Hematology ✔ Flashcards
what factors in the clotting cascade are procoagulant?
V VIII XI IX X II Fibrinogen Platelets
what factors in the clotting cascade do proteins C &S act on?
FVIIIIa
FVa
what factors in the clotting cascade does antithrombin act on?
Thrombin
FXa
what are the anticoagulant components of the clotting cascade?
TFPI Protein C Protein S Thrombomodulin EPCR Antithrombin
what is the natural state of the vessel wall?
anti-coagulant
what factors in the vessel wall make it anti-coagulant?
1) Expresses anticoagulant molecules Thrombomodulin, Protein C receptor; Tissue factor pathway inhibitor; Heparans 2) Does not express tissue factor 3) Secretes antiplatelet factors (Prostacyclin, NO)
what changes on the vessel wall make it pro-thrombotic?
infection, malignancy, vasculitis, trauma…
how does stasis in the vessels promote thrombosis?
- Accumulation of activated factors
- Promotes platelet adhesion
- Promotes leukocyte adhesion and transmigration
- Hypoxia produces inflammatory effect on endothelium
what are causes of stasis in the blood vessel?
immobility compression tumors viscosity (eg polycythemia) congenital
what anticoagulant drugs work immediately?
heparin - unfractionated (IV) or LMWH (SC)
Act directly anti-Xa and anti-IIa
which anticoagulant drug works delayed?
vitamin K antagonist (Warfarin)
what is dabigatran method of action?
anti-IIa anticoagulation
what is rivaroxaban or apixaban method of action?
anti-Xa
what is the INR derived from?
prothrombin time
how do you reverse heparin?
protamine
how do you reverse warfarin?
factor concentrate vitamin K
what are risk factors for VTE?
- infection
- inflammation
- immobility
- age
- flow obstruction
- trauma
- previous vte
- family history
- genetic traits
- obese
- chronic disease
- elderly
what is the empirical therapeutic treatment of DVT/PE?
- LMWH + Warfarin OR rivaroxaban
- stop LMWH when INR > 2 for 2 days
- continue for 3-6 months
what are the causes & findings in iron deficiency anemia?
Causes: blood loss, GI cancers, Urinary tract cancers, Renal cell carcinoma, Bladder cancer
Laboratory findings: Reduced ferritin, reduced transferrin saturation, raised TIBC
Fe deficiency is bleeding until proven otherwise!
what are two cancer/systemic disease associated anemias?
-leucoerythroblastic anemia
-acquired hemolytic anemia
(immune mediated or non immune - MAHA)
what is seen on blood film of leuco-erythroblastic anemia?
RCC & WCC precursor anemia
- teardrop RBCs
- nucleated RBCs
- immature myeloid cells
what are some causes of leucoerythroblastic film?
the core cause is bone marrow infiltration:
- cancer: hematopoietic or breast, bronchus, prostate
- severe infection (miliary TB, severe fungal infections)
- myelofibrosis (w/splenomegaly)
what are the common distinguishing features of any hemolysis?
- anemia
- reticulocytosis
- raised bilirubin (unconjugated)
- raised LDH
- reduced haptoglobins
what are the 5 main types of inherited hemolytic anemias?
1) membrane abnormalities
- Spherocytosis
- Elliptocytosis
2) Hemoglobin abnormalities
- structural (sickle cell disease)
- quantitative (thallasemias)
3) enzymes
- G6PD
what are the 4 types of acquired hemolytic anemias?
- auto-immune (see spherocytes and DAT+)
- cancer of immune system (lymphomas)
- disease of immune system (SLE)
- infection
when do you get a positive DAT test?
- idiopathic causes
- underlying lymphoma/chronic leukemia/SLE
what are causes of non-immune and DAT negative acquired hemolytic anemias?
- infection (eg malaria)
- MAHA (red cell fragments, low platelets, DIC, usually an underlying adenocarcinoma)
what symptoms do we see in MAHA?
