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127 Cards in this Set

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Peripheral smear: macro-ovalocytes and hypersegmented PMNs
megaloblastic anemias
what are the 2 defining characteristics of megaloblastic anemias
1. impaired DNA synthesis and 2. ineffective hematopoiesis
what are the 2 characteristics of impaired DNA synthesis seen in megaloblastic anemias?
1. delayed nuclear maturation and 2. DNA abnormalities - chromatin strand breaks
what does the marrow look like in megaloblastic anemias?
hyperproliferative, but many cells die within marrow
what cells are affected in megaloblastic anemia?
all dividing cells in the body - bone marrow: anemai or pancytopenia; GI: mucosal atrophy, glossitis; skin: hyperproliferative - constantly shedding, thin skin, fine hair
what are the 4 main causes of megaloblastic anemias?
1. B12 deficiency, 2. folate deficiency, 3. antifolate drugs - methotrexate, trimethoprim/sulfa antibiotics, 4. nucleoside inhibitors (AZT)
what are 3 anti-folate drugs that can cause megaloblastic anemia?
1. methotrexate, 2. trimethoprim, 3. sulfa antibiotics
what is pernicious anemia?
cobalamin deficiency due to autoimmune gastritis
what are the 5 most common causes of macrocytic anemia?
liver disease, reticulocytosis, meylodysplasia, alcoholism, hypothyrodism
what is the important function of folate?
transfer of one carbone fragments in many chemical reactions
what are the dietary sources of folate?
vegetables, fruits, cereals, and dairy products - heat liable, destroyed by cooking
what is the daily requirement and body stores of folate?
50 micrograms daily requirement; 5-10 milligrams body stores (stores can be depleted in a few months)
what happens to the body stores of folate if the enterohepatic circulation is interrupted?
the body stores can be depleted much more quickly
what is the most common cause of folate deficiency?
inadequate diet - tea and toast or alcoholism
what are the the less common causes of folate deficiency?
malabsorption, hemodialysis, AEDs, oral contraceptives, nitrous oxide (laughing gas)
what are 3 conditions where there is increased need for folate?
1. chronic hemolytic anemias (hemoglobinopathies and HS), 2. psoriasis, 3. pregnancy
what is associated with folate deficiency in pregnancy?
neural tube defects
what are the primary sources of cobalamin?
meat, eggs, dairy products
what is the daily requirement and body store of cobalamin?
0.1 microgram/day requirement; 2-4 miligrams - body stores; takes years to deplete body stores
what is the most common cause of cobalamin deficiency?
malabsorption
what are the less common causes of cobalamin deficiency?
dietary deficiency - strict vegans, infants of vegetarian mothers; congenital - deficiency of IF or transcobalamin II
what is key in cobalamin absorption?
intrinsic factor - produced by gastric parietal cells
where is cobalamin absorbed?
in the terminal ileum - absorbed efficiently as complex with IF
how can pancreatic insufficiency cause cobalamin deficiency?
pancreatic enzymes are needed to digest R-factors that are bound with cobalamin preventing the binding of IF - no pancreatic enzyme no binding sites for IF
what is the function of transcobalamin II?
it carries B12 in the blood and delivers it to tissues - ONLY carrier that can deliver it!)
what is the most common cause of cobalamin malabsorption?
pernicious anemia
what is blind loop syndrome?
stasis of the gut causes overgrowth of bacteria that compete for B12 causing malabsorption of B12
what parasite can cause B12 deficiency?
fish tapeworm - Diphyllobothrium latum
when I say Diphyllobothrium latum, you say:
cabalamin malabsorption
what happens to the gastric mucosa in pernicious anemia?
it is thinned, gastric crypts are destroyed and there is inflammation
what antibodies are specific for pernicious anemia?
anti-intrinsic factor - but they are not very sensitive
what antibodies are sensitive for pernicious anemia?
anti-parietal cell Ab - but they are not specific
what is tetrahydrofolate required for?
DNA synthesis - the conversion of dUMP to tUMP by thymidylate synthetase
what is cobalamin required for?
the regeneration of methylene-FH4 - it functions to regenerate the folate needed for DNA synthesis
what is the reaction that requires both folate and B12?
the conversion of homocysteine to methionine by methionine synthetase
what are the signs and symptoms of megaloblastic anemia?
weakness, fatigue, painful tongue and mouth, weight loss, loss of appetite, N&V, loose stools, pollor, angular cheilitis, dry smooth skin, smooth 'beefy' tongue, silvery or premature gray hair \
what is the rule of fives in megaloblastic anemia?
hypersegmented neutrophils on perihperal smear have > 5 nuclear lobes or >5% of neutorphils have 5 lobes
what is megaloblastic maturation?
nuclear-cytoplasmic asynchrony = large, immature nuclei in late erythroid precursors found in bone marrow
when are giant bands and metamyelocytes found?
in megaloblastic anemia
what are 3 supplimental lab findings in megaloblastic anemia?
