Unit 1 Flashcards
The cellular component of the blood makes up about ______% of its volume
40-45%
Serum
When clotted blood is centrifuged, the clear fluid that collect at the top of the tube. Lacks clotting factors which have been consumed to make the clot
Plasma contains:
Ends up where in a centrifuge tube?
Proteins, lipids, salts, carbohydrates. Sits at the top of the centrifuge tube on top of the buffy coat layer
Buffy coat layer contains:
Ends up where in a centrifuge tube?
White blood cells and platelets. Sits below the plasma on top of the RBCs
Where do the RBCs settle in a centrifuge tube?
At the bottom, below the buffy coat layer and plasma
hematocrit
The proportion of blood by volume made up of red blood cells
formula for determining hematocrit
the length of the RBC layer and dividing it by the total length of the column of blood [RBCs/(RBCs + buffy coat + plasma)].
the “differential” of a CBC
percentages of the different types of white blood cells in the blood
peripheral smear
A drop of blood can also be smeared on a glass slide, stained, and examined under the microscope to look for any abnormally shaped cells or cellular inclusions
What makes up the bulk of the cellular components of blood?
Erythrocytes
Unique features of an RBC
1) lack a nucleus
2) lack mitochondria
3) contain lots of hemoglobin
Do RBCs have mitochondria or nuclei?
They have these organelles in the bone marrow but lose them prior to their being released into the periphery.
hemolysis
premature breakdown and RBC destruction
Mutation causing sickle cell anemia
a substitution of valine for glutamic acid at the 6th position of the beta-globin chain) makes hemoglobin S
Why do RBCs have limited ability to respond to changes in the environment
mature RBCs lack nuclei, they can’t make new RNA. Once they’re released in the periphery, they have limited ability to repair themselves. Also, since they lack mitochondria, they are dependent on anaerobic metabolism for generation of ATP to maintain cellular processes
the most common human enzyme defect
glucose-6-phosphate dehydrogenase (G6PD) deficiency, an X-linked disorder seen in ~15% of the African male population can also be a cause for hemolytic anemia.
How do RBC to undergo large reversible deformations while maintaining its structural integrity?
2D elastic network of cytoskeleton, tethered to sites on cytoplasmic domains of transmembrane proteins embedded in the plasma membrane
Anemia can result from deficiency in the following vitamins/minerals: ____, ____, ____
iron, B12, Folic acid
erythropoietin is made in the
kidney
5 different types of WBCs
lymphocytes neutrophils (also known as polymorphonuclear cells or PMNs) monocytes eosinophils basophils
____________ are the key players in the adaptive immune response, which involves the development of “memory” following exposure to an infectious agent, providing the ability to respond more vigorously to repeated exposure to the same agent
Lymphocytes
“myeloid” cell types include
neutrophils, monocytes, eosinophils, and basophils
Innate immunity
protection against infection that relies on mechanisms that exist before infection, are capable of a rapid response to microbes, and react in essentially the same way to repeat infections
hemostasis
the arrest of bleeding
megakaryocytes
large, polyploid cells in the bone marrow that fragment to form platelets. 1 megakaryocyte=5000 platelets
what does the fibrinolytic system do?
breaks down formed clots
“Job” of innate immunity
to detect intruders that have ventured too deep into the body’s structures, and then arrange for their inactivation, destruction, and removal.
Innate immunity recognizes three sorts of things:
pathogen-associated molecular patterns (PAMP);
damage- associated molecular patterns (DAMP);
The absence of normal cell surface molecules
pattern-recognition receptors, PRR
Innate immune cells have PRR on their surface or on inner membranes to identify pathogen-associated molecular patterns (PAMPs).)
“Toll-like receptors,” TLRs
Each TLR can recognize a foreign molecular structure that we humans don’t have. Receptors on membrane for bacterial structures (cell wall structures, for example).
The factors released in an inflammatory response are
cytokines and chemokines
Inflammation
increased blood vessel diameter, stickiness, and leakiness, efflux of fluid and phagocytic white blood cells into the tissues. The intent is to quickly get defense and healing agents into the damaged or invaded area.
What part of the immune system is fastest? Innate or adaptive?
Innate is fastest, but it cannot adapt
Controlled substances are divided into 5 schedules according to potential for:
- Medical usefulness
- Abuse potential
- Degree to which they may lead to physical / psychological dependence if they are abused.
Which schedule has the highest potential for abuse? Are they prescribed?
Schedule 1, not prescribed because no medical use
Which schedule of drugs have the highest potential for abuse among those that can be prescribed?
schedule 2
Current requirements for prescribing controlled drugs:
- DEA number
- Schedule I drugs may not be prescribed.
- All schedule II - IV drugs require a prescription (in Colorado II - V).
- Schedule II prescriptions must be in ink in prescriber’s handwriting, and cannot be telephoned to pharmacist or refilled .
- Schedule III and IV (plus V in Colorado) may be telephoned to pharmacist and may be refilled no more than 5 times in 6 months (if so noted on prescription).
Components of a written prescription
drug name date ID of prescriber patient info Drug strength, quantity, dosage Directions to patient (regimen) refill info signature
Federal regulation of drugs
Controls drugs through the FDA
FDA regulates:
• Evaluation of safety and efficacy of new drugs prior to availability, removal of dietary supplements deemed unsafe
• Equivalency of brand name versus generic drugs
• Placement of drugs into prescription vs non-prescription categories
State regulation of drugs
Controls who may prescribe drugs through the licensing process of medical or dental boards. Exception is the prescribing of Controlled Substances which requires registration with the Drug Enforcement Administration (DEA)
Four Basic Drug Categories
Prescription – Controlled Substances – OTC - Dietary Supplements
The Food, Drug, and Cosmetic of 1938 (and Kefauver Amendments of 1962) requires that for new drugs:
manufacturers must demonstrate proof of efficacy (do they work?) as well as safety before they can be marketed to the public.
Pre-Clinical Testing of a new drug
5-8 years, animals,
• rodent and non-rodent species; pharmacology, drug metabolism, and toxicity .
• determine safe dosage range for humans.
• Successful review of data leads to Investigational New Drug (IND) application to the FDA. An NDA is filed for a specific indication (use).
