Haematology Flashcards
Hereditary haemachromatosis - mode of inheritance?
Autosomal recessive
Causes of microcytic anaemia
Iron deficiency
Thalassaemia
Anaemia of inflammation (aka anaemia of chronic disease) - not anaemia of CKD
Hyperthyroidism (rare)
Lead poisoning (rare)
Congenital sideroblastic anaemia (rare)
Actions of hepcidin
Blocks ferroportin gate in:
- Gut (decreased iron absorption)
- Macrophages (sequestration of iron)
Iron then unavailable for Hb synthesis > microcytic anaemia
This is what occurs in anaemia of chronic disease in setting of infection/inflammation > leading to IL-6
What does basophilic stippling suggest on a blood film?
Lead toxicity, especially if also microcytic anaemia
What is alpha thalassaemia?
Impaired production of alpha chains leading to excess beta chains > haemolysis
HbH disease > 3 gene deletion
Barts hydrops fetails > 4 gene deletion
Excess beta chains form beta tetramers > HbH bodies (“golf balls”)
Excess gamma chains form gamma tetramers - can be detected immunochromatographic strips
Typical presentation of alpha thalassaemia silent carrier?
Heterozygous for one gene deletion
Common in Maori, SE Asia, Africa
Hb normal/slightly reduced
MCV borderline, 75-85
HbH bodies rare
Gamma tetramers detected in 70%
No reproductive issues
Typical presentation of alpha thalassaemia 2 gene deletion (alpha trait)?
Either a-/a- or –/aa
Hb - slightly reduced, mild anaemia
MCV 65-75
HbH bodies usually detected in –/aa
Gamma tetramers detected in 80% of trans, 100% of cis
Use DNA testing
Reproductive implications
In cis - more common in SE Asia, worse
Typical presentation of alpha thalassaemia 3 gene deletion (HbH disease)?
Excess beta chains = beta tetramers = Hbh precipitates
Membrane damage and chronic haemolysis
Moderate anaemia (Hb 70-100)
MCV 50-65
Require transfusions and/oor gets iron overload
Typical presentation of alpha thalassaemia 4 gene deletion (Hb Barts)?
Hb Barts = gamma tetramers
Fetal or early post natal deatchh
Complications to mother as well - large placenta
What is beta thalassaemia?
Reduced synthesis of beta globin chains leading to excess alpha chains
Usually caused by mutations that cause: reduced expression or absent expression
Large deletions uncommon
Key diagnostic testing in beta thalassaemia?
HbA2 (>3.5% in beta thalassaemia)
Typical presentation of beta thalassaemia trait (beta thalassaemia minor)?
Asymptomatic - mild anaemia
MCV <72
Blood film: normal-mild microcytosis with anisocytosis, hypochromia, poikilocytosis
HbA2 3.6-5% (normal <3.5%)
HbF often elevated but variable
Typical presentation of beta thalassaemia major?
Hb 30-70
MCV 50-70
HbF ~90%
Expanded bone marrow, bony deformities
Hypersplenism
Hypercoaguable
Dependent on blood transfusions
Complications of iron overload subsequently
- Cardiac failure, delayed growth
Main difference between beta thalassaemia intermedia vs. major?
Major is transfusion dependent
Intermedia - Hb 70-100
Combination of alpha & beta thalassaemia?
Ok outcome - improves condition as it corrects globin chain imbalance - fewer precipitates of excess chains
Worse outcomes with things that affect both beta chains
- HbE + beta thal - variable but severe since few/normal beta chains
- HbS + beta thal - worsens sickle trait, closer to sickle disease
What does hypersegmented neutrophils suggest?
B12/folate deficiency
Causes of macrocytosis?
EtOH
Liver disease (esp. cholestatic)
Myelodysplastic syndrome
B12/folate deficiency
Drugs (phenytoin, cytotoxics, antivirals, MTX)
Reticulocytosis (haemolytic anaemia, bleeding)
- Reticulocytes are ~20% bigger!
Myeloma (25% of cases)
Haemochromatosis (causes macrocytosis, but not anaemic)
Aplastic anaemia (causes cytopenia with macrocytosis)
Hypothyroidism
Causes of normocytic anaemia?
Decreased production/reticulocytes:
- Inflammatory process (tends towards microcytic)
- Lack of nutrients (micro/macro)
- Lack of EPO (CKD)
- Infiltration of bone. marrow
- Marrow disease such as MDS (often macro)
- Chemotherapy
Increased loss/destruction:
- Acute bleeding
- Haemolysis (sometimes macrocytic)
Causes of extravascular and intravascular haemolysis?
