Haematology Flashcards
What are the hallmark findings on peripheral blood smear of HUS?
Presence of schistocytes
-These consist of fragmented, deformed, irregular, or helmet-shaped RBCs. They reflect the partial destruction of RBCs that occurs as they traverse vessels partially occluded by platelet and hyaline microthrombi.
The peripheral smear may also contain giant platelets
-This is due to the reduced platelet survival time resulting from the peripheral consumption/destruction.
INtrinsic pathway
APTT (II,V, 8,9,11,12)
Starts with collagen
Factors 8,9,11,12
calcium
EXtrinsic pathway
PT (PT (II,V,VII, X, fibrinogen)
Starts with trauma
Factors 13 and 7
Common pathway
Starts from factor X
X–>X+V–>prothrombin –>fibrinogen (–>fibrin) + platelets –> add factor 13 –> stable clot
FFP
FFP contains all the coagulation factors in normal concentrations and promotes coagulation of blood along the intrinsic, extrinsic and common pathways
about 10-15ml/kg
Cryoprecipitate
Cryoprecipitate contains mostly fibrinogen, factor 8, factor 13 and von Willebrand factor
Tranexamic acid
TXA is an antifibrinolytic that works to counteract the degrading effects that plasmin has on fibrin, thereby preserving stabilised fibrin to participate in the clotting process for longer
Protamine
Protamine reverses heparin in a ratio of 1 mg : 100 units
If the bleeding is thought to be a result of a heparin induced coagulopathy, protamine can be given if the APTT is ≥ 1.5 the normal levels
granulocytes
neutrophils, basophils, eosinophils
- increase granules in toxic granulation
monocyte
Type of leukocyte
diffferentiate into dendritic cells and macrophages
adaptive immunity
APC
APC
macrophages
dendritic cells
B cells
lymphocyte
- Natural killer cells (which function in cell-mediated, cytotoxic innate immunity)
- T cells (for cell-mediated, cytotoxic adaptive immunity)
- B cells (for humoral, antibody-driven adaptive immunity)
neutrophils
granular cells, PMN two kinds- killers and cagers Move to sites via chemotaxis innate immunity Oxidative burst
anisocytosis
‘funny shaped’
general term
poikilocytosis
‘abnormal shaped cell’
can refer to any abnormally shaped RBC >10% popn
rod/cigar cells (AKA pencil shape)
hereditary elliptocytosis
fe deficiency anaemia
Target cells
O with . in the middle
either due to increase in cell membrane or a decrease in Hb
Sickle cell anaemia
Fe deficiency
thalassemia
liver disease
Stomatocytes
MUST be present in >10% or is likely artifact
RBC with a slit-like central pallor, giving them the appearance of “coffee beans” or “kissing lips.
Loss of biconcave shape due to abnormal cell membrane
Causes: hereditary stomatocytosis, neoplastic disorders, liver disease, and Rh null disease.
Haematinic deficiency
lack of important factors for haem production
- folate
- b12
- iron
Disorders of red cell production
haematinic def marrow failure marrow replacement anaemia of chronic disease ineffective erythropoeisis dyserythropoeisis
Disorders of haemolysis
- Immune
- autoimmune
- alloimmune
- -> DAT to distiguish - non-immune
- inherited haemaglobinopathies
- inherited RCC membrane disorders
- inherited RCC metabolism disorders
- infection –> malaria
- physical damage –> MAHA, thermal, cardiac defects
MAHA
microangiopathic haemolytic anaemia –> caused by PHYSICAL damage. NOT inherited and NOT immune mediated
associated with DIC and sepsis
associated with HUS, TTP, SLE, malignancy, post total body irradiation, post transplant, drugs –>calcineurin inhibitors such as tacrolimus and cyclosporin); Sirolimus; mitomycin C; clopidogrel
Presence of fragmented RCC (shistocytes) and anaemia
Fe deficiency anaemia
Anaemia microcytosis and hypochromia Pencil/rod cells on film may have thrombocytosis (mech unknown) sometimes have target cells
Always secondary to something else
- nutrition
- increased demand –> low birth weight, adolescence
- blood loss
macrocytosis
- Can be normal in newborn as relative MCV is larger (adjusted in lab for age)
- massive reticulocytosis–> blood loss or ANAEMIA (i.e acute haemolytic anaemia)
- megaloblastic anaemia
- -> nutritional i.e B12, folate
- -> inborn errors of metabolism
- ->Drugs i.e azathioprine, mercaptopurine, mtx
- -> liver disease
- -> hypothyroidism (uncommon)
polychromasia
disorder where there is an abnormally high number of immature red blood cells found in the bloodstream as a result of being prematurely released from the bone marrow during blood formation. These cells are often shades of grayish blue.
