Heme/Onc Flashcards
Most common cause of anemia worldwide?
Iron defieciency
Crew cut appearance on skull xray
B-thalassemia major
Type of hemoglobin seen most commonly in B-thalassemia
HbF and HbA2
HbH disease is caused by mutation in
Three of the four alpha-globin loci
List the causes of RBC hemolysis that are due to external factors
Most acquired
- Mechanical (prostetic valve, microangiopathic hemolysis)
- Medications, burns, toxins etc
List the causes of RBC hemolysis that are due to intrinsic factors
Most often inherited
- sickle cell, hemoglobin c disease, thalassemia
- herditary spherocytosis, PNH
- G6PD deficiency, pyruvate kinase deficiency
Hemoglobinuria (dark urine) is predominently caused by hemolysis in this compartment
intravascular
Inheritance pattern of sickle cell
autosomal recessive
Mutation present in sickle cell
Valine for glutamate that the 6th position in B chain
Often the first manifestation of sickle cell
hand-foot syndrome
Presents in infancy– swelling of the dorsum of the hands and feet caused by avascular necrosis of the metacarpal and metatarsal bones
Painless hematuria in a sickle cell patient
Renal papillary necrosis
Hoe does hydroxyurea improve painfule sickle crises
Improves production of HbF which does not sickle
RBC protein deficient in hereditary spherocytosis
Spectrin and ankryn
Why does RBC assume spherical shape in hereditary spherocytosis? How does this relate the immune anemia?
Decreased surface area with maintained volume leads to a smaller cell that tries to maintain volume and “stretches” into a spherical shape– osmotically fragile
IHA- the RBC is eaten away by the speen resulting in reduced RBC membrane and the same concept above applies. Differnce is a positive direct coombs test
Inheritance pattern of G6PD deficiency
x-linked recessive (like duschene and hunters)
Peripheral blood smear findings in G6PD defieciency
Bite cells
Heinz bodies (different than howell-jolly)
Two forms of autoimmune hemolytic anemia (AIHA) and Ab types
Warm (IgG)– cancer, SLE, alpha-methyldopa
Cold (IgM)– Mycoplasma, elderly
Glocoprotein deficiency in PNH
CD55/DAF complex– binds the C3 convertase, C9/MAC complex
Phosphotidylinositol glycan A
Sugar water and Hams test
RBC subjected to sucrose– hemolyisis if PNH present
RBC subjected to acidified serum– Hemolysis if PNH present
Initial therapy for PNH
glucocorticoids
Most common cause of immune (idiopathic) thrombpcytopenic purpura (ITP)
Children– acute post viral syndrome
Adults– chronic idiopathic
Is there splenomegaly in ITP?
NO
Treatment for ITP
Corticosteroid and IVIG to saurate the immunoglobulins
Ab associated with TTP
ADAMSTS13
Ab present in HIT type 2
PF-4 (platelet factor 4) antibody
vWF is intimately related to this coag factor
Factor VIII
Treatment for vWdisease
DDAVP and Factor VIII concentrates which contain vWF
inheritance of hemophilia A
x-linked recessive
Mainstay of therapy for hemophila A
Factor VIII concentrate
Mixing study will have this effect on PTT in hemophilia A
Corrects the PTT
A normal level of this coagulation protein rules out DIC
Fibrinogen
-will be low in DIC
Inheritance and pathophys of ATIII deficiency
utosomal dominant
ATIII normall inhibits thrombin (potent activator of coag cascade) so lack of it leads to overactive thrombin and coagulation
Ab in antiphospholipid syndrome
against lupus anticogaulant (tested with russell viper venom) and anticardiolipin or B2 microglobulin
Protein C normally inhibits these factors
V and VIII
Protein C deficiency leads to thrombosis
Protein S is a cofactor of
Protein C
Pathophys of factor v leiden
Mutation in Factor V inhibits binding of protein C which normally inactivates it–> leads to overavtive Factor V and thrombosis
Patient presents with decreased vibratory sense and ataxia but the B12 level is borderline normal. What is the next best test?
methylmalonic acid level
becuase transcobalamin is an acute phase reactant it can be falsely elevated and appear normal
Pancreatic enzyme deficiency leads to b12 deficiency for this reason
pancreatic enxymes are needed to cleave B12 from the R-protein before it can be bound by intrinsic factor
Most accurate test for parvovirus in a sickle cell patient
Parvovirus B-19 PCR
Best initial test for G6PD deficiency
Peripheral smear
Most accurate test for G6PD deficiency
G6PD level 1-2mo. after an acute attack
mneumonic for TTP
FAT-RN
Fever
Anemia
Thrombocytopenia
Renal failure
Neurologic deficits (distinguishes from HUS)
What is the best test for PNH
CD55/59 testing via flow cytometry
Ham and sucrose tyest are obsolete
This immune modulator is used to treat PNH. How does it work
Eculizumab
inactivates C5 in complement and prevents RBC destruction
eculizumab=complement inhibitor
What is the preferred treatment for aplastic anemia for a patient too old for bone marrow transplant
antithymocyte globulin and cyclosporin
