Haematology Flashcards
give 3 causes of microcytic anaemia
TICS Thalassaemia Iron-deficiency Chronic disease (20% will be microcytic) Sideroblastic anaemia.
give 3 causes of normocytic anaemia
- bleeding
- anaemia of chronic disease (80% is normocytic)
- bone marrow failure; - renal failure (decreased erythropoietin)
- hypothyroidism
- haemolytic anaemia
- pregnancy
give 3 general symptoms of anaemia
classic = fatigue, dyspnoea, faintness
+ palpitations, headache, tinnitus, anorexia
give 3 general signs of anaemia
classic = conjunctival pallor
pallor, tachycardia
give a physiological cause of anaemia
pregnancy (normocytic)
give some causes of iron-deficiency anaemia
- inadequate intake: poor diet, poverty
- poor absorption: poor acid production, gastric surgery, coeliac
- excessive loss: GI bleeding, peptic ulcers (NSAID use), diverticulosis, neoplasm, menorrhagia
- increase requirement: infancy, pregnancy, hookworm
describe what is seen on a peripheral blood film in iron-deficiency anaemia
microcytic hypochromic RBCs, varying in size and shape (anisocytosis and poikilocytosis)
possible presenting features of iron deficiency anaemia?
koilonychias (spoon nails)
mouth changes - angular stomatitis, atrophic glossitis
fatigue, pallor, faintness, dyspnoea
pica (classic = ice craving)
In iron deficiency anaemia, what will happen to the iron, ferritin and total iron binding capacity (TIBC) (aka iron studies)?
iron and ferritin are decreased.
TIBC is increased.
transferrin saturation = low.
NB - ferritin is acute phase protein so may be raised in inflammation/infection/malignancy
how would you treat iron deficiency anaemia? how long would this treatment be given?
oral ferrous sulphate - given until anaemia resolved + further 3-6/12
consider transfusion if symptomatic at rest w/ dyspnoea and chest pain.
what are some side effects of ferrous sulphate?
nausea, abdominal discomfort, diarrhoea/constipation, black stools
what diagnostic tests would you perform if you suspected anaemia?
blood count and film (Hb, haematocrit, MCV, MCHC, peripheral blood smear).
iron studies, B12 etc.
tests for cause e.g. coeliac serology, endoscopy etc if IDA.
how would you treat anaemia of chronic disease?
treat underlying disease.
give Epo.
what is sideroblastic anaemia?
think of it as microcytic hypochromic anaemia that doesn’t respond to iron.
inherited or acquired disorder - body has enough iron but can’t incorporate it into Hb (ineffective erythopoeisis).
iron absorption is increased.
investigations for sideroblastic anaemia?
microcytic hypochromic anaemia.
blood film = dimorphic population of normal and hypochromic red blood cells.
iron studies: serum iron high, serum ferritin high, TIBC low.
marrow aspirate = presence of sideroblasts - “perinuclear ring of iron granules with Prussian Blue staining”
how would you treat sideroblastic anaemia?
mostly supportive.
iron chelation - desferrioxamine.
repeated RBC transfusions if needed.
avoid alcohol + vit C (they increase iron absorption).
if hereditary - consider Pyridoxine (vit B6).
give 3 causes of sideroblastic anaemia.
- inherited (XLSA - X-linked)
- myelodysplastic syndrome (MDS)
- myeloma
- PRV
- pyridoxine (B6) deficiency
- drugs (isoniazid)
- alcohol misuse
- lead toxicity.
what causes pernicious anaemia?
autoimmune atrophic gastritis - autoantibodies against parietal cells and intrinsic factor, so these are destroyed leading to achlorydia and B12 malabsorption.
associated with other AI disease - thyroid, vitiligo, DM.
risk of gastric cancer.
how does B12/folate deficiency lead to anaemia?
