Term
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Definition
• 100,000 – slight risk of bleeding
• 20,000-70,000 – increased risk of bleeding with trauma/surgery
• <20,000 – increased risk of spontaneous hemorrhage
• <10,000 – increased risk of spontaneous intracranial hemorrhage |
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Term
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Definition
• Peripheral Smear – Are platelets visible? Size? Granules?
• Platelet Count – how many platelets are in the blood?
• Bleeding Time – highly variable; normal < 9 minutes
• Platelet Aggregation/Secretion Studies – assess platelet responses to various chemicals |
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Term
| TCP of decreased platelet production due to? (4) |
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Definition
• Bone Marrow Disease – include 1o failure, invasion, or injury:
o 1o bone marrow failure – bone marrow idiopathically stops producing blood cells
o Bone marrow invasion – from metastatic cancer, myelofibrosis, or cancer in situ
o Bone marrow injury – reaction to drugs, radiation, chemicals, alcohol
• Nutritional Disorders – leading to lack of compounds necessary to build platelets
• Megaloblastic Anemia – Fe deficiency affects platelet production…
• Hereditary Disorder – involve decreasing megakaryocytes or producing bad megakaryocytes |
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Term
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Definition
| AI TCP, post-transfusion purpura, neonatal isoimmune TCP |
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Term
Disease: maternal antibodies to neonate platelets transferred in utero
o Mother – is Pla1 negative, and has been previously sensitized to Pla1 develops Ig’s
o Neonate – is Pla1 positive, and mother’s transferred serum mounts immune response |
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Definition
| • Neonatal Isoimmune Thrombocytopenia |
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Term
patient’s serum contains antibodies to platelet antigens of donor blood
o Pla1 – most common antigen on a platelet which can have antibody response
o Innocent bystander mechanism – often patient’s own platelets also destroyed in Ig response |
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Definition
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Term
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Definition
– antibodies produced against platelets:
o Acute – more common in children, preceded by viral infection; generally self-limited
o Chronic – commonly seen in women 20-40y, a chronic disorder, have normal bone marrow
Tx – give immunosuppressives, reduce platelet removal by macrophages
o Secondary – associated with disordered lymphoid function (e.g. SLE, lymphoma, leukemia) |
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Term
| common drugs Inducing Immune Thrombocytopenia |
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Definition
| ulfa drugs, penicillin, gold salts, dilantin, lasix |
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Term
| Review: mechs of drug-induced TCP |
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Definition
several different mechanisms drugs cause immune reaction:
o (Comp. “Hapten Mech”) – drug binds to platelet, Ig recognizes, platelet bystander destroyed
o (Protein/Drug Complex) – drug binds to platelet surface sturcture “complex” Ig attacks
o (Comp. “In Vivo Sensitization”) – drug binds to platelet surface antigen “neo-antigen” Ig |
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Term
| heparin-induced TCP mechanism cascade |
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Definition
1) Heparin & platelet factor IV combine (Hep-PF4)
2) IgG antibody binds to Hep-PF4 to form immune complex
3) Fc region of antibody binds to platelet, and platelet activates and granules released=>more recruited
4) Large quantities of PF4 released into plasma
5) PF4 will bind to more heparin, or heparin-like proteins (heparans) on endothelium
6) Immune response damages endothelium limb ischemia, myocardial infarction, stroke |
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Term
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Definition
| DIC, TTP, Splenic sequestration |
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Term
disorder of vWF proteolysis
o Mechanism – lack of ADAMTS 13, cleaves long vWF; without = massive platelet plugging
o No Fibrin – vWF platelet plugs don’t have fibrin (no clot cascade); fibrin = DIC |
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Definition
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Term
px with Microangiopathic hemolytic anemia – shows schistocytes on blood smear
Thombocytopenia – platelets reduced
Neurologic dysfunction – confusion
Renal Failure – can’t filter RBC’s? Hemolytic uremic syndrome…
Fever – also present |
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Definition
| TTP (classic pentad of findings) |
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Term
| causes of 2ndary thrombocytosis |
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Definition
in response to inflammation, hemorrhage, post-splenectomy, Fe def.
o Inflammation – body produces blood cells to fight infection
o Hemorrhage – makes sense for body to produce excess clotting factors to stop bleeding
o Post-splenectomy – no buffer for platelet storage
o Iron deficiency – can result in an increase in platelet count |
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Term
| 1ary thrombocytosis due to overactive platelets? T/F |
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Definition
| series of mutations leading to excess (often malformed) platelets; rare |
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