Haematology Flashcards
Haemoglobin structure
- 4 polypeptide chains and 4 haem groups
describe the haem group
what happens when oxygen binds
Haem consists of protoporphyrin ring and Fe group bound to 4 N atoms,it also has a histidine residue
the Fe2+ can make 2 bonds for o2 on either side of the plane
once oxygen binds to the haem groups it goes form the deoxyghaemologbin to the oxyhaemoglobin configuration, this involves the movement of the FE into the plane upwards pullign with it the histidine residue , this is because oxygen is very electrogenative and pulls the cloud of electron density towards itself
this movement causes a small change in overall protein conformation
describe this curve myoglobin vs hb
-M has higher affinity for oxygen whilst the heamoglobin exhibits cooperative binding, which means that once 1 oxygen binds, its easier for the other oxygens to bind
describe this curve fetal
fetal hb has a higher afffinity for oxygen than the mother’s hb due to the less avid binding of 2,3-BPG, this allows fetal HB toextract o2 from materal hb across the placenta
where does fetal erythropoeisis occur
yolk sac (3-8 weeks)
liver (6 weeks - birth)
spleen (10-28weeks)
bone marrow (18wks-adult)
young liver synthesises blood
Blood types
(antigens on surface, antibodies, donate from, donate to)
what happens if you donate to wrong b type
A B AB O
Anti B(IgM) Anti A(IgM) none Anti A + B (IgG + IgM)
AO B O A B O AB O
A AB B AB AB A B AB O
haemolytic reaction
whats special about the membranes of erythrocytes
they have Hco3-/cL- antiporter aallowing RBC to export HCO3- and transport co2 from periphery to the lungs for elimination
poikilocytosis
varying shapes
describe what this is? what are the stains used and how do they differ? why is this cell present? how do i calculate the amount of this cell there is? and if it appears ‘x’ what do you do?
reticulocyte
in Wrights stain (normal) they appear macrocytic and hypochromic with little RNA, but with fluroscnt dyeyou can see the ribosomal RNA
its a sign of boen marrrow functioning as a result of erythroid proliferation, this may be due to acute blood loss
reticulocyte % = patient Hct/ actual HCt (usually 45%) (normal RI = <3%, [with anaemia less than 3 = bone marrow not funcitoning, and more than 3 = haemolytic lysis])
with polychromasic you do the RI / 2 and if that is less than 3% then issue as above
poikilocytosis varying shapes
anisocytosis
sizes vary
anisocytosis varying sizes
polycythemia vera
polycythemia vera
what are these cells? how are they made? whats their lifespan? describe how they are activated?
- thrombocytes
- thrombopoietin stimulates megakaryocytes to synthesis them
- 8-10 days
- endothelial damage, they then aggreagate to form a platelet plug
where does the location of platelet storage in organ ‘x’, and why does it lead to ‘y’ surgery?
1/3 of thrombocytes are stored in the spleen and so patients with immune
what do platelets contain
C A S H - wc is released upon activation
Ca2+ (important for binding of the coagulation factors) , ADP, Serotonin (c platelet aggregation and Vasoconstriction of injured vessel wall) , Histamine
it also contains alpha granules wc are vWF, fibrinogen, fibrin, platelet facotr 4
what are platelets activated by
- ADP (wc is also released by platelets ; it interacts with the P2Y1 P2Y12)
- Thrombin (wc informs platelets that clotting sequence is activated)
- Thromboxane A2 a powerful platelet aggregator wc is also released by platelets
- Collagen fibres (within extravascular surfaces)
what happens when platelets are activated
- stick to the exposed endothelium via vWF (wc helps them adhere to the membrane since its concentrated at exposed membrane)
- aggregate with other platelets and forms primary platelet plug wc is very weak. this primary platelet plug consists of activated platelets sticking to injured vessel and the connective tissue outside it.
- platelets undergo a conformational change and become sticky spiny spheres
- they then secrete factors from platelet granules e.g fibrinogen, ADP, thromboxane A2
what are most cofactors and describe the synthesis of some?
