Altered Hematologic Function part 2

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Altered Hematologic Function part 2

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Alterations in Leukocytes andBlood Coagulation

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Leukocytes• White blood cells

• Defend body through:

– the inflammatory process

– phagocytosis

– removal of cell debris

– immune reactions

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White Blood Cell Types:Granulocytes and Agranulocytes

• Granulocytes –visible granules in the cytoplasm.

• Granules contain:

– Enzymes

– Other biochemicals that serve as signals and mediators of the inflammatory response

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Granulocyte cell types:

• Neutrophils – phagocytes

• Eosinophils – red granules, associated with allergic response and parasitic worms

• Basophils – deep blue granules - Release heparin, histamine and serotonin

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Agranulocytes• Granules too small to be visible

• Monocytes – become macrophages

• Lymphocytes – B cells and T cells = immune functions

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• WBC’s originate in red bone marrow from stem cells.

• Granulocytes mature in the marrow and have a lifespan of hours to days

• Agranulocytes finish maturing in blood, or in other locations. Monocytes live about 2 - 3 months, lymphocytes for years.

• Types of stem cells:– Pluripotent– Multipotent– Committed progenitor cells

• Multipotent blood cells:– Common lymphoid– Common myeloid

• Committed stem cell makes specific blood cells (CFU) – stimulated by erythropoietin, thrombopoietin, granulocyte-mononcyte CSF

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• Production of WBC’s increases in response to :

– Infection

– Presence of steroids

– Decreased reserve of leukocyte pool in bone marrow

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WBC Abnormalities• Leukocytosis – increased numbers of WBC’s

– May be a normal protective response to physiological stressors

– Or may signify a disease state – a malignancy or hematologic disorder

• Leukopenia – decreased numbers of WBC’s – this is never normal– Increases the risk of infections. – Agranulocytosis = granulocytopenia

Leukeopenia may be due to:

• Radiation

• Anaphylactic shock

• Autoimmune disease

• Chemotherapeutic agents

• Idiosyncratic drug reactions

• Splenomegaly

• infections

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Mononucleosis

• Self-limiting lymphoproliferative disorder caused by the Epstein-Barr Virus

• Infects 90% of people

• Incorporates into DNA of B cells causing production of heterophil antibodies

• Tc Cells are produced to limit numbers of infected B cells, accounts for increased numbers of lymphocytes.

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Leukemia• A malignant disorder in which the blood-

forming organs lose control over cell division, causing an accumulation of dysfunctional blood cells.

• Uncontrolled proliferation of non-functional leukocytes crowds out normal cells from the bone marrow and decreases production of normal cells.

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• Cause appears to be a genetic predisposition plus exposure to risk factors such as:

– Some disorders of the bone marrow and other organs that can progress to acute leukemias

– Some viruses

– Ionizing radiation in large doses

– Drugs

– Down syndrome and other congenital disorders

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Classification

• Aleukemic leukemia

• Leukemias are classified as:– acute or chronic

– Myeloid or lymphoid

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Acute Leukemias• Characteristics:

– Abrupt onset– Rapid progression– Severe symptoms– Histological examination shows increased

numbers of immature blood cells

• Survival rate-– Overall for acute leukemias the 5 year

survival rate is about 38 %, but certain types have increased survival rates due to advances in chemotherapy.

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Clinical manifestations• Signs and symptoms :

– Fatigue

– Bleeding

– Fever

– Anorexia and weight loss

– Liver and spleen enlargement Abdominal pain and tenderness – also breast tenderness

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• Neurologic effects are common:– Headache – Vomiting– Papilledema – swelling of the optic nerve

head – a sign of increased intracranial pressure

– Facial palsy– Visual and auditory disturbances– Meningeal irritation

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• Early detection is difficult because it is often confused with other conditions.

• Diagnosis is made through blood tests and examination of the bone marrow.

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Treatment• Chemotherapy

• Blood transfusions and antimicrobial, antifungal and antiviral medications

• Bone marrow transplants

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Chronic Leukemias• Characteristics:

– Predominant cell is mature but doesn’t function normally

– Gradual onset– Relatively longer survival time

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• The two main types of chronic leukemia are myeloblastic and lymphocytic.

• Chronic leukemia accounts for the majority of cases in adults.

• Incidence increases significantly after 40 years of age.

Course of disease

• Chronic phase of variable length (4years)

• Short accelerated phase (6-12 months)

• Terminal blast crisis phase (3 months)

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• Progress slowly and insidiously.• Initial symptoms are splenomegaly, extreme

fatigue, weight loss, night sweats and low grade fever.