Haemolytic anaemia
Lots of causes (see disorders of haemolysis)
Most common are:
ABO/resus incompatibility
post viral
hereditary spherocytosis
HUS
Can be associated with autoimmune phenomena (SLE) or immunodeficiency (SCID)
Can get: macrocytosis Raised reticulocytes Raised bili (more so in chronic) Raised LDH (break down) schistocytes polychromasia Need to do DAT to see if autoimmune
Treatment:
- support with folic acid
- avoid T/F as hard to provide compatible blood
- Warm(rather than cold agglutinan) antibody mediated autoimmune haemolytic anaemia responds to steroids
- treat underlying disease
- if can’t treat underlying disease AIHA may be refractory to Rx
Evan’s syndrome
Rare autoimmune disorder
- autoimmune haemolytic anaemia (DAT +ve)
- immune thrombocytopenia
Hereditary spherocytosis
Autosomal dominant
Fh in 75%
presentation heterogeneous
deficiency or dysfunction of RCC cytoskeleton (spectrin, ankyrin or band 3)
Splenomegaly almost always
can get gallstones in chronic disease
Low hb, raised retics
spherocytes and polychromasia
DAT negative if POSITIVE think SLE
Raised bilirubin and LDH
Ix:
Osmotic fragility testing (thalasemia and hereditary spherocytosis)
Eosin-5-maleimide (EMA) binding –> esp if no Fhx
-LOW result confirms Dx
Rx:
Folic acid
Splenectomy eventually (increased risk of encapsulated bacteria and VTE)
Cholecystectomy if sx gallstones
SLE autommune haemolytic anaemia
-similar presentation to hereditary spherocytosis (except HS is DAT negative)
-splenomegaly
-Low hb, raised retics
spherocytes and polychromasia
DAT POSITIVE
Raised bilirubin and LDH
Eosin-5-maleimide (EMA) binding
is a fluorescent dye that reacts to bind covalently to band 3 protein in the red cell membrane. Analysis by flow cytometry measures the fluorescent intensity of labelled intact red cells
used for dx of hereditary spherocytosis
LOW result confirms dx
Nucleated RBC
RBC which contain a nucleus
Look blue/purple –> similar to monocytes
Are big, immature rcc
only present in neonates or fetuses normally
Abnormally means high demand on bone marrow –> haemolytic anaemia
–> haemolytic disease of the new born
Haemolytic disease of the new born
ABO/Resus D
DAT positive
Spherocytes
Nucleated RBC
Low Hb
RCC agglutination on film
Spherocytes
round shaped rcc
present in all haemolytic anaemia to a degree
Agglutination
process that occurs if an antigen is mixed with its corresponding antibody called isoagglutinin. This term is commonly used in blood grouping .
This occurs in biology in three main examples: The clumping of cells such as bacteria or red blood cells in the presence of an antibody or complement
RBC agglutination
Clumping (agglutination) of red blood cells is frequently caused by cold agglutinins
causes: Spurious macrocytosis intravascular haemolysis C3 coating on RBC Post-viral Mycoplasma infection
Cold agglutinins
Cold agglutinins are autoantibodies produced by a person’s immune system that mistakenly target red blood cells (RBCs). They cause RBCs to clump together when a person is exposed to cold temperatures and increase the likelihood that the affected RBCs will be destroyed by the body
shistocytes
fragmented blood cells
aka helmet cells
caused by mechanical haemolysis
-HUS, DIC, TTP, cardiac valves, ECMO
Congenital TTP
Autosomal recessive
Defect in ADAMTS13 gene
ADAMTS13 gene processes a large protein called von Willebrand factor. It helps to prevent uneccesary clotting
Usually occurs in infancy and childhood but can occur when a woman is pregnant
Clotting in small blood vessels
fever and puprura/petechiae
Haemolytic anaemia - schistocytes Low Hb, Low Plt, Raised LDH and bilirubin Raised creatinine/proteinuria Coags normal
Rx: plasma exchange +/- immunosuppression
Beta thalassemia major
Note (intermedia, homozygous but less severe)
Note (minor –> genetic counsellor as a carrier)
Mutation of HBB gene on chromo 11
Autosomal recessive
No beta chains
Jaundice, fatigue, frotal bossing, gallstones, splenomegaly, maxillary hyperplaisa, dental malocclusion
Raised HbA2 (because can't make B chains) Mildly raised HbF
Ix:
Haemaglobin electrophoresis
Hb A2 and HbF measurement
Antenatal:
CVS, sequence B globulin chains
Rx:
- T/F dependent –> TF if <90. Hypertransfuse aim Hb>100 pre next TF
- iron chelation (as risk of iron overload). 3 drugs:
- deferoxamine –> SC over 8 hours, feel unwell. increased risk of cataracts
- Deferipone –> increased risk agranulocytosis
- Deferasirox –> increased risk of renal impairment - Transplant –> matched sibling. done first 10-12 years
Risk of Fe toxicity: Diabetes arthritis heart depositions--> arrythymias, CHF cirrhosis of liver
Alpha thalassemia
AR
Defect chromo 16p
Jaundice, fatigue, frotal bossing, gallstones, splenomegaly
Haemaglobin electrophoresis
- beta chains in aduts
- gamma chains in neonates
Haemoglobin BARTS
= only gamma chains if no HA2 (results in death in neonate as poor affinity 02
chronic benign neutropenia
1:100,000 assoc with minor infections less than 4 years old (90% occur <14 months) \+ve anti-neutrophil autoantibodies 95% remission 7-24 motnhs
Sickle cell
less severe if also inherited a thalassemia trait
abnormality in B chain SS
Issues are vasoccclusive crises, aplastic, haemolytic and sequestration
Rx: splenectomy Rare TF Hydroxyurea ameliorates disease by increasing HbF Risk of proliferative retinopathy
Schwachman diamond syndrome
AR
Shwachman-Diamond syndrome is the second most common cause of inherited pancreatic insufficiency after cystic fibrosis and the third most common inherited bone marrow failure syndrome after Fanconi anemia and Diamond-Blackfan anemia.