- most are proenzymes and so when functioning require co-factors like ca2+ and phospholipids
take too much warfarin
dangerous because inhibiting VIT K (vit k epoxidase reductase) and so carboxylation of the glutamate residues of cofactors 2 9 10 7 can’t occur and so they dont form carboxyglutamate and aren’t attracted to the positive ca2+ released
treatment is;
- give vit k to reverse warfarin
- if severe bleeding give vit k + FFP (fresh frozen plasma) / PCC (prothrombin complex concentrate) (wc is just the serum part of blood and contains clotting factors)
*
how is vit k made?
by enteric bacteria
and so neonatals that lack this enteric bacteria must be given vit k early on to prevent neonatal vit k deficiecny
anticoagulation and coagulation factors
coagulation factors
- all cofactors
anticoagulation factors
NATURAL
- protein s and protein c
- antithrombin
SYNTHETIC
- heparin (works by enhancing the activity of antithrombin)
- lwmh like enoxaprin, dalteparin
- direct factor Xa inhibitor apixaban
- fondaparinux (similar to heparin used for DVT)
describe and draw the whole pathway for bloodclotting
- intrinsic pathway is triggered by negatively charged surfaces ( like glass tube with scientists used to experiment with,blood still clots but theres no damage to endothelium - the reason it clots is the negatively charge surface)
describe how anticoagualtion occurs
- protein s and c made in the liver and works to cleave and inhibit facotr 8a and 5a
- antithrombin inhibits thrombin (IIa) and factors VIIa, IXa, Xa, XIa, XIIa
heparin enhances the activity of antithrombin
what happens to the fibrin clot soon after its formed
-platelets die; as they die actin-myosin filaments in the fibrin contract causing the wound to close up, (also due to the contraction you push fluid out the clot toughening it up)
what happens to the fibrin clot post repair
fibrinolysis
- macrophages recognise adn break down the fibrin clot adn it is destroyed by plasmin (the enzyme that is responsible for fibrinolysis)
its broken down into D-dimers and FDP (fibrin degradation products)
then it undergoes fibrous repair adn becomes replaced by granulation tissue and then a tiny scar
PLASMIN
made by the liver as plasminogen then acitvated by tissue plasminogen activator tPA wc circulates the blood
the other 2 plasminogen activators are ;
- streptokinase (found in streptococci)
- urokinase (found in urine)
they workby breaking down fibrin mesh
- tPA is prefered to streptokinase as an antithrombotic because it has a higher affinity for fibrinogen than strep. and also because its not antigenic (produce antibodies) so can be given more than once
which is better tPA or streptokinase and why?
whats a side effect of these drugs
tPA because not antigenic (since it doesnt come from a bacteria it doesnt cause antibodies to be made)
tPA has higher affinity for fibrinogen than streptokinase
bleeding more readily in the gums, or nose, or sometimes in the brain
what happens after surgery in terms of acitivity of members of the coagulation family
decreased activity of fibrinolytic activity wc remains low for 7-10days which coincides with the time period where many thrombi are formed postoperatively
what are the 3 coagulation pathways and how do you measure them?
intrinsic , extrinsic then complementary/combined pathway
I = APTT
E= PP
I to Ia = TT
Haemophilias
A = factor 8 deficicency XR
B = factor 9 defiency XR
C = factor 11 defeiecnecy AR
coagulation factor disorders aquired and congential
A ;
- liver disease
- vit K defiency
- anticoagulants
- Warfarin because it inhibits VitK
C
- Haemophilia A B
Haemphilias symptoms and treatements and how do they present in a blood test
Presentation in bloodtest:
- prolonged PT time
Symptoms ;
- haemarthroses (bleeding into joints)
- mucousal bleeding
- epistaxis (nose bleeding)
- prolonged bleeding from cuts, dental work
- bleeding excessively post trauma
treatment for HA = Inject with factor 8
treatment for HB = inject with FActor 9
how to tell the difference with vWF disease and HA
how does heparin work?
