Is heparin induced thrombocytopenia a hypersensitivity?

Is heparin induced thrombocytopenia a hypersensitivity?

The most dangerous hypersensitivity reaction to systemic heparin use is heparin-induced thrombocytopenia (HIT II), a type II antibody-mediated hypersensitivity reaction against complexes of platelet factor 4 and heparin [2].

Which laboratory result is the most critical in recognizing heparin induced thrombocytopenia HIT?

Which tests are useful for diagnosing heparin-induced thrombocytopenia? In patients with an intermediate or high pretest probability of HIT, an enzyme-linked immunosorbent assay (ELISA) to detect heparin-platelet factor 4 (PF4) immunoglobulin G (IgG) antibodies is the first diagnostic step.

How is heparin induced thrombocytopenia detected?

The criteria for diagnosis of HIT include:

1. normal platelet count before the commencement of heparin.
2. thrombocytopenia defined as a drop in platelet count by 30% to <100×109/l or a drop of >50% from the patient’s baseline platelet count.

Can you test for PF4?

A test for heparin-induced thrombocytopenia (HIT) antibody, also called heparin-PF4 antibody, is performed to detect antibodies that develop in some people who have been treated with heparin.

What are the symptoms of an allergic reaction to heparin?

Get emergency medical help if you have signs of an allergic reaction: nausea, vomiting, sweating, hives, itching, trouble breathing, swelling of your face, lips, tongue, or throat, or feeling like you might pass out. Heparin may cause you to bleed more easily, which can be severe or life-threatening.

What happens in heparin induced thrombocytopenia?

Heparin-induced thrombocytopenia (HIT) occurs when a patient receives heparin, a blood-thinning medication, and subsequently forms antibodies against heparin and the platelet factor-4 (PF4) complex.

Why does heparin bind to PF4?

PF4 is an abundant chemokine present in the alpha granules of the platelets. PF4 can combine with the anticoagulant heparin to form an antigen that can induce the production of IgG antibodies. This immune complex of PF4-heparin and the IgG antibody can activate platelets by binding to the platelet FcRγIIA receptor.

What is PF4 heparin?

PF4 is a member of the CXC subfamily of chemokines that possesses high affinity for heparin and other large, anionic molecules. 39. PF4 is expressed in megakaryocytes and stored in platelet α-granules from which it is released upon activation. 40,41. After its release, PF4 binds to GAG on vascular cell surfaces.

What are the symptoms of heparin induced thrombocytopenia?

Thrombocytopenia is common in hospitalized patients, so the symptoms of HIT can go unheeded. However, if a patient is being given heparin, symptoms such as lesions at injection sites, chills, fever, labored breathing, or chest pain, should be considered signals of possible HIT.

What is heparin induced?

Heparin-induced thrombocytopenia ( HIT) is the development of thrombocytopenia (a low platelet count), due to the administration of various forms of heparin, an anticoagulant . HIT predisposes to thrombosis (the abnormal formation of blood clots inside a blood vessel) because platelets release microparticles…

How do you treat heparin induced thrombocytopenia?

Treatment for heparin-induced thrombocytopenia. Heparin injections or infusions should be stopped. Alternative anticoagulation may be required to prevent life-threatening thrombosis. This is usually with factor Xa inhibitors such as danaparoid, or direct thrombin inhibitors such as bivalirudin or dabigatran.

Does Lovenox cause heparin induced thrombocytopenia?

As with other heparin-like drugs, Lovenox can cause low blood platelets (thrombocytopenia). In many cases, this is mild and causes no other problems. Rarely, though, a severe reaction known as heparin-induced thrombocytopenia (HIT) may occur.