Haematology Flashcards
What does a high reticulocyte count mean?
This is the concentration of immature RBCs.
High - increased brood loss and haemolytic anaemia as bone marrow is working harder to replace lost cells
What causes a microcytic anaemia?
Iron deficiency
Thalassemia
Sideroblastic anaemia (production of ringed abnormal RBCs)
What causes a normocytic anaemia?
Acute blood loss
Anaemia of chronic disease
Haemolytic anaemia
Multiple myeloma
What causes a macrocytic anaemia ?
B12/folate deficiency
Alcohol
Reticulocytosis
Liver disease
Pregnancy
What are the signs of iron deficiency ?
Koilonychia
Angular stomatitis
Glossitis
Blood tests show elliptocytes and abnormal nuclei
What is thalassaemia?
Beta thalassemia trait (minor):
- Mild hypochromic, microcytic anaemia (microcytosis dispropriate to anaemia)
- Raised hbA2
- Usually asymptomatic
Beta thalassemia major:
- Severe symptoms
- Usually require regular blood trasnsfusions with chelation therapy alongisde to remove excess iron (DFO, DFP, DFX)
What causes B12 anaemia?
Perniocuious anaemia
Malabsorption
Dietary (veggie/vegan)
B12 is absorbed in the terminal ileum via intrinsic factor
What causes folate anaemia?
Dietary (not enough green veg)
Malabsorption
Drugs (trimethoprim, phenytoin, methotrexate)
What causes haemolytic anaemia?
Any anaemia due to premature destruction of RBC (this can be intravascular or extravascular)
EXTRAVASCULAR:
Heritable:
- Haemoglobinopathies: sickle cell, thalassemia
- Membrane defects: hereditary spherocytosis/elliptocytosis
- Enzyme defects: G6PD deficiency, pyruvate kinase deficiency
Acquired:
- Autoimmune (DAT+) - drug induced
- Hypersplenism
- Infection (malaria)
INTRVASCULAR:
(brown urine!!):
Mechanical valves
Infusion of hypotonic solution
Acute transfusion reaction
What is Coombs test?
DAT direct antiglobulin test which looks for autoimmune haemolytic anaemia
What causes erythropoiesis?
The kidney produces erythropoietin due to:
- RBC haemolysis
- Lack of oxygen
- Androgens
- Thyroid hormone
This then leads to reticulocyte formation and after 3 days these will leave the bone marrow and become RBC
For this reason, chronic hypoxia or increased ego will cause secondary polycythemia
What blood test results do you get in haemolytic anaemia and why?
High reticulocyte count
High LDH
High globin (due to haemoglobin being broken down )
High haem > more iron and more unconjugated bilirubin
Howell-Jollybodies
What is G6P deficiency?
G6P is an enzyme which contributes to reducing free radical formation during energy production, this keeps the cell healthy
Deficiency causes build up of free radicals causing damage to the RBCs - this means they will be cleared by the reticuloendothelial system
What causes a high/low neutrophil count?
High:
Bacterial infection
Steroids
Inflammation
Malignancy
Low:
Chemotherapy
Agranulocytosis by the 4Cs - carbamazepine, clozapine, colchicine, carbimazole
What causes a high/low lymphocyte count?
High:
Viral infection
CLL
Chronic infection
Low:
Viral infection
HIV
Chemotherapy
Bone marrow failure
What causes a high/low monocyte count?
High:
Bacterial infection
Autoimmune disease
Leukemia
Low:
Acute infection
Steroids
Leukemia
What causes a high/low eosinophil count?
High:
Allergy
Parasites
Drug reactions
Low:
Nil
What causes a high/low basophil count?
High:
Leukemia
Hypersensitivity
Myeloproliferative disorder
What causes thrombocytopenia?
Decreased production of platelets - bone marrow failure, megaloblastic anaemia
Increased destruction - DIC, TTP, ITP, SLE, CLL, viruses, drugs
What causes thrombocythemia ?
Primary - myeloproliferative disorders
Secondary - bleeding, inflammation, infection, malignancy
What is a myeloproliferative disorder?
A group of neoplastic disorders involving the bone marrow cells that produce RBCs, platelets or fibroblasts (everything except WBCs)
- Polycythaemia vera
- Essential thrombocythaemia
- Chronic myeloid leukemia
- Primary myelofibrosis
What do myeloid cells and lymphoid cells produce?
Myeloid - All blood cells except for lymphocytes
Lymphoid - lymphocytes
What are granulocytes and how is production stimulated?
Granulocytes encompasses neutrophils, basophils and eosinophils
Production stimulate by GM-CSF
What are the features of a myeloproliferative disorder ?
