Compare and contrast heparin induced thrombotic thrombocytopaenia syndrome (HITTS) and thrombotic thrombocytopaenlc purpura (TTP) with respect to their pathogenesis, clinical features, relevant laboratory findings, and treatment.
Condition |
TTP |
HITTS |
Aetiology 1 mark each |
|
Autoantibodies to platelet factor 4 (PF4) complexed with heparin |
Clinical Features 1 mark each |
Small vessel thrombosis- Microangiopathic haemolytic anaemia with multisystem involvement but renal and CNS dominate- |
Occurs within 4-10 days of heparin administration- arterial and venous thrombosis, thrombocytopenia |
Laboratory 2 marks each |
Low platelets, intravascular haemolysis with evidence of micrangiopathic changes to RBC morphology. LDH, Haptoglobin, COOMBS test, ADAMTS 13 deficiency |
Ant PF4 antibody, Functional Assays- (serotonin release, Heparin induced platelet activation) |
Treatment 1 mark each |
Plasmapharesis is the mainstay of treatment for Acquired TTP, FFP for hereditary TTP |
Cessation heparin Non heparin based anticoagulation ( Lepuridin etc) |
A "compare and contrast" question is typically something that benefits from a tabulated answer.
Observe:
Domain | HITS | TTP-HUS |
Pathogenesis |
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Clinical features |
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Classic "pentad"
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Laboratory findings |
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Treatment |
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George, James N. "Thrombotic thrombocytopenic purpura." New England Journal of Medicine 354.18 (2006): 1927-1935.
Peyvandi, Flora, et al. "von Willebrand factor cleaving protease (ADAMTS‐13) and ADAMTS‐13 neutralizing autoantibodies in 100 patients with thrombotic thrombocytopenic purpura." British journal of haematology 127.4 (2004): 433-439.
Tsai, Han-Mou. "Advances in the pathogenesis, diagnosis, and treatment of thrombotic thrombocytopenic purpura." Journal of the American Society of Nephrology 14.4 (2003): 1072-1081.
Oh's Intensive Care manual: Chapter 97 (pp. 993) Therapeutic plasma exchange and intravenous immunoglobulin therapy by Ian Kerridge, David Collins and James P Isbister
Kakishita, Eizo. "Pathophysiology and treatment of thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS)."International journal of hematology 71.4 (2000): 320-327.
Noris, Marina, and Giuseppe Remuzzi. "Hemolytic uremic syndrome." Journal of the American Society of Nephrology 16.4 (2005): 1035-1050.
Kappler, Shane, Sarah Ronan-Bentle, and Autumn Graham. "Thrombotic Microangiopathies (TTP, HUS, HELLP)." Emergency Medicine Clinics of North America (2014).
Moake, Joel L. http://www.danielyoung.net/articles/NEJM%20TTP-HUS%202002.pdf "Thrombotic microangiopathies." New England Journal of Medicine 347.8 (2002): 589-600.
Arepally, Gowthami M., and Thomas L. Ortel. "Heparin-induced thrombocytopenia." New England Journal of Medicine 355.8 (2006): 809-817.
Patel, Vipul P., Matthew Bong, and Paul E. Di Cesare. "Heparin-induced thrombocytopenia and thrombosis." AMERICAN JOURNAL OF ORTHOPEDICS-BELLE MEAD- 36.5 (2007): 255.
Greinacher, Andreas. "Heparin-induced thrombocytopenia." New England Journal of Medicine 373.3 (2015): 252-261.