Haematology Flashcards
What is polycythaemia (erythrocytosis)?
an increase in Hb, PCV and RBC
What is absolute polycythaemia?
true increase in red cell volume, primary or secondary
What is relative or stress/spurious polycythaemia?
normal red cell volume, decreased plasma volume, can occur in dehydration and burns
Is Hb or PCV a better indicator for polycythaemia?
PCV, as Hb could be low during iron deficiency
What is a normal PCV in the blood?
45%
Primary causes of polycythaemia?
polycythaemia rubra vera, epo receptor mutations, high oxygen affinity Hb
Secondary causes of polycythaemia?
increase in epo from hypoxia, smoking, high altitude, chronic lung disease, anoxia and tumour
What is polycythaemia rubra vera?
stem cell disorder with an alteration in the pluripotent progenitor cell, >95% in JAK2 mutations
What is the JAK2 gene?
a signal transducer, especially those triggered by haemopoetic growth factors
Symptoms of polycythaemia rubra vera?
tiredness, depression, vertigo, tinnitus, hypertension, angina, intermittent claudication, severe itching after hot bath, gout and peptic ulcer, plethora, deep dusky cyanosis, splenohepatomegaly, easy bleeding
What complications can polycythaemia lead to?
thrombosis
Treatment of polycythaemia?
venesection, chemo (IFN and hydroxyurea), low dose aspirin for thrombosis prophylaxis, anagrelide, radioactive 32P, surgery to prevent leukaemia (splenectomy), keep PCV and platelet count low, cytotoxic myelosuppresion hydroxycarbamide, regular removal of blood, phlebotomy to keep haematocrit
How many polycythaemia cases develop into myelofibrosis or AML?
myelofibrosis in 30%
AML in 5%
What will investigations show in polycythaemia?
raised haematocrit, Hb, RCC, MCV, raised WCC and platelets, neutrophil leucocytosis, o2 sat >92%, thrombocytosis, splenomegaly,
What will bone marrow show in polycythaemia?
bone marrow hypercellular with prominent megakaryocutes, low epo
What is the WHO diagnostic criteria for polycythaemia?
2 major and 1 minor or main major and 2 minor
What are the major criteria for polycythaemia?
Hb>16.5g/dL in women and 18.5d/dL in men
red cell mass >25% above normal
JAK2 617V F mutation
What are the minor criteria for polycythaemia?
BM biopsy showing hypercellularity
low serum epo
endogenous erythroid colony in vitro
increased serum uric acid and vit b12 and vit b12 binding protein
What is the prognosis of polycythaemia without treatment?
6-18 months
Why is uric acid increased in polycythaemia?
increased RBC breakdown, increases uric acid
Treatment of secondary polycythaemia?
phlebotomy to maintain circulation and reduce viscosity
treat underlying condition
o2 for hypoxia, weight loss, smoking cessation, surgery to correct AV shunts
hydroxyurea
What is disseminated intravascular coagulation?
widespread inappropriate fibrin deposition within the vasculature from increased tissue factor
What are the causes of DIC?
infection - meningococcaemia, septicaemia, malaria, varicella, CMV, HIV
malignancy - AML, mucin secreting adenocarcinoma
obstetric complications - amniotic fluid embolus, retained placenta, septic abortion
anaphylaxis
trauma, burns
liver failure
pancreatitis
heat stroke, acute hypoxia, blood loss, snake venom
Pathophysiology behind DIC?
activation of the coagulation pathway in response to infection, this uses up platelets and coagulation factors so secondary activation of fibrinolysis leading to fibrin degradation products which inhibit fibrin polymerisation, and no platelets left for other clotting
Clinical features of DIC?
acutely ill, shock, can be no bleeding or widespread haemorrhage, bleeding from mouth, nose, venepuncture
Where in the body is mainly affected by DIC?
skin, brain and kidneys
What will investigations show in severe DIC?
prolonged PT, APPT, TT low fibrinogen level high FDPs and D dimer due to intense fibrinolytic activity, stimulated by the prescence of fibrin severe thrombocytopaenia blood film shows fragmented RBC
What will investigations show in mild DIC?
without bleeding
raised FDPs
increased synthesis of coagulation factors and platelets
normal PT, APTT, TT and platelets
What is the treatment of DIC?
transfusion of platelet concentrates, FFP, cryoprecipitate and RBCs if bleeding
activated protein c concentrates
NO inhibitors of fibrinolysis as may cause fibrin deposition
Complications of DIC?
gangrene from thrombosis
Are PT and APTT intrinsic or extrinsic?