- Diseases of the elderly
- All cell lines affected but one cell line affected more than most
- Hypercellular bone marrow
- Splenomegaly (if bone marrow not able to produce sufficiently)
- Rapid cell turnover causing HIGH URIC ACID and GOUT
- Can transform into acute myeloid leukaemia
Which genetic mutations tend to cause myeloproliferative disorders?
CML - BCR-ABL translocation (9;22) on philadelphia chromosome
Polycythaemia vera, primary myelofibrosis, essential thrombocythemia - V617F mutation causing activation of JAK2
What does JAK2 kinase do?
Stimulates erythropoietin and thrombopoeitin RECEPTORS but not the GM-CSF
(epo and tepo will actually decrease in these conditions due to negative feedback mechanism)
This causes huge increase in RBC and platelets but not WBCs
How does PV usually present?
Raised Hb
Plethoric appearance
Pruritis (itchy!!) after a hot shower
Splenomegaly
Hypertension
Hyperviscosity in the form of thrombus
Low ESR
Blood is THICK! Think what this would cause
How is PV investigated?
FBC/film - all cell lines high
JAK2 (present in 95%)
Serum ferritin
Renal, LFTs
If JAK negative:
- Red cell mass
- Arterial oxygen sats
- Abdo USS
- Serum EPO (low)
- Bone marrow aspirate and trephine
- Cytogenetic analysis
- BFU-E culture
What are the criteria for JAK2 postive PV?
Must have:
1. High hct or raised red cell mass
2. Mutation in JAK2
What are the criteria for JAK2 negative PV?
Must have:
1. High hct or raised red cell mass
2. Absence of JAK2 mutation
3. No cause of secondary erythrocytosis
Plus either one of:
- Palpable spleen
- Presence of acquired genetic abnormality
Or 2 of:
- High platelts
- High neutrophils
- Radiological evidence of splenomegaly
- Low serum epo
How is polycythemia vera treated?
Frequent blood withdrawals
Daily low dose aspirin
Hydroxycarbamide (slight increased risk of secondary leukaemia)
Cytoreductive surgery
How does essential thrombocythemia usually present?
Can be asymptomatic
Headache
Dizziness
Bruising
Thrombosis
How is ET investigated?
FBC/film - high platelets
JAK2/CALR/MPL mutation
How is ET treated?
- Aspirin to reduce clot risk
- Cytoreductive surgery
- Hydroxycarbamide
How does CML usually present?
Neoplastic disease of mature myeloid cells (basophils, eosinophils, neutrophils)
Incidental finding
Fever and night sweats
Splenomegaly
Weight loss
Bleeding and petechia
Gout (uric acid production from cell breakdown)
Hyperviscosity syndrome
What are the 3 clinical phases of CML?
- Chronic
- Accelerated
- Blast crisis (symptoms of AML)
How is CML investigated?
FBC/film - increased myeloid cells
Cytogenetics - translocation (9:22) involving the ABL:BCR genes on the philadelphia chromosome
How is CML treated?
- Tyrosine kinase inhibitors (imatinib); taken as a tablet daily
- PCR monitoring of BCR:ABL
- Hydroxyurea and interferon alpha 2nd line
- Stem cell transplant
What are the side effects of imatinib?
Pleural effusion, rash, cramps, vomiting, oedema
What is primary myelofibrosis and how does it present?
Build up of scar tissue in the bone marrow impairing its ability to make normal cells. As a result, cell production moves to the SPLEEN
It can arise as a progression of PV/ET
Fatigue, weakness
Fullness in left upper abdomen (splenomegaly)
How is MF investigated?
FBC/film - pancytopenia or pancythemia, tear drop pokilocytes/dacrocytes and nucleated RBCs
Bone marrow biopsy - collagen fibrosis, JAK2/MLP/CALR mutations
How is myelofibrosis managed?
Generally incurable except for allogenic stem cell transplant
Symptomatic treatment includes transfusion, allopurinol, splenectomy, folic acid, JAK2 inhibitors (-nibs)
A blood test shows normal Hb with microcytosis - what causes this?
Polycythaemia vera
(May cause iron deficiency secondary to bleeding)
What are the lymphoproliferative disorders?
B lymphocytes overproduction > plasma cell dyscrasia > multiple myeloma/waldenstroms
T lymphocytes overproduction > ALL/CLL/hairy cell
What is multiple myeloma and how does it present?
Neoplastic disease of PLASMA cells
CRAB presentation:
Calcium increased
Renal impairment
Anaemia
Bony lesions
BACK PAIN!!!! due to paraprotein clogging
African ethincity common
What is the pathophysiology of multiple myeloma?
