Blood Flashcards
The correct name for RBCs =
The correct name for WBCs =
RBCs= Erythrocytes
WBCs = leukocytes
Lifespan of an erythrocyte is __
120 days
All blood cells are derived from:
Haematopoietic stem cell
Myeloid stem cells matures into:
Erythrocytes, platelets, eosinophil, neutrophils, basophils
What is leukaemia
Cancer of the haematopoietic stem cell in bone marrow
What are the 4 classifications of leukaemia (in chronology of when they present)
Acute Lymphoblastic
Chronic Lymphoblastic
Chronic Myeloid
Acute Myeloid
Outline acute lymphoblastic leukaemia
- acute proliferation of a single type of lymphocyte (usually beta)
- causes replacement of other cells in bone marrow
- most common cancer in children (peaks ~2-4 yrs age)
Outline Chronic lymphoblastic leukaemia
chronic proliferation of lymphocytes (usually B)
Richter’s transformation = can transform into high-grade lymphoma
what are ‘smudge cells’ and what do they suggest?
during preparation of blood film, the fragile WBC rupture to leave a smudge on the film
Chronic lymphoblastic leukaemia
Outline Chronic Myeloid Leukaemia
3 phases:
Chronic (~5 years durations, often asympto)
Accelerated (abnormal blast cells)
Blast (even high proportions of blast cells, often fatal)
Outline Acute Myeloid leukaemia
Most common leukaemia in adults
Blood films will show Auer Rods (rods in the cytoplasm)
Define pancytopenia
(pan = many, cyt = cell, penia = lack of)
A lack of all 3 cellular blood components,
Anaemia, Leukopenia, thrombocytopenia
What are oral manifestations of leukaemia
- New/rapidly changing gingival hyperplasia +/- bleeding, ulceration, petechial haemorrhages (pinprick red/brown macules on hard palate)
How is leukaemia diagnosed
Bone marrow biopsy
FBC (full blood count)
CT, MRI, PET
Define lymphoma
Umbrella term encompassing a range of cancers derived from lymphocytes
What is the difference between lymphoma and leukaemia?
Leukaemia = develops in bone marrow
Lymphoma = develops in lymph nodes
What outlines Hodgkin’s lymphoma?
- Prescence of Reed-sternberg cells (multinucleated cells in lymph nodes)
- preferentially in cervical lymph nodes
Risk Factors for Hodgkin’s lymphoma
- Family history
- HIV/AIDs
- EBV (Epstein-Barr Virus)
Tx for Hodgkin’s lymphoma
Radiotherapy as often well localised
What differentiates Hodgkin’s vs non-Hodgkin’s lymphoma?
Presence (Hodgkins) or absence (non-hodgkins, (85% of lymphomas) of Reed-Sternberg cells
Clinical presentation of Non-Hodgkin’s lymphoma:
- Cervical lymphadenopathy
- fever
- night sweats
- Cancer red flags (unexplained weight loss, loss of appetite, fatigue)
Tx of non-Hodgkin’s lymphoma
depends of grade of disease
combo of local radiotherapy and chemo (Rituximab)
Define Myeloma
Blood cancer arising from plasma cells (B lymphocytes that produce specific antibodies)
Same thing as multiple myeloma (it’ll always occur in more than one location)
Aetiology of Myeloma
DNA is damaged during development of plasma cells, causing abnormal replication, all producing the same antibody
Problems associated with myeloma
normally issues come from the build-up of the excessive antibody (paraprotein)
- deposition into organs can cause kidney failure
What are the key CRAB features of Myeloma?
C - calcium (hypercalcaemia)
R - Renal failure
A - anaemia
B - bone disease
Dental impacts of myeloma
Hyperviscocity of blood - spontaneous bleeding
impaired renal function
MRONJ from medications
What can happen after a bone marrow transplant?
Graft vs Host Disease
Effects of leukaemia/myeloma on pt:
- infections from lack of WBCs (longer lasting, more severe)
- bleeding and bruising in skin from thrombocytopenia
- medications
- side effects of chemo
Define Anaemia
reduction of haemoglobin in the blood
what are the normal ranges of haemoglobin?