-red cell fragments
-low platelets
-DIC
-bleeding
There is often an underlying adenocarcinoma.
what are the type of polycythemia?
Polycythemia can either be ‘true’ i.e. polycythemia vera or can be secondary ie. raised EPO and inappropriate to what you expect to see.
Causes of secondary - hepatocellular cancer, bronchial cancer, renal cancer
what carcinomas are associated with secondary polycythemia?
HCC
bronchial
renal
what is polycythemia vera?
acquired mutatoins in JAK2 leading to clonal myeloproliferative disorder
what 3 types of cells are immature WBC?
myelo-/lympho-blasts
promyelocytes
myelocytes
what are causes of neutrophilia (raised WCC)?
- steroids
- underlying neoplasia
- tissue inflammation
- myeloproliferative/leukemic disorders
- infection
what blood signs indicate a malignant cause of neutrophilia?
-neutrophilia basophilia plus immature cells (myelocytes)
-splenomegaly
Suggests CML.
-neutropenia + myeloblasts. Suggests AML.
what causes reactive eosinophilia?
- Parasitic infestation
- allergic diseases (e.g. asthma, rheumatoid, polyarteritis, pulmonary eosinophili)
- Underlying Neoplasms (esp. Hodgkin’s, T-cell NHL)
- Drugs (rxn eg erythema mutiforme)
when do we see monocytosis?
- TB, brucella, typhoid
- Viral; CMV, VZV, sarcoidosis
- chronic myelomonocytic leukaemia (MDS)
when do we expect to see neutrophil counts elevated?
- bacterial infection
- autoimmune tissue necrosis
- all types of neoplasia
- CML
when do we expect to see eosinophil counts increased?
- parasitic infections
- allergic reactions
- Hodgkin’s
- Non-hodgkin’s lymphoma
when do we see basophil counts increased?
- pox viruses
- CML
what is a reactive lymphocytosis?
when only lymphocytes are raised (not other aspects of WCC)
what infections can cause a reactive lymphocytosis?
- EBV
- CMV
- Toxoplasmosis
- infectious hepatitis
- rubella
- herpes
what diagnosis might we expect if we see small lymphocytes or smear cells?
- CLL
- Non Hodgkin’s lymphoma
what characterizes myelodysplastic syndromes?
the development of a clone of marrow stem cells with abnormal maturation resulting in functionally defective blood cells and a numerical reduction in blood cells
what are some blood/bone marrow morphological features in myelodysplastic syndromes?
- Pelger-Huet anomaly (bilobed neutrophils)
- Dysganulopoieses & mature hypersegmented look of neutrophils
- Dyserythropoiesis of red cells
- Dysplastic megakaryocytes
- Increased proportion of blast cells in marrow (normal < 5%)
- ringed sideroblasts (hemosiderin deposits) that stain with prussian blue
- Auer rods
what is the pathophysiology of myelodysplasia?
deterioration of blood counts –> consequences of marrow failure –> development of AML (in 50% within 1 year) –> die from AML, infection, or bleeding
are there any treatments for myelodysplastic syndromes?
1) allogenic SCT
2) intensive chemo
But neither of these are very effective at all
how do we treat myelodysplastic syndromes?
1) supportive - blood products; antimicrobials; growth factors
2) biological modifiers - immunosuppressants, azacytidine, lenalidomide
3) chemo therapy
4) SCT
what happens in bone marrow failure?
damage or suppression of stem/progenitor cells results in pluripotent hematopietic cells which impairs the production of all peripheral blood cells
how do we classify bone marrow failure?
primary or secondary
what are causes of primary bone marrow failure?
- congenital: Fanconi’s anemia
- diamond-blackfan anemia
- kostmann’s syndrome
- idiopathic aplastic anemia (acquired)
what cells are involved in Fanconi’s anemia?
multipotent stem cell failures
what cells are involved in Diamond-Blackfan anemia?
rbc progenitors
what cells are involved in Kostmann’s syndrome?
neutrophil progenitors
what cells are involved in aplastic anemia?
multipotent stemm cells (same as Fanconi’s)
what are some causes of secondary bone marrow failure?
