platelet disorders part 2 Flashcards
What are thrombocytopenias
low platelet count
what is considered sever thrombocytopenia
<50,000 platelets
spontaneous bleeding with ‘trauma’
true spontaneous bleeding not until 10-20,000 platelets
what is the presentation of thrombocytopenias
excessive/repetitive bleeding
excessive bruising (with minimal trauma)
bleeding at unusual sites (hemarthrosis)
excess mucosal bleeding
petechiae
how is thrombocytopenia worked up
CBC with platelet count
peripheral smear
platelet function analysis (PFA)
CMP to assess kidney and liver function
D-dimer to assess for concurrent thromboses (TTP, HUS, DIC, HIT)
what are the causes of thrombocytopendias
SPUD
sequestration
production (decreased)
Utilization (increase) - hemorrhage, DIC
Destruction (TTP, ITP, Drugs (HIT), Infection (HUS))
what is DIC
disseminated intravascular coagulation
occurs in sick patients: sepsis, trauma, OB emergencies, burns, cirrhosis, malignancies
associated with high rate mortality rate - actual rate difficult to discern due to co-morbid conditions
what happens in DIC
coagulation and fibrinolysis pathways in ‘overdrive’
“consumption coagulopathy” - clots everywhere, leads to organ ischemia, uses up platelets and other clotting factors, other areas in body start to bleed from minor injury
both too much and too little blotting at the same time
Kidneys, liver, lungs, brain are most susceptible to organ damage
what are the types of DIC
Acute and chronic DIC
what is acute DIC
quick, large trigger - sepsis, trauma
platelets cant compensate with production
LIFE THREATENING
What is chronic DIC
continuous or intermittent small trigger - malignancy
can compensate - increased production, liver clearance of FDPs
what is the presentation of acute DIC
bleeding, oozing, bruising, petechiae
thrombocytopenia
prolonged PT/aPPT
decreased plasma fibrinogen
elevated d-dimer
increased thrombin time
reduced levels of coag factors
evidence of hemolysis on peripheral smear
renal, hepatic, respiratory dysfunction
shock
what is the presentation of chronic DIC
most are asymptomatic
venous/arterial clots without other explanation
platelet counts normal or mildly elevated
normal PT/aPTT
normal or mildly elevated plasma fibrinogen
elevated d-dimer
evidence of hemolysis on peripheral smear
what is the workup for DIC
high index of suspicious in at risk patients
CBC, peripheral smar and coag panel (PT, aPTT, fibrinogen, D-dimer)
Thrombocytopenia + fibrinogen + D-dimer
what is the treatment for DIC
primary - treatment of underlying disorder
hemodyamic stabilization +/- ventilator support
whole blood transfusions - severe bleedings
platelet transfusion
coag factor repletion
what do we not use for treatment for patients in DIC
anticoagulants or antifibrinolytics
what is TTP
thrombotic thrombocytopenia Purpura
thrombotic microangiopathy
characterized by “small vessel platelet-rich thrombi”
no apparent cause
uncommon before age 20
F>M
EMERGENCY - fatal if not treated properly (stoke, brain damage, MI, renal failure)
what is the cause of TTP
deficiency in ADAMTS13 enzyme - hereditary
- procoagulant state
antibody (acquired)»_space; hereditary
what is the presentation of TTP
acute or insidious onset - generally episodic, can last days- weeks - months
presents with unusual bleeding/bruising + petechiae/purpura +: fever, weakness, fatigue, dyspnea, dizziness, abd pain, N/V, AMS, HA, visual changes, confusion, lethargy, syncope, seizure, focal deficits, tachycardia, CP, MI, CHF, arrhythmias
often have renal, GI or CNS involvement
often associated with anecedeent URI/ flu-like illness
what is the workup for TTP
CBC with diff
SEVERE HEMOLYTIC ANEMIA + THROMBOCYTOPENIA in otherwise healthy person
avg platelet count - 20,000
avg. hematocrit - 21%
avg. hemoglobin - 80 g/L
peripheral smear shows schistocytes (helmet cells), reduced platelets
normal plasma fibrinogen, PT, aPTT
ADAMTS13 assay
what is the plasmic scope for TTP
6+ = pressumed dx of TTP - check ADAMTS13
what is the treatment of hereditary TTP
give plasma infusion to replace
what is the treatment of acquired TTP
urgent initiation of plasma exchange is mainstay
- TPE- therapeutic plasma exchange AKA plasmapharesis
Ideally start within a few hours
continue until platelet count normalizes (>150,000)
what is the treatment of refractory acquired TTP
rituximab, vincreistine, cyclophosphonamide
what is the generalized treatment options for TTP
start immunosuppression with steroids
+/- VTE prophylaxis if needed for clinically significant clots
Splenectomy if TTP acquired and not responding
what is the prognosis for TTP
usually takes about 11 plasma exchanges to normalize platelet count
25-50% have exacerbation (recurrence within 30 days of treatment)
about 1/3 of pts have a relapse
increase severity of ADAMTS13 deficiency and presence of autoantibodies = higher risk for recurrence
