Week 6 - Haematology Flashcards
3 main functions of the blood?
- transport
- immune system
- coagulation
what does blood transport?
oxygen
nutrients
hormones
waste
blood is composed of?
plasma and cells
in blood: what is plasma composed of?
proteins, lipids, nutrients, hormones, electrolytes, water
in blood: what type of cells are there and what are their functions?
where are these cells produced?
- red blood cells: oxygen and carbon dioxide transport
- white blood cells: immune system
- platelets: clotting
cells are produced in the bone marrow
full blood count - what does it test for?
the number and size of cells
full blood count: what does WBC stand for? what is its normal value? what is indicated if too high or too low?
- white blood cells
4. 00 - 11.00 - too high: leukocytosis
- too low: leukopaenia
full blood count: what does RBC stand for? what is its normal value?
- red blood cells
3. 80 - 5.30
full blood count: what does Hb stand for? what does it reflect? what is its normal value? what happens when below normal value?
- Haemoglobin
- reflects quantity and quality of red blood cells
115-165 - lack of haemoglobin indicates anaemia
full blood count: what does Hct stand for? what does it reflect? what is its normal value?
- Haematocrit
- ratio of the volume of RBCs to the total volume of blood
0. 370-0.470
full blood count: what does MCV stand for? what does it reflect? what is its normal value? what is indicated when MCV is too high or too low?
- mean cell volume
- reflects the size of red blood cells
- 78.0- 99.0
- too big = macrocytic
- too small = microcytic
full blood count: what does MCH stand for? what does it reflect? what is its normal value?
- mean corpuscular hemoglobin
- calculation of the average amount of hemoglobin contained within each of a person’s red blood cells
- 27.0-32.0
full blood count: what does Plts stand for? what is its normal value? what is indicated if count is too low or too high?
- platelet count
- 150-400
- if too high: thrombocythaemia
- if too low: thrombocytopaenia
full blood count: what does Neut stand for? what is its normal value?
- neutrophil count
- 2.00-7.50
full blood count: what does Lymph stand for? what is its normal value?
- lymphocyte count
- 1.50-4.00
describe blood film of patient with neutrophilia?
increased neutrophil presence - sign of infection
describe blood film of patient with malaria?
RBCs infected, parasites visible within cells
bone marrow sample: taken from?
iliac crest or sternum
tests for coagulation?
- activated partial thromboplastin time
- prothrombin time (PT)/ international normalized ration (INR)
- test the function of coagulation
anaemia: deficiency of? how does it occur?
anemia is a haemoglobin deficiency
caused by either the lack of cells or lack of hemoglobin itself
anaemia: causes?
- lack of raw materials
- problem with red cell production
- longevity problem (normal RBC lifespan 120 days)
- losses from circulation
anaemia: what goes into the production of red cells?
- raw materials (iron, B12, folate)
- erythropoetin (increases RBC production in response to falling o2 lvls
- production in bone marrow
- circulation
anaemia due to lack of raw materials:
name the raw materials lacking and why they may be lacking
- iron & folic acid: dietary, rarely malabsorbtion
more likely during periods of increased demand e.g. pregnancy - vitamin B12: pernicious anaemia - autoimmune disease. antibodies attack intrinsic factor which aid absorption of B12
describe blood film of patient with iron-deficiency anaemia
size of red cells reduced, pale in color
anaemia due to production problem: name a hormone that could contribute to anaemia if lacking. reason for this?
- lack of erythropoietin
- could be due to renal failure, since kidneys produce erythropoietin
anaemia due to production problem: bone marrow failure due to? x4
- aplastic anaemia: all cells affected, loss of function
- chemotherapy/immunosuppresants
- haematological malignancy
- anaemia of chronic disease: chronic disease changes the way iron is managed in body
anaemia due to losses from circulation: name 2 examples that could result in a loss of circulating blood, leading to anaemia
- blood loss
- haemolysis: destruction of cells in circulation
anaemia due to losses from circulation: blood loss is the most common cause of anaemia. name 4 reasons for blood loss?
- GI bleeding: possibly due to ulcers and polyps
- menstruation: menorrhagia
- trauma/post operative bleeding
- from other organs: unusual
anaemia due to losses from circulation: what is haemolysis? what are examples of it?
haemolysis: destruction of cells in circulation
- autoimmunity: antibodies attacking RBCs
- abnormal RBCs: sickle cell anaemia, thalassaemia
describe blood film of patient having sickle cell anaemia
RBC has obvious sickle shape, will not pass through spleen or capillary beds -> anaemia
type of anaemia influences? and what will this affect in the blood count?
- type of anaemia influences the cell size
- cell size affects mean cell volume in the FBC
microcytic: caused by what type of anaemia?
- iron deficiency anaemia
macrocytic: caused by what type of anaemia?
- B12/ folate deficiency
- autoimmune
normocytic: what is it? caused by what time of anaemia?
- anaemia without change in volume of cells
- marrow, renal failure leading to anaemia
signs and symptoms of anaemia?
symptoms:
- tired, weak
- breathless
- dizzy
- palpitations
- those specific to cause e.g. blood loss
signs:
- pale
- rapid pulse
- may be oral features (depending on type)
anaemia: management?
- history and examination
- establish type of anaemia
- establish cause
how to establish type of anaemia?
how to establish cause of anaemia?
- simple blood tests - FBC, blood film, Iron, B12, folate
- may require more complex tests i.e. identify bleeding source, cause of hemolysis
anaemia: treatment?
- replace what’s missing:
1. iron sulphate, folic acid, B12
2. erythropoietin
3. blood transfusion if severe and symptomatic - address underlying cause
anaemia - dental aspects:
- oral abnormalities from what deficiencies will present to dentists?