Clinical trials, phase 1
Clinical pharmacology (1 yr) [Is it safe, pharmacokinetics?] • Very select normal volunteers (usually < 100, healthy males, 18-45 y/o) • Toxicity (dose level of first appearance) and metabolism studies • Determine if animal / human response differ significantly
Clinical trials, phase 2
Clinical investigation (2 yrs) [Does it work in patients?]
• Select patient pool (200-300), no other medical problems.
• Comparison to placebo or existing treatment.
• Safety and efficacy, final dosing and regimen adjustments
• Usually at university or government medical center under supervision of IRB with patient consent.
Clinical Trials, phase 3
Full scale clinical trial (3 yrs) [Does it work, double blind?]
• 1000-6000 patients, settings similar to ultimate use of drugs.
• Efficacy measured against established therapy. Monitor adverse reactions from chronic use.
• Positive results after unmasking of code may result in approval of New Drug Application (NDA)
Post-marketing Surveillance, phase 4
- required to submit reports to the FDA of adverse effects of drugs on market
- Studies often continue after approval. Collect data on mortality / morbidity - monitor safety under actual conditions of use
- Study groups omitted during phases I and II (high risk-pregnancy, elderly, children); also patients with multiple disease
- FDA can revoke approval/restrict drug use (e.g., require certain lab tests to be performed) if unpredictable adverse effects become apparent when drug is made available to large, uncontrolled populations
- Low incidence drug effects will be missed in phases I-III
Pharmaceutical Equivalents
Drugs containing same:
- active ingredient (s) in the same dosage formulation (capsule, tablet, solution, etc.) that have the
- route of administration
- strength or concentration
Pharmaceutical Alternatives
Drug products containing the same therapeutic moiety, but are different:
- salts, esters, or complexes of that moiety,
or
-different dosages forms (e.g., capsules vs tablets) or
-strengths (e.g., 200 mg vs 250 mg)
Bioequivalent Drug Products
• pharmaceutical equivalent formulations that display comparable bioavailability
Bioavailability
the rate and extent to which the active ingredient is absorbed from a drug formulation and becomes available at the site of action (i.e., drug molecule entering bloodstream).
How is bioavailability measured?
The extent of absorption (bioavailability) is measured by the area under the plasma concentration-time curve (AUC)
How is the rate of absorption measured?
the rate of absorption is estimated by the maximum of peak drug concentration (Cmax)
Therapeutic Equivalents
Pharmaceutical equivalents that, when administered to the same individual in the same dosage regimen, provide the same efficacy and safety.
Is proof of efficacy required for drugs and dietary supplements?
evidence via clinical trial is required for drugs, no proof of efficacy is required for dietary supplements
Is proof of purity required for drugs and dietary supplements?
for drugs yes, and for dietary supplements-yes since 2011
Is quality control required for drugs and dietary supplements?
yes, for both
1 grain=____ mg
64.8mg
1gram= _____ grains
15.43
1 drop= ____ mL
0.05
1t= ___mL
1T=___mL
5mL
15mL
1fluid oz= ___mL
1 quart= ___ mL
1 pint= ___mL
1 gallon= ___mL
30
946
473
3785
anemia
insufficient red cell mass to deliver oxygen to peripheral tissues
thrombosis
formation of a clot within a blood vessel, occludes flow
Five ties of WBCs in the blood
lymphocytes, neutrophils, monocytes, eosinophils, basophils
How many platelets come from a single polypliod megakaryocytic?
5000
lymphoma
“extramedullary”=outside of bone marrow. Collection of malignant lymphoid cells in the lymph nodes and lymph organs
Leukemia
malignant cells arise from bone marrow and are usually in the bloodstream. Can be acute or chronic, and lymphoid or myeloid
Acute Leukemia
cells are immature in their degree of differentiation and clinical course is usually rapidly progressive without intervention
Chronic leukemia
cells are more mature in their differentiation and disease follows a more indolent clinical course
lymphoid leukemia
arises from a lymphocytic origin
Myeloid leukemia
arising from one of the myeloid cell types in the marrow (neutrophils, monocytes, eosinophils, or basophils)
Flow cytometry uses a ____ to measure the scattering of light
laser
Coulter principle
counts cells and sizes as the cell passes through a hole, the voltage drops and is measured (proportional to cell size)
RBC count units
millions/uL or godzillion (10^12)/L
Hemoglobin abbreviation and units
HGB, g/dL or g/L. In vitro measurement of [Hb] released by lysed cells in whole blood
Hematocrit abbreviation and units
HCT, ratio of total RBC volume/whole blood, how much of a given volume of blood is occupied by RBCs, expressed as % or L/L
MCH
Mean cell hemoglobin: the mean quantity of Hb in a single red cell.
Units: picograms
MCH=(HGB/RBC) X 10
MCHC
mean cell hemoglobin concentration: average [Hb] in red cells
Units: g/dL or g/L
MCHC=(HGB/HCT) X 100
MCV
mean cell volume: the mean size of the red cells counted
Units: femtoliters fL (10^-15)
MCV=(HCT/RBC) X10
Patter recognition receptor
PRR, primitive protein expressed by the innate immune system that identifies PAMPs on intruders
Pathogen-assocaited molecular pattern
PAMP, molecules associated with a group of pathogens that are recognized by the innate immune system. Recognized by PRRs and TLRs
Toll-like receptor
TLR, a type of PRR that recognizes foreign molecular structure that humans don’t have. TLR binding triggers a cascade that leads to inflammation and release of cytokines/chemokines
Damage-associated molecular pattern
DAMPs, molecules that initiate an immune response (noninfectious, whereas PAMPs initiate/perpetuate an infectious response), expressed by cells in trouble, cells that have been invaded, etc
Common patterns recognized by TLRs
lipoproteins, zymosan, glycolipids, dsRNA, ssRNA, lipopolysaccharides, flagellin, unmethylated CpG in DNA
What is the final transcription factor that is most commonly activated in inflammation?