PT - extrinsic
APTT - intrinsic
What makes up cryprecipitate?
fibrinogen, factor VIII
What are the 2 main platelet disorders?
idiopathic thrombocytopenic purpura
thrombotic thrombocytopenic purpura
What is a petechia?
individual purple spots in a purpuric rash
What is thrombocytopenia?
a reduced platelet production in the bone marrow, excessive peripheral destruction of platelets or sequestrian in an enlarged spleen
What causes immune/idiopathic thrombocytopenia purpura (ITP)?
immune destruction of platelets after binding to Fc receptors on macrophages - caused by congenital thrombocytopenia (absent or malfunctioning MK in BM), infiltration of bone marrow (lymphoma, leukiemia, myeloma), reduced TPO production (liver disease), low platelet production (low B12/folate, low TPO, toxins), dysfunctional production of platelets (myelodysplasia)
What is the onset like for children and adults in immune/idiopathic thrombocytopenia purpura (ITP)?
acute in children
chronic in adults
At what age is immune/idiopathic thrombocytopenia purpura (ITP) most common in children?
2-6years
What are the symptoms of children immune/idiopathic thrombocytopenia purpura (ITP)?
mucocutaneous bleeding, severe bleeding (recent viral infection)
Is immune/idiopathic thrombocytopenia purpura (ITP) more common in males or females?
females
What other diseases is immune/idiopathic thrombocytopenia purpura (ITP) associated with?
autoimmune illnesses, CLL, solid tumours, HIV
Clinical features of immune/idiopathic thrombocytopenia purpura (ITP)?
rare major haemorrhage if severe, easy brusing, purpura, epistaxis, menorhagia, bleeding, splenomegaly
What will investigations show in immune/idiopathic thrombocytopenia purpura (ITP)?
isolated thrombocytopenia, bone marrow examination, platelet autoantibodies, increased or normal megakaryocytes in bone marrow, FBC, peripheral blood smear
Treatment of immune/idiopathic thrombocytopenia purpura (ITP) in children?
no treatment unless serious bleeding
Treatment of immune/idiopathic thrombocytopenia purpura (ITP) in adults?
1 - oral corticosteroids
IV IgG to raise platelet count
2 - splenectomy
3 - high dose corticosteroids, IV IgG, chemo
anti D immunoglobulin, immunosuppressants, platelet transfusion
When would you not have to treat immune/idiopathic thrombocytopenia purpura (ITP) in adults?
when platelets are >30x90^9/L unless they are having surgery
What can cause immune thrombocytopenia?
heparin induced, neonatal induced, post transfusion purpura
How do neonates cause immune thrombocytopaenia?
due to fetamaternal incompatibility for platelet specific antigens
How does blood transfusion cause thrombocytopaenia?
rare, but also occurs in patients previously immunised by blood transfusion of pregnancy
Where are platelets destroyed in immune/idiopathic thrombocytopenia purpura (ITP)?
in the spleen
What is thrombotic thrombocytopenia purpura (TTP)?
platelet consumption leads to profound thrombocytopenia
Causes of thrombotic thrombocytopenia purpura (TTP)?
familial or acquired
secondary to cancer, HIV, pregnancy, certain drugs, idiopathic
Treatment of thrombotic thrombocytopenia purpura (TTP)?
plasma exchange to increase ADAMTS-13, plasmapheresis, corticosteroids, rituximab
How can you monitor treatment in thrombotic thrombocytopenia purpura (TTP)?
platelet count and serum LDH
Where do micro thrombi from thrombotic thrombocytopenia purpura (TTP) usually affect?
kidneys, heart, brain
Neurological symptoms caused by thrombotic thrombocytopenia purpura (TTP)?
stroke, headaches, delirium, bizarre behaviour, hallucination
What anaemia occurs in thrombotic thrombocytopenia purpura (TTP)?
microangiopathic haemolytic anaemia - small blood clots damage RBC causing intravascular haemolysis
pathology behind thrombotic thrombocytopenia purpura (TTP)?
reduced ADAMTS-13 so reduced break down of ultralarge von willebrand factor multimers (ULVWM), so it accumulates, with platelet aggregation and clots in multiple organs
What conditions have microangiopathic haemolytic anaemia?
thrombotic thrombocytopenia purpura (TTP), DIC and HUS
complication of thrombotic thrombocytopenia purpura (TTP)?