by neutralising the effect of thrombin
whats present in serum
no blood clotting factors and fibrinogen
what sets off the intrinsic pathway
factor 12
what sets off the extrinsic pathway
phospholipids and tissue factor
does aspirin affect the clotting time
no the it just increases the clotting time
how does activated protein c work
inactivating factor 8a and 5a wc are needed to activate 10, and 10 is the one whoch starts the complementary pathway
leaving a tournique on for too long will cause the specimen to be
hemoconcentration because the blood pool just above the tournique hence why it should be removed within 1/2 minute
what does anaemia mean?
whats normal Hb range
whats the normal symptoms and signs
lower Hb concentration than normal range
varies with sex, gender, age, ethnicity
difference between itp ttp hus
ITP
idiopathic thrombocytopenia purpura
- immune cause where the plateles are destroyed by the bodies own immune cells a they bind to GpIIb/IIIa receptors on the membrane of the platelets
- can be idiopathic or secondary to autoimmune disorder; like viral infections (HIV,HCV), malginancy (CLLchronic lymphocytic leukaemia - too much WBC) or drug reactions
- presentation ; bleeding (in mucousal membranes like gums)
labs ; ^ bleeding time
blood film ; thrombocytopenia/ or nothing/ bone marrow bioposy ^ megakaryocytes
ttp
thrombotic thrombocytopenia purpura
lots of blood clots form (due to increasedvWF - because of ADAMTS-13 deficiency - wc keeps vWF conc low and in check) as a result more clotting occurs
lab results: schisocytes becasue a the RBC try to move past the bclots (plateles attatched to vWF) thet are sliced in half and ^ bleeding
TPP (the terrible pentad) presentation: thrombocytopenia (due to the plateles being used up) anaemia(because the RBC are being lysed)fever (systemic response)neurological symptoms and renal dysfunction
hus
haemolytic uremic syndrome
015:H7 E.coli strain the pateint is infected with . you get it from uncooked meat and raw leafy veg. this bacteria causes the release of shiga-like toxin which results in bloody diarhhoae
-mostly kids present
schisocytes (but in the kidney) , ^ creatinine
presentation: anaemia, thrombosytiopeania, specific to the kidney so acute kidney injury (de to v blood suply to the kidney)
dic
disseminated intravascualr coagulation
= inappropiate widespread clotting activation wc c v in coagualtion factors and plateles so ^ bleedign time
presentation: SSTOP Making New Thrombi
snake bites, sepsis (due to gramnegative), trauma, obstretic complications, pancreatitis, malignancy, nephrotic syndrome, transfusion)
labs; shicsocytes, ^ D-dimers (because body trying to break down the clots) , v fibrinogen busing it make clots
labs: ^ bleeding time
alpha thalassemia
alpha
- chromosome 16 - there are 2 genes for alpha on each chromosomes so 4 altogether
- the condition involved deletion of the gene not mutation, and the pattern can be cis or trans. (cis = on the same chromosome both genes affected inheritance pattern so you have 2 genes on same chromosome affected) (trans = 1 gene on each chromosome is affected)
- 4 types:
- silent carrier state; a a a - ; asymptomatic
- a-thalassaemia trait; a a - - ; cis or trans ; microcytic and hypochromai, looks like beta thalassemia minor
- haemoglobin h disease ; tetramers of beta-globin forming microcytic, hypochromic anaemia with heinz bodies and target cells (resembles beta-thalassaemia intermedia)
- hydrops fetalis; —-, all 4 genes deleted, excess y-globin forms tetramers in feotus called Hb Bart wc cant deliver o2
beta thalassemia
on chromosome 11 , the condition is caused by a mutation and not a deletion