- marrow infiltration
- hematological (leukemia, lymphoma, myelofibrosis)
- tumors
- radiation
- drugs/chemicals
- autoimmune
- infections
what drugs can cause a bone marrow failure (eg aplastic anemia)?
- cytotoxic drugs
- gold salts
- chloramphenicol
- sulphonamide antibiotics
- thiazides
- carbimazole
what are the two age groups in which aplastic anemia peaks?
15-24 year olds
>60 year olds
how do we classify aplastic anemia?
1) idiopathic (70-80% of cases)
2) inherited
3) secondary
what are the potential causes of inherited aplastic anemia?
1) dyskeratosis congenita
2) fanconi anemia
3) shwachman - diamond syndrome
what are the potential causes of secondary aplastic anemia?
- radiation
- drugs
- viruses (eg hepatitis)
- SLE
Aplastic anemia presents with the ‘triad’ of bone marrow failure symptoms. What are those?
1) anemia (fatigue, breathless)
2) leucopenia (infections)
3) platelets (easy bruising/bleeding)
how do we diagnose aplastic anemia?
1) cytopenia in the blood
2) hypocellular bone marrow
what are some differential diagnoses for aplastic anemia?
Hypoplastic MDS / Acute Myeloid -Leukaemia
- Hypocellular ALL
- Hairy Cell Leukaemia
- Mycobacterial infection
- Anorexia Nervosa
- Idiopathic Thrombocytopenic Purpura
how do we determine if someone has ‘severe’ aplastic anemia?
Camitta criteria
what are the Camitta criteria?
for diagnosis of severe aplastic anemia -
2 out of 3 of the following features….. reticulocytes low, neutrophils low, platelets low, bone marrow <20% cellularity
how do we manage bone marrow failure?
- Seek a cause
- Supportive (bloods, Antibiotics, Iron Chelation Therapy)
- Drugs to promote marrow recovery (Oxymetholone, Growth factors)
- Immunosuppressive therapy
- Stem cell transplantation
what are some complications of aplastic anemia?
- relapse
- clonal haem disorders (myelodysplasia, leukemia)
- solid tumors
what is Fanconi’s anemia?
- most common form of inherited aplastic anemia
- AR/X-linked
- multiple mutated genes responsible for abnormalities in DNA repair and chromosomal fragility
- the patient has a normal blood count at birth but marrow failure and pancytopenia develop slowly from age 5-10 years old.
how do we treat fanconi’s anemia?
- supportive
- androgens can transiently improve counts but have hepatic toxicity
what congenital malformations may occur in patients born with fanconi’s anemia?
- Short Stature
- Hypopigmented spots and café-au-lait spots
- Abnormality of thumbs
- Microcephaly or hydrocephaly
- Hyogonadism
- Developmental delay
what is dyskeratosis congenita?
An inherited disorder (via 3 patterns, involving abnormal telomeres) characterized by bone marrow failure, cancer predisposition, and somatic abnormalities.
what classic triad do patients with dyskeratosis congenita present with?
- skin pigmentation
- nail dystrophy
- leukoplakia
what type of anitbodies are Rh immune antibodies?
IgG (won’t cause immediate reaction)
what technique is used in Group & Save blood tests?
indirect antiglobulin technique
how are RBC kept?
- stored at 4C for 35 days. Must be transfused within 4 hours of leaving the fridge.
- transfuse 1 unit RBC over 2-3 hours
how are platelts kept?
- need to be RhD compatible
- stored at room temperature for 1 week
- transfuse 1 unit of platelets over 20-30 min
what are the indications to transfuse RBC?