NF-kB
cytokine
short range mediator made by any cell that affects the behavior of the same or another cell
chemokine
small cytokines that are short range mediator made by any cell, primarily cause inflammation. The are CHEMOtactic cytoKINES, can recruit phagocytic WBCs (like around a splinter)
______ are the cells that bridge innate and adaptive immunity
dendritic cells (DC)
Dendritic cells
phagocytic, antigen-presenting cells. At a would site, DC activated by cyto/chemokines, takes up material from invaders. Activated DC leaves, travels to nearest draining lymph node. Shows material to lymphocytes to get adaptive immune response
T cells
survey the surfaces of the cells by recognizing antigens presented by DCs with their surface receptors. this activates the T cell, it proliferates, daughters travel to antigen innovation site, release lymphokines to augment inflammation, attracts macrophages and monocytes
B cells
Recognize antiges via cell surface receptors, become activated, proliferate. They secrete Abs (soluble versions of the receptors)
IgG
most abundant, 2 adjacent IgG molecules bind an antigen and cooperate to activate complement, a system of proteins that enhance inflammation and pathogen destruction. Pass from mom–> baby
IgM
large polymetric immunoglobulin. 1st Ab to appead in blood after exposure to antigen (better at activating complement than IgG), gets replaced by IgG
IgD
form of Ab inserted into B cell membranes as their antigen receptor
IgA
Most important class of Ab in secretions (saliva, tears), resistant to digestive enzymes
IgE
attach to mast cells. when they encounter an antigen it will cause the cast cell to make prostaglandins, leukotrines, and cytokines and release its granules with powerful inflammatory mediators like histamine. Allergy symptoms! Role in parasite resistance
Type 1 hypersensitivity
too much IgE, seen in asthma and anaphylactic shock
anaphylactic shock
mast cells suddenly degranulates, release histamine
Type 2 immunopathology
autoimmunity due to Abs reacting to self
treated with immunosuppresant and anti-inflammatory drugs
Type 3 immunopathology
Abs made to soluble antigens, activate inflammation and damage tissue
symptoms: arthritis, glomerulonephritis, pleurisy, rash, systemic lupus erythematosus (SLE)-Abs attach DNA, RA=Abs attack abs
Chronic frustrated immune response
antigen is not “self” but something that cannot get rid of: IBC, celiac
type 4 immunopathology
T cell mediated, can be autoimmune.
TB, hepatitis
Reticulocyte count
measures how fast RBCs are made and released into blood. Measured as a % of 1000 red cells counted
Normal=0.4-1.7% of red cells counted
Reticulocyte index
RI: corrects reticulocyte conunt for [red cells] and stress reticulocytosis
RI=reticulocyte count X (patient HGB/Normal HGB) X (1/stress factor)
Normal RI between 1.0 and 2.0
Symptoms of anemia
shortness of breath, fatigue, rapid HR, dizziness, claudication or pain with exercise, pallor
Physical signs indicating anemia
tachycardia, tachypnea, dyspnea, conjunctiva, lymph nodes and size of liver/spleen
Family history indications for anemia
gallstones, jaundice, splenomagaly, splenectomy, cholysystectomy
Distribution of iron in the body
65% Hb 6% Mb 25% Ferritin small amt transferrin <1% in enzymes
Major causes of iron deficiency
decrease in iron uptake, increased iron loss, increase in iron requirements (infancy, pregnancy, lactation, adolescence)
Labs for iron deficient anemia
decrease in O2 carrying capacity (HGB, HCT, decrease in production (low reticulocyte count, RI)
later…
CBC will show microcytosis, low MCV, hypochromia
addtl tests may show decreased serum iron, increased total iron binding capacity, low serum ferritin, increased erythrocyte protoporphyria
Effects of over accumulation of iron
damage to liver, heart, and endocrine glands
Treatments for over accumulation of iron (hemochromatosis)
(increased absorption)-therapeutic phlebotomy
Treatment for hemosiderosis (often from transfusions)
IF or sc/sq chelators (desferal). Some are now oral
lifespan of a platelet, number produced per day
7-10 days, 200 billion produced/day
lifespan of an erythrocyte, number produced per day
120 days, 175 billion produced/day
lifespan of neutrophil, number produced per day
7 hour half life, 70 billion produced per day
Embryonic hemaptopoiesis occurs in the:_____. This ceases after ____months
yolk sac, 3
Fetal hematopoiesis takes place in the_____ between months __ and __
liver and spleen, 2, 7
By the time of birth, hematopoesis occurs in the:
bone marrow (entire skeleton active bone marrow)
hematopoiesis outside of the bone marrow after birth is abnormal and called
extramedullary hematopoiesis
Marrow space is encased by _____ bone, and interspersed by _____ bone lined by osteoblasts and osteoclasts
cortical, trabecular
Between trabecula is a network of vascular ______ with walls of _____ endothelial cells
sinusoids, leaky
ASYMMERTRIC CELL DIVISION
1 HSC daughter and 1 multipotent progenitor cell made after a HSC divides
Progenitor cells can be:
Multipotent, oligopotent, or lineage restricted
Multipotent progenitor cells
capable of differentiating to all lymphoid and myeloid lineages
Oligopotent progenitor cells
common myeloid progenitor cells and common lymphoid progenitor cells
What type of progenitor cell comes after Oligopotent progenitor cells?
Lineage-restricted progenitor cells
One lineage-restricted progenitor cell, in this case a blast forming unit-erythroid (BFU-E), gives rise to around _____ mature red blood cells
2000
________ – BLUE on Wright stain
_______ – PINK on Wright stain
ribosomes
hemoglobin
Erythropoesis species order
Pronormoblast, Basophilic Normoblast, Polychromatophilic Normoblast, Orthochromic Normoblast, Reticulocyte, Mature RBC
Timespan of erythropoesis
2 – 7 days for pronormoblast-orthochromic normoblast
1 day to extrude the nucleus from orthochromic normoblast
Reticulocyte matures 2 – 3 days in bone marrow before it is released into the peripheral blood
Rate of _________ determines the hemoglobin level of normal individuals
Initiated by ________, a hormone produced by the kidneys
erythropoiesis, erythropoietin
Functions of erythropoetin
- Activate stem cells of bone marrow to differentiate into pronormoblasts
- Increases rate of mitosis and maturation process
- Increases rate of hemoglobin production
- Causes increased rate of reticulocyte release into peripheral
blood
Granulocyte types are distinguished from each other by the appearance of their:
secondary (specific) cytoplasmic granules
staining of secondary granules in granulocytes
Neutrophils: pink to rose-violet granules
Eosinophils: reddish-orange granules
Basophils: dark purple granules
Auer rods are only seen in _______ under abnormal conditions
myeloblasts
Granulopoiesis order
Myeloblast>Promyelocyte> Myelocyte > Metamyelocyte > Band > Segmented Granulocyte
Main cytokine initiating neutrophil production:
Granulocyte-colony stimulating factor (G-CSF)
Myeloblasts, promyelocytes, and myelocytes undergo cell division (mitotic pool) time frame
(4 – 5 cell divisions, 3-6 days spent in this pool)
Do Metamyelocytes, bands, and segs divide? How long do they spend in the maturation and storage pools?
