Thrombocytopenia Flashcards
thrombocytopenia
platelet counts less than 150,000
- common cause of abnormal bleeding
- decreased production of platelets or increased destruction of platelets
- sequestration
types of thrombocytopenia
ITP
NATP
TTP
TAR
ITP
immune thrombocytopenic purpura
PP of ITP
antibody that binds to plateltet membrane
-common in children after a viral infxn
CF of ITP
1-4 wks post viral illness
-abrupt onset of petechia, brusing, epistaxis
+/- hemorrhagic bullae on skin and mucus membrane
- no splenomegaly
- heparing is the drug tha tmost commonly cuases ITP like rx in hospitalized pts (HIT)
can be caused by SLE or CLl
drugs that may cause ITP
sulfonamides, quinine, thiazides, cimetidine, gold,
lab eval of ITP
severe thrombocytopenis, smear that shows megathrombocytes, coag studes are normal
dx of ITP
PE
tx of ITP
- benign self-limiting
- if indicated: steroids, IVIG, anti-D immunoglobulin (chronic ITP)
what should you avoid in ITP
antiplatelet meds (nsaid)
NATP
neonatal alloimmune thrombocytopenic purpura
PP of NATP
- Occurs as the result of sensitization of mother to antigens present on fetal platelets
o Antibodies cross the placenta & attack fetal platelets
o Infant at risk for intracranial hemorrhage in utero
lab dx of NATP
fetal scalp sampling or percutaneous umbilical blood smpaling to measure fetal platelet count
tx of NATP
c-section, infants may need steroids after birth
TTP
- congenital or acquired def of enzyme needed to cleave von willebrand factor
- congenital is RARE and often fatal
- women, HIV +
what can preciptate TTP?
estrogen use, preg, drugs (quinidine and ticlopindine)
CF of TTP
- jaundiced or pale
- purpura, petechiae, pallor, abdom pain, microangiopathic hemolytic anemia, fever
- may have renal dz
- +/- pancreatitis, recurrent episodes are common
Lab evaluation of TT
o Severe thrombocytopenia
o Typically have schistocytes in circulation (red cell fragmentation)
o RBC destruction
o Negative Coombs’ test
o Markedly elevated LDH. Increased indirect bilirubin
o Coagulation tests are normal
tx of TTP
plasma exchange, prednisone and antiplatelt
HUS
hemolytic uremia syndrome
HUS?
similar to TTP but found primarly in kids (younger than 10, particularly after infx w. e coli, shigella, or salmonella
what can precipitate HUS in adluts?
preg and estrogen use
lab values of HUS?
similar to TTP, but thrombocytopenia is less severe
tx of HUS
kids- conservative, fluids/ electorlyte balance
adults -plasmapheresis
TAR
Thrombocytopenia w. absent radii syndrome
TAR?
congenital megakaryocytic hypoplasia, autosomal recessive
** associated w/ orthopedic abnormalities
CF of TAR
**uppper extremities (thumbs are present)
- no radii is pathognomonic
- thrombocytopenia resolves over time (usually by 1 year)
tx of TAR
freqent platelet transfusion up to age 1 yr
DIC
disseminated intravasuclar coagulation
DIC?
severe illness that laters the homeostasis btw hemorrhage and thrombosis, so there is activation of both coagulation and fibrinolysis
what conditions are associated w/ DIC
spesis, burns , tissue injurt, obstetric complications, truama, ashyxia, malignancy, cirrhosis, sever transfusion rxn
CF of DIC
- Generalized hemorrhage in patients with severe underlying systemic illnesses
- Diffuse bleeding diathesis, GI and pulmonary bleeding, hematuria
- Thrombotic lesions affect the extremities, skin, kidneys, and brain
- Ischemic and hemorrhage strokes can occur
dx of DIC
skin and mucous membrane bleeding (particularly at puncture/wound sites) and shock are more common. Thrombosis (commonly digital ischemia and gangrene) less often predominates
- Thrombocytopenia, prolonged PT and PTT, elevated D-dimers (most sensitive) and fibrin, decreased fibrinogen and factor V and VIII levels, peripheral smear shows schistocytes. Also microangiopathic hemolytic anemia
tx of DIC
- Supportive treatment, correction of underlying disorders PROMPTLY and AGGRESSIVELY
- Component blood transfusions are important, particularly the replacement of fibrinogen through the administration of cryoprecipitate. The role of heparin is controversial
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