characterization of a clinically described heparin-like substance in plasma causing bleeding

Heparin-like substances (HLS) have been described in various clinical situations, including in settings of liver disease associated with infection, transplant, and metastasis. HLS are generally attributed to circulating glycosaminoglycans. Initial results for this patient showed coagulopathy due to liver disease without HLS. Two weeks after liver transplantation, a 10 year-old female with liver failure patient began to bleed from catheter insertion sites, mouth, and nares and HLS was suspected. The patient subsequently died and these clinical samples resulted in the isolation of a single heparan sulfate (HS) present at high concentrations in the plasma. Analysis of this HS showed it had an intermediate between heparin and HS with low antithrombin-mediated anticoagulant activity. We speculate that this 10-year old patient might have a platelet function defect influenced by this unusual HS. Endothelial defects not measurable by our methods might have also contributed to the observed bleeding complications.