5-7 days in maturation and storage pools; 3 times as many cells as in the mitotic pool
Where are neutrophils located once they enter the bloodstream?
50% circulate freely (circulating pool);
50% adhere to walls of blood vessels
(marginal pool)
Continually move between pools
Average time a neutrophil spends in peripheral blood is:
10 hours
Neutrophil Granulocytes contain____ and have prominent _____ activity
destructive enzymes, most famously myeloperoxidase, used to destroy infectious organisms, most commonly bacteria
phagocytic
Mature segmented neutrophil granulocytes are also known as _____, for ‘polymorphonuclear leukocytes’ (due to their highly and variably segmented nuclei), and also by the abbreviated terms ‘segs’ and ‘polys.’
PMNs
Mature eosinophils usually have _ nuclear lobes
Lifespan of around ____ days
2, 8-12 days
Eosinophil Granulocytes contain
destructive enzymes, which are used to fight organisms too big to phagocytose (fungi, protozoans, parasites)
minimal phagocytosis
In addition to parasite/fungus/protozoa, Eosinophil Granulocytes modulate
mast cell activity in hypersensitivity response/allergic disease
Main cytokine initiating eosinophil production:
Interleukin-5 (IL-5)
Both ______ and ______ are involved in hypersensitivity/allergic processes, and in innate defenses against microbes
Basophil Granulocytes and Mast Cells
Main cytokine initiating basophil production is:
IL3
Main cytokine initiating mast cell production is
Stem Cell Factor (SCF) for mast cells
MATURE BASOPHIL appearance
- Prominent large dark blue (basophilic) cytoplasmic granules, which obscure the nucleus
- Multilobular but non-segmented nucleus
- Found in blood and marrow at low levels
Early T-lymphoid progenitor cells migrate to the ____, the site of:
thymus
T cell maturation
Where does B cell maturation occur
in the marrow
Monopoiesis is initiated by
M-CSF (monocyte-colony stimulating factor)
Mature monocytes circulate in peripheral blood an average of __ days, before entering tissue to become _______
Some mature monocytes and macrophages reside in the ______
20
macrophages
marrow
Monopoiesis order
monoblast > Promonocyte > Monocyte
A million platelets are produced every ____ (around _______ a day), and can be increased by up to ___ fold
second, 100 trillion, 20 fold
Megakaryopoiesis is Initiated by action of the cytokine ________ on an megakaryocyte/erythroid progenitor cell
thrombopoietin (TPO)
Are megakaryoblasts abundant?
No, rare! though they account for only 0.05% of nucleated marrow cells
Description of megakaryocytes
Very large cells with highly folded, multilobular nuclei and abundant finely granular cytoplasm. They possess pseudopods, which they insert in bone marrow sinuses to allow direct shedding of platelets into the circulation
ITEMS COMMONLY ASSESSED ON BM EVALUATION:
ON THE ASPIRATE SMEARS
- Marrow Differential
- Cell Morphology
- Iron Content
ITEMS COMMONLY ASSESSED ON BM EVALUATION:
ON THE CORE BIOPSY
- Marrow Cellularity - Myeloid:Erythroid Ratio – normally 2:1 to 4:1. - Megakaryocyte Frequency
- Focal Findings
MARROW CELLULARITY rough estimation
ROUGH RULE IS THAT MARROW CELLULARITY (AS A PERCENTAGE) SHOULD APPROXIMATELY BE 100 – AGE
Why could marrow be HYPERCELLULAR?
- increased proliferation of one more lineages; usually due to increased signalling by HGFs (e.g. secondary erythroid hyperplasia in smokers)
- Could be neoplastic due to a neoplasm of hematopoietic cells
Hypocellular marrow is categorized as either:
hypocellular (cellularity decreased but some marrow cells present) or aplastic (marrow cells essentially absent)
Possible causes or hypocellular marrow
- Possible causes include: - autoimmune attack on marrow cells – -viral attack on marrow cells - -hematopoietic neoplasms - –malnourished state (rare)
Fetal hemoglobin is comprised of
a2y2
hemoglobin A2 is made of
a2d2
When substrate binding alters the binding affinity for additional substrate
allosteric binding
When oxygen is low and does not occupy any of the 4 sites, Hb is in the __ conformation
T (taut)
The phenomenon of binding to substrate leading to increased affinity for additional substrate
positive cooperativity
Because of ______, the oxygen dissociation curve for Hb is sigmoidal
cooperativity
P50
values for Hb and Mb
the partial pressure of oxygen at which the oxygen carrying protein is 50% saturated
Hb: 27mmHg
Mb: 2.75mmHg
What is the PPO2 in the tissues?
40mmHg
numbers defining shape of Hb O2 dissociation curve
10-10 30-60 60-90 40-75 (PP-%saturation)
Factors causing a RIGHT shift of Hb curve
decreased pH, increased temp, increased DPG
Factors causing a LEFT shift of the Hb curve
increased pH, decreased temp, decreased DPG
How does 2,3-BPG (DPG) alter Hb’s O2 affinity?
it is a byproduct of anaerobic glycolysis pathway that binds to deO2 Hb and stabilizes it in the T configuration leading to a decreased affinity of the Hb for O2
Embryos have 3 hemoglobins present between 4 and 14 weeks:
Describe O2 affinity
Gower 1 (Z2E2), Gower 2 (a2E2), and Portland (Z2y2). higher O2 affinity than HbA
Why do fetal cells have a higher affinity for O2?
because HbF binds 2,3-BPG poorly, stabilizing Hb in the R state, shifting the curve to the left
At birth, there is _____% HbF and ___% HbA
65-95, 20
Who might have elevated fetal hemoglobin levels?