there are 2 variations of the beta gene:
- B0 = abscence of production of the beta globin
- B+= reduction in beta globin production
types of beta thalassemia:
- b-thal. minor / b-thal. trait; heterozygous so bb+/ bb0 ; asymptomatic with a mild anaemia (very microcytic and hypochromic RBC) resembles a-thalassemia trait
- b-thalassaemia intermedia; heterozygenous; mild form are homozygous beta thalassaemia // severe variants of heterozygous B+B0 or B+B+
- b-thala. major; B0B0 = no beta globin production depend on blood tranfusion , symptoms manifest 6-9 months after birth b thats when the beta chains substitite the gamma chains
aer a and b single genes
a is duplicate and b is single
what is the ratioof expression of a:nona globin chain proteins
1:1
what is the blood smear of thalassameia
- microcytic and hypochromic due to the less Hb
- anisopoikilocytosis (varying shapes and sizes)
- target cells, heinz bodies and nucleated blood cells
how does thalassaemia disturb the RBC
it causes aggregates to forms like HbH and Btha intemedia and these insiluble aggregates of a and beta chains getoxidised
once oxidisaed they cause :
- prmature death of erythoid preursors withinthe bone marrow causes ineffective erythropoieses
- excess destruction of mature RBC in spleen c reduced RBC survival = haemolytic anaemia as well as a microcytic anaemia
consequences of bad thalassaemia (HbH disease and b thal. intermedia)
- extramedullary haemopoiesis ; occurs to compensate for the RBC that are dying so haemopoieses occurs in bones that dont usually part take in it, like bones of the face , this impairs growth and causes abnormal skelteal changes
- spelenomegaly, hepatomegaly, and explansion of haemopoiesis into the bone cortex
- reduced oxygen delivery leads to stimulation of EPO wc further contributes to the drive to make more RBC
- iron oveerload is the major cause of death due to excess abdosprotion from diet as a resultof more erythropoiesis and transfusions (haemosiderein build up)
whats the major cause of death in thalassaemia
heteroxygous b thalassaemia with one normal trait
Bb+/Bb0
they are okay, they ahve microcytic RBC due to abnomarllities in the Hb, but total Hb content okay since their erythropoiesis is okay and effective
anaemia only come sometimes when theres a hgh demand likepregnancy or persistent infection
why does b thalas major only present 6-9 months after birth
because body switches from fetus gamma Hb to HbBadult in that time period
how does HbH disease present
haemoltic anaemia
hypochomic and mucrocytic (d Hbv)
target cells, heinz bodies, nucleated blood cells
splenomegally and severe anaemia
treatments for tha
beta inter sometimes need transfion but major and HbH disease both need transfuions
200mg iron = 400ml blood tranfusion
this can build up the iron content and so get transfusion associated haemosiderosis
can use iron chelating substances like desferrioxamine
what should you do witha pregnant thalassemia family
counseeling
sickle cell disease what is it
normal
AR
but in times of high oxygen demand due to membrane defect
it occurs due to the membrane glutamic acid being substituted with valine,at position 6 valine is hydrophobic and causing the Hb S to polymerasise at low oxygen tension forming haemoglobin polymers that result in the deformation of RBC membrane leading to sickle shape
whats the difference between homo and hetero sickle cell people and whatsthe inheritance pattern of the disease
AR
-
homo: HbSS more likely to get it along side other haemoglobinopathies like HbS/C or HbS/E or beta thala
- hetero; carriers have resistance to malaria because falciparum parasite finds it diffult to grow.