B12 and folate needed for DNA synthesis - developing red cells can’t divide, they are stuck as large immature cells (megaloblastic) which then become macrocytic RBCs
what signs characterise pernicious anaemia?
mild jaundice due to haemolysis - pallor + jaundice = “lemon tinged skin” is classic.
headache is hallmark of megaloblastic anaemia.
what specific tests would you perform if you suspected pernicious anaemia?
FBC, blood film etc and:
- intrinsic factor antibody
- antiparietal cell antibody (90% sensitive, but not specific as elevated in atrophic gastritis)
- Schilling test (radiolabelled B12)
give some causes of folate deficiency
poor diet.
increased demand - pregnancy or increased cell turnover.
malabsorption (coeliac)
drugs, alcohol, MTX (inhibits folic acid synth).
folate present in green veg, nuts, liver.
get macrocytic anaemia but NO neurological signs - B12 deficiency you also get peripheral neuropathy and neuropsych issues.
how would you investigate and treat folate-deficiency anaemia?
blood film shows macrocytic RBCs, hypersegmented neutrophils.
do other anaemia bloods.
oral folic acid (1-5mg) + B12 for 4 months min. treat cause.
if pancytopaenia present as well consider packed RBC transfusion.
give some acquired causes of haemolytic anaemia
Immune mediated:
- due to autoantibodies and direct antiglobulin +ve (Coombs’ positive), often part of another autoimmune condition (SLE, scleroderma etc).
Non-immune mediated:
- direct antiglobulin (Coombs) negative
- infection e.g. hep B and C, malaria
- microangiopathic haemolytic anaemia - HUS, TTP, DIC
give some hereditary causes of haemolytic anaemia
- Enzyme defects - G6PD deficiency, pyruvate kinase deficiency
- Membrane defects - hereditary spherocytosis, elliptocytosis
- Abnormal Hb production - sickle cell disease, thalassaemia
what is aplastic anaemia?
anaemia due to bone marrow failure
triad = pancytopenia with hypoplastic marrow and no abnormal cells
marrow stops making all cells
give some causes of aplastic anaemia
major associations = pregnancy, coeliac, SLE
acquired causes:
- idiopathic (50%)
- drug/toxin exposure (NSAIDs, penicillamine, gold)
- post viral (esp hep)
inherited causes:
- Fanconi anaemia (AR)
- Shwachman-Diamond syndrome (AR)
give 2 specific features of aplastic anaemia
bruising with minimal trauma.
blood blisters in mouth.
presents with neutropenia (infections), anaemia symps and thrombocytopaenia (bleeding and bruising)
what test would you perform in aplastic anaemia? what would it show?
bone marrow biopsy - hypocellular marrow with increased fatty spaces. no abnormal cell population
how would you treat aplastic anaemia?
if asymptomatic - give neutropenic regimen.
if severe - matched related allogenic marrow transplant (can be curative) + RBC and Plt transfusion + abx.
what is sickle cell anaemia?
autosomal recessive disorder causing production of abnormal beta globin chains.
HbSS/HbAS instead of HbA (HbAS is carrier state)
sickle shaped cells disrupt the blood cell, haemolyse earlier and causes varying degrees of anaemia.
obstruction of small blood capillaries leads to painful crises, organ damage and increased vulnerability to infection
being a carrier of sickle cell protects you against what disease?
falciparum malaria
what is the pathogenesis of sickle cell anaemia?
HbS polymerizes if hypoxia/acidosis causing RBCs to sickle - rigid, fragile cells that occlude small vessels and have short lifespan (haemolyse).
describe the clinical features of vaso-occlusive crises seen in sickle-cell anaemia
severe pain due to effect on marrow of microvascular occlusion. acutely painful hands and feet.
dactylitis. visual floaters. chest/abdo pain (mesenteric ischaemia). chronic renal failure.
avascular necrosis femoral head/bone infarcts.
general symps/signs - parent with sickle cell anaemia/trait. symps of anaemia + haemolysis = jaundice, pallor, lethargy, tachycardia.
what is splenic sequestration?
a type of sickle-cell crisis:
vaso-occlusion produces acute painful enlargement of spleen.
pooling of RBCs in spleen = hypovolaemia = circulatory collapse and death.
immediate transfusion needed.
give 3 long-term complications of sickle-cell disease
poor growth, bone problems, infections, leg ulcers, neurological complication, gallstones, retinal disease, lung fibrosis, pulmonary hypertension
what tests would you perform in a case of sickle cell disease? what would you see?