renature babies, infants of mothers with diabetes, hemolytic anemias, myelodysplasia, leukemia
HbA2 comprises __% of adult Hb
2%
______ is generally found in people with high-affinity hemoglobin variants because of
erythrocytosis, increased EPO release
____ is generally found in people with low-affinity hemoglobin
cyanosis
To bind oxygen, hemoglobin needs to be in the __ form. If iron is in the ____ form, _______ results
reduced, ferrous +2 form
ferric +3, methemoglobin
Methemoglobinemia can occur because of too much ______ production or because of decreased methemoglobin reduction.
methemoglobin
** may be acquired or genetic
How can methemoglobinemia be acquired?
oxidation of heme by free radicals, exposure to chemicals (benzocaine), nitrate contaminated water
Genetically cause methemoglobinemia is most often a _______ deficiency
cytochrome b5 reductase
Methemoglobinemeia causes a ___ shift of the Hb curve
left
When might you suspect methemoglobinemia?
Cyanotic but normal arterial blood gas. Blood doesn’t turn red when exposed to O2
_____ is given intravenously to patients with methemoglobinemia and acts as an electron acceptor
methylene blue
CO ____ Hb’s affinity for O2
increases
Symptoms of CO poisoning
headache, malaise, nausea, dizziness,
High levels: seizures, coma, MI
Treatment for CO poisoning
100% O2 and hyperbaric O2
pulse oximetry maybe incorrect because of
incorrectly placed probes, nail polish, dark skin, shivering, anemia, shock, abnormal hemoglobins
What can be used to detect carboxyhemoglobin and methemoglobin?
co-oximetry
Cond’ts associated with anemia of chronic disease
chronic infections, chronic non-infectious inflammatory diseases, malignant diseases, Pb poisoning, renal insufficiency, endocrine disorders
Lead inhibits:
attachment of the iron to the porphyrin ring so hemoglobin cannot be synthesized
Signs and symptoms of renal insufficiency-caused anemia
fatigue, pallor, decresed exercise tolerance, dyspnea, tachypnea
What type of anemia is generally seen with renal insufficiency?
normochromatic, normocytic with EPO deficiency
Symptoms of adrenal insufficiency
nausea, vomiting, dehydration, weakness and circulatory collapse
anemia with hypothyroidism
mostly normochromatic and normocytic. Decreased retics and RI
(may be microcytic or macrocytic)
anemia with hyperthyroidism
usually normocytic, Decreased retics and RI
may be microcytic
anemia with adrenal insufficiency
mild normocytic anemia, Decreased retics and RI
Treatment of anemia from chronic infection/inflammation/malignancy
treatment of underlying disease to decrease cytokines and interleukins. For some diseases treat with EPO
Treatment for anemia caused by lead intoxication
chelation of Pb with administration of specific agents to relieve intoxication
Treatment for renal insufficiency anemia
EPO
Treatment for anemia caused by endocrine disorder
hormone replacement
EPO should only be used when:
1) Absolute deficiency
2) decrease out of proportion to the hematocrit level and where a response has been documented
RBC transfusions should be used when
the severity of anemia has potential for cardiovascular decompensation
sideroblastic anemia
Impaired production of protoporphyrin or incorporation of iron. Iron in mitochondria surround nucleus
Both B12 and folate deficiency causes ______anemia because they arrest in S phase, undergo destruction
megloblastic
Although anemia is most common, B12 and folate deficiency causes ____ and _____ in some patients
neutropenia, thrombocytopenia
Folate is absorbed in the _____ and B12 is absorbed in the ____
jejumum
terminal ilium
Folate is absorbed in the ____, then it is ____ and stored in the ____
jejunum, methylated, liver
Main causes of B12 deficiency
autoimmune disease (anti-IF), intrinsic factor deficiency, malabsorption, defective transport/storage, metabolic defect
The main cause of folate deficiency is:
But other causes include:
dietary insufficiency
malabsorption, drugs and toxins, folate metabolism errors, increased demands, increased loss or metabolism
Increased demands for folate include:
hemolysis, pregnancy, psoriasis, myeloproliferative disorders
Is folate or B12 deficiency more likely associated with alcohol abuse and poor nutrition?
folate
Which deficiency develops more quickly-folate or B12?
Folate deficiency is rapid (weeks-months)
B12 is slow (years-usually prob. with malabsorption)
Hematologic changes of B12 and Folate deficiency
- megaloblastic precursors (red and white)
- erythroid hyperplasia
- peripheral bloos macrocytosis, ovalocytes, hypersegmented neutrophils
- increased bill
- RI<1
severe hematologic changes seen in B12 and folate anemia
poikilocytes, fragmentation, neutropenia, thrombocytopenia
Are neurological symptoms classic in folate or B12 deficiency?
B12, infrequent in folate
Neuro features of B12 deficiency
sensory loss first
proprioception
ataxia, spasticity, gait disturbances, + babinski
cognitive and emotional changes
If a person has neurological symptoms from a B12 deficiency, do they always have anemia? Are neuro symptoms reversible
Nope, 20% don’t.
Neuro symptoms may be irreversible
Lab tests for both B12 and folate deficiency
increased MCV, low RI and retic count, increased unconjugated bill, increased LDH
Tests that would show B12 change but normal folate
serum methylmalonic acid, serum 2-methyl citric acid would be increased in B12 deficiency but normal for folate
95% of B12 (cobalamin) deficiency arise from ____ causes
GI (particularly absorption of B12)
The _____ test can be used to test the absorption of B12
schilling
If it is unclear whether a patient has B12 or folate deficiency, give ____ first. Why?