AKI
clinical features of thrombotic thrombocytopenia purpura (TTP)?
fiond purpura, fever, fluctuating cerebral dysfunction, microangiopathic haemolytic anaemia, red cell fragmentation, AKI
How does thrombotic thrombocytopenia purpura (TTP) affect lactic dehydrogenase levels?
raises them due to haemolysis
What can cause over anticoagulation?
warfarin, heparin, rivaroxaban, dabigatran
What converts fibrinogen to fibrin?
thrombin
Anitdote of rivaroxaban and dabigatran?
none
antidote of heparin over anticoagulation?
protamin
What is thrombocytosis?
platelet count above 400x10^9/L leading to thrombosis
Causes of thrombocytosis?
splenectomy, malignant disease, inflammatory disorders, major surgery, post haemorrhagic, myeloproliferative disorders, iron deficiency
Treatment of thrombocytosis?
treat underlying cause, aspirin, hydroxycarbamide to reduce platelet count, dialysis
What does the liver produce to stimulate platelet production form magakaryocytes by binding to platelet and MK receptors
thrombopoietin
What is the charge on an activated platelets phospholipid surface
negative - to allow coagulation factors to blind
What produces thromboxane A2?
arachidonic acid in platelets via COX-1
function of thromboxane A2?
induces aggregation and vasoconstriction
What conditions consume platelets?
DIC, TTP, HUS, HELELP, major haemorrhage
What is heparin induced thrombocytopenia?
development of an IgG antibody against the complex form between platelets and heparin and instead binds to and activates platelets forming thrombosis and platelet consumption, most at risk after unfractioned heparin treatment or cardiac bypass surgery
What is Von Willebrand Disease?
deficiency of von villebrand factor leading to impaired platelet adhesions and aggregation
Treatment of heparin induced thrombocytopaenia?
alternative anticoagulation, never reexpose to heparin
How does heparin induced thrombocytopaenia present?
sharp fall in platelets 5-10 days after starting heparin treatment
What are the 2 types of P2Y12 receptor inhibitors?
thienopyridines and non thienopyridines
Types of thienopyridines?
clopidogrel - hepatic CYP2c19 conversion into active metabolite 2 step process
prasugrel - single CYP step therefore faster transformation into active metabolite, rapid action but greater risk of bleeding
Types on non theinopyridines?
ticagrelor - reversibly binding oral P2Y12 anatgonist, does not require metabolic conversion to an active form, so faster onset of action
Example of GP IIbIIIa inhibitors?
tirofiban - non peptide tyrosine derivative, rapid onset, rapid reversibility of anti platelet effect
Life span on platelets?
7-10 days
shape of platelets?
disc shape to allow them to flow close to endothelium
How are old platelets removed?
phagocytosed by splenic macrophages in red pulp
Function of thrombopoietin?
decrease in platelets, cause increase in TPO to increase binding to MK and platelet receptors to increase platelet production
Platelet physiology?
platelets adhere to damaged endothelium via collagen and vWF. Binding of collagen stimulates cytoskeleton shape change for increase in SA, releases ADP, fibrinogen, thrombin and Ca2+ from platelet granules. Aggregation of platelets by fibrin, coagulation factors bind.
What chromosome if vWF gene on?
12
What are the 4 types of vWF disease?
1 - poor quantitative deficiency (autosomal dominant)
2 - qualitative abnormality (autosomal dominant)
3 - near complete deficiency (autosomal recessive)
4 - type normandy
Clinical features of type 1 and 2 vWF disease?
bleeding post trauma or surgery, epistaxis and menorrhagia
Clinical features of type 3 vWF disease?
severe bleeding but rare joint and muscle bleed
Treatment of vWF disease?
desmopressin, plasma derived factor VIII concentration that contain vWF treat bleeding and surgery, cryoprecipitate
function of vWF?
binds to GpIb receptor on platelets to subendothelial collagen and transport of factor VIII
Causes of vit K insufficiency?
warfarin, malabsorption, alcholism, CF, CKI, cholestatic disease
Symptoms of vit K insufficiency?
inrease PT and PTT, bruising, haematuria, GI bleeding
Treatment of vit K insufficiency?
