protein c deficiency 25/12/2010 by: mohammed alsaidan
TRANSCRIPT
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Protein C deficiency 25/12/2010
BY: MOHAMMED ALSAIDAN
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Protein C deficiency
• AR, usually presents in the neonatal period with • purpura fulminans (PF) • severe disseminated intravascular coagulation (DIC)• venous thromboembolism (VTE)
• Asymptomatic : 1 in 500 healthy individuals• clinically significant : 1 in 20 000
• Most parents of infants with severe protein C deficiency are asymptomatic
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Protein C
• Protein C is a vitamin K-dependent coagulation protein
• Synthesized in hepatocytes
• Activated after complex formation with thrombin on the endothelial cell receptor
• It cleaves critical sites in the activated procoagulant factors V and VIII, thus inactivating these enzymes
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Protein C level
• Mild , moderate sever
• The mean level in a healthy term infant is 40 IU /dL
• lower limit of normal in infants of 25 IU /dL
• Later: approximately 60 IU/dL
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Labs
• At the ontset of skin lesions: • normal Coagulation studies• elevated D-dimer• undetectable plasma protein C activity
• Rapidly after onset of PF : • thrombocytopenia• hypofibrinogenaemia• prolongation of the PT
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Clinical features
• Foetal demise or die from DIC before diagnosis
• Most affected infants are congenitally blind from thrombosis into the developing vitreal vein
• Evidence of prenatal arterial ischaemic stroke on MRI
• Recurrent episodes of PF triggered by infection, trauma, and minor decreases anticoagulation
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Protein C deficiency
• PF originates with red or purpuric lesions at pressure points
• Histologically, PF lesions consist of fibrin clots in small venules of the subcutaneous fat.
• Low INR short-term bridging anticoagulation with low-molecular-weight heparin or protein C replacement with concentrate, to prevent VTE, DIC and PF
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Protein C deficiency
• No anticoagulation required when plasma protein C concentrations above 50% around surgery and above 20% during baseline conditions
• Infants managed with intensive anticoagulation and/or protein C replacement have exhibited normal growth in longterm follow-up
• Some will have developmental delays and/or cognitive impairment
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T H A N KYO U