B12. Giving folate to a B12 deficient patient induced neurological symptoms
Management for cobalamin deficiency
1mg injections weekly for a few weeks, then monthly. If malabsorption not an issue, 2ug orally 2x a day
Management for folate deficiency
1mg/day orally or parenterally
Does anemia reverse quickly for B12 or folate deficiency?
both! Retics after 2-3 days, peak 7-10 days HGB increases in 1-2 weeks WBC increase in 1 week MCV lower in weeks-months blood count normal in 8 weeks
When B12 is ingested, it binds to a protein carrier _____. It is absorbed in the ____. It binds ___ and it stored in the ____
intrinsic factor (IF)
terminal ilium
TcII
liver
The most common cause of B12 deficiency is
pernicious anemia due to autoimmune destruction of IF-producing parietal cells
Cytopenias are dues to either
increased destruction or decreased production (or in rare case, both)
In cytopenias due to increased destruction, what would you expect to see? Why?
compensatory hyperplasia of one or more lineage
In cytopenias due to decreased production, what will you see?
marrow will not show a compensatory hyperplasia
PETECHIAE
microhemorrhages within skin
indicative of thrombocytopenia
What might a giant platelet indicate?
usually indicates increased thrombopoeisis
‘leukemoid reaction’
usually secondary to severe infectious or inflammatory disease
Findings characteristic of leukemia reaction over CML
- Signs of infectious or inflammatory disease
- Toxic-appearing neutrophils on blood smear (toxic granules, Dohle bodies)
- Normal basophils levels in blood
- Normal appearing megakaryocytes in marrow
Findings characteristic of CML over a leukemia reaction
- No symptoms
- Enlarged spleen and/or liver
- Neutrophils do not have toxic features on blood smear
- Absolute basophilia
- Abnormal-appearing megakaryocytes in marrow
Myelophthisis
replacement of bone marrow by fibrosis, tumors or granulomas.
pancytopenia
reduction in the number of RBCs, WBCs, and platelets.
CBC findings of iron deficient anemia (IDA)
Decreased: RBC, HGB, HCT, MCV, MCH, MCHC
Increased: RDW
Morphological features seen on the peripheral blood smear in cases of Iron Deficient Anemia
decreased absolute RBC number, RBCs are mycrocytic and hypochromatic, large central pallor
Typical CBC findings of megaloblastic anemia
Decreased: RBC, HGB, and HCT
Increased: MCV, MCH, RDW
Morphological features seen on peripheral blood smear for megaloblastic anemia
Macrocytic RBCs (but decreased in number), large central pallor, hyper segmented neutrophils
Most common causes of megaloblastic anemia
B12 and folate deficiency
Etiology and pathogenesis of megaloblastic anemia
Results from inhibition of DNA synthesis, so cells arrest in S phase and continue to grow without division–> macrocytosis
Hemolysis
decrease in red cell survival or an increase in turnover beyond the normal range
Generally, marrow reticulocytes develop in the marrow for __-___ days, but during stress or hemolysis, maturation may decrease to __-__ days
10-14 days
5-7 days
Most RBC death occurs in the ____, while 10% occurs _____
spleen (extravascular-macrophages of reticuloendothelieal system)
intravascual
Cellular processes associated with normal turnover of RBCs
- decrease in red cell enzyme with age
- oxidative injury over time
- change in calcium balance
- changes in membrane carbohydrate and surface constituents
- antibodies to membrane constituents
Intravascular hemolysis
Hb released into circulation, tetramer dissociates into dimers which bind haptoglobin. This complex is removed from circulation by liver. Iron can be oxidized to form methemaglobin. Dissociation of glob in releases me theme, which binds to albumin. These are taken up by hepatic parenchymal cells and converted into bilirubin
Extravascular hemolysis
RBC ingested by macrophages of reticuloendothelieal system. Heme separated from glob in, iron removed, stured in ferritin. Porphyrin ring –> bilirubin (lipid soluble), conjugated with glucuronic acid by P450 (H2O soluble), expelled as fecal urobilogen
Morphology of hemolytic anemia
traditionally spherocytes
Bilirubin levels in hemolytic anemia
total bili increased (most is unconjugated)
Housekeeping enzymes LDH and SGOT in hemolytic anemia
increased because there is RBC destruction
Hemoglobin lab results in hemolytic anemia
increased with intravascular hemolysis
Haptoglobin lab results in hemolytic anemia
very low levels in intravascular hemolysis
Methemalbumin, metheme in hemolytic anemia
increased with intravascular hemolysis
Hereditary spherocytosis
familial hereditary disorder characterized by anemia, intermittent jaundice, splenomegaly, and responsiveness to removal of spleen.
Multiple molecular bnormalities, spectrin is most common. Hallmark = loss of membrane=spherocyte, osmotic fragility
clinical features of Hereditary spherocytosis
1:5,000, anemia, jaundice, variable onset, 75% AD, 25% AR.
Presenting complications: hyperhemolysis, aplastic crisis
laboratory findings of Hereditary spherocytosis
variation in HCT, HGB (mild to severe anemia possible)
Increased RI, MCHC
Decreased MCV
spherocytes
unconjugated hyperbilirubinemia, osmotic fragility
What problem with Hereditary spherocytosis might be observable on an Xray?
bilirubin stones (cholelithiasis, cholecystitis)
G6PD deficiency
X linked recessive, wide variety of AA substitutions =variety of enzyme activities
Worldwide, highest distribution in S. Europe, Africa, S. Chins, India, SEA—>relationship to malaria
Pathophysiology of G6PD deficiency
Loss of G6PD activity=inability to make G-SH (oxidant stress), oxidation of hemoglobin, denatured glob in attaches to membrane (heinz bodies) + oxidation spectrin–>decreased deformability of RBC=trapped in spleen–>extravascular hemolysis
Clinical features of G6PD deficiency
- intermittent episodes of acute anemia, hyperbiliruinemia, hemolysis, reticulocytosis,
- associated with oxidant stress: infection, drug, ingestion of certain foods.
- Chronic hemolytic anemia
- neonatal hyperbili
- many drugs contraindicated
Morphological features of G6PD deficiency
no specific morphological features, may see microspherocytes, “blister” cells or “bite” cells
Autoimmune hemolytic anemia
Abs to universal RBC antigens, causes either intravascular or extravascular hemolysis. Two types: warm (IgG) and cold (IgM)
cold autoimmune hemolytic anemia
Mostly IgM, one specific type of IgG, aggressively activate complement through C5-9 complex—> intravascular hemolysis
Warm autoimmune hemolytic anemia
Usually IgG with a high affinity to the RBC membrane with very little and incomplete complement activation—> Extravascular hemolysis
Direct Coombs test
blood sample from a pt. with autoimmune mediated hemolytic anemia has Abs attached to the surface antigens when extracted from the pt. Incubated with Coomb’s reagent which forms links between the human Abs stuck to the surface.–> perceptible agglutination
Indirect Coomb’s test
Pt’s serum (containting Abs) is added to donor blood. Abs stick to Donor’s blood antigens and form complexes, anti-human Ig’s (coomb’s Abs) are added. Agglutination of RBCs occurs when coomb’s Abs bridge the Abs stuck to RBCs
Clinical findings of autoimmune hemolytic anemia
- acute or chronic onset of anemia with pallor, jaundice, and dark urine
- Decrease in HGB, increased retics, increased bili
- Presence of DAT (direct Ab test-coomb’s test)
- may have spherocytes (also can have teardrop or bite cells
What does the spleen do?
