Hematopoiesis (Part III) Flashcards
What is the MCV like in Megaloblastic Hyperplasia?
it is greater than 100
what does the bone marrow look like in megaloblastic hyperplasia?
it is hypercellular with giant metamyelocytes and band forms
what commonly causes megaloblastic hyperplasia?
folate or vitamin B12 deficiency
what causes a deficiency in vitamin B12?
vegetarianism or an intrinsic factor deficiency
what causes a deficiency in folate?
alcoholics or increased metabolic needs for folate such as in pregnancy
What causes an intrinsic factor deficiency?
gastrectomy and pernicious anemia
how does the peripheral blood look in megaloblastic hyperplasia/anemia?
anemia is present with enlarged oval red blood cells and hypersegmented neutrophils
in megaloblastic anemia, the bone marrow is hypercellular- so why do you have an anemia?
well the megaloblastic erythro forms are actually destroyed at a higher rate, so we have decreased bone marrow production and decreased reticulocytes
What could cause a macrocytic anemia?
megaloblastic anemia, B12 deficiency, Folate deficiency, and alcoholic liver disease
What does the bone marrow look like in aplastic anemia?
there is pancytopenia of all cell lines- hypocellular bone marrow
what causes aplastic anemia?
toxins or certain drugs (especially chemotherapy agents)
Under which MCV classification and reticulocyte count is aplastic anemia under?
normocytic with a low reticulocyte count
what are the most common forms of metastatic carcinoma to go to the bone?
breast, prostate, lung, and kidney
what happens whenever a tumor or other process crowds the bone marrow?
hematopoietic elements are displaced or destroyed
under which MCV classification would leukemia/ metastasis be under?
normocytic with a low reticulocyte count
what can bone marrow replacement result in?
myelophthisic anemia where there is mechanical crowding which causes nucleated RBCs and granulocyte precursors
what does a peripheral blood smear look like in myelophthisic anemia?
leukoerythroblastosis–> nucleated and tear drop RBCs and immature WBCs; suggestive of displacement of hematopoietic elements by another process
what is extramedullary hematopoiesis?
when hematopoiesis occurs in organs outside of the bone marrow
where does extramedullary hematopoiesis frequently occur?
spleen, liver, and lymph nodes; occurs in normal fetal development
when does extramedullary hematopoiesis occur (not in fetal development)?
in chronic and severe anemic states from a variety of causes, extramedullary hematopoiesis can occur as a compensatory response
how does extramedullary hematopoiesis present?
as a discrete mass-like lesion which can cause local issues or it can present more diffusely without a well defined mass
what is a big histological clue that extramedullary hematopoiesis is occurring?
the presence of multiple megakaryocytes (cells that are readily identifiable by their large size and large multilobated nuclei
what are schistocytes and when are they seen?
they are fragmented RBCs; seen in microangiopathic hemolytic anemia such as DIC or TTP/HUS
what occurs in the microangiopathic hemolytic anemias?
small thrombi form within blood vessels, decreasing platelets, and causing blood cells to fragment as they travel through vessels
What causes “bite” cells and Heinz bodies?
G6PD deficiency
What is sickle cell anemia?
deformed erythrocytes due to polymerized abnormal hemoglobin S
What causes spherocytes to appear on a peripheral blood smear?
hereditary spherocytosis caused by a genetic abnormality in the structural components of the red blood cell membrane
what do both sickle cell anemia and hereditary spherocytosis lead to?
increased destruction of red blood cells
what is a good reference range for WBCs?
4.8-10.8 x 10^3/ML
what makes up the majority of the WBC constituents in the peripheral blood of adults?
neutrophils
what makes up the majority of the WBC constituents in the peripheral blood of children?
lymphocytes
of the lymphocytes, which count is higher?
T lymphocytes
what are 5 causes of neutrophilia?
acute bacterial infection, medications (glucocorticoids, catecholamines), cigarette smoking, physical stress, and myeloproliferative neoplasms/leukemia
What are bacterial infections associated with?and what is this?
left shift- when immature leukocytes, especially band neutrophil forms are released from the bone marrow into the peripheral blood due to increased cytokine activity
What are bands hematpoietically derived from?
metamyelocytes and metamyelocytes are derived from even more immature granulocytes
What could happen if the left shift is severe enough?
metamyelocytes are also identified along with bands
What is frequently seen in conjunction with left shifts?
toxic granulation
what is toxic granulation due to?
accelerated neutrophil maturation as the bone marrow tries to pump out more and more acute inflammatory cells to fight the infection
How can toxic granulation be seen?
as dark coarse granules within neutrophils, especially in inflammatory conditions
what is a leukemoid reaction?
marked leukocytosis with increased neutrophilia not due to leukemia; overactive inflammatory reactions driven by increased interleukin production, especially IL-6
how do leukemia and leukemoid reactions differentiate?
the enzyme leukocyte alkaline phosphatase is typically elevated in leukemoid reactions unlike in leukemia
what could cause leukemoid reactions?
drugs, infection, or carcinoma
what does the bone marrow look like in leukemoid reactions?
the bone marrow would show complete maturation without increased myeloblasts
what is the WBC count in leukemoid reactions?
> 50000 with increased neutrophils
What is the chief differential of leukemoid reaction?
a leukemic process such as chronic myelogenous leukemia
how is chronic myelogenous leukemia characterized?
by a spectrum of differentiation with myeloblast cells
what is the median WBC count seen in chronic myelogenous leukemia?
100,000
what are the phases of chronic myelogenous leukemia (CML)?
chronic phase–>accelerated phase–> blast phase
what is the end result of CML?
pancytopenia