1. increased LDH, 2. increased unconjugated bilirubin, 3. decreased haptoglobin
what are the early neurologic signs of cobalamin deficiency ?
paresthesias of distal extremities - reduced vibration and position sensation
what are the later neurolgoic signs of cobalamin deficiency?
clumsiness, ataxia, weakness, hyperrflexia, positive babinski and romberg signs
what is the pathology behind the neurological manifestations of cobalamin deficiency?
myelin degeneration (SAM is required for myelin production), loss of axons in dorsal and lateral columns of spinal cord and cerebral cortex
what are the cortical manifestations of cobalamin deficiency?
denemtia, altered metnal status and bizarre behavior
what is the treatment of the neurologic manifestations of cobalamin deficiency?
B12 supplementation may reverse all neurologic manifestations - long standing change may not be reversible
what can happen if you give folate to a cobalamin deficient patient with neurological signs?
folate may accelerate the neurological progression
what are the 3 primary lab tests to distinguish folate or cobalamin deficiency?
1. serum cobalamin, 2. serum folate, 3. erythrocyte folate level
what are the secondary lab tests to distinguish folate or cobalamin deficiency?
serum methymalonic acid (MMA) and serum homocysteine levels
what are the lab findings for 1. serum B12, 2. serum folate, 3. RBC folate, 4.serum MMA and 5. homocysteine in cobalamin deficiency?
1. serum B12 - ↓, 2. serum folate - normal/increased, 3. RBC folate - ↓, 4.serum MMA - ↑, 5. homocystein - ↑
what are the lab findings for 1. serum B12, 2. serum folate, 3. RBC folate, 4.serum MMA and 5. homocysteine in folate deficiency?
1. serum B12 - normal, 2. serum folate - ↓, 3. RBC folate - ↓, 4.serum MMA - normal, 5. homocystein - ↑
of RBC folate, serum MMA and homocysteine levels, which one differs between folate and cobalamin deficiencies?
MMA - in cobalamin it is increased, in folate it is normal; other two have identical changes in both deficiencies
is serum folate or RBC folate a more stable lab value?
RBC folate - reflects last few weeks. Serum can reflect last meal
what test is most sensitive for cobalamin deficiency?
increased MMA is most sensitive for cobalamin deficiency
what is the possible effect fo folate of cobalamin deficiency on iron?
either may decrease iron absorption due to atrophy of the GI tract
what picture would you see if you had a folate or cobalamin deficiency + an iron deficiency?
MCV may be normal, may see dimorphic RBC population, hypersegmented neutrophils may be present
what is the treatment for folate deficiency?
oral therapy
what is the treatment for cobalamin deficiency?
parenteral therapy (loading) followed by oral supplements - must follow up!!
what are the consequences of HbSC?
retinopathy, aseptic necrosis of femoral head, acute chest syndrome in 3rd trimester
how is G6PD deficiency inherited?
x-linked recessive
polychromasia with bite or blister cells and Heinz bodies
G6PD deficiency
how is HS inherited?
Ad
what is the etiology of HS?
verticle attachment problem - ankryin defect
what is the etiology of hereditary elliptocytosis?
hornizontal problem - spectrin problem
what can cause normocytic, normochromic hypoproliferative anemia?
hypothyroidism and hypogonadism
what is seen with HbS beta-thal
similar to sickle cell anemia
microcytosis with traget cells and normal Hb (or slightly decreased)
homozygoud HbE
mild microcytic anemia with spherocytes and target cells
HbCC
what is "splenic conditioning"?
seen in HS - spleen participates in membrane loss and spheocytic transformation
what are the characteristics of intravascular hemolysis?
direct complement mediated - formation of MAC, IgG or IgM
what are the characteristics of extravascular hemolysis?
IgG or complement on surface (not MAC) - opsonization leads to phagocytosis by macrophages or spleen and sometimes the liver
what Ig is involved in col hemolytic anemia?
IgM - fixes complement; usually extravascular but if enough complement are fixed can by intravascular
what infections are associated with cold hemolytic anemia?
mycoplasma pneumonia, EBV(mono)
what Ig is associated with warm hemolytic anemia?
IgG - may or may NOT fix complement
what is idiopathic autoimmune hemolytic anemia?
usually warm IgG hemolytic anemia that is directed against an Ag in the Rh system present in all non-Rh-null pts
how do you diagnose idiopathic autoimmune hemolytic anemia?
incrased reticulocyte count, LDH and unconj. Bilirubin; decreased hepatoglobin; POSITIVE DAT, has low ANA titer
what happens in drug absorption type immune hemolytic anemia?
