RBC I, HS and Sickle Cell Putthoff Flashcards
definition of anemia
reduction of total circulating red cell mass below normal limits
microcytic normochromic anemias are generally what disorders
disorders of Hb synthesis
MCV tells you what in CBC
microcytic, normo or macro
What is Mean cell Hb [ ]
average concentration of Hb in given volume of packed RBC
what is RDW
ratio of largest RBC to smalles
signsof anemia
pale, weakness, malaise and fatigue
dyspnea on mild exertion
what are normal Hb limits
male 13-17 female 12-15
what are normal MCV limits
80-100
what are normal MCHC limits
30-40
what is normal RDW limits
11-15
hypoxia due to anemia causes what changes in liver, myocardium and kidney
fatty changes
what are complications from acute blood loss
oliguria and anuria from renal hypoperfusion
HA dizziness and faintness
what are causes of chronic blood loss
GI lesions
gynecologic disturbances
how many days for reticulocytes to be made
5
difference in blood cell response to minimal acute bleeding and severe
minimal basically only reticulocytosis
severe is reticulocytosis and thrombocytosis
what are common features with hemolytic anemias
shortened red cell life span below 120 days
elevated EPO levels
accumulation of Hb degradation products
what is extravascular hemolysis
when RBC are destroyed in phagocytes (this is normal)
clinical features of extravascular hemolysis
anemia, splenomegaly and jaundice
what is haptoglobin
alpha2 globulin that binds free Hb and prevents its excretion in urine (decreased in hemolytic anemia)
what is intravascular hemolysis
mechanical injury, complement fixation, intracellular parasites or exogenous toxic factors
causes of intravascular hemolysis
cardiac valve damage, thrombotic narrowing
repetative physical trauma
signs of intravascular hemolysis
anemia, hemoglobinemia, hemoglobinuria, hemosidinuria and jaundice
NOT splenomegaly
what bilirubin is elevated in hemolytic anemias
unconjugated
when is conjugated bilirubin elevated?
biliary tract obstruction
what type of Hb abnormalities lead to hemolytic anemia
deficient production
structurally anormal
What is hereditary spherocytosis
inherited disorder caused by intrinsic defects in RC membrane skeleton that render red cells spheroid, less deformable and vulnerable to splenic sequestration and destruction
What is inheritance pattern of hereditary spherocytosis
autosomal dominant
what is compound heterozygosity in hereditary spherocytosis
inheritance of 2 different defects
most severe form
red brown urine from hemolytic anemia is from what
methemoglobin because dec haptoglobin
gallstones in a patient with hemolytic anemia are most likley composed of what
heme pigments
what is hemosiderosis
when there is iron accumulation
hemosiderin (iron containing pigment)
what is life span RBC in HS
10-20 days
what are the common mutations of HS
ankyrin, band 3
spectrin or band 4.2
do HS cells have normal mean cell Hb [ ]
no it is increased
clinical findings of HS
anemia, splenomegaly and jaundice
what do the RBC look lik ein HS
spherocytosis (dark staining hyperchromic RBC without central zone pallor)
HS get stuck where
in cords of billroth in the spleen and thus prone to macrophages
HS are more prone to destruction by hypotonic solutions why
osmotic lysis because influx of water with little room to expand
what occurs if the RBC destruction overweighs RBC production
chronic hemolytic anemia
what usually causes an aplastic crisis in HS
parvovirus
how does parvovirus affect RBC
kills RBC progenitors ceasing RBC production for 1-2 weeks
what is Tx for HS patient in aplastic crisis
transfusions until immune response clears the infection
what are hemolytic crisis in HS patients
intercurrent events leading to increased splenic destruction of red cells
what is Tx for Hs patients
splenectomy
What deficiency is an example of hemolytic disease due to RBC enzyme defect
G6PD deficiency
what occurs in G6Pd
abnormalities in the hexos monophosphate shunt or glutathione metabolism resulting from deficient or impaired enzyme function reduce ability of red cells to protect themselves against oxidative injuries and lead to hemolysis
what causes the episodic hemolysis of G6PD deficiency
