General Flashcards
Constituents of the blood
Plasma
RBCs
Platelets
WBCs
What % of blood is plasma
55%
What % of the blood is RBCs, Platelets or WBCs
45%
Where are RBCs produced
Bone marrow
Describe appearance of RBC
Biconcave
Anucleated
Lifespan of RBC
120 days
Where does eryptosis occur
Old RBCs are destroyed by spleen, liver and bone marrow
Types of WBCs
Granulocytes
Lymphocytes
Monocytes
Types of Granulocytes
Neutrophils
Basophils
Eosinophils
Features of neutrophil (appearance etc)
Multi-lobular nucleus
Phagocytic and play a role in inflammation, infection and myeloid leukemia
Features of eosinophil (appearance etc)
Bi-lobular or tri-lobular nuclei
Show diurnal variation, being more common in morning
Number raised in parasitic infections
Features of basophil (appearance etc)
Associated with hypersensitivity reactions
Similar role to mast cells - secrete histamine when stimulated
Types of lymphocytes
T cells - mediators in cellular immunity
B-cells - mediators in humoral immunity e.g. antibody mediated responses
Types of T-cells
Cytotoxic (CD8+)
T-helper (CD4+)
Features of lymphocytes
Numbers increase in viral infection, inflammation and leukaemia
Numbers decrease in HIV and chemotherapy
Features of monocytes
Immature cells that differentiate once they leave the bloodstream
Many monocytes form macrophages
Where are platelets derived from
Megakaryocytes in bone marrow
Functions of platelets
Major role in clotting:
Platelet plug and Coagulation cascade (cascade helps to strengthen the platelet plug, ultimately producing fibrin)
Functions of thrombin
Converts fibrinogen to fibrin
Activates factor XIII to XIIIa
Positive feedback effect on further thrombin production
What factors in coagulation cascade are inhibited by warfarin/vitamin K deficiency
2 (pro-thrombin), 7, 9, 10
What factor in coagulation cascade is inhibited by Heparin or NOACs
Xa
What is function of plasmin
Cuts fibrin into fragments
Prevents blood clots from growing and becoming problematic
Important of liver to clotting
Liver synthesises many coagulation factors
Liver produces BILE sals needed for Vitamin K absorption
Examples of Haematological investigations
FBC
Reticulocyte count
Serum ferritin (measure iron levels in body)
Blood film
What can a FBC show you
Red blood cell volume WBC volume Platelet volume Hb conc Mean corpuscular volume etc
Purpose of Reticulocyte count
Allows you to see how quickly the bone marrow is producing new RBCs
What is implied by a low reticulocyte count
indicative that something is preventing RBCs from being produced e.g. a haematinic deficiency
What is implied by a high reticulocyte count
Indicate that RBCs are being lost or destroyed (e.g. bleeding / haemolytic anaemia). New RBC production is increased to act as a compensatory mechanism
When can serum ferritin be falsely high?
Inflammation
Malignancy
Describe process of blood film
Smears of blood are placed onto slides and then examined under a microscope.
Types of Blood film
Thick
Thin
What can you examine with thick blood film
examination of a large amount of blood for the presence of parasites
What can you observe with thin blood film
Observation of RBC morphology, inclusion and Intra/Extra-cellular parasites
Normal function of Hb
To carry and deliver oxygen to tissues
What is the characteristic genetic abnormality in Chronic Myeloid Leukaemia? t(15;17) ATRA gene t(9;22) Philadelphia chromosome t(8;21) AML/ETO gene t(8;14) cMYC oncogene
t(9;22) Philadelphia chromosome
Resulting in 210-kDa fusion protein –activated tyrosine kinase
Chronic myeloid leukamia:
Describe investigations and their results
FBC - high WCC
Film - Left shift + basophilia
Treatment of Chronic Myeloid Leukaemia and how it works
Imatinib:
Blocks abnormal tyrosine kinase activity
Can result in molecular remission
BCR -ABL mutations may result in resistance
What class of drug best describes Rituximab?
Monoclonal antibody
How does Rituximab work
Monoclonal antibody that targets CD20 expressed on cell surface of B-cells
Chimeric mouse/human protein
Infusional side-effects
Widely used
Which age group is characteristically affected by Hodgkin’s lymphoma?
Teenagers and young adults
How is myeloma bone disease usually assessed?
Plain X-ray
Lytic lesions seen
How do lytic lesions result from myeloma bone disease
Production of Osteoclast-activating factors OAFs include RANKL, IL-3 and TNF-α
Examples of Osteoclast-activating factors
RANKL, IL-3 and TNF-alpha
What is the correct mechanism of action for the anti-emetic drug Ondansetron? Peripheral D2 antagonist Central D2 antagonist Anti-cholinergic 5HT3 antagonist
5HT3 antagonist
For chemo induced
Anti-emetic for gastostasis
Pro-kinetics
In sickle cell anaemia what would you expect to see the reticulocyte count?
Raised
How many RBCs are lost per hour in body
9 billion
Bacterial infection usually causes? Low lymphocytes Low neutrophils High lymphocytes High neutrophils
High neutrophil count
Which best outlines the approach to the management of a patient with suspected febrile neutropaenia?
Encourage fluids and paracetamol
Perform cultures and wait for results before starting antibiotics
Perform cultures and start oral antibiotics
Perform cultures and start broad spectrum iv antibiotics
Perform cultures and start broad spectrum iv antibiotics
Treatment of Febrile Neutropaenia
Haematologic emergency ABC Perform cultures Broad spectrum iv Abs with 1 hour E.g. Tazosin and Gentamicin
Malignant spinal cord compression usually presents with:
Back pain, ataxia and sensory neuropathy
Back pain, spastic paresis and a sensory level
Perianal numbness and urinary incontinence
Weak legs impaired joint position sense
Back pain, spastic paresis and a sensory level
*Treatment of malignant spinal cord compression
Emergency Urgent MRI Bed rest + pressure area care Steroids Analgesia Chemo or Radiotherapy
How does Aspirin exert its antiplatelet effect?
Inhibition of Cyclooxygenase enzyme
How does Tirofiban exert its antiplatelet effect
Inhibition of Glycoprotein IIb-IIIa
How does Clopidogrel exert its antiplatelet effect
Inhibition of P2Y12
Describe platelet function
P2Y12 and Glycoprotein IIbIIIa help make ARACHIODONIC ACID
->PGH2:
with COX1 -> TXA2
or with COX2 -> PGI1
