Disorders of the blood Flashcards
What are the main functions of the blood? (4 points)
- Ability to transport nutrients
- Ability to carry and remove waste
- Ability to transport host depences
- Ability to self repair
What makes up the blood? (5 points)
- Cell component
- Plasma proteins (albumin, globulin)
- Lipids
- Nutrients
- Water
Is it easy to make artificial blood?
No, as a lot of things make up normal blood and it is tricky to include all of these things into artificial blood
What does ‘FBC’ stand for?
- Full blood count
What does ‘CBC’ stand for (used in America)?
- Complete blood count
What does ‘RBC’ stand for?
- Red blood cells
What does ‘RCC’ stand for?
- Red cell count
What does ‘WCC’ stand for?
- White cell count
What does ‘PLT’ stand for?
- Platelets
What does ‘HCT’ stand for?
Haematocrit
What is haematocrit?
- What proportion of the blood volume is cells and what proportion is liquid
What does ‘MCV’ mean?
- Mean cell volume
What is anaemia?
- Low haemoglobin levels
- Can have loads of RBC’s with little Hb which causes anaemia or can have few RBC’s with loads of Hb so no anaemia
What is Leukopenia?
- Low White blood cell count
What is thrombocytopenia?
- Low platelets
What is Pancytopenia?
- All cells reduced (low in number)
- Will generally mean that bone marrow is not working as this is where the cells are produced
What happens if someone has 1 blood cell deficiency?
- Reactive change to the invironment
What has happened if someone has multiple blood cell deficiencies?
- Bone marrow failure
What is polycythaemia?
- Raised Hb (opposite to anaemia)
What is leucocytosis?
Raised White blood cell count
What is thrombocythemia?
Raised platelets
What happens if there is one blood cell that is being over produced?
Reactive or pre-neoplastic
What is it called when multiple blood cell levels are raised?
- Pre-neoplastic (myelodysplasia)
What is Leukaemia?
- Neoplastic proliferation of white cell
- usually disseminated (spread through the blood)
What is Lymphoma?
- Neoplastic proliferation of white cells
- BUT not in the circulation, usually a solid tumour
Blood transfusions can be given where one or more components of the blood have to be replaced quickly. Give examples of these components? (3 points)
- Red cells
- Platelets
- Clotting factors
Blood transfusions can be given where the bone marrow cannot produce blood cells. Give 2 examples of these blood cells?
- Red cells
- Platelets
What are the types of antigens in the blood (2 points)
ABO system
- A
- B
- O
- AB
D system (rhesus)
= + or -
What 2 things indicate that a blood transfusion is needed?
- Blood loss
- Specific production problems
(RBC, platelets, plasma proteins - clotting factors, albumin, gamma globulins)
Why in general should you AVOID giving a blood transfusion if at all possible?
- Because we don’t always know what else is in the blood
What is the 1 completely safe way of getting a blood transfusion?
- By giving yourself a blood transfusion
- If getting for example a hip replacement done - patient usually looses about 2 units of Hb - if the paitnet knew they were getting this operation on 8-12 weeks can take blood from the patient before this and it can be stored so when the patient has the operation you can take their blood and transfuse it back into them
What is the process of giving a blood transfusion?
- Sample taken from patient
- Tested against known blood types
- Tested against donated sample
- Matched blood given to patient
What is the first stage in the process of giving a blood transfusion?
Sample taken from the patient - need to find out about their blood
What is the second stage in the process of giving a blood transfusion? (3 points)
Tested against known blood types:
- Basic ABO compatibility
- Rhesus compatibility
- Does not always detect irregular antibodies
What is the third stage in the process of giving a blood transfusion?
- Blood from patient tested against donated sample
- If donated sample and patients sample when put together don’t do anything bad then it should be safe to give them the transfusion
What is the fourth stage in the process of giving a blood transfusion?
- Matched blood is given to the patient
What blood group is a universal donor?
- O
What are 3 possible blood transfusion complications?
- Incompatable blood
- Fluid overload
- Transmission of infection
Incompatible blood is a possible blood transfusion complication. What can this lead to? (4 things)
- RBC lysis
- Fever, jaundice, death
Fluid overload can be a blood transfusion complication. What can this lead to?
- Heart failure
- If a patient is healthy and is not lacking volume but only the extra cells then extra fluid may make any possible heart condition worse
Transmission of infection is a possible blood transfusion complication. What can this lead to? (3 points)
Blood borne viruses
- CMV, Hep B, Hep C, HIV, TT virus
Prion disease
- vCJD
Bacterial Infections
- Syphilis
What is haemostasis?
- The stopping of a blood flow
When does the clotting cascade work?
- continuous process that happens all the time - the rate at which it happens is what changes
What does fibrinolysis in the clotting cascade break down?
- The fibrin inhibitor
What are the three different categories of haemostatic disorders?
- Vascular component
- Cellular component
- Coagulation component
What does a haemostatic disorder of the vascular component cause?
- Retraction of vessel (collagen disorder)
- People who make abnormal collagen means the blood vessels will not act as they should
What does a haemostatic disorder of the cellular component cause?
- Changes in platelets number and function
What does a haemostatic disorder of the coagulation component cause? (2 points)
- Prevents adequate clotting
- Prevents clot lysis
To check that platelet function is okay you can heck the ‘bleeding time’ of a patient. What is this?
