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34 Cards in this Set
- Front
- Back
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What is a differential WBC count?
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A quantification of the RELATIVE numbers of different types of leukocytes present in the blood
Supplement to, NOT a substitute for, the critical exam of a blood smear by the physician |
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The differential WBC count, in combination with the total WBC, allows calculation of...?
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ABSOLUTE numbers of the WBC present in peripheral blood
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What is leukocytosis?
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WBC count > 12000/mm3
Can be caused by many pahysiologic and pathologic conditions Most cases due to increase in PMNs, although increases in other WBCs can also be responsible |
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Common causes of leukocytosis?
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1. Severe exercise or stress
2. Drugs - steroids, epi, drug rxns 3. Acute inflamm states -- acute infection (bacteria, some viruses/parasites) -- acute gouty arthritis -- IBD 4. Chronic inflamm states -- chronic infections (TB, fungal) -- autoimmune d/o's (RA) 5. Tissue necrosis -- MI -- crush injuries 6. Metabolic d/o's -- diabetic acidosis -- uremia 7. hemorrhage 8. hematopoietic malignancies -- leukemias -- lymphomas 9. other tumors 10. surgical stress |
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Three pathophysiologic mechs of leukopenia?
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1. decreased production
2. decreased survival -- increased utilization -- autoimmune destruction 3. redistribution |
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Examples of decreased production WBCs leading to leukopenia?
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1. Aplastic anemia
2. Vitamin B12 or folate deficiency 3. Myelodysplastic syndromes 4. BM invasion by cancer |
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Examples of decreased survival of WBCs leading to leukopenia?
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1. Felty's syndrome
-- in pts w/ RA 2. other autoimmune d/o's |
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Examples of redistribution of WBCs leading to leukopenia?
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1. splenomegaly
2. acute infection in which most WBC migrate to the infected area |
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Pertinent clinical hx of pt w/ abnormal WBC?
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--symptoms, how long?
--fever, wt loss, frequent infections, bleeding --hx of recent acute illness --family hx of cancer --hx of chronic illness --hx of exposure to toxic or carcinogenic agents |
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Pertinent PE of pt w/ abnormal WBC?
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-- patient appear acute or chronically ill?
-- lymphadenopathy -- hepatomegaly -- splenomegaly -- easy bruising, other signs of bleeding -- signs of infection -- signs of organ infilt by a tumor sich as gingival hypertrophy or soft tissue masses |
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Basic Laboratory Tests
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1. Total WBC, Hb, platelet count
-- isolated WBC abnormality OR -- Hb, platelets also abnorm 2. Differential WBC -- any abnormally high/low -- immature cells -- any undiff blasts 3. Review smear yourself |
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Other tests utilized in the eval of abnormal WBC?
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1, cytochemical stains for classif of leukemias
2. immunophenotypic analysis to determine cell lineage -- myeloid -- lymphocytic, etc 3. cytogenetic analysis of hematopoietic cells -- estab dx of some leukemias and to determine their prognosis |
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Acute leukemia
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Untreated survival: days of wks
Duration of symptoms at presentation: days of weeks Condition of pt at presentation: usually very ill Presence of signs of BM failure: usually high Proportion of blasts in peripheral circulation: usually high Leukemia infiltration of non-reticuloendothelial organs: frequent Maturation arrest: Yes |
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Chronic leukemia
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Survival untreated: months or yrs
Duration of symptoms at presentation: months or years Condition of pt at presentation: few symptoms, sometimes asymptomatic Presence of signs of BM failure: unusual Proportion of blasts in peripheral circulation: low Leukemia infiltration of non-reticuloendothelial organs: unusual Maturation arrest: NO |
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What are the chronic leukemias?
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Chronic lymphocytic leukemia (CLL)
Chronic myelocytic leukemia (CML) |
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Chronic lymphocytic leukemia (CLL) incidence?
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Most common leukemia in the Western Hemisphere
More frequent in elderly population and in males |
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CLL onset?
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Insidious
As many as 1/3 are diagnosed incidentally or during routine exams |
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CLL symptoms?
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malaise
fever lymphadenopathy night sweats weight loss occasionally infection or autoimmune phenomena |
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CLL PE?
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Normal to...