Extravascular - usually means splenic haemolysis
(MOST)
Intravascular - complement mediated in PNH, microangiopathic, heart valves (mechanical)
What does spherocytosis suggest?
Hereditary spherocytosis or autoimmune haemolytic anaemia
In AIHA - macrophages remove membrane from RBCs resulting in spherocytes
Haemolytic anaemia screen?
Hb
Blood film
Reticulocytes
Bilirubin (unconjugated)
Low haptoglobin
Direct antiglobulin test (DAT)
LDH
Blood film changes suggestive of post-splenectomy?
Howell Jolly bodies (nuclear remnant)
Target cells
Spherocytes
Odd cells
Thrombocytosis
Lymphocytosis
Causes of acquired hyposplenism?
(1) Infarction
- Sickle cells, essential thrombocythaemia, polycythaemia vera
(2) Atrophy/hypofunction
- Coeliac, fermatitis herpetiforms, IBD
- Autoimmune (SLE/RA/GN)
Bone marrow transplantation & GVHD
- HIV/AIDS
(3) Infiltration
- Amyloid, sarcoid, leukaemia, myeloproliferative
What type mutations occur in hereditary spherocytosis and inheritance?
In red cell membrane/skeleton proteins
E.g. Ankyrin, Band 3, Spectrin, Protein 4.2
Autosomal dominant inheritance
Can do DAT to test
Consequences of hereditary spherocytosis?
Anaemia
Life long excessive breakdown of Hb
Pigment gallstones (also occurs in other chronic haemolytic states, e.g. sickle cell)
Splenectomy may be indicated in certain situations
Blood film changes suggestive of G6PD deficiency?
Bite cells, keratocytes
X-linked
Role of G6PD and consequences
Precipitates of Hb (Heinz bodies) results in bite cells
Heinz bodies = Heinz beans = beans = G6PD def
Drugs that cause drug-induced oxidative haemolysis?
Sulphonamides
Dapsone
Antimalarials
Cotrimoxazole
Naphthalene
Etc.
Causes of rouleaux?
High globulins/fibrinogen
- Chronic infection/inflammation
- Monoclonal proteins
Causes of reactive lymphocytes?
EBV
CMV
Toxoplasmosis
Reactive lymphocytes = reactive CD8+ T cells
Causes of cold agglutinins?
EBV
Mycoplasma
Lymphoma
If cold agglutinin + haemolytic anaemia:
- Primary, Cold Agglutinin Disease
> Strongly associated with distinct lymphoma
- Secondary, Cold Agglutinin Syndrome
> 2’ infection, lymphoma etc.
Fragile cells, smear/smudge cells, basket cells - cause?
CLL
Hairy cells on blood film?
Hairy cell leukaemia
Hairy cells on blood film?
Hairy cell leukaemia
Clefted, cerebriform cells of Sezary syndrome
T cell lymphoma
Granular lymphocytes of large granular lymphocyte leukaemia
Associated with neutropenia/RA
Felty Syndrome
Reed-Sternberg Cell
Hodgkin Lymphoma
B cell surface markers
CD19, CD20
Kappa, lambda
T cell surface markers
CD3, CD4
CD5, CD8
Granulocyte surface markers
CD33, CD13, CD15
Most common cause of TTP (thrombotic thrombocytopenic purpura)?
Transient auto antibody against ADAMTS13 (levels <10%)
Results in excessively long VWF multimers, which binds platelets and activates clotting. Red cells then fragmented by fibrin strands leading to microangiopathic haemolysis.
Characteristic presentation of TTP?
All have thrombocytopenia and microangiopathic haemolytic anaemia.
Most common: non specific, abdo pain, nausea, vomiting and weakness
Microthrombi everywhere - esp. brain, kidneys
Treatment of TTP?
Plasma exchange to replace ADAMTS13 and to remove antibodies
Mortality: 90> 20%
Abnormalities of VWF?
What is HUS (haemolytic uraemic syndrome)?
Like TTP but mainly affects kidneys
Usually in children
90% of cases caused by Shiga toxin
> Would have preceding bloody diarrhoea/abdo pain
5% due to strep pneumoniae
> Usually preceding pneumococcal disease
5% atypical HUS
> Inherited mutations in complement
Often requires dialysis
Binds quite specifically to receptors in kidneys (Gb3), kids/children tend to have high levels
What is type 1/2/3 Von Willbrand Disease?
