Heme Flashcards
Haptoglobin
Protein that mops up free Hb allowing its clearance in the spleen
In hemolytic anemia, haptoglobin decreases b/c it is all consumed
Thalassemia genetic inheritance
Autosomal recessive
Hemochromatosis clinical features
ABCDH Arthralgia Bronze skin Cardiomyopathy, liver cirrhosis Diabetes Hypogonadism (anterior pituitary damage)
Thalassemia
Defects in production of alpha (SEA and Africa) or beta (Mediterranean) chains of Hb resulting in ineffective erythropoiesis and hemolysis in spleen or BM
beta-Thalassemia peripheral blood smear
Microcytic
Teardrop
Target
Hypochromatic
Beta-thal treatment
Lifelong regular monthly transfusions to suppress endogenous erythropoiesis
Iron chelation (deferoxamine) to prevent iron overload in organs and formation of free radicals
Folic acid supplementation
Consider allogenieic bone marrow transplant or cord blood transplant as cure
Splenectomy
Alpha-thal
4 alpha globin genes
All 4 = Hb Barts, typically hydrops fetalis, incompatible with life
3/4 = HbH, presents in adulthood, decreased MCV, decreased Hb, splenomeg
1 or 2/4 = no tx required
Alpha-thal peripheral blood smear
Screen for HbH inclusion bodies with supravital stai
Sickle cell genetic inheritance
Autosomal recessive due to mutant beta globin gene (Glu –> Val substitution)
Sickle cell trait
Pt asymptomatic except during extreme hypoxia or infection
Increased risk of renal medullary carcinoma
Functional asplenism, increased susceptibility to encapsulated organisms
S. pneumoniae
N. meningitidis
H. influenza
Salmonella
Sickle cell treatment
Folic acid
Hydroxyurea to enhance production of HbF
Tx of vaso-occlusive crisis (O2, hydration, correct acidosis, analgesics)
Transfuse if Hb <50-60h/L
Sickle cell prevention
Vaccination (pneumococcus, meningococcus, H. influenza) Prophylactic penicillin (3mo-5yo)
Warm autoimmune hemolytic anemia
IgG
Idiopathic
Secondary to lymphoproliferative d/o (ie. CLL)
Secondary to AI disease (ie. SLE)
Drug-induced
Spherocytes on blood film
Tx: corticosteroids, immunosuppression, splenectomy, folic acid, rituximab (2nd line to steroids)
Cold autoimmune hemolytic anemia
IgM
Idiopathic
Secondary to infection (ie. EBV)
Secondary to lymphoproliferative d/o (ie. CLL)
Agglutination of blood film
Tx: warm patient, rituximab regimens (1st line), plasma exchange (2nd line for high IgM levels), folic acid
Most common type of hereditary hemolytic anemia
Hereditary spherocytosis
G6PD
Defiency in glucose-6-phosphate dehydrogenase –> RBC sensitivity due to oxidative stress
X-linked recessive
Episodic hemolysis precipitated by oxidative stress, drugs, infection, fava beans
May present in neonates with prolonged jaundice
G6PD blood smear
Heinz bodies
Bite cells as they pass through spleen
G6PD tx
Folic acid
Stop offending drugs and avoid triggers
Transfusion in severe cases
Thrombocytopenia
Plt < 150 000/uL
Plt < 50 000
increased risk of procedural and surgical bleeding (<100,000 for neurosurgeries)
Plt < 20 000
increased risk of severe bleeding with fever and/or coagulopathy
Plt < 10 000
Increased risk of spontaneous bleeding (ie. ICH)
Heparin-associated thrombocytopenia
Plt >100 x 10^6, direct heparin mediated plt aggregation (non-immune)
Self limited
Continue with heparin therapy
Heparin-induced thrombocytopenia (HIT)
immune-mediated reaction following tx with heparin (typically within 5-10d) leading to thrombocytopenia and subsequent coag activation
Stop heparin, can never have again
4T score for heparin
Thrombocytopenia
Timing of plt count fall
Thrombosis or other sequelae
Other causes for thrombocytopenia
Thrombotic thrombocytopenic purpura pathophysiology
ADAMTS-13 protease activity decreased –> vWF not cleaved –> large multimer on endothelial surface –> plt adhere and aggregate –> diffuse small vessel clotting = MAHA
