ALTERATIONS IN HEMATOLOGIC SYSTEM

pathophysiology exam 2

blood components

RBCs, WBCs, platelets, plasma

Hematopoiesis steps

1. stem cells

2. proliferation/differentiation of bone marrow stem cells into mature blood components

3. colony stimulating factors (CSF) promote growth of hematopoietic cell colonies

4. *blood cells do NOT divide, only proliferate in marrow

1. Vessel spasm/vasoconstriction

endothelial injury stimulates blood vessel contraction, reduces blood flow to the injured vessel

2. formation of platelet plug

Von Willebrand Factor ( VWF) is released from endothelium - results in platelet aggregation at the site of injury

3. blood coagulation

protects from excessive blood loss, intrinsic or extrinsic pathway, clotting factors, conversions of prothrombin to thrombin & fibrinogen to insoluble fibrin threads

4. clot retraction

begins a few mins after clot is formed, actin & myosin in clot begin to contract, plasma (w/o) fibrinogen is squeezed from clot causing it to shrink

5. clot dissolution/lysis

begins shortly after clot is formed, activation of plasminogen, slow release of tissue plasminogen (t-PA) from injured tiissues & endothelium converts plasminogen to plasmin, plasmin digests fibrin strands, dissolving the clot

normal platelet count

150,000-400,000

thrombocytosis

platelet count = >1,000,000

thrombus

stationary clot within vessel

embolus

traveling clot in circulatory system

thrombocytopenia

platelet count = <100,000 (less than/equal to)

Von Willebrand Disease

inherited autosomal dominant disorder, usually diagnosed in adults

Hemophilia A

inherited X linked recessive disorder, mostly males/children, deficiency in factor VIII, **bleeding into joints

Liver Disease

the liver is responsible for synthesizing all except 3 coagulation factors

Vitamin K Deficiency

Vitamin K is synthesized by intestinal bacteria & is essential for the activation of several coagulation factors

Disseminated Intravascular Coagulation (DIC)

**widespread bleeding & clotting at the same time

Pathogenesis for DIC

• endothelial damage → activation of clotting cascade

• widespread clotting with multiple thrombi & emboli in vessels all throughout the body

• platelets & clotting factors are depleted faster than replaced

• widespread clotting stimulates fibrinolysis → bleeding

• ability to form clots is depleted → hemorrhage eventually occurs

anemia

too few RBCs

polycythemia

too many RBCs

normal RBC count

4.2-6.1 cells/mcL

normal hemoglobin (Hgb)

~12-16 g/dL

normal hematocrit

3x Hgb

H&H

hemoglobin & hematocrit

Hemoglobin (definition)

protein found in RBCs

Hematocrit (definition)

measure of total percentage of RBCs in blood

erythropoiesis

production of RBCs

Erythropoietin

hormone released by kidneys that tells bone marrow to make more RBCs

RBC lifespan

~120 days

oxyhemoglobin

hemoglobin bound with oxygen

1. 95-98% saturated with O2 in arterial blood

2. 75% saturated in venous blood

affinity

hemoglobin’s ability to bind & hold onto oxygen

blood loss anemia

excessive blood loss (acute or chronic)

hemolytic anemias

excessive destruction of RBCs

sickle cell disease

autosomal recessive, “sickling” of hemoglobin S molecule, molecule changes shape when person experiences cold/stress/physical exertion/infection/illness/dehydration/acidosis/hypoxia

acquired hemolytic anemias

caused by drugs, chemicals, toxins, venoms, or infections such as malaria that destroy cell membranes

iron deficiency anemia causes

inadequate dietary intake, increased iron demands, excessive iron loss

megaloblastic anemias

• vitamin B12 deficiency - required for DNA synthesis in RBC (inadequate dietary intake or lack of intrinsic factor in stomach [pernicious anemia])

• folic acid deficiency anemia - required for DNA synthesis (inadequate dietary intake or malnutrition)

aplastic anemia

• also called pancytopenia

• reduction of all types of blood cells

  • caused by radiation, chemicals, toxins, infections

chronic disease anemias

anemias due to underlying disease

• causes: chronic infections, inflammation, cancer, **chronic renal failure

acute hemolytic transfusion reaction

• Mostly caused by ABO incompatibility 

• Life-threatening 

• Recipient's antibodies attack & destroy donor RBCs 

• Manifestations: Back/flank pain, fever chills, DIC, epistaxis (nosebleeds), shortness of breath, hypotension, tachycardia, hematuria (blood in urine), renal failure 

Polycythemia 

• Abnormally high RBC mass with increased H&H  

• Causes: dehydration, increased RBC proliferation (polycythemia vera), increase in erythropoietin levels 

• Manifestations: poor concentration, dizziness, headache, hearing/vision changes, hypertension, higher risk for clotting 

kernicterus

rare neurologic syndrome caused by excessive accumulation of unconjugated bilirubin in infant brain cells

leukopenia

decrease in absolute number of leukocytes in the blood

(most commonly effects neutrophils)

neutropenia

neutrophil count = <1,000

agranulocytosis

most severe form of neutropenia,
^ neutrophil count is <200 cells/uL

Infectious mononucleosis

“mono”

• self-limiting viral disease

• caused by Epstein-Barr virus or cytomegalovirus

• transmitted via oral secretion

malignant lymphomas

diverse group of solid tumors made of neoplastic lymphoid cells

• B&T lymphocytes

• 2 types: Hodgkin Lymphoma & Non-Hodgkin Lymphoma

Hodgkin Lymphoma

• form of lymphoma that features the presence of the Reed-Sternberg Cell

• PAINLESS enlargement of lymph node or group of lymph nodes

• unknown cause

NON-Hodgkin Lymphoma

• more common, absence of Reed-Sternberg Cell

• cause = unknown

• widespread, enlarged, painless lymph nodes

leukemias

• malignant neoplasms originating hematopoietic cells

  • immature neoplastic cells overcrowd the bone marrow & invade blood stream

leukemia classification

progression: acute (malignancy occurs early in cell development) or chronic (more mature cells)

type of blood cell: lymphoid or myeloid

4 types of leukemia

a. Acute Lymphocytic Leukemia (ALL)

b. Acute Myelocytic Leukemia (AML)

c. Chronic Lymphocytic Leukemia (CLL)

d. Chronic Myelocytic Leukemia (CML)

Acute Leukemias

• excessive # of undifferentiated, immature blast cells

• ^ immature cells do not function correctly

• rapid rate of growth, sudden onset

Chronic Leukemias

• excessive # of mature WBCs

• mature WBCs are abnormal & do not function correctly

• slower rate of growth

• symptoms take longer to appear

Lymphocytic Leukemias

• involves lymphoid cells

• 2 types: ALL & CLL

Myelocytic Leukemias

• involves myeloid cells

• 2 types: AML & CML

manifestations of all types of leukemias:

• increased risk of infection

• malaise

• abdominal pain

• bone pain

• fever

• headache

• N/V

• thrombocytopenia

• bleeding

multiple myeloma

• cancer of B cell plasma cells (immunoglobulins)

• catagorized by which immunoglobulin is abnormal

• cause = unknown