consweunces of sickle cell formaiton
-
vaso-occlusive : occlusion of small capillaries from sickle cells getting trapped,leasing to :
- recurrent acute pain and syndromes like a stroke or acute chest syndomre as well as
- chronic kidney disease and
- joint damagefromavascular necrosis
- anaemia: sickle shaped cells undergo haemolysis shortening the lifespan fo RBC from 120 days to 20/30 days
-
jaundice and gallstones : due to increased bilirubin resulting in chronic haemolyis
- splenic atrophy: vasoocculsion in the splenic artery cause necrosis and infarction therefore more suscpetible to infections
treatment for sickle cell
transplant stem cell transplant
what are aquired haemolytic anaemias
- microangiopathic haemolytic anaemia ; RBC damaged due to taruma like haert valve cuse RBCto snag as they pass through small vessels laden with fibrin strands in situations where there is an icreased activation of the coagulation casade like DIC or TTPor HUS or ITP
schistocytes
snagged RBC
microangiopthic haemolytic anaemia
hus (haemoltyic uremic syndrome O15:H7 ecoli
autoimmune haemolytic anaemias
antibodies binding to RBC and breakign them down
can result from infection in like kids (chest infections) or lymphomas (cancoer of lympoid system)
classified as warm IgG or cold IgM based on temps at which they react best in the lab
spleen recongised antibody bound RBC adn removes it
autoimmune haemolytic anasemia
cold IgM or warm IgG is how they are classified based on what tempretures they react best in the body
direct Coombs test is a way to detect these antibodies or complement bound RBC but mixing patients blood with anti-human globin anitbody and if the patients RBC is coate with antibodies then this anti-human globin antobody will attatch and clump the blood . this means the patients haemolysis is due to an immune related reason
test for immune related haemolytic anaemia
direct Coombs test, where you mix patients blood with anti-human globin antibodies and if the patients RBC is coated with AB then it will bind and cause the b to clump together , this can beseen in a test tube and is a + result
difference between IgG and IgM in automimmune haemolytic anaemias
IgM binds to RBC at colder temps so at more distal body sites like the fingetips and earlops adn so you find agglutination at these sites, (sy= pallor fingertips/ earlobes/ ischaemia and sometimes even gangrene)
once this blood circuates to centralparts of the body (warmer temps) the IgM fall off the RBC membrane and agglutination disappears , but IgG binds which is more dangerous.
it causes whole to form in the membrane directly destroying RBC and also causes macrophages in the spleen to recognise them as abnormal and so detroy them shortening lifespan of RBC
other causes of haemotlyic anaemia apart from aquired and hereditary (immune ) types
oxidants and chemicals (lead poisoning) heat damage and enzyme actions in reactions to snake bites or even foot strike haemolysis in runners
hereditary haemolytic anaemias
pyruvate kinase deficiency
- AR but theres a dominant form
- due to a mutation in the PKLR gene; there are 4 pyrivate kinase isoenzymes 2 of which are coded by PKLR gene ,(L expressed in the liver and R in the eRythrocytes)
- mutation in thsi genes causes a deficicency of the enzyme and so the patient ussualyhas mild symptoms and dont require b transfusion but some people who have it adly need b transfusions
- pyruvate kinase deficency the glyclysis pathway is distrubed and so you cant make ATP,
- this measn that the NA/K+ ATPase pump is no longer functioning, so K+ is just being lost continuously and since its osmotically active h20 moves out the cell so the RBC undergoes lysis
G6PDH
- XR
- rate limiting enzyme of pentose pathwyay
- so v NADPH so ^ oxidative stress since glutathione cat be reduced
- so these patients get recurrenti infections due to them being unable to form superoxides well since NADPH oxidase is required for that in respiratory burst
- damaged RBC then are removed by spleen. because you get aggregation of proteins within the RBC and they form heinz bodies
what should you do before giving patients drugs for haemolytic anaemia
screeen for G6PDH defcicey its relly common
hereditary spherocytosis
- AD
- membrane proteins ( spectrin, band 3 , band 4.2 , ankyrin) are abnormal which are involved in vertical interactions between the cytoskeleon adn lipid bilayer of the mebrane
- damage/ mutation to the genes coding for these causea. vesiculation of the unsupported membrane components leading to progressive reduction in membrane: sA ratio anso the membrane takes a spherocyte formation (parts of membrne are extruded because ccytoskelton is missing so its just lipid and lipid is gone)
- this change is shape is now less flexibleand gets trapped and damaed and they are rmoved
- on blood film they contain howell-jolly bodies (parts of RNA is still in the RBC and its on a blood film , it shows the spleen isnt doing it jo to remove it.