Exocrine pancreatic insufficiency
metaphyseal abnorm
may progress to marrow aplasia
Neutropenia/neutrophil migration defect (can have cyclical neutropenia–> •Recurrent bacterial infections of the upper respiratory tract, otitis media, sinusitis, pneumonia, osteomyelitis, bacteremia, skin infections, aphthous stomatitis, fungal dermatitis, and paronychia are common
high risk AML with GCSF
Congenital neutropenia
signficant infection hx - pneumonia, abscess, gingivitis
elevated monocytes or eosinophils (+ low neu)
Multigene disorder >50% mutation in neurtrophil elastane gene (ELANE)
Kostman's syndrome --> form of CN -assoc with cognitive defects and seizures HAX1 mutation - early onset and severe infections -may need high levels gcsf
DDAVP
promotes release of vWF through releasing endogenous factor VIII
Used in treatment of mild haemophilia A and thrombocytopenia and VWD
Wikott aldrich syndrome
X-linked recessive
- atopic dermatitis
- thrombocytopenic purpura
- small defective plts
- high infection risk
Fanconi anaemia
AR
-very rarely is X-linked
-defect in FA pathway –> important in DNA repair
–> defect results in abnormal cell build-up
- rapidly dividing cells affected esp bone marrow
= bone marrow failure with pancytopenia
- Most common congenital bone marrow failure syndrome (2nd is Diamond black, 3rd is Schwachmann diamond)
- Type of chromosomal breakage syndrome (along with telangectasia ataxia)
-Significant increased risk of leukaemia esp AML
-significant increased risk of head/CNS, neck, GI, genital
=10-30% of children with this will get at least 1
Dysmorphic features:
- ABNORMAL THUMBS
- ABSENT RADII
- cafe au lai spots
- strabismus
- low set ears
- hearing loss
- short
- triangular facies,
- microcephaly
- -abnormal kidneys, decreased fertility
Ix:
Chromosomal breakage studies
Acute splenic sequestration crisis
Splenic sequestration occurs primarily in infants, as early as five weeks old. Approximately 30% children with sickle cell anaemia will have splenic sequestration.
This presents as engorgement of the spleen, a rapid increase spleen size, hypovolaemia and a decreased haemoglobin. Reticulocytosis may be present
It is often precipitated by URTI, bacteraemia, viral infection.
The treatment is to stabilise haemodynamically, and then carry out a prophylactic splenectomy after the first event.
vwd
Von Willebrand disease patients often have normal clotting tests, and if they are abnormal usually have a prolonged APTT AND bleeding time.
Aspirin ingestion
Aspirin would be expected to produce a prolonged bleeding time.
Diamond Black fan anaemia
-Usually AD
Congenital erythroid aplasia (within the bone marrow)that usually presents in infancy (can present later)
- different compared to Schwachman diamond syndrome and Fanconi which are congenital bone marrow failure syndromes with true pancytopenia
- Profound megaloblastic anaemia
- May have low WCC and Plt but not a profound pancytopenia
- Increased risk of AML
-Approximately half of individuals with Diamond-Blackfan anemia have physical abnormalities such as microcephaly, low frontal hairline, hypertelorism, ptosis broad, flat bridge of the nose,small, low-set ears, microngathia
Ix:
- Profound anaemia +/- low plts/wcc
- Absent reticulocytosis
- Absent erythroid progenitors in the BMA, bland film nil significant poikilocytosis