exposures that generat oxidant stress like infections
What infections can trigger hemolysis in G6Pd
viral hepatitis, pneumonia, thyphoid fever
what is characterisitc of G6Pd on peripheral smear
red cells with heinze bodies and bite cells
inheritance pattern of G6Pd
recessive X linked trait
distribution of G6Pd
mediterannean and men
middle eash
what drugs can cause hemolysis in G6Pd
sulfonamides, antimilarials, nitrofurantoins
what type of hemolysis occurs in G6Pd
intra and extravascular
which variant of G6PD has greater hemolysis
Mediterranean
why don’t G6PD patients present with splenomegaly or cholelithiasis
because the hemolytic episodes occur intermittently
how long does it take for acute intravascular hemolysis to occur in G6PD
2-3 days following exposure to inciting agent
What is Sickle cell disease
hereditary hemoglobinopathy caused by point mutation in beta globin that promotes polymerization of deoxygenated Hb leading to RBC distortion, hemolytic anemia, microvascular obstruction and ischemic tissue damage
What are the main types adult Hb
HbA (2 alpha 2 beta)
HbA2 (2 alpha 2 gamma)
what is Hbf
2 alpha 2 lambda
what point mutation is in sickle cell disease
glutamate for valine on 6th codon of beta globulin
characteristics of PS of sickle cell
anisocytosis and poikilocytosi
what is anisocytosis
different sizes of RBC
what is poikilocytosis
different shapes of RBCs
2 heterozygotes of sickle cell trait have a child. change of child haveing homozygous?
1/4
what is thoughs on why africans have higher HbS
protection against falciparum malaria
What are major pathologic findings with HbS
stack into polymers when deoxygenated
cause chronic hemolysis, microvascular occlusions and tissue damage
what are clinical signs of sickle cell disease
severe hemolytic anemia assoc with reticulocytosis, hyperbilirubinemia and presence of irreversibly sickled cells
what are the “pain crisis” assoc with sickle cell disease
vaso-occlusive crises that are episodes of hypoxic injury and infarction that cause severe pain in affected region
most common sites of vaso occlusive crisis in Sickle cell disease
bones lungs liver brain spleen penis
what are the clinical manifestations of the pain crisis in sickle cell
hand foot syndrome or dactylitis
why do infants with sickle cell disease not become symptomatic until 5-6 mo old
because HbF prevents polymerization of HbS
what is HbS HbC
disease with sickling but not as severe as sickle cell
how does mean cell Hb [ ] affect sickle cell disease
increased MCHC facilitates sickling
dec opposite
how does pH affect HbS
low pH reduces O2 affinity for Hb
more sickling
where does sickling tend to occur
in microvascular beds with slow transit times
spleen and bone marrow
inflammed tissues
what is Acute Chest Syndrome
particularly dangerous type of vaso occlusive crisis involving the lungs which typically presents with fever, cough and chest pain and pulmonary infiltrates
severity of hemolysis in sickle cell disease relates to what
the orecentage of irreversibly sickled cells
how does sickle cell affec tNO levels
fre eHb released from lysed cells binds and inactivates NO
how do the vasoocclusive crisis affect the eyes in sickle cell disease
loss of visual acuity, even blindness
what are Howell Jolly bodies
small nuclear remnatns in red cells due to asplenia
“crew-cut” on XRay is indicative of what
expansion of marrrow
what is autosplenectomy and when is it seen
enlargement of spleen early childhood that leads to infarction, fibrosis etc
what are sequestration crisis
children with intact spleens that have rapid enalrgement leading to hypovolemia and sometimes shock
what are aplastic crisis in sickle cell disease
infection of RBC progenitors with parvovirus B19
what does the chronic hypoxia fro sickle cell cause
impairment of growth and development
organ damage of spleen heart kidneys and lungs
hypertropy renal medulla that could lead to hyposthenuria
what infections are sickle cell patients mroe prone to
pneumococcus, meningococcus, H influenza
how is fetal Dx of sickle cell known
amniocentesis or chorionic biopsy
Tx for sickle cell
DNA synthesis inhibitor hydroxyurea
stem cell transplantation maybe cure
