Thrombocytopenia Flashcards
What is the most common cause of thrombocytopenia
Infection induced
What are the more common infectious causes of thrombocytopenia
Often with gram negative systemic infections, or HIV virals
Typically resolves once underlying infection is treated
What are the drugs that cause thrombocytopenia
Associated with many drugs including chemotherapy agents and antibiotics
Treatment is to withdrawal medication
What is the pathophysiology behind HIT
• Typically results in a mild thrombocytopenia and places the patient at greater risk for clots.
• Typically post exposure a patient develops an antibody complex of anti-heparin/PF4 that activates platelets
• Typically occurs 5-14 days post exposure
What are the four Ts of HIT
• Four Ts
o Thrombocytopenia
o Thrombosis
o Timing
o Other causes
Diagnostic testing for HIT
ElISA testing will test for the antibody complex
• Serotonin Release Assay will test for the ability for a patient’s serum plts to activate in the presence of heparin
Treatment for HIT
• Discontinue Heparin
• Can use Dabigatron instead, do NOT use LMWH, if longer anticoagulation is needed patient can be transitioned to warfarin
• Imaging studies to determine presence of clots
HIT treatment
• Discontinue Heparin
• Can use Dabigatron instead, do NOT use LMWH, if longer anticoagulation is needed patient can be transitioned to warfarin
• Imaging studies to determine presence of clots
Patho of ITP
• An immune mediated disorder the results in the destruction of platelets and the inhibition of plt release from megakarytocytes
• Associated with SLE, HIV, and Hep C infections
ITP symptoms
• Mucosal bleeding, thrombocytopenia, bruising, petechiae, GI bleeding, heavy menstrual bleeding, and wet purpura, retinal hemorrhages
Diagnostics for ITP
• CBC with thrombocytopenia
• Normal blood smear
• HIV, Hep C, and SLE testing
ITP treatment
• Reserved for those with plt count <30k
• Without bleeding, thrombocytopenia, or impending bleeding
o Prednisone, IVIG, anti Rh globulin
• With bleeding, thrombocytopenia
o High doeglucocorticoids
o IVIG or antiRh
o Rituximab
o TPO receptor agonist if all other treatments fail
o Splenectomy if all treatments fail
TTP pathophysiology
• A hemolytic anemia, thrombocytopenia, renal failure, fever, and neurologic findings
• Related to a deficiency of or antibody to ADAMST13
• ADAMST13 is an enzyme which cleaves VWF. The ultra large VWF molecules are thought to contribute to pathologic platelet adhesion and aggregation.
• ADAMST13 <10% is typically when TTP is seen
• More common in women and pregnant or HIV infected individuals
Symptoms of TTP
• New thrombocytopenia with potential renal failure
Diagnostics for TTP
• Increased LDH, indirect bilirubin, and retic count
• Decreased haptoglobin
• Negative direct anti globulin test
• Peripheral blood smear: positive for polychormasia and schistocytes