FBC. - low Hb.
blood film - sickle cells and target cells (pale centre). Howell-Jolly bodies.
sickle solubility test - HbSS/HbAS instead of HbA
Hb electrophoresis - distinguishes HbSS and HbAS.
how would you treat sickle cell disease?
aim to diagnose at birth via screening (newborn blood spot).
pneumococcal vaccine + penicillin prophylactically + genetic counselling + parental education.
hydroxyurea (need monthly blood tests) - increases HbF production.
repeat blood transfusions if needed.
describe the genetics of beta thalassaemia
mutations in beta-globin genes (chromosome 11) leading to no/reduced beta chain production (either beta0 or beta+).
seen in individuals of mediterranean, africa, or SE asian descent.
mainly autosomal recessive, but might still report family hx.
how does beta thalassaemia cause anaemia?
decreased/absent synthesis of beta-globin leads to excess alpha production + membrane damage/cell destruction.
get ineffective erythropoeisis and increased haemolysis.
what are the features of minor beta thalassaemia?
symptomless carrier state. mild anaemia. hypochromic and microcytic. often gets muddled with IDA.
beta/beta+ or beta/beta0
(silent carrier has normal haem parameters)
what are the features of medium (aka intermediate) beta thalassaemia?
presents similarly to major but as a toddler rather than in first year.
beta+/beta+ or beta0/beta+
doesn’t require transfusions.
what are the features of major beta thalassaemia?
severe anaemia - needs regular transfusions.
presents in 1st year with progressive pallor, abdo distension (hepatosplenomegaly) and characteristic head shape (skull bossing), failure to thrive.
beta0/beta0
how would you treat beta thalassaemia?
1) minor/trait = genetic counselling, iron advice (avoid unless deficient)
2) medium = genetic counselling, transfusion if symptomatic anaemia (e.g. infection, periop) + iron monitoring with chelation (desferrioxamine)
3) major = genetic counselling + regular transfusion to >10g/dL + iron monitoring with chelation.
± splenectomy
± assess for haematopoeitic stem cell transplant (curative)
what are the genetics of alpha thalassaemia?
gene deletions (not point mutations as in beta) in alpha globin chain genes on chromosome 16.
decreased/absent synthesis of alpha globin –> excess beta production —> ineffective erythropoeisis –> anaemia and haemolysis.
mainly autosomal recessive.
sub-saharan africa + middle east + SE asia - corresponds to malaria distribution.
describe the features of a 4+ gene deletion alpha thalassaemia
aka major alpha thalassaemia or Bart Hydrops Fetalis.
no alpha chains synthesised.
death in utero.
describe the features of a 3 gene deletion alpha thalassaemia
leads to beta tetramers, which are detected on electrophoresis.
aka HbH disease.
moderate anaemia symptoms and splenomegaly, jaundice/gallstones.
may present in childhood (more severe), with family history, from the right geographical areas.
describe the features of a 2 gene deletion alpha thalassaemia
alpha thalassaemia trait.
microcytosis ± mild anaemia - mixed up with IDA a lot.
how many alpha globin gene deletions may a patient have and still appear clinically normal?
1 - and would be silent carrier.
what is glucose-6-phosphate dehydrogenase (G6PD) deficiency?