- major blood loss
- perioperatively
- post chemotherapy
(Hb < 70-80)
when do we use irradiated blood for transfusions?
required for highly immunosupressed patients, who cannot destroy incoming donor lymphocytes: which can cause (fatal) transfusion associated graft versus host disease (TA-GvHD)
when do we give patients platelets?
CONTRAindicated in heparin-induced thrombocytopenia, TTP.
- massive transfusion
- prevent bleeding in surgery or post chemo
- active bleeding with platelet dysfunction
when do we give FFP?
- massive transfusion
- DIC
- liver disease
what clotting factors does FFP contain?
all of them
what is the treatment of choice for warfarin reversal?
FFP is not the treatment of choice to reverse warfarin: PCC (prothrombin complex concentrate)
how do we classify adverse reactions to transfusions?
- acute (<24 hours)
- delayed (>24 hours)
what are the potential causes of acute blood transfusion reactions? (6)
- ABC incompatible
- allergy/anaphylaxis
- infection (bacterial)
- TACO (transfusion associated circulatory overload)
- TRALI (acute lung injury)
- febrile non-hemolytic rxn
what are the potential causes of delayed blood transfusion reactions?
- delayed hemolytic transfusion antibodies
- infection (viral, vCJD)
- TA-GvHD (graft vs host)
- post transfusion purpura
- iron overload
what is the causes of Febrile Non-Haemolytic Transfusion Reaction (FNHTR)?
white cells releasing cytokines during storage - cause chills, fever, rigors in patient when transfusion happens. Just stop/slow transfusion and treat with paracetamol
what is the cause of an allergic transfusion reaction?
allergy to a plasma protein in the donor which is common in recipients esp. if they have other allergies. It can cause a wheeze or itchy rash - stop/slow transfusion and give IV antihistamines
what are the symptoms or signs of an acute intravascular hemolysis from ABO incompatibility?
- IgM mediated
- restlessness
- chest/loin pain
- fever
- vomiting
- flushing
- collapse
- dec. BP/ inc. HR, inc. temperature
- hemoglobinuria
how does bacterial contamination of transfusion blood present?
- restless, fever, vomiting, flushing, collapse
- dec. BP/inc. HR/ inc temperature
The bacterial growth can cause endotoxin productoin which causes immediate collapse.
what is TACO (with relation to transfusions) and how does it present?
- Transfusion associated circulatory overload
- pulmonary edema/fluid overload
- SOB, dec. O2, inc. HR, inc BP
- CXR shows fluid overload and/or HF
what is TRALI (in relation to transfusions) and how does it present?
-transfusion related acute lung injury (ARDS) from anti-WBC antibodies in the donor interacting with antigen on patient’s WBCs
These aggregates get stuck in the pulmonary capillaries and release neutrophil proteolytic enzymes/toxic O2 metabolites causing lung damage.
- SOB, dec. O2 sats, inc. HR/BP (similar to TACO)
- CXR will show bilateral pulmonary infiltrates within 6 hours of transfusion
what is the pathophysiology of transfusion associated GvHD?
graft vs host disease happens when the donor’s blood contains some lymphocytes that are not destroyed and recognize the patient’s tissue HLA antigens as foreign. They then attack the patient’s gut, liver, skin and bone marrow. This causes severe diarrhea, liver failure, skin desquamation, bone marrow failure, and death some weeks after transfusion. It is very rare but ALWAYS fatal, so in those known to be immunosuppressed we always irradiate blood components
what happens in post-transfusion purpura?
Purpura appear 7-10 days after the transfusion of blood/platelets and usually this resolves in 1-4 weeks but it can cause some life threatening bleeding. The purpura appear due to very low platelet count - i.e. platelet destruction has occurred. The treatment is infusing IV Ig.
what can happen in thalassemic patients related to their monthly transfusions?
iron overload (can cause organ damage) Tx - desferrioxamine (iron chelation)
what happens in hemolytic disease of fetus/newborn?
