Hematology Flashcards
describe the image
hereditary spherocytosis
note the anisocytosis and several hyperchromic spherocytes
Howell-Jolly bodies (small nuclear remnants) are also present in the red cells of this asplenic patient (seen on the right)
describe the type of anemia that is seen in the image
normocytic anemia with predominant extravascular hemolysis
describe the etiology of the condition seen in the image
- etiology = intrinsic/genetic defect in RBC membrane proteins
- ankyrin (AD)
- spectrin (AR)
- band 3.1
describe the pathogenesis of the condition seen in the image
- pathogenesis:
- reduced RBC membrane stability → loss of small fragments during normal shearing stresses in the blood circulation → spherocytosis to accommodate → unable to traverse the splenic sinusoids → phagocytosis and destruction by splenic macrophages → splenomegaly usually seen due to functional hypertrophy
describe the change in SA:V ratio in the condition seen in the image and what it affects
- decreased SA:V ratio (spheres) → pack more Hb → no central pallor → increased MCHC (due to cell becoming more concentrated) & increase in RDW
in the condition seen in the image, ___ can deliver O2 normally but ___ recognizes them as foreign
in the condition seen in the image, spherocytes can deliver O2 normally but the spleen recognizes them as foreign → chronic extravascular hemolysis
describe the presentation of the condition seen in the image
- mild to chronic hemolytic anemia, jaundice, fatigue, dragging sensation in LUQ due to splenomegaly
describe the lab findings in the condition seen in the image
- ↑ reticulocytes (reticulocytosis)
- ↑ LDH
- ↑ MCHC (only condition that has this)
- ↑ RDW
- ↑ unconjugated bilirubin
- ↓ MCH
describe the osmotic fragility test in relation to the condition seen in the image
- osmotic fragility test:
- in 65% of patients with HS, RBCs lyse prematurely compared to normal when exposed to increasingly hypotonic solution
describe the complications of the condition seen in the image
- all anemias → LVH → LHF → RHF → CHF
- rapid production of RBCs uses folate → folate def. anemia → megaloblastic anemia
- increased risk of aplastic crisis due to Parvovirus B19 (infects normoblasts/erythroid precursors) → reticulocytopenia in chronic hemolytic anemia
- bilirubin gallstones → cholecystitis due to supersaturation of bilirubin in bile → increased chance of precipitation
in the condition seen in the image, there is an increased risk of aplastic crisis due to ____
in the condition seen in the image, there is an increased risk of aplastic crisis due to Parvovirus B19 which infects normoblasts/erythroid precursors
describe the treatment for the condition seen in the image
splenectomy & folic acid supplements
will see HJ bodies upon splenectomy
describe the image
G6PD
as the splenic macrophages pluck out the Heinz bodies inclusions, “bite cells” are produced
describe the image
G6PD
red cells with precipitates of denatured globin (Heinz bodies) shown by supravital staining
describe the type of anemia seen in the condition in the image
normocytic anemia with predominant intravascular hemolysis (due to abnormality in HMP shunt)
describe the etiology of the condition seen in the image and name the 2 types of mutations
- etiology = X-linked recessive
- 2 types of mutations (role against falciparum malaria)
- G6PD A (African variant) = mild version → only older RBCs are affected
- G6PD (Mediterranean variant) = more severe → even younger RBCs are affected
describe the pathogenesis of the condition seen in the image
- pathogenesis: abnormal enzymes are misfolded
- ↓ G6PDH → ↓ NADPH → ↓ GSH → oxidative injury by H2O2 → intravascular hemolysis
- oxidative stressors = fava beans, infections/antibiotics, antimalarial & sulfa drugs
- mechanism: oxidation of SH groups on globin chains of Hb → Hb precipitates as Heinz bodies → damage to RBC membrane → intravascular hemolysis (predominantly)
describe lab findings seen in the condition in the image
- blood
- ↑ LDH
- ↑ unconjugated bilirubin
- ↑ free Hb
- ↑ reticulocytes
- ↓ haptoglobin (made by liver to bind free Hb)
- urine
- free hemoglobin → hemoglobinuria & hemosiderin → hemosiderinuria → dark urine
___ is the most accurate test for the condition seen in the image, but the downside is ____
G6PD assay is the most accurate test for the condition seen in the image, but the downside is may have to wait 2 months b/c reticulocytes produced at time of crisis do NOT reflect the enzyme deficiency – only mature RBcs do
list the most common outcome and complications of the condition seen in the image
self-limiting: complete resolution
- usually self-limiting with complete resolution after hemolytic event
- Hb (as is hemosiderin) is toxic to renal tubules → acute tubular necrosis → acute renal failure
describe the presentation of the condition seen in the image
- asymptomatic until exposed to injurious agent
- 2-3 days after oxidant stressor: acute hemolysis, fever, jaundice, fatigue, dark urine (due to free Hb)
- NO splenomegaly (differential from HS due to being intrinsic)
in the condition seen in the image, the most common predisposing factor for episodes is ____
in the condition seen in the image, the most common predisposing factor for episodes are infections
NADPH is needed for resp. burst
describe the type of anemia seen in the image
normocytic anemia with predominant extravascular hemolysis
describe the etiology of the condition seen in the image
- AR point mutation at position 6 of B-globin
- glutamic acid (polar) replaced by valine (neutral/non-polar) → removes biconcavity
- homozygotes (HbS, HbS) = sickle cell anemia
describe the cause of sickling and types of crises in the condition seen in the image
- crisis (increased sickling) caused by: hypoxia, acidosis, infection, dehydration, hypothermia, HbC (glutamic acid is replaced by lysine)
