Myeloproliferative Flashcards
How are myeloproliferative syndromes generally characterized?
Too many blood cells
General definition of polycythemia vera (PCV)
Too many RBCs
General definition of essential thrombocytosis (ET)
Too many platelets
General definition of chronic myelogenous or chronic myeloid leukemia (CML)
Too many neutrophils
Define myelofibrosis
Too many RBCs, platelets and neutrophils with prominent immature RBCs
Describe myeloproliferative syndromes
- Neoplastic blood cell disorders
- Insidious onset w/vague symptoms
- Splenomegaly
- Cure NOT possible
Describe polycythemia vera
Elevated RBC mass a/w a mild increase in WBCs and platelets
Etiology of PCV
JAK2 gene mutations in 90% of cases
PE findings of PCV
- Ruddy complexion
- Mild splenomegaly
Diagnostic tests of PCV
- Total body plasma volume
- Total body RBC volume or mass
- Difficult to obtain in practice
Lab findings of PCV
- Normal ABG
- Normal Fe/TIBC
- Normal or slightly high B12
- Normal folate
- Low serum erythropoietin
Treatment of PCV
- Decrease Hct via phlebotomy until Fe deficient
- AVOID chemo drugs (Hydrea)
- Anagrelide can be used to decrease platelets
- Ruxolitinib can decrease platelets/splenomegaly but may cause severe anemia (pt must be JAK2 positive to work)
What are the lab findings of a patient with well controlled PCV?
- Normal (or near normal) Hct
- Low MCV
Why should chemo drugs such as Hydrea be avoided in PCV patients?
Increase the risk of secondary leukemias
How can Anagrelide be used to treat PCV?
Decreases platelet count
How can Ruxolitinib be used to treat PCV?
- Decreases platelets and splenomegaly
- May cause severe anemia
- Only works if pt is JAK2 positive
WHO definition of Essential Thrombocytosis (ET)
Platelet count over 600,000 without other etiologies (Fe deficiency, co-existent infection/inflamm process, bleeding, other myeloproliferative disorder)
Clinical presentation of ET
- MC in females
- HA, easy bruising/bleeding
- PE usually normal (mild splenomegaly may be present, but massive splenomegaly should suggest another diagnosis)
Lab findings of ET
- Normal Hgb and Hct
- Normal or slightly high WBCs (normal diff)
- Normal Fe/TIBC
- High platelets w/giant plts
- JAK2 V617F present
How can elevated platelets affect chem labs of a patient?
Increased K - released from platelets when clot forms in serum tube
How can elevated platelets affect ABG results?
Decreased pO2 - due to hypermetabolic state in ABG syringe if not quickly cooled on ice
Treatment of ET
- Conservative and symptom based (lower platelets until pt is asymp)
- Anagrelide or Hydrea are mainstays
What is CML characterized by?
- High WBC count w/immature blood cells normally seen in BM but now in peripheral blood
- Thrombocytosis and anemia are common
- Basophilia is almost diagnostic
What is the most significant factor of CML?
Philadelphia chromosome creating uncontrolled WBC production
Lab findings of CML
- Normal ESR
- Low leukocyte alkaline phosphatase
- Bands, meylocytes on smear
- Hypercellular BM w/less than 5% blasts
Phases of CML
- Chronic (modest symptoms)
- Accelerated
- Blast Crisis (clinical picture looks like acute leukemia)
Treatment of CML
- Refer to hematology
- Goal is complete molecular remission
- Imatinib (oral TKI, minimal side effects)
What is imatinib used to treat?
CML
How does imatinib work?
Blocks ATP binding site of ABL kinase
Characteristics of myelofibrosis w/myeloid metaplasia (MMM)
- Increased marrow reticulum
- Increased marrow fibrosis
- Extramedullary hematopoiesis
- Splenomegaly
Why is early MMM sometimes difficult to distinguish from other myeloproliferative syndromes?
Increased marrow reticulum can be seen in most other myeloproliferative syndromes
Classic lab finding of MMM
Leuko-erythroblastic peripheral smear (showing immature RBCs and WBCs)
Treatment of MMM
Mainly supportive
- Anemia treated w/transfusion
- Splenectomy
- Hydrea or Ruxolitinib to control hypermetabolic symptoms
- BM transplant potentially curative
Poor prognosis factors for MMM
- Over 65 yo
- WBC over 25,000
- Blasts over 10%
- Constitutional symptoms
- Hgb less than 10
What s/s are NOT seen in myelodysplastic syndromes (MDS)?
Splenomegaly and extramedullary hematopoiesis
MDS is characterized by?
- Cytopenias (usually of more than 1 cell line)
- Often a chromosomal abnormality but NOT always
What is aplastic anemia characterized by?
Pancytopenia a/w bone marrow hypoplasia
Treatment of aplastic anemia
- Supportive until definitive treatment planned by heme
- Transfusion
- BM transplant potentially curative
Describe pure red cell aplasia (PRCA)
- Very rare
- Only RBC precursors affected
- Etiologies and associated diseases are similar to aplastic anemia
- Treatment is immunosuppression, supportive, sometimes anti-virals
Who is affected by MDS?
Primarily older adults (over 70)
NOT rare
Splenomegaly suggests MDS OR MPD?
MPD
Clinical presentation of MDS
- Insidious onset of fatigue
- SOB
- Possibly angina
Typical lab findings of MDS
- Macrocytosis and abnormally formed RBCs/WBCs
- Hypercellular BM w/dysplastic changes
Lab finding that indicates better prognosis for MDS
Ringed sideroblasts
Lab finding that indicates worse prognosis for MDS
Increased percentage of blasts
What does RAEB-2 indicate in MDS?
Poor prognosis - survival less than 6 months
Treatment of MDS
- Mainly supportive
- BM transplant for younger patients
What type of treatment should be avoided in MPS if possible?
Chemo