Pentad of TTP
- Thrombocytopenia*
- MAHA*
- Renal failure
- Fever
- Mental status change
- = only ones required for dx
TTP treatment
PLEX (plasma exchange) +/- steroids
Improvement in neurological signs is initial indicator of response
Avoid platelet transfusion unless life-threatening bleed (“peeing into the ocean”)
MEDICAL EMERGENCY
HUS
Predominantly in children/elderly 90% secondary to Shiga toxin Similar to TTP (severe thrombocytopenia, MAHA, AKI, blood diarrhea) 3 criteria: - Hemolytic anemia - AKI - Thrombocytopenia
HUS tx
Supportive (fluids, RBC transfusion)
Some evidence for PLEX
Most common inherited bleeding disorder
von Willebrand disease
vWD inheritance
Autosomal dominent
vWF function
- Platelet aggregation
2. Chaperone for Factor VIII
vWD treatment
Desmopressin (DDAVP) - causes release of vWF and Factor VIII from endothelial cells
TXA (stabilize clot formation)
Hemophilia genetic inheritance
X-linked recessive
Hemophilia A
Factor VIII deficiency
Hemophilia A tx
Desmopressin in mild form
Factor VIII concentrate for : prophylaxis or on demand
TXA
Hemophilia B
Factor IX deficiency
Hemophilia B tx
Factor IX concentrate
TXA
Vitamin K dependent factors
1972
X, IX, VII, II, proteins C&S
Vit K deficiency
INR/PT is elevated out of proportion to elevation of the aPTT
Vit K deficiency tx
Vitamin K PO if no active bleeding
If bleeding –> Vit K 10mg IV
If life threatening bleeding, give prothrombin complex concentrate (PCC) or FP if C/I
Factor deficiency in liver disease
Deficient synthesis of all factors except VIII
Order levels of Factor V, VII, VIII
Etiologies of DIC
OMITS Obstetric complications Malignancy Infection Trauma Shock
Coagulopathies a/w increased INR only
Warfarin Vit K deficiency Factor VII deficiency Factor VII inhibitors Liver disease
Coagulopathies a/w increased PTT only
Hemophilia A and B Heparin Antiphospholipid Ab Intrinsic factor inhibitors Factor XI and XII deficiency
Extrinsic factor
Factor VII
Intrinsic factor
Factors XII, XI, IX, VI
Coagulopathies a/w increased INR and PTT
Prothrombin deficiency Severe fibrinogen deficiency Factor V and X deficiency Severe liver disease Severe vitamin K deficiency
Common pathway factors
Factor V
Factor X
Factor II (Prothrombin)
Factor I (Fibrinogen)
Tear drop cells on blood smear
Myelofibrosis
Thal major
Megaloblastic anemia
Poiilocytosis on blood smear
Fe def anemia
Myelofibrosis
Hypersegmented neutrophils on blood smear
Megaloblastic anemia
Coagulation studies in vWD
PT normal
PTT increased
Bleeding time increased
PT measures
Extrinsic and common pathways
Factor I (fibrinogen)
Factor II (prothrombin)
Factors V, VII, X
PTT measures
Intrinsic and common pathways
XII, XI, IX,VIII,X,V,II and I
Chronic lymphocytic leukemia (CLL)
Proliferation of mature Bcells in pts who are generally >65yo
B-cells grow out of control and accumulate in bone marrow and blood –> eventually crowd out healthy blood cells
CLL complications
Lymphadenopathy
Hepatosplenomegaly
Anemia
Infections
CLL tx
Early stages: not treated
Late stages: Chemo and monoclonal ab (ritxuimab: monoclonal AB against CD20 cells)
Hodgkin Lymphoma cells
Reed-sternberg
Most common inhibitor in clinical practice
Lupus anticoagulant
Most common factor-specific inhibitor
Factor VIII
ITP treatment
Steroids
IVIG
Splenectomy
Rituximab
3 common forms of MAHA
TTP
DIC
HUS
TTP lab values
Plts down Fibrinogen normal D-Dimer normal Schistocytes + PTT/PT normal
DIC lab values
Plts down
Fibrinogen down
D-dimer higher
PTT/PT increased
HIT dx
ELISA assay to detect AB
If +ve, serotonin assay
Serotonin = marker of plt activation
Auer rod
Pathognomonic for AML
blast of myeloid lineage
Acute lymphoid leukemia
