Sunday, January 16, 2011

Thrombocytopenia.


Decreased platelet count.
Is characterized by spontaneous bleeding which is evident at platelet count below 20,000/μL, 20,000 to 50,000 may lead to post-traumatic bleeding.

a prolonged bleeding time
normal PT and PTT.

Sites of bleeding in thrombocytopenia – following are common sites but bleeding can occur from any site though.
Skin and mucous membranes
Petechie
Ecchymosis
Hemorrhagic vesicles
Gingival bleeding and epistaxis

Menorrhagia

Gastrointestinal bleeding

Intracranial bleeding

Spontaneous bleeding after trauma

Thrombocytopenia is one of the most common hematological manifestations of AIDS.

Causes of Thrombocytopenia:

Decreased production of platelets
Generalized diseases of bone marrow
Aplastic anemia: congenital and acquired
Marrow infiltration: leukemia, disseminated cancer
Selective impairment of platelet production
Drug-induced: alcohol, thiazides, cytotoxic drugs
Infections: measles, human immunodeficiency virus (HIV)
Ineffective megakaryopoiesis
Megaloblastic anemia
Myelodysplastic syndromes

Decreased platelet survival

Immunologic destruction:

Autoimmune: idiopathic thrombocytopenic purpura, systemic lupus erythematosus
Isoimmune: post-transfusion and neonatal
Drug-associated: quinidine, heparin, sulfa compounds
Infections: infectious mononucleosis, HIV infection, cytomegalovirus

Nonimmunologic destruction:

Disseminated intravascular coagulation
Thrombotic thrombocytopenic purpura
Giant hemangiomas
Microangiopathic hemolytic anemias

Sequestration: Hypersplenism

Dilutional.

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