IV phylomenadione, vit supplements, vit k rich foods
What is haemophilia?
X linked recessive bleeding and bruising disorder
What is haemophilia A?
factor VIII deficiency, normal vWF
Clinical features of haemophilia A?
mild - bleeding after injury or surgery later in life
moderate - severe bleeding post injury, occasional spontaneous bleeds
severe - frequent spontaneous bleeding into joints and muscles lead to deformity
What are the factor VIII levels in haemophilia A?
normal = 50-150iu/dL
mild = >5
moderate = 1-5
severe =
What will investigations show in haemophilia A?
low factor VIII, coagulation factor assay, increased PTT, normal PT, increased APPT
Treatment of haemophilia A?
educate, counselling, testing, avoid anticoagulants
mild - desmopressin
severe - require IV replacement with plasma concentration factor VIII
What is the half life for factor VIII and therefore how many time is replacement necessary?
12 hours, twice a day
What complications can haemophilia A lead to?
patients immune system may start to reject the IV plasma factor VIII
joint destruction by recurrent bleeding
Which is more common haemophilia A or B?
A
What is haemophilia B?
factor IX deficiency (xmas disease)
Treatment of haemophilia B?
educate, counselling, testing, avoid anticoagulants, desmopressin, IV infusion of factor IX, gene therapy
What is the half life of factor IX and how often is a given in haemophilia B?
18 hours, twice a week
Complications of haemophilia B?
joint destruction by recurrent bleeding
What is malaria?
an infectious disease caused by parasitic Plasmodium, spread by the female Anopheles mosquito
What are the 4 species of the plasmodium infection?
plasmodium falciparum, plasmodium virax, plasmodium ovale, plasmodium malariae
Which plasmodium species causes a more severe illness?
plasmodium falciparum
Which plasmodium species is most likely to relapse after many years?
plasmodium virax and plasmodium ovale
Symptoms of malaria?
fatigue, night sweats, flu like symptoms, fever of 41, diarrhea, nausea, vmiting, anaemia, splenomegaly, siezures
Complications of malaria?
cerebral malaria, anaemia, DIC, blackwater fever, jaundice, splenic rupture, tertian fever, quartan fever
What is Tertian fever?
fever that recurs every second day for 48 hours
What is Quartan fever?
fever that recurs every fourth day
What does cerebral malaria cause?
decreased consciousness, confusion, convulsions, coma
What is blackwater fever?
widespread intravascular haemolysis causing dark urine
If a patient presents with fever and foreign travel, what should you think of?
malaria
When does mortality increase with malaria?
if less than 3 years or pregnant
When do malaria symptoms usually present?
within a month of bite
What is used for malaria diagnosis?
thick and thin blood films - look at the number of infected cells to detect level of parasitaemia
What medications are given for malaria prophylaxis?
atovaquone with proguanil or quinine with doxycycline
What does the treatment of malaria depend on?
type of malaria, severity and where is was caught
What medications are used to treat malaria?
atovaquone with proguanil or quinine with doxycycline
contraindications for atovaquone-proguanil?
pregnant/breast feeding, severe kidney problems
Side effects of atovaquone-proguanil?
stomach upset, headaches, skin rash, mouth ulcers, expensive
Why are Chloroquineand proguanil not prescribed for malaria as much now?
largely ineffective against plasmodium falciparum, but good in places where that species is less common
Investigations for malaria?
bloods
blood film - parasites on Giemsa stained thick/thin film
renal time PER
antigen detection kits
lumbar puncture to exclude bacterial infection
What disease protects against malaria?
sickle cell disease (and lacking the Duffy antigen)
What malaria species causes anaemia and hepatosplenomegaly?
p.vivax, p.ovale
How does a mosquito infect a human with malaria?
female mosquito is infected after taking a blood meal containing gametocytes and the protozoa develop in the mosquito and the sporozoites migrate to the salivary glands so inoculate a human when biten
Where do sporozoites migrate to in the mosquito in malaria?
salivary glands
What happens to sporozoites once inoculated in a new human host?
travel to liver, infect hepatocyts, and multiply then from schizonts and then merozoites, the hepatocytes then rupture so merozoites released into the blood stream, continue to replicate until RBC ruptures which can then be transferred to feeding mosquito
How could vaccines prevent malaria?