- types of crises: painful vaso-occlusive, hemolytic, splenic sequestration & aplastic crisis
describe the pathogenesis of the condition seen in the image
- pathogenesis: HbS polymerizes when deoxygenated → polymers aggregate into needle-like structures → sickle cells
describe the complications of the condition seen in the image
- prone to small vessel thrombosis → infarct
- sickled cells are “sticky” due to increased expression of adhesion molecules on their surface
- pooling of blood in the spleen aka sequestration crisis → rapid splenic enlargement and entrapment of sickled RBCs → hypovolemia → reticulocytosis present in peripheral blood → infarct → splenic fibrosis → autosplenectomy → HJ bodies
describe what is seen in blood serum levels in the condition seen in the image
- blood:
- ↑ reticulocytes
- ↑ LDH
- ↑ unconjugated bilirubin
- ↑ free Hb (dark urine)
- ↓ haptoglobin
the best screening test for the condition seen in the image is ____
the best screening test for the condition seen in the image is metabisulfite screen which causes cells with HbS to sickle
the test used for definitive diagnosis of the condition seen in the image is ____
the test used for definitive diagnosis of the condition seen in the image is hemoglobin electrophoresis (most accurate)
describe the treatment for the condition seen in the image
- bone marrow transplant
- hydroxyurea (stimulates HbF, increased NO, decreased platelet aggregation)
- vaccines after splenectomy
- folic acid
describe the presentation of the condition seen in the image in children
- children:
- crew-cut appearance & chipmunk face (due to hematopoiesis in skull)
- failure to thrive
- dactylitis (swollen hands and feet due to vaso-occlusive infarcts in bones → aseptic necrosis of metacarpal bones)
- spleen (crisis → splenomegaly → autosplenectomy due to fibrosis → recurrent encapsulated bacterial infxn = most common cause of death in children)
describe the presentation of the condition seen in the image in adults
sickle cell anemia
___ is the most common cause of death in adults with the condition seen in the image
acute chest syndrome: necrotizing pneumonia due to vaso-occlusion of pulm. arteries is the most common cause of death in adults
describe the type of anemia seen in the condition in the image
hypochromic microcytic anemia with extravascular hemolysis
describe 1 α-gene deletion
gene deletions on chr. 16
- 1 gene deleted = asymptomatic
describe the effect of 2 α genes deleted
- 2 genes deleted = miild anemia w/ increased RBC count
- cis deletion = increased risk of severe thalassemia in offspring
describe the effect of 3 α genes deleted
- 3 genes deleted = severe anemia
- B chains form tetramers (HbH) → high affinity for O2 → severe tissue hypoxia
- HbH is prone to oxidation → precipitated inclusions in older RBCs → extravascular hemolysis
- B chains form tetramers (HbH) → high affinity for O2 → severe tissue hypoxia
describe the effect of 4 α genes deleted
-
4 genes deleted = lethal in utero (hydrops fetalis)
- γ chains form tetramers (Hb Barts) → extremely high affinity for O2 → no O2 reaches the tissues
describe the etiology of the major form of the condition seen in the image
- point mutations of chr. 11
- absent B chain (B° caused by mutation in splicing/chain termination)
- diminished B chains (B+ caused by mutation in the promoter region)
describe genetic composition in B-thalassemia minor vs. B thalassemia major
- B-thalassemia minor = (B/B+) = mild asymptomatic anemia
- B-thalassemia major = (B°/B°), (B+/B+), (B+, B°) = severe transfusion-dependenent anemia; abnormal Hb causes occlusions in small blood vessels
describe the pathogenesis and presentation of the major form of the condition seen in the image
- no B chains (no HbA which is α2B2), which leads to an increase in HbF (α2γ2) and HbA2 (α2δ2)
- expansion of hematopoietic marrow in skull → chipmunk face, frontal bossing & crew-cut appearance due to erythroid hyperplasia in flat bones
- intramedullary hemolysis → ineffective erythropoeisis b/c α chains are not paired with B chains → α chains precipitate and form tetramers
- extravascular hemolysis: splenomegaly, fatigue, jaundice, brown discoloration of skin due to iron overload
describe the blood investigations found in the major form of the condition seen in the image
- blood:
- ↑ LDH
- ↑ reticulocytes
- ↑ RDW
- ↑ serum iron & ferritin
- ↓ TIBC
describe the diagnosis of the major form of the condition seen in the image
- diagnostic: Hb electrophoresis → no A band b/c no B chain, prominent F and normal/slightly elevated A2
describe what is seen on peripheral blood smear of the major form of the condition seen in the image
- PB:
- target cells, normoblasts, reticulocytes, anisocytosis, poikilocytosis due to extramedullary hepatopoeisis
the most common cause of death in the major form of the condition seen in the image is ____
the most common cause of death in the major form of the condition seen in the image is heart failure due to 2° hemochromatosis (due to increased blood transfusions)
describe the complications of the condition seen in the image
- aplastic crisis → due to Parvovirus B19
- folic acid deficiency due to chronic hemolytic anemia
- bacterial infections from iron-loving bacteria (Vibrio & Yersinia enterocolytica)
- bilirubin gallstones
- failure to thrive
describe the type of anemia seen in the image and why it is significant
microcytic hypochromic anemia
most common cause of anemia
list the 4 causes of iron deficiency
which is the most common in the Western world?
- dietary deficiency
- impaired absorption
- increased requirements
- chronic blood loss
- commonest cause of iron def. in the Western world
- where iron def. anemia is due to chronic GI blood loss until proven otherwise
- commonest cause of iron def. in the Western world