- IgG antibodies from mom can cross placenta and destroy fetal RBCs
- cause fetal hemolytic anemia, potentially hemolytic disease of newborn (leading to hydrops fetalis or kernicterus)
what is the mechanism of action of prophylactic anti-D Ig injections?
RhD positive (fetal) red cells get coated with anti-D Ig and then they get removed by the mother’s reticuloendothelial system (spleen) before they can sensitise the mother to produce anti-D antibodies. To be effective, this must be given within 72 hours of the ‘sensitizing event’
what are potential ‘sensitizing events’ for pregnant mom?
- delivery of child that is RhD +
- spotaneous miscarriages if ERPC needed
- amniocentesis
- CVS
- abdominal trauma
- ECV
- stillbirth/IUD
what changes to FBC occur in pregnancy?
-mild anemia (rise of plasma volume by more than red cell mass) -macrocytosis -neutrophilia -thrombocytopenia (inc. platelet size)
what can iron deficiency in pregnancy cause?
- IUGR
- prematurity
- PPH
how much iron & folic acid is recommended in pregnancy?
-60mg Fe
-400 mcg Folic acid
in healthy mom
what can cause thrombocytopenia (low platelet counts) in pregnancy?
- physiological*
- pre-eclampsia*
- ITP (immune thrombocytopenia)*
- microangiopathic syndromes
- bone marrow failure
- leukemia
- hypersplenism
- DIC
what is the pathophysiology of MAHA?
MAHA = microangiopathic hemolytic anemia. It is due to a deposition of platelets in small blood vessels leading to a thrombocytopenia and fragmentation/destruction of RBC within the vasculature. Ultimately, this leads to organ damage.
what do you see on the blood film of a pregnant woman with MAHA?
- RBC fragments
- low platelets
- polychromasia
what tests are safe to perform in pregnancy for VTE exclusion?
-doppler safe
-V/Q safe
If indicated and necessary, CXR OK.
-d-dimer is NOT useful for the exclusion of thrombosis because it is often elevated in pregnancy
what factors increase the hypercoagulable state of the woman inducing an increased risk of thrombosis in pregnancy?
- reduced venous return
- changes in vessel wall
- hyperemesis (dehydration)
- obesity
- pre-eclampsia
- operative deliveries
- inc. maternal age
- previous VTEs
- parity
- multiple pregnancy
- any pre-existing sickle cell diseae or nephrotic syndrome
- IVF (risk of ovarian hyperstimulation)
what is treatment of VTE in pregnancy?
- TED stockings
- early mobilisation
- maintain hydration
- LMWH as for non-pregnant (because it does not cross placenta)
- Do NOT convert to warfarin (crosses placenta)*
- Stop for labour or planned delivery, esp. for epidural
what are the leading causes of mortality in pregnancy?
- VTE
- pre-eclampsia/eclampsia
- ectopic pregnancies
- hemorrhage
- amniotic fluid embolism
- genital tract sepsis
what is an amniotic fluid embolism and how does it present?
Sudden onset shivers, vomiting, shock –> DIC –> death
Usually in third trimester and presumed to be due to tissue factor in amniotic fluid
if mom is a carrier of hemoglobinopathy what are her further options?
- test partner first.
- Proceed
- Prenatal diagnosis@ CVS sampling (10-12 weeks) or Amniocentesis (15-17 weeks)
- cffDNA (fetal blood sampling)
- Ultrasound screening for hydrops
what happens to a sickle cell mom in pregnancy?
- HbSS (HbS clinically abnormal)
- vaso-occlusive crises will become more frequent and anemia/chronic disease exaggerated
- potential fetal complications: IUGR, miscarriage, pre term labor, VTE
how do we treat sickle cell moms in pregnancy?
- RBC transfusions (top up/exchange/prophylactic)
- alloimmunisation
- extended phenotype for Group & Saves (RhD, RhC, RhE, Kell….)
what is a lymphoma?
a neoplastic malignant tumor of lymphoid cells usually found in LNs, lymphoid organs, skin, or ‘anywhere’ systemic