mortality rate still 10-20% even if treated with plasma exchange
what is the morbidity of TTP
persistent neuro deficits in 5-13%
chronic renal insufficiency about 25%
renal failure requiring HD in 3-8%
persistent ADAMMTS 13 deficiency - increased risk of stroke
what are the differences between TTP and DIC
TTP: hereditary OR acquired, normal PT and aPTT, normal fibrinogen, normal d-dimer. tx: plasma exchange, FFP, steroids; NO PLATELETS
DIC: acquired, elevated PT and aPTT,reduced fibinogen, elevated d-dimer. tx: primary cause, FFP, or cryoprecipitative; GIVE PLATELETS
what is hemolytic-uremic syndrome (HUS)
presents similary to TTP except: mostly in kids, primarily related to bacterial infection»_space; hereditary
typically from Shiga-toxin (e.coli): prodrome: bloody diarrhea
antibodies, antidiarrheals increases risk for HUS
what is the work up of HUS
evidence of hemolytic anemia - low Hgb, schistocytes on periopheral smear
thrombocytopenia (platelets about 40,000)
renal injury - hematuria, proteinuria, AKI, reduced UOP, +/- HTN
+ MUTATION IN GENES ENCODING COMPLETMENT OR
+ STOOL CULTURE
what is the treatement of HUS
supportive care
hemodialysis if severe renal impairemnt
management of HTN
urgent plasma exchange if complement mediated only - not helpful for shiga-toxin mediated HUS
what is Immune Thrombocytopenia purpra (ITP)
aka idiopathic thrombocytopenia purpura
low platelet count -can be short term (acute - kids) vs chronic (adults) - 6 months
F>M
what is the prognosis for ITP
children = better prognosis
adults = often stabilize but rarely go into remission
can impact pregnant women
what is the cause of ITP
poorly defined - auto-antibodies to platelet antigens
primary or secondary types
primary - no identifiable trigger
secondary - trigger by CA, infection, etc
what is the presentation of ITP
asymptomatic
fatigue (debilitating)
petechiae/purpura
mucous membrane bleeding
nose bleeds
excessive or prolonged menstrual bleeding
overt hemorrhage or hematomas
what is the workup of ITP
diagnosis of exclusion - no definitive diagnosis
isolated thrombocytopenia
+/- large platelets on peripheral smear without abnormal morphology
other labs largely normal, except consistent with any trigger
+/- iron deficiency related to any bleeding
consider HCV and HIV screen - may be presenting symptom
what is the treatment of ITP
no cute
acute ITP (kids) - usually resolves on its own
goals = prevent bleeding and stabilize platelet count
if severe or impending bleeding or platelet count: high dose steroid, IVIG, platelet transfusion
what is Heparin-induced thrombocytopenia (HIT)
adverse reaction to heparin adminitstation
what are the types of HIT
type 1 and type 2
type 1: non-immune, day 1+, platelets will normalize spontaneously, can continue heparin (more common)
type 2: immune mediated, antibody preodunction, day 5-14 if heparin naive (more severe)
what is the effects of type 2 HIT
increasing platelet activation leads to more clotting
total platelet numbers fall
characterized by: UNEXPLAINABLE DROP IN PLATELET COUNT IN PT ON HEPARIN, steady drop, not fluctuation, expect stable hgb/hct - bleeding not the problem
How is HIT scored
4Ts for HIT score
Thrombocytopenia
Timing of platelet count fall
Thrombosis or other sequelae
oTher cause of thrombocytopenia
what is the treatment of HIT
discontinue heparin
start alternate anticoagulant
evaluate for HIT with PF4 ELISA
if ELISA (+), confirm with serotonin release assay
what should be avoided in patients with HIT
Coumadin - depletes vitamin K dependent natural anticoagulants
Platelet transfusion
what is thrombocytosis
elevated number of platelets greater than 400,000
a myeloproliferative disorder (megakaryocyte)
*underlying malignancy (secondary or reactive)
essential or primary thrombocythemia
associated with JAK2 mutations
F>M ages 50-70
what is the presentation of thrombocytosis
often asymptomatic
can present with throboses
some present wtih abnormal bleeding
associated splenomegaly
seizures, migraines, TIA
pregnancy complications
more rare is erythromelalgia
what is erythromelalgia
painful burning of the hands
how is thrombocytosis worked up
elevated platelet count
mild WBC elevations
normal RBCs
peripheral smear: large platelets otherwise normal morphologies
who is at high risk of thrombocytosis
age >60
WBC count >11,000
history of thromboses
comorbid malignancy
connective tissue disorders, IBD, TB - inflammation/infection
what is the treatment of thrombocytosis
goal = platelet count <500,000
first line = oral hydroyurea - causes myelosupression
ASA 81mg daily - prevention of thromboses, tx of erythromelalgia
if emergency platelet lowering required - plateletphoresis
what is the prognosis of thrombocytosis
lifespan greater than 15 years s/p diagnosis
10-15% progress to bone marrow fibrosis within 15 years
1-5% progress to acute leukemia iwthin 20 years
high risk for splenomegaly - splenic infart