Clearance of intravascular particles
adaptive immune response: origin of IgM agglutinins, esp. for encapsulated organisms
Main risk of splenectomy
overwhelming sepsis (particular S. pneumonia) Risks highest in kids <5 but also adults (220X risk of sepsis of normal pop)
Management of splenectomy
1) vaccinate against H. influenza b, S pneumonia and meningiococcal before splenectomy
2) Prophylactic antibiotics
3) See Dr immediately for fever >38.5 (lifelong)
What globin genes are clustered on chromosome 11?
epsilon, gamma, delta, beta
What globin genes are clustered on chromosome 16?
Zeta2, Zeta1, Alpha2, Alpha1
Structural variant seen in Hb C
B6 witch of Glu–> Lys, crystallization
Sickle cell disease
Occurs with 2 abnormal B genes. Many variations but common ones are HbS, Hb C, Hb E, B+ thalassemia, B0 thalassemia
Sickle cell anemia is really a problem with the vasculature. Explain
vasculature gets damaged as a response to “sticking” of RBCs (WBCs). The sicking of a RBC is reversible, but the membrane damage (especially to post-capillary venues) is irreversible. Hypoxia, oxidant injury, apoptosis, abnormal vasoregulation, Inflammation of endothelial tissue causes remodeling and narrowing
Sickle cell trait
One normal B chain, One Bsickle chain. HbA> HbS , normal CSC, rare splenic infarct in white males at high altitude
Reticulocyte count is strongly elevated in :
and slightly elevated in:
HbSS, Hb SB0 thalassemia
Hb SC disease, Hb SB+ thalassemia
Direct damage to endothelium in sickle cell anemia
up regulation of adhesion molecules, exuberant repair mechanisms, apoptosis
The severity of sickle cell anemia is strongly correlated with
RBC adhesion
What was correlated with diminished survival in sickle cell patients in the Cooperative Natl. history study?
Constitutive elevation of WBCs
Sickle cell solubility testing
detects the sickle hemoglobin in concentrations as low as 8-20% so it cannot distinguish sickle cell trait from the disease or the type of disease
What is the most accurate way to diagnose hemoglominophaties?
hemoglobin separation on a gel, can also use isoelectric focusing, HPLC
Characteristics of a Sickle cell
sickle shaped, rigid, sticky (even when not sickled), lived for increased Retics
Which hemoglobinopathies might microcytosis and hypochromia suggest?
thalassemsia
Which hemoglobinopathies might target cells suggest?
thalassemsi, Hemoglobin C (if crystals are present)
What is a preventable cause of death in infants with Sickle cell disease
splenic damage, trapping of RBCs
overwhelming bacterial infections, preventable with prophylactic penicillin
Sickle cell and stroke
large vessel ischemic stroke:intimal hyperplasia, proliferation of fibroblasts and smooth muscle, slitting of internal elastic lamina
Adults at risk for CNS hemorrhage (same as above-weakened vessels)
Sickle lung disease
progressive obliteration of pulmonary vasculature: Begins with restrictive changes, frequently leads to pulmonary hypertension, leading cause of death in adults with sickle cell disease/ Loss of vasoregulation, decreased exhaled NO, administration of arginine may improve plum. hypertension
Sickle nephropathy in HbSS
Initial hyperfiltration and enlarged glomeruli
10-15% HbSS patients, sidled cells adhere in afferent/efferent arterioles, RBC fragments deposited in basement membrane
Sickle Retinopathy in HbSS
11-45% pts. causes retinal detachment, hemorrhage, blindness
What bone/muscular problems can be associated with HbSS?
Avascular necrosis of femoral/humeral heads, leg ulcers, chronic pain syndrome
Acute sickle cell event
endothelial injury (hypoxia, cytokines)-vascular leak, endothelial retraction from increased RBC adhesion in post-capillary venues, vascular disruption and inflammation, vasoconstriction (decreased NO)
Treatment of sickle cell pain
Goal: get endothelium less sticky. Antibiotics for fever, pain control, O2 and hydration
Acute chest syndrome/multiorgan failure in HbSS
rapid onset of low O2, chest pain, fever, worsened anemia.
- kidney, liver failure possible
- rapid transfusion therapy is critical
Treatment of hemoglobinopathies
transfusion, induction of HbF (hydroxyurea, butyrate), bone marrow transplant
Why aren’t bone marrow transplants done on all sickle cell patients?
Only 17% of eligible recipients have suitable HLA-matched sibling donor
How does transfusion therapy help HbSS? What are the risks?
dilutes sickled RBCs, decreases stroke risk and abnormal flow to cerebral vessels. Risks: infection, alloimmunization, iron overload
hydroxyurea characteristics
induces fetal hemoglobin, reduces sickle hemoglobin polymerization, increases MCV, less hemolysis with improved anemia, less RBC adhesion, increased NO generation, decreases vascular injury. Also decreases WBC
Clinical effects of hydroxyurea
- reduction in acute pain events and acute chest syndrome
- Improvement in mortality
- no evidence of reduction in chronic organ injury
Pathophysiology of Thalassemias
Decreased synthesis of α- or B-globin chains
leads to imbalance in chains
- free excess chains bind to RBC membrane
- membrane oxidative injury
- increased membrane rigidity
- decreased membrane stability(B-thalassemia)
Manifestations of Thalassemias
Underproduction of normal Hb Small RBC: (↓MCV) ↓MCH, MCHC, normal RDW Increased RBC fragility → ↓ RBC survival Increased Retics Increased release of RBC contents: (unconjugated) bilirubin, LDH, AST, splenomegaly Bilirubin gallstones Anemia MAY be present
Consequence of iron overload:
Growth delay
Endocrinopathies
Severities of a-thalassemia gene deletions
1-gene deletion = Clinically silent (MCV normal)
2-gene deletion= Microcytosis ± anemia (nl/low)
3-gene deletion= Microcytic anemia (Hb H disease) (low)
4-gene deletion= Fetal hydrops (intrauterine death)
Which a-thalassemsis are transfusion dependent?
sometimes HbH
HbH disease symptoms
hypochromia, microcytic anemia, increased retics, splenomegaly, cholelithiasis, iron overload, infection, anemia exacerbated by vitamin deficiency
Can electrophoresis be used to diagnoses a-thalssemia?