Reduction in VWF/function
Type 1 - reduced level
Type 2 - reduced function
Type 3 - very very low levels (both alleles affected)
What are 4 functional tests of VWF?
(1) VWF activity assay
- GP1b binding
(2) Ristocetin co-factor acvitiy
- Alters conformation (mimicking shear forces) induces platelet binding
(3) Collagen binding assay
(4) Factor VIII levels
If VWF has decreased function (<0.7), then type II VWD
Causes of acquired von Willbrand syndrome?
(1) Valvular disease - Heyde syndrome
CHD, shear-stress-induced proteolysis
(2) ET/PV/myeloproliferative disease
- Excessive binding to abnormal platelets + proteolysis
(3) Autoantibody-mediated loss of function in myeloma/lymphoma & SLE
Mixing studies
- Results for deficiency + inhibitor?
Factor deficiency - haemophilia, warfarin, liver disease
> Mixing study will show correction
Inhibitor - heparin, antiphospholipid etc.
> Mixing study will not correct completely
Management of triple positive (lupus anticoagulant, anti-cardiolipin, anti-beta2glycoprotein1)?
Needs wafarin rather than DOACs
4T scoring system for HIT (heparin induced thrombocytopenia)?
Typical onset for HIT is 5-10 days post exposure
If re-exposed within 30 days, platelet count will drop within 1 day
Most common mutation in haemophilia A?
Inversions of intron 22 (in 40-45% of severe patients)
> 2000 defects in F8
Point mutations 67%
Small insertions/deletions 25%
Management of Haemophilia A
(1) Replacement/substitution therapy
Prophylactic therapy 2-3x/week with FVIII
30% of severe haemophilia A will develop inhibitors/alloantibodies within first 20-30 days
(2) Activated prothrombin complex concentration
- FEIBA (factor 8 inhibitor bypass activity)
- Contains II, VIIa, IX, X
(3) Recomobinant FVIIa Novoseven
(4) Emicizumab - bispecific antibody that mimics FVIII activity by binding to activated IX and X - mediating activation of X
- For patients with FVIII inhibitors + severe haemophilia A
What is haemophilia B?
Deficiency in factor IX
“Christmas disease”
Factor IX on X chromosome
X-linked recessive
If on warfarin, INR ≥1.5 and life threatening bleeding:
IV Vitamin K 5-10mg
Prothrombinex
+/- FFP
Effect on DOACs on coagulation tests?
Not reliably… But can be helpful…
Definition of febrile neutropenia
Fever >38 + neutrophils <0.5
Tumour lysis syndrome - manifestations?
Increased uric acid
Hyperkalaemia
Hyperphosphataemia
Hypocalcaemia
Oedema, fluid overload, seizures, muscle cramps
(Phosphate binds to the calcium)
Diseases at high, intermediate and low risk for TLS?
High risk:
- Burkitt Lymphoma, WBC >100, LDH 2x ULN
Intermediate risk:
- Early stage NHL, T cell lymphomas
- WBC 50-100
- LDH 2x ULN
Low risk:
- Indolent NHL, myeloma, CML
- WBC <25
- LDH <2x ULN
Indications for CAR-T cells
Relapsed refractory ALL
Relapsed/refractory DLBCL after failure of ≥2 lines of therapy
Relapsed/refractory mantle cell lymphoma after failure of BTK inhibitor
Complications of CAR-T cells
Cytokine release syndrome
- Fevers, chills, dyspnoea, nausea, headaches, tachycardia etc.
Neurotoxicity
- Headache, confusion/agitation, seizures
Management of CRS/neurotoxiciity 2’ CAR-T cells
Symptomatic management - antibiotics, fluids, paracetamol
Tocilizumab (8mg/kg)
Dexamethasone 10-20mg
DLBCL
Most common lymphoma
Biopsy: large and small cells, diffuse pattern, loss of normal architecture
Tend to grow quickly & infiltrate
B symptoms
Pedal oedema - 2’ pelvic lymphadenopathy
Generalised pruritus
Anorexia/fatigue
Splenomegaly
DLBCL - standard therapy?
R-CHOP
Rituximab
Doxorubicin
Vincristine
Prednisone
Indications for treatment for CLL?
Anaemia/thrombocytopenia (Hb/platelets <100)
Painful lymphadenopathy
B symptoms
Lymphocyte doubling <6 months
Rapidly enlarging lymph nodes/organs
AIHA/idiopathic TTP refractory to immunosuppressants
Investigations for MM?