- hence why these pateints have splenomegaly
anaemia of chronic disease why does it cause anaemia
- inflammatory response: ^ hepcidin adn therefore c the ferroportin to be abosrbed and disintergraeted by cell, so more iron stored and not released so cant be used hence the anameia
- chronicdiseases that invovle the bowels are issues becaue you cant absorb the dietary iron
anaemia of chronic kindey diseas
- the underlying caue of th condition is associated with increased cytokines, that causes increased hepcidin to be released by lthe liver and so the ferroportin is absorbed and disintegrated by the cell
- also reduced erythropieotien due to kidney damage so erythropoiesis doesnt occur as efficenctly so less RBC
- dialysis causes damage to RBC
- RBCalso have a reucd life span due to uraemia
- so these patients get iron
uraemia
raised level of urea in the blood
this is a symptom of chronic idney disease, and so this uremia inhibits megakaryotcyes leading to low platelet count and also reduced the lifespan of RBC
treatment of anaemia od chronc diseases
- treat underlying condition
- if associated with renal failure then give recomibinant human erythropoietin
- also ensure that vit b12, folat and iron levels (iron given if ferrtin <200microg /L or low CHr) are adequate
possible haemotological abnormalities of renal failure interms of
RBC
WBC
platelets
rhematoid arthritis how treated? and how is ut associatedw anaemia?
treated with steroids and NSAIDS, DMARDS (disease modifying agents) LIEK CORTICOSTEROIDS, CHEMOTHERPAY, BIOLOGICAL AGENTS (MONOCLONAL AB)
- ANAEMIA IN THIS CASE IS MULTIFACTORAL:
- ^ inflammatory markers
- immunosupressants c neutropenia
- thrombocytopenia due to Autoimmune reaction or splenenomegaly
felty’s syndrome
triad involving : RA, splenomegaly and neutropenia
neutropenia is d to splenomegaly c peripheral destruction of neutrophils
and failure of bone marrow to produce neutrophils as there is insensitivity of the myeloid cells to the stimulator GCSF
liver disease and its hematological features
will cause protal hypotension wc causes b to back up to the spleen = spleneomegaly wc c
- splenic sequestration of cells
- overactive removal of cells
low blood counts
- mroe bleedign b less cofactors
- endothelial dysfucntion
- thrombocytopenia
- defective platelet function
- portal hypertension can cause gastric varices (dilated veins prone to bleed due to the higher blood pressure)
- spleenic pooling
- increased destriction
- target cells can be seen on film due to the uncreased cholesterol:phospholipid ration due to liver disease
haematological features of liver disease based off these cause:
- alcohol excess
- viral hepatitis
- autoimmune liver disease
- alcholol:
- directly toxic to bone amrroe cells so c pancutopenia (all things low)
- secondary malnutrion common (usually folic acid deficicney )
- viral:
- bone marrow failured to aplastic or hypoplastic marrow as a result of the viral heptitis
- autoimmune:
- thrombocytopenia and neutropenia
post operative reactive changes
RBC
WBC
platelets
- RBC:
- anaemia due to bloss post or pre
- temporary polycythemia vera due to dehydration
- WBC:
- neutophila die to post op reaction or sever bleeding
- neutropenia due to severe sepsis
- platelets:
- thrombocytopenia. due to drugs, DIC or sepsis
- thrombocytosis due to post-op reactive, infetion , bleeding
haemotlgoical changes with cancer
RBC
WBC
platelets
- RBC:
- anaemia due to bleeding in the bowel, bladder , iron deicicent, ACD, treatments - chemo
- polycythemia ; EPO producing tumours
- WBC:
- neutropenia due to tumour cells infiltrating the bone marrow
- neutrophilia due to inflmmation, infection
- platelets:
- thrombocytopenia deu to sepsis , chemo, DIC, marrow infiltrated
- thrombocytosis due to inflammation, infection, bleeding, iron deficiecny
leucoerythroblastic film
spilling out from the bone marrow into the blood when the marrow is under stress
- on film you see: granulocyte precursors, and nuceleated RBC seen on blood film
- causes are : sepsis, bone marrow infiltration by carcinoma or haemtological maligancy, severe megaloblastic anaemia, primary mylofibrosis, leaukaemia, storage disorders