Plasma cells proliferate and produce paraprotein which is a faulty monoclonal antibody
How is MM diagnosed?
Serum paraprotein (immunoglobulin electrophoresis)
Serum free light chain blood test
Blood film rouleax - increased plasma viscosity due to immunoglobulin overproduction
How is MM treated?
- Chemotherapy
- Bisphosphonates
- Stem cell transplant
- Stop nephrotoxic drugs
What is Waldenstroms macroglobulinaemia?
A rare type of blood cancer which affects B-lymphocytes (which produce IgM).
B-lymphocytes abnormally divide and accumulate, causing damage to blood vessels
What are the symptoms of Waldenstrom’s macroglobulinaemia ?
Epistaxis and other bleeding
Impaired/blurred vision (These are due to the effect of blood flow changes on small blood vessels)
Anaemia
Parasthesia
Enlarged LN, spleen and liver (due to abnormal cell accumulation)
How is Waldenstrom’s macroglobulinaemia investigated?
FBC/film - anaemia, low platelets
Electrophoresis - M-spike due to IgM levels
Cytogenetics - MYD88 and CXCR4 gene mutation
How is Waldenstroms treated?
If asymptomatic - watchful waiting
If symptomatic - plasmapheresis, RBC/platelet transfusion, chemotherapy (eg. rituximab)
What is acute leukemias?
Neoplastic disorder of immature myeloblasts or lymphoblasts (early haematopeitic stem cells) in the bone marrow
- Immature cells proliferate and replace most of the bone marrow cells, crowding out normal haematopoeisis
- Increased blasts in the peripheral blood then cause leukostasis
- These blasts metastasize throughout the body
What investigations should be done in a patient with suspected acute leukemia and what would they show?
Bloods - anaemia (normocytic or microcytic), pancytopenia, high number of blasts *can also get WBC >100,000
Tissue biopsy - huge nuclei
Bone marrow biopsy - blast cells (>20%)
Cytochemical analysis - PAS, peroxidase, esterase, sudan black
Cytogenetics -
Remember - early cells (blasts) are larger and immature, they lose their ability to differentiate but are able to replicate = CANCER !
What are the risk factors for the acute leukemias?
- Genetic predisposition eg. Downs syndorme
- Haematological disease (hodgkin’s lymphoma and MM)
- Ionizing radiation (UV, x-ray, gamma ray)
- Chemotherapy
What are the symptoms of acute leukemias and why?
CLINICAL FEATURES ARE ABRUPT
Bone pain - blast accumulation in bone marrow
Fatigue - pancytopenia
Infections - pancytopenia
Bleeding - pancytopenia
Painless lymphadenopathy
Testicular enlargement - blast cells travel to testes
Hepatosplenomegaly - as bone marrow not producing normal cells
How are the acute leukemias treated (2 phases)?
- Remission induction phase:
- High dose chemotherapy to suppress all cell lines (its prone to infection)
- Give myeloid growth factors (decrease morbidity but not mortality)
- Give RBC and platelets - Consolidation phase:
- Purpose is to prolong remission and increase survival
- Start once WCC normalised
- Chemo, radiation or bone marrow transplant
- Use gene expression profiling to guide therapy
If chemotherapy not suitable, can give cytarabine and azacitidine
What are the specific features of ALL?
- More common in children (newborn - 14)
- Parotid and testicular involvement
- Extramedullary involvement (outside bone marrow)
Do lumbar puncture to assess for CNS involvement
What are the specific features of AML?
- More common in adults (40-60)
- Assoc with Downs syndrome, NF1, males
- Risk of DIC
- Previous MDS/CML
- Auer rode and peroxidase +ve
What is CLL and what are the features?
A lymphoproliferative disorder causing accumulation of mature, functionally incompetent lymphocytes
- Often asymptomatic and diagnosed incidentally
- Typically elderly, caucasian males
- Hepatomegaly and lymphadenopathy
- Prognosis via ‘The Rai System’ (I-VI)
- Often no treatment required
- Can progress to DLBCL
What do investigations show in CLL?
FBC - anaemia and thrombocytopenia (if severe)
Blood film - many small, mature lymphocytes with SMUDGE cells
10% of patients with CLL will progress to diffuse large B cell lymphoma. What are the features of this?
Fever, increased lymphadenopathy and high LDH = think DLBCL
What is the prognosis of the chronic leukemias?
CML - chronic, accelerated and blast phase (in which it can transform to AML)
CLL - often never progress, better prognosis
What is a lymphoma?
A neoplastic disorder of mature lymphocytes in lymphoid tissue, in which abnormal lymphocytes collect in lymph nodes, particularly in the armpits, groing and neck.