FBE - anaemia, thrombocytopenia
EUC - check renal function
Calcium
Skeletal survey
Protein electrophoresis
SFLC
BM biopsy - >10% plasma cells
Indications for MM treatment?
CRAB or SliM criteria
> 60% plasma cells
SFLC >100
MRI lesions >5mm
Hyper Ca2+
Renal failure
Anaemia
Lytic lesions
Management of MM
Chemotherapy based regimens
- Bortezomib + cyclophohsphamide + dex (VCD)
- Bortezomib + doxo + dex (PAD)
- Vincristine + doxo + dex (VAD)
Non-chemotherapy regimens:
- Thalidomide/lenalidomide and dex
- Carflizomib/bortezomib
-Daratumumab
Autologous stem cell transplant
APML genetics + treatment
t(15:17)(q22:a12)
ATRA + arsenic
Indications for treatment of follicular lymphoma?
GELF criteria/FLIPI:
Nodes >7cm
>3 nodes >3cm each
B symptoms
Splenomegaly >16cm
Compression of vital organs
Serous effusions
Lymphocytes >5
Cytopenias
What is SLiM criteria for MM?
S - sixty, >60% clonal plasma cells in bone marrow
Li - Light chains, SFLC >100
M - MRI, more than 1 5mm or greater lesion
Blood film for lead poisoning?
Microcytic anaemia
Basophilic stippling
Where is vWF secreted from?
Endothelial cells (Weibel-Palade bodies), secreted in ultra-large form
Then cleaved by ADAMTS13
What can affect VWF levels?
Blood type O - lower levels
Exercise/stress - increases levels
Heyde syndrome?
Aortic stenosis + GI bleeding (2’ AVMs) + acquired VWF
Classification criteria for antiphospholipid syndrome?
Persistent presence of antiphospholipid antibodies, measured by at least 1 of 3 tests:
(1) Lupus anticoagulant (e.g. APTT, dilute Russell viper venom time)
(2) Immunoassay for anti-beta2 glycoprotein antibodies (IgG/IgM)
(3) Immunoassay for anticardiolipin antibodies (IgG/IgM)
Classification criteria for antiphospholipid syndrome?
Persistent presence of antiphospholipid antibodies, measured by at least 1 of 3 tests:
(1) Lupus anticoagulant (e.g. APTT, dilute Russell viper venom time)
(2) Immunoassay for anti-beta2 glycoprotein antibodies (IgG/IgM)
(3) Immunoassay for anticardiolipin antibodies (IgG/IgM)
Positivity correlates with increased risk of thrombosis
What factors are involved in extrinsic pathway (PT)?
Factor III (tissue factor)
Factor VII
What factors are involved in intrinsic pathway (APTT)?
Factor XII
Factor XI
Factor IX
Factor VIII
What is the common pathway in clotting cascade?
Factor Va and Factor Xa
(+ calcium)
Activates prothrombin (II) to thrombin (IIa)
Thrombin then activates fibrinogen (I) to fibrin (Ia)
Factor XIIIa helps stabilise fibrin network
What does activated Protein C and Protein S inhibit?
Activated protein C and protein S form activated Protein-C complex which inhibits factors Va and VIIIa
What is Factor V Leiden?
DNA point mutation (guanine for adenine)
Leads to APC (activated Protein C complex) resistance therefore Factor V remains active
What does antithrombin do?
Degrades thrombin and factors IXa and Xa.
Activates tissue plasminogen activator.
What does antithrombin do?
Degrades thrombin and factors IXa and Xa.
Activates tissue plasminogen activator.
Factor V Ledein - mechanism of inheritance?
Autosomal dominant
Pathophysiology behind heparin induced thrombophilia?
Antibodies against platelet-factor-4 (PF-4) therefore increased activation of platelets and thus depletion
Cell surface markers for CLL?
CD5, CD19, CD20 and CD23
Most common genetic variant in hereditary haemochromatosis?
C282Y (1)
- Esp. common in white people of European ancestry
H63D (2) - less common
Role of hepcidin?
Controls iron absorption in intestine and iron release from macrophages via its binding to ferroportin
Low hepcidin levels = increased iron absorption and release from macrophages
High serum hepcidin = inflammation, CKD
Low serum hepcidin = iron deficiency anaemia
Primary site of synthesis - liver
Excreted by kidney and reabsorbed in proximal tubules