(penicillin type): dose dependent reaction where drug binds to RBC surface; usually not severe
what happens in neoantigen type drug related hemolytic anemia?
combo of drug bound to RBC antigen - Ab fixes complemetn, MAC forms = intravascular hemolysis; not dose related (can occur at low doses); cephalosporins!
what happens in autimmune (Aldomet) drug-related hemolytic anemia?
drug induces autoimmune state that is like IAHA - does not require presence of drug; associated with T-cell dysfunction
define TTP
intravascular thrombi composed of vWF and platelets that fragemtn RBCs as they pass through the thrombi
what causes TTP?
deficiency of vWF cleaving enzymes; ADAMTS13
what causes HUS?
shiga-Toxin produced by E.coli (0157:H7), shigella;
what are the symptoms of HUS?
renal insufficiency, hematuria, vairable micorangiopathic hemolysis, thrombocytopenia
what are the characteristics of pregnancy associated mechanical hemolysis?
microangiopathic lymolysis, often HTN, edema and proteinuria
what is HELLP?
mechanical hemolysis in pregnancy: Hemolysis, Elevated Liver enzymes, Low Platelets
what must be matched for RBC transfusion?
must give units that lack any ABO Ag that a pt has Ab against
what must be matched for plasma transfusion
must give units that lack Ab against ABO on patient's RBC
what mismatch causes the most serious transfusion reaction?
when Type O pt gets Type A RBCs
what type of transfusion reaction occurs with Anti-D (Rh) Ab?
usually delayed and extravascular
when is "type and screen" used?
for pt with low probability of needing transfusion
what are the 3 indications to give RBCs?
1. provide oxygen carrying capacity, 2. replace blood lost acutely, 3. treat severe anemia in normovolemic pts
what are the indications to give platelets?
active bleeding with platelet <50K, not bleeding, platelet <10K, pt who is bleeding and needs surgery, pt who was on cardiac bypass pump
what are the contraindications of giving platelets?
1. TTP, heparin induced thromboyctopenia; avoid in ITP
what Ag do platelets have?
ABO and HLA; not Rh
which blood component is the most dangerous?
platelets - must be kept at room temp = bacterial contamination
what does fresh frozen plasma contain?
all clotting factors - Factor VIII loses activity the most in 5 days
what do you need to match for FFP transfusion?
ABO, Rh doesn't matter
how much FFP do you need to give?
at least 10-20 ml/kg
what are the indications of FFP?
multiple factor deficiency, rapid correction of warfarin, treat TTP, DIC
what are the contraindications of FFP
not for volume replacement
what is not inactivated in FFP?
viruses
what is in cyroprecipitate?
fibrinogen, factor VIII, vWF, XIII and fibronectin - fibrinogen is most important
what are the indications of cryprecipitate?
low fibrinogen, facotr XII deficiency; not indicated to replace VIII or vWF
what is cyroprecipitate tested for?
infeciton but not treated; not treated to inactivate viruses
what cause acute intravascular hemolytic transfusion reaction?
type 2 HS - due to ABO mismatch - usually clerical error
what is the cause of delayed immune hemolytic transfusion reaction?
atypical Abs - Kidd; extravascular
what causes febrile non-hemolytic transfusion reaction?
Ab against WBC in unit or can be do to cytokines; A type 2 HS rxn
what is the most common transfusion reaction?
allergic
what causes allergic transfusion reaction?
Ab against plasma protein in the unit
what do you give for allergic reactiosn?
diphenhydramine = benadryl
what causes anaphlyatic shock reaction post-transfusion?
IgA in unit given to pt who has a IgA deficiency and thus Anti-IgA Abs
define transfusion associated acute lung injury
non-cardiogenic pulmonary edema during or shortly after transfusion
what causes transfusion associated acute lung injury?
high titer anti-HLA or anti-leukocyte Ab in transfused plasma reacting against WBC in recipients blood - activated WBC cause lung injury
what is the number one cause of death due to transfusion?
transfusion associated acute lung injury
what causes transfusion associated circulatory overload?
rapid infusion of large volume can precipiate CHF or pulmonary edemia in pts with compromised cardaic fucntion
what is the cause of GVHD?
immunocompontent lymphocytes (T-cells) are transfused into a severely immunocompromised pt with malignancy or after receiving certain drugs - causes transfused cells to attack host
what is the risk of transfusions from closely related persons?
the recipient's immune system doesn't recognize transfused WBC as foreign BUT transfused WBC DO recognized recipient as foreign - and attack them
what are the consequences of transfusion associated GVHD?
bone marrow failure and apasltic anemia
what in irradiated blood indicated?
fetus, neonates, congential immune deficiencies, allogenic and autologous BMT, hemtalogic maligancies, aplastic anemia, solid tumors, HLA matched platelets, granulocyte transfusion and related/directed tumors
what cells cause GVHD?
t cell mediated
what are blood units tested for?
HIV, HBV, HCV, syphilis, west nile virus, HTLV-1; some tested for chaga
what infections are not screen in blood units?
CMV (most commonly passed on), malaria, vCJD, parovirus, babesiosis
thalassemia: microcytic anemia + normal Hb electrophoresis
alpha-thal trait
thalassemia: microcytic anemia + decreased HbA and increased HbA2 and HbF
beta-thal minor
thalassemia: microcytic anemia + no synthesis of HbA
beta-thal major
thalassemia: microcytic anemia + >90% HbF
beta-thal major
thalassemia: no anemia + 50% HbA and 50% HbS
sickle cell trait
thalassemia: microcytic anemia + HbS and HbF
sickle cell disease