- how will undergoing GA be affected?
- iron, B12, folate deficiency
- O2 capacity affected in anaemia,
- need to verify sickle cell status in all patients of black-african or carribean descent before GA
name 2 white cell disorders?
- neutropenia
- haematological malignancy
neutropenia: caused by?
- bone marrow failure
- auto-immune causes (viral infection)
neutropenia - clinical features?
there is risk of?
- infection of the mouth and throat: candida, virus (herpes), commensal bacteria
- risk of life threatening disseminating infection: from oral infection, from other source
neutropenia - dental aspects:
take note high risk of?
what to avoid?
- high risk of serious disseminated infection
- avoid invasive treatment when suspected i.e. patients on chemotherapy, clinical suspicion
heamatological malignancies: caused by?
name and describe 2 examples
- majority caused by uncontrolled proliferation of white cells
- leukaemia: proliferation of immature cells in blood and bone marrow
- proliferation of cells within lymphoreticular system - nodes, liver, spleen, bone marrow
leukaemia: caused by?
name the 2 forms?
- proliferation of primitive blood cells
- acute (common in children) and chronic
acute leukaemia: presentation?
chance of 5 year survival?
- marrow failure: anaemia, infection, bleeding
- lymphadenopathy
- soft tissue infiltration
- chance finding
- 50% overall
describe the blood film of a patient with leukaemia?
reduced proportion of RBCs
increased presence of lymphocytes
chronic leukaemia:
- affects who?
- may transform to?
- presentation?
- adults
- may transform to acute (blast transformation)
- anaemia, lymphadenopathy
describe the blood film of a patient with chronic leukaemia?
lymphocytes more normal looking - darker and denser
not as low proportion of RBCs
lymphoma: state the 2 main types?
- hodgkin’s lymphoma
- non-hodgkin’s lymphoma
hodgkin’s lymphoma
- mainly affects?
- presentation? (physical and systemic)
- prognosis?
- young adults
- presentation: lymphadenopathy
systemic:
fever, weight loss, severe night sweats, itch, anaemia - 5 year survival - 80%
non-hodgkin’s lymphoma
- presentation in older adults?
- prognosis?
- lymphadenopathy
- systemic: fever, weight loss, anorexia
- prognosis: variable, 50% 5 year survival
haematological malignancies - treatment?
- supportive: transfusion, infection management
- chemotherapy
- radiotherapy
- bone marrow transplant: autologous, allogenic
- novel therapies
haematological deficiencies - what are the primary presentations to dentist?
- atypical infections
- bleeding
- lymphadenopathy
- gum infiltration
coagulation: depends on?
- number and function of platelets
- coagulation cascade
what happens at the site of bleeding after vessel injury? how does it lead to the clot formation?
vessel injury leads to:
- vasoconstriction
- platelet aggregation
- coagulation cascade
clot formation is due to the coagulation cascade and platelet aggregation
platelet problems:
how can they occur? give an example of each
- deficiency: lack of raw materials, e.g. B12, folate
- production problem: bone marrow failure
- destruction:
immune related: autoimmune thrombocytopaenic purpura
portal hypertension: spleen sequestration
platelet aggregation problems: commonly due to?
commonly due to impairment in function because of medical therapy
- aspirin, clopidogrel, dipyridamole
platelet aggregation problems: management?
- treat underlying cause
- platelet transfusion may be necessary
coagulation cascade problems: example of a generalised deficiency?
- protein deficiency:
e. g. liver disease, severe malnutrition
coagulation cascade problems: examples of specific deficiencies?
- congenital problems:
haemophilia, von Willebrand’s disease - drugs: warfarin and heparin + other new agents replacing warfarin and heparin
haemophilia A & B:
- what type of genetic disorder?
- what is each type of haemophilia characterized by?
- severity?
- X-linked genetic disorder
- absent/low clotting factors
VIII - Haemophilia A
IX - Haemophilia B - severity varies
von Willebrand’s disease:
- what kind of genetic disorder?
- characterized by what problem?
- autosomal dominant (males and females affected)
- platelet/ factor VIII function problem
haemophilia/von Willebrand disease: treatment? how does each method work?
- factor replacement: early or prophylactic
- DDAVP (desmopressin): helps body release factor VIII stored within vessel linings
- tranexamic acid: inhibits clot breakdown
haemophilia/von Willebrand’s disease dental considerations - risk management? associated conditions?
risk management:
- avoid trauma
- preparation for bleeding i.e. operations
associated conditions:
- HIV
- hepatitis
coagulation: what is the most common drug prescribed?
what else does it treat?
mechanism?
how to monitor progress?
warfarin
- atrial fibrillation, prosthetic heart valves, DVT, pulmonary embolisms
- interferes with clotting activity
- monitor by INR
warfarin replacements
- increasing usage
- no need for INR testing
coagulation - other drugs?
how are they administered?
heparin + other low weight molecular heparins (dalteparin)
- injectable anticoagulants
- usually in hospital, sometimes community
coagulation - manifestation of problems?
cutaneous bleeding:
- petechiae
- purpura
- ecchymoses
mucosal surface bleeding:
- oral
- GI: either by vomiting blood, melaena, rectal bleeding
- menorrhagia
- haematuria
traumatic bleeding
- post-operative
- on minor trauma
- joints: haemarthroses (haemophilia)
coagulation - dental aspects?
what to look out for?
what happens if there is suspected bleeding disorder?
what if there is a known bleeding disorder?
- identify in history: specific diseases, drugs, symptoms (post-op bleeding, mucosal bleeding)
- do not proceed with treatment, refer patient to GP or hospital first
- liase with GP/haematologist, be aware of specific guidelines for anticoagulants
