Hemophilia A medical therapy
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Fahd Yunus, M.D. [2] Vahid Eidkhani, M.D.
Overview
There is no definitive treatment for Hemophilia , the mainstay of therapy is supportive and preventative care. It is recommended that patients diagnosed with hemophilia be referred to hemophilia treatment centers (HTC), which provide coordinated care between physicians (usually hematologists), nurses, social workers and other staff who specialize in bleeding disorders.[1]
Medical Therapy
Most hemophilia patients require regular supplementation with intravenous recombinant factor VIII/ IX, also known as replacement therapy.[2] This is highly individually determined. Apart from "routine" supplementation, extra factor concentrate is given around surgical procedures and after trauma, as well as emergently during any bleeding episode. Recombinant factor VIII/ IX concentrates do not contain any plasma or albumin, and therefore do not carry the risk of transmitting bloodborne viruses.[3]
Other therapeutic options include cryoprecipitate, fresh frozen plazma (FFP), desmopressin (DDAVP), and anti-fibrinoltytic agents.
- Cryoprecipitate contains moderately high concentrations of factor VIII and IX and may be given for joint and muscle bleeds. However, as it is derived from blood it carries risk of viral contamination
- FFP (fresh frozen plasma) contains clotting factors VIII and IX at significantly less concentrations than cryoprecipitate. As such, it is not routinely recommended as first-line therapy for hemophiliacs with bleeding episodes, given that the high amount of volume required to correct the coagulation deficit may result in circulatory volume overload
- DDAVP, or desmopressin, is a synthetic hormone which stimulates the release of factor VIII. It may be given to patients with mild, or sometimes moderate, hemophilia to treat minor bleeding. It could also e used in the treatment and management of mild to moderate cases of Hemophilia B, however its elevator effect is much more prominent regarding plasma factor VIII concentration than factor IX.
- Anti-fibrinolytic medications, most commonly epsilon aminocarproic acid, may be given orally or intravenously to prevent clots from being dissolved. It is often given orally prior to dental work to reduce risk of bleeding
- Patients with hemophilia may also require transfusion of packed red blood cells if excessive bleeding results in anemia
A particular therapeutic conundrum is the development of "inhibitor" antibodies against factor VIII/ IX due to frequent infusions.
- 20-30% of patients with severe hemophilia A develop antibodies to clotting factor VIII, called inhibitors. The development of inhibitor antibodies in Hemophilia B patients is estimated to be only about 3% to 5%[4].
- Inhibitors prevent replacement therapy from being effective as they target the recombinant factor VIII/ IX and prevent them from working
- If a patient develops an inhibitor to factor VIII/ IX, physicians may either attempt to infuse larger doses of recombinant clotting factor, or try different clotting factor sources
- These antibodies may self-resolve with time. No definitive therapy exists otherwise for patients who develop inhibitors to factor VIII/ IX
- Recently, Immune Tolerance Induction (ITI) therapy is being researched as a means of helping patients with hemophilia and factor inhibitors. ITI involves overcoming the immune reaction and desensitizing the body to the foreign factor concentrate infusion. ITI is expensive, time-intensive, and requires the oversight of multiple medical professionals, and is best coordinated at a hemophilia treatment center (HTC)[5]
References
- ↑ Konkle BA, Josephson NC, Nakaya Fletcher S. Hemophilia A. 2000 Sep 21 [Updated 2014 Jun 5]. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2016. Available from: http://www-ncbi-nlm-nih-gov.laneproxy.stanford.edu/books/NBK1404/
- ↑ Franchini M, Mannucci PM (2012). "Past, present and future of hemophilia: a narrative review". Orphanet J Rare Dis. 7: 24. doi:10.1186/1750-1172-7-24. PMC 3502605. PMID 22551339.
- ↑ Treatment of Hemophilia – World Federation of Hemophilia. Available at http://www.wfh.org/en/page.aspx?pid=642. Accessed on Sept 20, 2016
- ↑ DiMichele D (2007). "Inhibitor development in haemophilia B: an orphan disease in need of attention". Br J Haematol. 138 (3): 305–15. doi:10.1111/j.1365-2141.2007.06657.x. PMID 17614818.
- ↑ Inhibitors | Hemophilia | NCBDDD | CDC. Available at http://www.cdc.gov/ncbddd/hemophilia/inhibitors.html. Accessed on Sept 20, 2016