X linked haemolytic condition caused by mutation in the G6PD gene leading to G6PD enzyme deficiency.
common in parts where malaria is common as it’s protective!
what does G6PD do?
catalyses step one of pentose phosphate pathway (similar glycolysis) which generates NADPH (important for red cells to protect from oxidative stress) - protects RBC membrane from damage
does G6PD deficiency affect mainly men or women?
men
give some precipitants of G6PD deficiency crises
henna.
favism (ingesting fava/broad beans).
drugs (cephalosporins), infections.
what are the features of an acute G6PD deficiency haemolytic episode?
anaemia, fever, jaundice, dark urine (suggests intravascular haemolysis).
N&V, dehydration, AKI (due to haemoglobin precipitates).
bite and blister cells, Heinz bodies on blood film
OR - may present as prolonged neonatal jaundice rather than linked to acute eps/triggers.
what is polycythaemia?
an increase in Hb, PCV - packed cell volume (haematocrit) - or RCC (red cell count)
PCV = % by volume of RBCs in blood
what is the difference between relative and absolute polycythaemia?
relative = low plasma volume, but no change in cell numbers. absolute = increase in RBC mass.
who gets relative polycythaemia?
middle aged obese males, smokers, high alcohol intake, hypertension
what causes primary polycythaemia?
polycythaemia rubra vera - malignant proliferation of a clone from one pluripotent marrow stem cell - myeloproliferative disorder of predominantly red cells.
what causes secondary polycythaemia?
due to hypoxia - high altitudes, chronic lung disease, heavy smoking
what gene mutation causes polycythaemia rubra vera?
JAK2 - V617F somatic mutation.
Ph negative.
In polycythaemia rubra vera, what is there an excess proliferation of?
red cells, white cells and platelets - hyperviscosity/hypervolaemia.
it’s a clonal haematopoietic disorder w/ erythrocytosis, thrombocytosis, leucocytosis + splenomegaly.
give 3 symptoms of polycythaemia
headache, dizziness, tinnitus, visual disturbance, itching/pain/redness of extremitites after warm bath, burning in fingers and toes. plethoric appearance (red and full).
features of thrombosis/bleeding e.g. stroke, PE, MI, DVT etc
give 3 things you might find on examination in polycythaemia
facial plethora (red, turgid face), splenomegaly (only in PRV), gout, arterial/venous thrombosis
why do polycythaemia patients get gout?
increased urate from RBC turnover
what will the marrow of a patient with polycythaemia rubra vera show? other Ix for PRV?
hypercellularity with erythroid hyperplasia - “trilineage growth”
other Ix:
- chromium studies = elevated RBC mass
- RBC shows raised Hb, raised haematocrit, raised WBC, raised plts.
how would you treat polycythaemia rubra vera?
Rx aims to keep low haematocrit + reduce risk of thrombosis.
- venesection
- hydroxycarbamide (cytoreduction, used if high risk)
- low dose aspirin (75mg)
- manage CV RFs
how would you treat secondary polycythaemia?
treat primary cause.
oxygen therapy + smoking cessation.
list 4 risk factors of DVT
increasing age, pregnancy, synthetic oestrogens (pill, HRT), trauma, surgery, past DVT, cancer, obesity, immobility, thrombophilia
what other disease may a DVT present as?
pulmonary embolism
describe the clinical features of a DVT
warm, tender calf, with erythema. fever. pitting oedema.
what investigations would you do on a patient with a suspected DVT?
D-dimer - -ve result excludes DVT, +ve doesn’t mean it is DVT.
doppler US.
give 4 features included in the Wells score
active cancer, immobility, major surgery in last 4 weeks, local tenderness, swollen leg, pitting oedema, collateral superficial veins
how would you manage a patient with a DVT?
LMWH or fondaparinux - short term anticoagulation.
warfarin or NOAC - long term anticoagulation.
compression stockings.
mobilise, stop the pill.
what steps can be taken to prevent DVT?
stop the pill.
early mobilisation.
compression stockings/leg elevation.
