Exam 2 -- Hematology #1 Flashcards
What is the function of blood?
Carries nutrients, Abs, hormones, oxygen, and waste; forms clots, regulates body temperature through vasodilation and constriction
What are the components of blood?
55% plasma (which is 90% water and 10% proteins), 44% RBCs, and 1% WBCs and platelets
What are the types of white blood cells?
Leukocytes (monocytes, basophils, eosinophils, neutrophils) and lymphocytes (B cells, T cells, and natural killer cells)
Where does hematopoiesis occur (in adults)?
Mostly in the bone marrow, though it can occur in the liver and spleen if there is a severe enough need.
Red bone marrow contains stem cells that differentiate into ________, ___________, and _____________.
RBCs, WBCs, and platelets
How long do RBCs live?
About 120 days
Erythropoietin is produced in what organ(s)?
Kidneys (90%) and liver (10%)
Starting with the pronormoblast, list the stages of development of an erythrocyte (RBC).
Pronormoblast–>Normoblast, which then expells its nucleus and is released from the bone marrow and becomes a–>Reticulocyte, which circulates for a couple of days until it is finally a mature–>Erythrocyte
What roles do vitamins B12, B9, and B6 have in terms of blood?
B6 helps with hemoglobin creation; B9 helps with RBC creation; B12 helps with both
How many hemoglobin molecules are there per RBC?
280 million
What is the basic structure of hemoglobin?
Four heme groups (with iron), two alpha globin chains and two beta globin chains
When and where does hemoglobin synthesis occur?
In mitochondria of developing RBC in the bone marrow
Hemoglobin has two formations – T and R. Which formation has low affinity for oxygen?
T formation (Taut, or Tight, oxygen can’t get in)
Hemoglobin has two formations – T and R. Which formation has high affinity for oxygen?
R formation (Relaxed)
What is the Bohr effect?
A phenomenon in which oxygen dissociates from hemoglobin wherever CO2 concentrations are high (which acidifies the blood); oxygen associates with hemoglobin wherever CO2 concentrations are lower (higher blood pH).
When it is time for a RBC to die, it is sent to the spleen. What happens to the hemoglobin?
The heme and globin portions are dissociated from each other. The iron is removed from the heme portion, and the heme portion is converted to bilirubin. Bilirubin is transported from the spleen to the liver. The liver converts bilirun to bile to be used in digestion. Eventually bilirubin is excreted by the kidneys.
Mean corpuscular volume (MCV) measures what?
The average volume of RBCs.
Anemia is defined as decrease in what?
RBCs or hemoglobin
Which gender has a higher prevalence for anemia?
Females
What are the symptoms of anemia?
Fatigue, HA, fainting, angina, claudication, palpitations
What are the signs of anemia?
Pallor, tachycardia, cardiac failure, brittle or spoon shaped nails, pica (eating things that have no nutritional value)
Types of anemia can be based on the mean cell volume and/or hemoglobin concentration (too little, normal, too much) or a shortened lifespan of RBCs. What is the MCV of microcytic anemia?
Less than 80 fL (normal is 88 fL)
What are the different types of microcytic anemias?
Iron deficiency anemia, thalassemia, and sideroblastic anemia
True or false: sideroblastic anemia is the most common cause of anemia
False; iron deficiency anemia is the most common cause of anemia
Amongst men, women, and children, which are more commonly affected with iron deficiency anemia?
Women and children –women lose more blood, children have higher need because of growth phases
How much iron is normally absorbed by the body? How much can be absorbed if iron is taken as a supplement?
10% normally absorbed; 20-30% in supplements
Where can iron be stored in the body?
Liver, spleen, bone marrow
What are some causes of iron deficiency anemia?
Blood loss, pregnancy, growth phases, poor diet, celiac disease (malabsorption), NSAIDs (GI bleeding), gastric bypass surgery
What is the CDC recommended daily intake of iron for individuals 30 years of age?
Men: 11 mg/day; women: 18 mg/day
What is the treatment for iron deficiency anemia?
Oral iron supplement (ferrous sulfate, 100-200 mg/day)
If a patient you suspected of having iron deficiency anemia does not improve with iron supplements, what are a few differentials you need to consider?
TB, Crohn’s, rheumatoid arthritis, lupus, polymyalgia rheumatica, sideroblastic anemia, thalassemia
What is the underlying issue in thalassemia?
No/few alpha or beta globin chains produced
What are iron levels like in a patient with thalassemia, low, high, or normal?
Normal
What is the cause of thalassemia?
Autosomal recessive disorder
At what age does thalassemia manifest?
6-12 months
Thalassemia is more common in what parts of the world?
Africa and the Mediterranean
What are the treatment options for thalassemia?
Blood transfusion, folic acid supplement, bone marrow transplant
What is the underlying issue in sideroblastic anemia?
There is excess iron in the bone marrow and RBCs, but it can’t be incorporated into the hemoglobin
Sideroblastic anemia can be caused by a genetic disorder or it can be acquired. What type of genetic inheritance pattern is seen in this disease?
X-linked recessive (so more common in males)
Sideroblastic anemia can be caused by a genetic disorder or it can be acquired. What are some acquired causes of this disease?