maintain high antibody levels to prevent infection
can prevent transfer
can prevent progression of disease
What drug inhibits haem metabolism?
lumfantrine
What drug inhibits falciporum sarcoplasmic?
endoplasmic reticulum calcium ATPase
What drug inhibits haem polymerase?
chloroquine, and quinine
What drug inhibits plasmodial protein synthesis?
doxycycline
What measure help prevent malaria?
mosquito eradication, bed nets, insect repellent, antimalarial prophylaxis
Management of uncomplicated malaria?
chloroquine
artemisnin based drug
primaquine to eradicate hepatic hyponozoiles to prevent relapse
artemisinin based combination therapy
Management of severe malaria?
IV artesunate, ICU for ventilation, blood tranfusion, monitor fluid balance, treat complications e.g. hypoglycaemia
What is hyperreactive malarial splenomegaly?
exaggerated immune response to repeated infections causing anaemia, massive splenomegaly, elevated IgM levels
What is anaemia?
reduced red cell mass w/wo reduced Hb concentration
What is the normal Hb conc for male and female?
male = 13.1-16.6g/dL female = 11-14.7d/dL
What is a normal MCV?
82-96fl
Life span of RBC?
120 days
Where are RBC produced and removed?
produced in bone marrow, removed in spleen, liver, bone marrow and blood loss
What are the 3 sizes of RBC?
microcytic
normocytic
macrocytic
What does anaemia cause?
reduced O2 transport, tissue hyposxia, increase tissue perfusion, increase O2 transfer to tissues
What investigations show be done for anaemia?
WBC. platelet, reticulocute, blirubin, blood film, ferritin, transferritin
Anaemia symptoms?
tired, malaise, reduced exercise tolerance, SOB, angina, claudication, symptoms of underlying cause, palpitations
Signs of anaemia?
pallow, pale mucous membranes and palmar creases, glossitis, angular stomatitis, kylonichia
What is the most common form of anaemia?
microcytic
what causes microcytic anaemia?
iron deficiency, chronic disease, sideroblastic anemia, thalassaemia
What foods have iron in?
vegetables and grains
Where is haem iron absorbed?
proximal intestine via the intestinal haem transporter HCP1 in the duodenum (upregulated in iron deficiency and pregnancy)
Is haem iron or non haem iron more rapidly absorbed?
haem
What is haem used for?
Hb production
What causes lack of iron?
use more, lose more, lack of it in diet, bleeding
What is the usual serum iron level?
13-32umol/L
How is iron transported in the body?
2 ferric ions bound to transferrin, normally only 1/3 saturated, iron then binds to erythoblasts and reticulocytes in marrow and removed
How much iron is stored in the HB?
2/3rds
When is other iron stored?
reticuloendothelial cells, hepatocytes and skeletal muscle cells and plasma
How is iron lost?
faeces, urine, sweat, menstruation
What conditions cause an increase in iron?
hereditary haemochromatosis (mutation in HFE gene) and secondary haemochromatosis (iron overload from blood transfusion)
What causes iron deficiency?
blood loss from GI or uterus, hookworm, poor diet
Clinical features of iron deficiency?
brittle nails, spoon shaped nails, atrophy of papillae of tongue, angular stomatitis, brittle hair, dysphagia and glossitis
What will investigations show in iron deficiency anaemia?
microcytic hypochromic RBC, decreased iron, increase binding sites, decreased serum ferritin, increased serum soluble transferrin receptors
What is the treatment of iron deficient anaemia?
treat the cause, ferrous sulphate 200mg, treat for 3 months post resolving
Side effects of ferrous sulphate medication?
constipation
What chronic diseases cause anaemia?
TB, Crohn’s, RA (inflammatory disease)
How does chronic disease cause anaemia?
high levels of hepadin, lack of erythropoetin and renal disease cause decrease of iron from bone marrow to erythroblasts, inadequate erythropietin response to the anaemia and decreased RBC survuval
What is normocytic anaemia?
seen in anaemia of chronic disease, endocrine disorders and some haemotological disorders
What are the two types of macrocytic anaemias?
megaloblastic and non megaloblastic depending on bone marrow findings
What is a megaloblastic anaemia?
presence of erythroblasts with delayed maturation due to defective DNA synthesis in bone marrow
What causes folate deficiency?
poor intake, excessive utilization, malabsorption