• Chronic lymphocytic leukemia involves predominantly B cells; only rarely are T lymphocytes involved.– Programmed cell death of these cells does not take

place as it would normally.– These old cells do not produce antibodies

effectively– Other blood cell types decrease– Infiltration of liver, spleen, lymph nodes and salivary

glands.

Treatment

• Chemotherapy

• Monoclonal antibodies

• Bone marrow transplant

• Non-myeloablative transplant – “graft-vs.-leukemia” effect.

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Multiple Myeloma

• Cancer of plasma cells

• Osteolytic bone lesions

• Light chains can be toxic to kidneys

• Replacement of bone marrow and stimulation of osteoclasts

• fractures, hypercalcemia, plasmacytomas, heart failure and neuropathy

• Chemotherapy, bone marrow transplant35

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Lymphomas• These affect the secondary lymph tissue –

lymph nodes, spleen, tonsils, intestinal lymphatic tissue. These may be thought of more as a solid tumor, since it occurs in solid tissue as opposed to the blood.

• Two types:

– Hodgkin’s Lymphoma (Disease) and

– Non-Hodgkin’s Lymphoma

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Hodgkin’s Lymphoma• Distinguished from other lymphomas by

the presence of Reed-Sternberg (RS)

• Begins in a single node and spreads – cancerous transformation of lymphocytes and their precursors.

• Cause is believed to be genetic susceptibility and infection with the Epstein-Barr virus.

• Other – tonsillectomy or appendectomy, wood working

38http://pleiad.umdnj.edu/hemepath/T-cell/graphics/6811lennertsrscellhi.jpg

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Clinical Manifestations• Painless swelling or lump in the neck

• Asymptomatic mass in the mediastinum found on x-ray

• Intermittent fever, night sweats

• Weakness, weight loss

• Obstruction / pressure caused by swelling lymph nodes can lead to secondary involvement of other organs.

• Anemia, elevated sedimenation rate, leukocytosis, and eosinophilia

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Treatment

• Treatment:– Chemotherapy– Radiation– Prognosis good with early treatment, but early

detection is difficult– The five year survival rate is 83%.

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Non-Hodgkin’s Lymphoma

• This is a generic term for a wide spectrum of disorders that cause a malignancy of the lymphoid system

• Causes may be viral infections, immunosuppression, radiation, chemicals, and Helicobacter pylori.

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• The lymphoma arises from a single cell that has alterations in its DNA.

• Clinical manifestations:– Localized or generalized lymphadenopathy– Nasopharynx, GI tract, bone, thyroid, testes

may be involved.

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• With only involvement of the lymph nodes survival rate is good

• Individuals with diffuse disease do not live as long.

• Treatment bone marrow transplant – or autologous (from the same individual) stem cell transplant

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Thrombocytes - platelets• Characteristics – produced by the

fragmentation of megakaryocytes – so are cell fragments

• Life span is about 3 days

• Many are held in the spleen

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Coagulation or Hemostasis• Soluble proteins (fibrinogen) are converted

into insoluble protein threads

• Many proteins and factors are part of the clotting cascade, including calcium.

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Terminology in bleeding disorders

• Petechiae- pinpoint hemorrhage

• Purpura – larger, less regular

• Ecchymoses – over 2 cm – bruise

• Hematoma – blood trapped in soft tissue

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Disorders of platelets• Thrombocytopenia – decreased numbers

of platelets (below 100,000/mm3)

• Can lead to spontaneous bleeding, if low enough, and can be fatal if bleeding occurs in the G.I. Tract, respiratory system or central nervous system.

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• Can be congenital or acquired; acquired is more common.

• Seen with:– Generalized bone marrow suppression– Acute viral infection

– Nutritional deficiencies of B12, folic acid and iron

– Bone marrow transplant– drugs, especially heparin, and toxins, thiazide

diuretics, gold, ethanol…– Immune reactions

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• Heparin induced thrombocytopenia is an immune mediated reaction (IgG) that causes platelet aggregation and decreased platelet counts 5 – 10 days after heparin administration in 5 – 15 % of individuals. Can cause thrombosis and emboli.

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Thrombocythemia• This is an increased number of platelets.

• If the platelet count rises high enough ( over 1 million/mm3), can get intravascular clot formation or hemorrhage.

• Can be primary thrombocytothemia – cause unknown, or

• Secondary thrombocytothemia – occurs after splenectomy when platelets that would normally be stored in the spleen remain in blood.– Also due to rheumatoid arthritis and cancers.

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Disorders of Coagulation• Clotting factor disorders prevent clot

formation.

• May be genetic:– Hemophilia and Von Willebrand’s– genetic

absence or malfunction of one of the clotting factors

• Or acquired - usually due to deficient production of clotting factors by the liver:– Liver disease– Dietary deficiency of vitamin K