More common in children
Most common malignancy in children
85% cure rates with intensive chemo
Harder to tx in adults
Acute myeloid leukemia
All malignant cells are blasts Myeloid malignancy arising in BM Results in pancytopenia More common in adults Auer rods
Clinical findings of multiple myeloma
CRABi hyperCalcemia Renal failure Anemia Bone pain and pathological fractures Infections
CML specific mutation
Philadelphia chromosome
CML vs MDS
CML has HIGH blood counts due to malignancy of mature myeloid cells (–> splenomeg)
MDS has LOW blood counts due to abnormal maturation of myeloid cells (–> apoptosis)
CLL
Older adults
Very slow progressive malignancy
Malignancy of mature lymphoid cells which often spreads to lymph nodes (BM and LN affected)
HIGH lymphocyte counts but cells look normal on smear
Need flow cytometry to prove cells are malignant
Multiple myeloma
Malignancy of plasma cells (B lymphocytes that secrete antibodies)
Malignant plasma cells STAY in BM and wipe out healthy BM, send out clonal antibody that causes renal failure
Can detect clonal antibody via SPEP (single band in MM vs smear in healthy adult)
Lab that marks the most advanced stage of Fe def and indicates imminent Fe deficiency anemia
High free erythrocyte protoporphyrin (heme synthesis requires presence of protoporphyrin and Fe; when there is not enough Fe, FEP levels rise and Hb levels fall)
Stages of Fe-def anemia
Low ferritin Low serum iron Rise in serum transferrin Increased TIBC Decreased TSat Free ertyhrocyte protorphyrin levels rise
Massive PE treatment
Signalled by hemodynamic instability (ie. hypotension)
- stabilize pt (ie. NE to bring up BP)
- TPA
Warfarin reversal
PCC/Octaplex (contains X, IX, VII, II)
Vitamin K
Free erythrocyte porphyrin
Use when dx of beta thal minor is unclear
Normal in pts with beta thal trait
Elevated in pts with Fe deficiency or lead poisoning
When to manage pt inpatient for DVT
Massive DVT
Symptomatic PE
High risk bleeding with anticoagulant therapy
Comorbid conditions or other factors that warrant in-hospital care
Preferred tx for outpatient DVT management
LMWH
Warfarin
Compression stockings
INR above which you should stop warfarin AND consider vitamin K
6
Gallstones in a child should prompt you to think about…
Hereditary spherocytosis
Spectrin and/or ankyrin deficiency –> reduced flexibility of cell –> more prone to damage
Test to confirm dx hereditary spherocytosis
Osmotic fragility test
+ smear: spherocytes without central pallor, howell jolly bodies
negative coombs test
++ family hx
Most common hereditary thrombophilia
Factor V Leiden
Caused by mutation to Factor V which causes activated resistance to protein C –> increased Factor V availability to increase generation of thrombin –> increased coagulability
Dx: Activated Protein C resistance assay and genetic testing of factor V gene /mRNA
Protein C function
Inactivates Factor V and VIII
Protein S function
Cofactor to Protein C
Length of tx for DVT
3mo for reversible cause
6mo for unknown cause
Indefinitely for recurrent DVT
AIHA
Normocytic anemia
Evidence of hemolysis (LDH, jaundice, high bili, low haptoglobin)
Splenomegaly
Reticulocytosis
Smear: Spherocytes, reticulocytes, elliptocytes
Acute hemolytic transfusion reaction
ABO incompatibility due to clerical error
Fever, chills, hemoglobinuria, FLANK PAIN, discomfort at infusion site –> –> renal failure and DIC
Dx: + Coombs test, hemoglobinuria, repeat type and cross match showing mismatch
Tx: Stop transfusion, supportive care
Calcium and albumin correction
Every albumin drop by 10, calcium increases by 0.2
vWd diagnosis
Ristocetin cofactor activity
ristocetin induces coagulation when vWF present, so if added to blood without vWF –> no coagulation