Males = 13.5 g/dL
Females = 11.5g/dL
What is MCV (Mean Corpuscular volume)
describes size of erythrocytes, measures mean cellular volume
Give 2 examples of what causes Macrocytic anaemia
Macrocytic - large RBCs
-B12 deficiency anaemia
- Folate deficiency anaemia
Give an example of what causes microcytic anaemia
Iron-deficient anaemia (usually due to diet, chronic blood loss)
Key causes of anaemia:
- reduced production (chronic inflammation, leukaemia, marrow failure)
- increased loss of RBCs (bleeding, haemorrhoids, trauma, peptic ulcer)
- increased demand (pregnancy, malignancy)
Signs and symptoms of anaemia:
- pale conjunctiva
- depapillation of tongue (smooth)
- common oral ulcerations
Tx of anaemia:
Treat the cause =
Folate deficiency - folate tablets
iron deficiency - iron tablets
B12 deficiency - B12 intramuscular injections
Dental relevance of anaemia
- lots of dental presentations
- Reduced O2 carrying capacity (sedation/GA risk)
- more prone to candidiasis
What is thalassemia, and what are the two types?
Hereditary condition (autosomal recessive) affecting the globin protein chains of haemoglobin, RBCs break down more easily
2 types: Alpha is affects the alpha chains, Beta if affects the Beta chains
What are some presentations of thalassemia?
Splenomegaly - spleen swells to collect all destroyed RBCs + act as seive
Dental Relevance of thalassemia:
- Chronic anaemia
- Cirrhosis
- iron deposition in all glands (inc. salivary) = xerostomia
- GA and sedation risk from <O2 carrying
Aetiology of Sickle Cell Anaemia
Mutation in the HBB (Beta-Haemoglobin Gene)
Autosomal Recessive - causes sickle shaped RBCs and Haemolytic anaemia (anaemia from excess haemolysis)
Outline what happens during a sickling crisis:
Umbrella term for acute conditions:
- Painful > sickle shape clogs capillaries, causing distal ischaemia
- Sequestration > sickle cells pool in liver, spleen
- Aplastic > Bone marrow just gives up producing RBCs
Outline the steps involved in Haemostasis:
- Vascular spasm
- platelet plug
- blood coagulation
- growth of fibrous tissue
What is the intrinsic pathway of haemostasis?
exposure of sub-endothelium collagen in vessel wall
What causes the extrinsic pathway of haemostasis?
cells releasing Tissue Factor after damage, foreign body
What pathways does Warfarin Act on?
2, 7, 9 ,10
Which pathways does Apixaban, Rivaroxaban and Edoxaban act on?
Activation of factor X -> Xa
Outline clot breakdown
Thrombin catalyses plasminogen to plasmin, which causes fibrinolysis
Describe the action of aspirin
Irreversibly binds to platelets, inactivates COX enzymes required for thromboxane (kickstarts platelet aggregation, inflammation)
Describe action of clopidogrel
Binds to P2Y12 receptor, irreversibly presents ADP mediated aggreagation
Takes a long time to wear off
irreversible antiplatelet
Frequency of platelet turnover
~ every 10 days
Do you stop clopidogrel or aspirin for dental surgery?
No. (they bind irreversibly, stopping it the day before is going to do nothing anyway)
Never give aspirin to ____
Children: link to Reye’s syndrome (high morbidity, multi-organ swelling)
How is the INR calculated
Prothrombin time of pt / prothrombin time of a control group
prothrombin relates to factor 7 activity
What is the half-life of warfarin?
around 48 hours
Why do you not stop warfarin for dental care?
if you do, pts are at an increased risk of severe thromboembolic event (there’s a reason they’re on it in the first place)
What can cause dangerous interactions with warfarin?
Antifungals, antibiotics, grapefruit juice, NSAIDs
Metronidazole, Erythromycin
Carbamazepine (decreases INR)
What is tranexamic acid used for?
prevents blood clot from being broken down, promotes clotting in surgery in secondary/tertiary care centres (expensive)