Hepatosplenomegaly Lymphadenopathy Signs of anemia |
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CLL treatment?
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Incurable
Cryotherapy is given for palliation of systemic symptoms, lymphadenopathy, or signs of BM destruction Important component of treatment is early dx and treatment of infections since pts prone to develop serious infections duto to hypogammaglobulinemia |
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CLL median survival?
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measured in years
depends on stage at diagnosis |
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Chronic myelocytic leukemia (CML) symptoms?
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-- Many are asymptomatic at diagnosis
-- May present w/ LUQ pain or early satiety due to splenomegaly Other symptoms: weight loss fever night sweats |
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CML PE?
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usually unremarkable except for splenomegaly
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When is CML diagnosis suspected?
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Patient presencts w/ leukocytosis in which all stages of granulocyte development are present in peripheral blood
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Other CML findings?
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splenomegaly
thrombycytosis eosinophilia and/or basophilia decreased leukocyte alkaline phosphatase (LAP) score |
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Also assoc w/ which chromosomal abnormality?
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Philadelphia chromosome
t(9;22) |
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Clinical course of CML?
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Chronic phase:
-- 3-4 years -- asymptomatic Accelerated phase: -- systemic symptoms -- increased WBC count despite therapy -- increased basophilia, eosinophilia -- increase proportion of blasts and immature cells in circ and BM Blast crisis: -- indistinguishable from acute leukemia -- response to treatment is worse than acute -- patients usually die in matter of weeks |
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CML treatment?
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1. BM transplantation -- ONLY curative treatment
-- mostly used in younger pts w/o major comorbid illness, espec if they have HLA compatible sibling 2. Interferon + cytarabine (ara-c) -- older pts or pts that lack suitable donors 3. hydroxyurea -- only controls WBC count and does not delay onset blast crisis 4. imatinib mesylate -- inhib bcr-abl tyrosine kinase, the constitutive abnormal gene product of the Philadelphia chromosome |
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Leukemoid rxns vs CML?
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Leukemoid rxns can be confused w/ CML
Leukemoid rxn is extremely high WBC count that can mimic leukemia Leukemoid rxns typically consist of mature PMNs, the majority of which are banded or earlier forms -- platelets may be increased, but rarely more than 60K -- basophilia and eosinophilia are ABSENT -- LAP is normal or increased -- BM shown myeloid hyperplasia w/o other abnormalities |
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Symptoms of acute leukemias?
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Manifestations of BM failure including:
easy fatiguability easy bruising or bleeding from mucosal surfaces fever infection anemia thrombocytopenia decrease of fxnal PMNs Bone pain and arthralgia may be also seen, espec in young patients |
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Physical findings of acute leukemias?
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Minimal symptoms:
- pallor - increased - ecchymosis - petechiae - retinal hemorrhages Monocytic leukemias: - gingival hypertrophy - skin and tissue infiltration Hepatomegaly and lymphadenopathy can be seen occasionally at diagnosis, especially in acute LYMPHOCYTIC leukemias |
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Lab abnormalities of acute leukemias?
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Most present w/ pancytopenia
Small proportion present w/ WBC of 100,000 -- increased risk of leukostasis due to impedence of blood flow from intravascular clumping of blood -- can manifest as mental changes, cranial nerve palsies, dyspnea, or respiratory failure due to thrombi in circulation |
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How do we diagnose acute leukemias?
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-- Bone marrow aspirate and biopsy exam
-- cytochemistry -- immunotyping by fluoresce activated cell sorting using monoclonal Ab directed at leukemia-specific Ag -- cytogenetic analysis of the blood or bone marrow at dx |
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Treatment for acute leukemias?
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1. aggressive chemo to clear BM of blasts and restore normal hematopoiesis
-- called induction chemo -- even when pts attain complete remission, further chemo necessary to prevent recurrence (consolidation chemo) ALL: -- benefit from low dose chemo given p.o. for prolonged periods of time (1 or 2 yrs), called "maintenance chemo" -- also require prophylactic chemo or radiotherapy of the CNS since this can be a "sanctuary" of the disease that can contribute to relapse -- 30-35% can be cured w/ conventional chemo AML: -- 25% can be cured w/ conventional chemo Once patients relapse after chemo, the only curative treatment is a BM transplant (in selected patient group) |