A-globin is part of every hemoglobin, so there is no difference in the relative quantities. Must have microcytosis w/o iron deficiency and normal electrophoresis
Hb E disease
(GlyLys at 26) – unstable mRNA so less production
β-thalassemia major (Cooley’s anemia)vs
β-thalassemia trait:
Both genes for beta chains are missing vs
one gene missing
β Thalassemia minor (trait): Clinical Syndromes
Minor or no anemia (↓ MCV ↓MCH ↑RBC)
β Thalassemia intermedia
Moderately severe anemia
May have splenomegaly
Growth delay, bone deformities
Increased iron absorption with hemosiderosis
Thalassemia major (Cooley’s anemia or HbEβo)
severe transfusion-dependent anemia
splenomegaly
Growth delay, endocrine failure
dense skull/marrow expansion with osteopenia
Increased iron absorption with hemosiderosis
Treatment of βoThalassemia (Cooley’s Anemia)
Transfusion Therapy
Induction of Fetal Hemoglobin ~ hydroxyurea therapy ~ butyrate therapy Bone Marrow Transplant ~ standard of care in βothalassemia (Cooley’s anemia
Survival of βoThalassemia (Cooley’s Anemia)
- W/o transfusions
- Trasfusions with RBCs
- Transfusions + chelation
-W/o transfusions: >20 years
Should iron supplements be given to those with thalassemias?
Iron supplementation should NOT be given unless clearly iron deficient, microcytosis is not due to low iron stores
Possible causes of microcytic anemia
- Iron deficiency
- Thalassemia syndromes
- Severe lead poisoning (children)
- Chronic disease/inflammation
What is involved in initial screening for safety of blood transfusions?
donor interview, review of high risk behavior, abbreviated physical appearance, HCT, skin prep to reduce infection
What infectious diseases are screened in transfusion blood samples?
Syphilis, Hep A,B, C, HIV 1, 2, HTLV I, II, WNV, CMV
The fact that there are alterations in antigens on blood cells that do not result in functional differences is an example of
alloantigens
When do people develop Abs to blood types other than their own?
By 1 year
Pre transfusion testing of donor’s blood
ABO, Rh(D), antibody screen
Crossmatch
add recipients’s serum to donor cells and look for agglutination at RT. Add coomb’s to look for IgG complement, takes about 45 min
In an urgent situation, what kind of blood is used?
O, Rh(D) negative
Acute hemolytic transfusion reaction (pathophys, symptoms, mgmt)
Hemolysis of transfused cells iwht activation of clotting, inflammatory mediators, and renal failure.
fever, chills, nausea, chest pain, back pain, pain at transfusion site, hypotension, dyspnea, dark urine
risk is low, mortality hush. Stop transfusion, IV fluids and diuretics, heparin
Delayed hemolytic transfusion reaction (pathophys, symptoms, mgmt)
formation of alloantibodies post-transfusion, destruction of red cells by extravascular hemolysis
fever, jaundice, anemia
Supportive care and detection, definition, and documentation for future care
(Transfusion reaction) Febrile reactions (pathophys, symptoms, mgmt)
leukoagglutins in recipient cytokines or other biologically active compounds
Fever, maybe chills
Supportive, consider leukocyte poor products for future
(Transfusion) allergic reactions (pathophys, symptoms, mgmt)
Most causes not identified
itching, hives, chills/fever, in severe cases anaphylaxis, dyspnea, pulmonary edema
Transfusion related acute lung injury (pathophys, symptoms, mgmt)
w/i 4 hrs after transfusion. Pt: infection surgery, cytokine therapy
Blood factors:lipids, Abs, cytokines
Two factors interact and result in lung injury
Tachypnea, dyspnea, hypoxia, diffuse interstitial marlins with normal cardio exam
Supportive, consider yonder products
Transfusion related: Dilutional coagulopathy (pathophys, symptoms, mgmt)
massive blood loss
Bleeding
replacement of clotting factors or platelets
Bacterial contamination of blood transfusion (pathophys, symptoms, mgmt)
bacteria/endotoxin
chills, high fever, hypotension, symptoms of sepsis or endotoxemia
Stop transfusion , ID organism, antibiotics and supportive care
Graft vs. host disease (pathophys, symptoms, mgmt)
lymphocytes from donor transfused into immunoincompetent host
Can involve skin, liver, GI tract, bone marrow
Preventative management
Iron overload in transfusion patients (pathophys, symptoms, mgmt)
increased iron, no way to excrete
dysfunctional organ symptoms
iron chelators: deferoxamine, Exjade
What is Toll? Why is it important?
single gene that controls innate immunity in a fly. Toll knock outs die from invaders. The flies only have innate immunity, no adaptive immunity
How many toll like receptors do humans have?
10
Are toll-like receptors (TLRs) on the outside or inside of a cell?
TLRs can be on the inside or outside to recognize foreign threats (dsRNA or cell wall, respectively)
Toleragen
antigen that does not create an immune response
immunogen vs antigen
antigen: anything that reacts with the immune system
immunogen: known to cause immune response.
EX: flu vaccine makers want the best immunogen of all of their possible antigens.
“Crossing over” of lymph and blood occurs in the:
post capillary venules
allotype
genetically determined difference in molecular structure of an antibody between members of the same species (generally a 1-2 amino acid substitution of the constant heavy or light chain). No biological significance
Isotype
present in all members of a species, the class of an antibody heavy or light chain: IgM, IgG, IgA are all isotopes
Idiotype
variation on an individual, unique differences in the antibody binding region (hyper variable region)