LMWH/fondaparinux.
how does fondaparinux work as an anticoagulant?
factor Xa inhibitor - prevents the final coagulation pathway from continuing, preventing formation of fibrin clot.
how do heparins work as anticoagulants?
activate antithrombin, which inactivates thrombin and factor Xa.
LMWHs also act to inhibit factor Xa directly.
how would you stop bleeding in an over-anticoagulated patient?
IV vitamin K - warfarin ‘antidote’
protamine = heparin antidote
what is disseminated intravascular coagulation?
massive activation of clotting cascade leads to lots of fibrin deposition within vessels.
using up all your platelets and coagulation factors forming these intravascular clots - so get bleeding elsewhere.
give 2 causes of DIC?
sepsis. major trauma/burns. advanced cancer. obstetric complications. acute promyelocytic leukaemia.
how does DIC present?
1) symps/signs of systemic collapse - oliguria, hypotension, tachycardia
2) bleeding - bruising, purpura, haemorrhage, petechiae, oozing, haemturia
- generalised bleeding from 3 unrelated sites = think DIC
what results would you find on investigation of a patient with DIC?
Decrease: platelets, fibrinogen, factor V, factor VIII
increased: prothrombin time (PT), activated partial thromboplastin time (aPTT), D dimer, fibrin degradation products
other than treating the underlying cause, how would you manage a patient with DIC?
- call intensive care
- maintain blood volume and tissue perfusion - stop bleeding, platelet transfusion, FFP (fresh frozen plasma) and cryoprecipitates (2nd line but no ABO match needed)
what is immune/idiopathic thrombocytopenia purpura (ITP)?
isolated thrombocytopenia thought to be due to antiplatelet autoantibodies leading to immune destruction of platelets in spleen.
typically occurs in children w/preceding viral illness or in middle aged women.
what are the main features of ITP?
easy bruising/bleeding, petechial rash on skin/mucosa, haemorrhagic bullae in mouth, gum bleeding, menorrhagia.
isolated thrombocytopenia - low platelets, but everything else is normal.
how would you manage ITP?
Ix - FBC, blood smear (to rule out other causes), bone marrow biopsy (rule out malignancy)
Rx - if severe active bleeding: immunosuppression with IVIG + prednisolone, + platelet transfusion. works within 1-5/7 and lasts 4/52.
if chronic - rituximab + splenectomy.
what is thrombotic thrombycytopenia purpura (TTP)? pathophysio?
MED EMERGENCY - 95% FATAL. consider in any pt w/haemolytic anaemia + thrombocytopenia.
deficiency of protease that breaks down vWF (ADAMTS-13) - widespread platelet adhesion/aggregation leading to microvascular thrombosis + thrombocytopenia. red cells passing these clots rupture due to shear force.
what is thrombocytopenia?
low platelets - either decreased production or increased destruction
give some causes of TTP. RFs?
congenital
sporadic
autoantibody mediated - pregnancy, SLE, infection
RFs - black, overweight, F, pregnacny
how might a patient with TTP present?
pentad of:
- fever
- renal failure (raised urea/cr)
- haemolytic anaemia (pallor, jaundice, pruritus)
- thrombocytopenia (purpura, ecchymosis, menorrhagia)
- neuro change (coma, focal neuro, seizure, headache, confusion)
+ may get GI symps (N&V&D)
haemolytic anaemia
how would you treat a patient with TTP?
urgent plasma exchange + prednisolone (immunosuppression) + antiplatelet agent (aspirin)
DO NOT GIVE PLATELETS.
long term aspirin decreases plt aggregation.
Rituximab targets ab production
what is haemophilia A?
X-linked (boys!) recessive inherited factor VIII deficiency.
A&B both tend to present in toddlers. bleeding to muscles and joints.
how would a patient with haemophilia A present?
early in life/after surgery or trauma.
bleeds into joints and muscles - arthropathy and haematomas.
how would you diagnose and treat haemophilia A?
factor VIII assay
IV recombinant factor VIII. avoid IM injections, aspirin, NSAIDs (bleeding risks).