AML, CML, isoniazid (TB medication), alcohol, lead toxicity, rheumatoid arthritis
How would you treat sideroblastic anemia?
Pyridoxine (B6, for hemoglobin formation), treat any underlying condition, blood transfusion
In aplastic anemia (which is a normocytic anemia), MCV is normal. How do hemoglobin levels and hematocrit appear? What causes this change?
Both are decreased due to loss (or underproduction) of pluripotent stem cells in the bone marrow. Since the stem cells are affected, WBC and platelet counts are low, too.
True or false: the prevalence of normocytic anemia increases with age
True.
True or false: the main cause of aplastic anemia is idiopathic
True.
What are some causes of aplastic anemia?
Chemical exposure (benzene, toluene, glue sniffing), infection (hepatitis, TB, HIV), chemotherapy meds, pregnancy
Pancytopenia refers to low counts of RBCs, WBCs, and platelets. What signs/symptoms can be seen with low levels of each of these components of blood?
Anemia (low RBC), frequent infections (low WBC), easy bruising, nose bleeds (low platelets)
Macrocytic anemia features high MCV (>100 fL). How might the shape of these large RBCs differ from normal?
Balloon or tear-drop shape
Macrocytic anemia is very commonly caused through vitamin deficiency. What are some causes of vitamin deficiency?
Alcohol (decreases absorption of vitamin B), liver disease, methotrexate (B9 deficiency), vitamin B6 or B12 deficiency, abnormal B9
Pernicious anemia is a type of macrocytic anemia. What is the underlying issue in this disease?
Loss of intrinsic factor (secreted during digestion; important for vitamin B12 absorption)
What is a possible cause of pernicious anemia?
Autoimmune attack of parietal cells that release intrinsic factor
True or false: pernicious anemia is common in the elderly
True.
Some drugs that act in the stomach can decrease intrinsic factor release. Name two drugs that can have this effect.
Pepcid, Prilosec (they decrease parietal cell function)
What are the symptoms of pernicious anemia?
Symmetric paresthesia in fingers and toes, progressive weakness and ataxia, smooth tongue without papillae, dementia, hallucinations, optic atrophy* (if you see bilateral optic nerve pallor, possible B12 deficiency)
What is some testing you can do for vitamin B12 deficiency?
B12 levels, bone marrow biopsy, serum bilirubin (would be increased), Schilling test
Describe the Schilling test.
Patient ingests radioactive B12. An hour later, an IM injection is given to saturate liver B12 binding sites. This is done so that if radioactive B12 is absorbed from the GI system as it should be (i.e., if intrinsic factor is present), the radioactive B12 passes into the urine instead of binding in the tissues. You want to see more than 10% of the radioactive B12 passed into the urine. If less, give them intrinsic factor. If this helps with absorption, this is indicative of pernicious anemia.
How would you treat pernicious anemia?
Oral or IM B12, folic acid supplement
What is the recommended daily intake of B12?
2.4 ug
What is the recommended daily intake of folate?
400 ug
Hemolytic anemia is characterized by shortened life of RBCs (less than 100 days) and increased plasma hemoglobin due to this breakdown. Sickle cell anemia is one type of hemolytic anemia. What ethnicity has a higher prevalence of sickle cell anemia?
African*
Sickle cell disease is a genetic disease. What is its inheritance pattern?
Autosomal recessive
The sickling in sickle cell anemia occurs because one amino acid in hemoglobin is replaced by another, which causes the hemoglobin to collapse on itself. Which amino acid is replaced with which other amino acid?
Glutamic acid is replaced by valine*, which is hydrophic (hence the collapsing)
The sickling of sickle cell disease is exacerbated by what factors?
Infection, dehydration, cold, stress
What are some consequences of cell sickling?
Reduced RBC life, impaired RBC circulation, infection, vaso-occlusive crisis
What is a vaso-occlusive crisis?
Pain in hand/feet/bones, pulmonary HTN, acute chest pain, leg ulcers, neurologic complications
What are some ocular manifestations that can occur in sickle cell anemia?
Retinopathy (“sea fan”), retinal detachment, artery occlusions, fibrosis
What is some testing you can do for sickle cell disease?
Blood smear, Hemoglobin S (for sickled)
How would you treat sickle cell disease?
Fluids, oxygen, pain meds for acute attacks, antibiotics, vaccines, transfusion if severe, hydroxyurea (helps inhibit sickling)
What is polycythemia vera?
Proliferation of RBCs and myeloid cells – kind of the opposite of anemia
What is the prognosis of a person with polycythemia vera if treated? If untreated?
10 years if treated, 6-18 months if untreated
What causes polycythemia vera?
Mutation of JAK2 gene
What are the symptoms of polycythemia vera?
HA, weakness, sweating, burning/tingling in extremeties, transient vision loss, scotomas, ophthalmic migraines, retinopathy, hypercoagulation
True or false: CBC for polycythemia vera would reveal elevated hemoglobin, WBC, platelets, and RBC
True.
How would you treat polycythemia vera?
Hydroxyurea (severely reduced RBC production), remove blood, Jakafi