- Cut someone and see how long it takes for them to stop bleeding
- If have the right number of platelets generally the platelet function will be normal
- Assume the function is okay unless have a huge number of platelets
Aspirin and NSAID’s will have a permanent effect on platelets. How long before new platelets are formed?
- 7-10 days
For the coagulation component of haemostatic disorders what do you need an adequate amount of clotting factors and an adequate range of clotting factors. What causes an inadequate range of clotting factors?
A hereditary deficiency - Factors V, VIII, IX and XI
To prevent a haemostatic disorder in the coagulation component, what do you need a proper balance between?
- Thrombotic and thrombolytic systems
- If you can make lots of clot but cannot break down again then you have a lot of solid fibrin in your blood vessles - important
- If clots don’t break down adequately then will get clots where they shouldn’t be
Why do people with haemophilia suffer to varying degrees?
- Women tend not to get haemophilia as it is an X-liked clotting factor so if women has 1 abnormal X chromosome then they will still make 50% of the normal clotting factor
- Whereas if men, have one Y and one abnormal X chromosome then they may only make 5%. 10% or any variety of % of normal clotting factor
In a clinical situation when should yo ask if a patient has a history of prolonged bleeding?
- After extractions
- After minor cuts
In a clinical situation what should you look for visual signs of is a patient has a haemostatic disorder? (3 points)
- Purpura
- Ecchymosis
- Petechiae
What is purpura?
- A rash of purple spots on the skin caused by internal bleeding from small blood vessels
What is ecchymosis?
- A discolouration of the skin resulting from bleeding underneath, typically caused by bruising
What is petechiae?
- A small red or purple spot caused by bleeding into the skin
What are the possible investigations you can take to test for haemostatic disorders?
- FBC (platelet numbers)
- Bleeding time (platelet function)
- INR (how easily you can produce a clot) and APPT
- LFT (clotting factor synthesis)
What does LFT stand for?
- Liver function test
What is haemophilia a inherited deficiency of?
- VIII or IX
What effect does haemophilia have on a patient?
- Varying effecr - mild, moderate, severe
- MALES are affected, FEMALES are carriers
What diseases can haemophilia lead to due to blood transfusions? (3 points)
- HBV, HCV, HIV
Thrombophilia is an excessive tendency to clot. Why is this life threatening?
- Can cause a pulmonary embolism
Thrombophilia is a genetic condition but can be exacerbated by thrombo-promoting actions. What are 5 examples of these?
- Smoking
- Immobility - travel
- Surgery
- Pregnancy
- Medicines - oestrogen contraceptive pill
What is therapeutic coagulopathy?
- Where the coagulation system is manipulated by medicine to make clotting less likely
What does therapeutic coagulopathy do? (2 points)
Reduces the platelet adhesion and function
- Usually prevent arterial thrombosis
Reduce activity in the coagulation cascade
- Usially prevent venous thrombosis
What are 3 examples of standard antiplatelet drugs?
- Aspirin
- Dipyrimadole
- Clopidogrel
What are 2 examples of new antiplatelet drugs?
- Prasugrel
- Ticagrelor
W hat is an example of a standard anticoagulant drug?
- Warfarin
What are 3 examples of new anticoagulant drugs?
- Apixaban
- Dabigatran
- Rivaroxaban
What should you always do in a dental respect in relation to haemostatic disorders before treating a patient? (3 points)
- ALWAYS ask about bleeding
- ALWAYS look for bleeding problems
= Skin - red spots or purpura
= Mucosa - purpura or blood blisters
- If in doubt TEST first
= FBC, INR, APPT
If you, as a dentist, know the patient has a haemostatic problem, what should you do? (3 points)
- Ask ADVICE from a dental specialist
- Follow available SDCEP guidance for dental care delivery
- REMEMBER local haemostatic measures
What do you need to know about Porphyria?
- It is BAD
What is Porphyria?
- A group of rare genetic disorders. Called porphyria’s because they cause a build up of chemicals called porphyrins or the simpler chemicals used by the body to make porphyrins
- It is an ABNORMALITY in haem metabolism
How much of the population has porphyria?
- 1 : 10,000
What are the 2 main groups of porphyria?
- Hepatic porphyrias
- Erythropoietic porphyria’s
What is a big problem with people who have porphyria?
- They dont know they have it until they have an acute episode
What are 3 clinically relevant porphyria’s?
Variegate
- Afrikaans decent
Acute intermittent
- Any population group
Hereditary coproporphyria
What are the possible clinical effects of a patient who has porphyria? (4 points)
- Photosensitive rash
- Neuropsychiatric disturbance in acute attacks
(motor and sensory changes, seizures and autonomic disturbances)
- Hypertension and tachycardia
- May be fatal
What are 5 possible triggers of porphyria?
Poorly understood
- Many drugs (important from dental point of view - especially LA)
- Pregnancy
- Acute infections
- Alcohol
- Fasting
What is CMV?
- Cytomegalovirus
What is the prion disease - vCJD?
- Varient Creutzfeldt- Jakob disease
What blood tests could you ask for to test someone’s coagulation? (3 points)
- Ask for FBC
- Platelet Test
- Bleeding time
How does aspirin inhibit the formation of blood clots?
- By preventing platelets from producing a chemical called thromboxane A-2, Which normally induces platelet clumping
- Without thromboxane A-2, platelets cannot stick together and join with fibrin to make blood clot
What is the INR test (international normalised ratio)? (2 points)
- A measure of the patients prothrombin time based on what it would be if measured using the WHO international reference reagent. The INR is used as a standard for monitoring the effects of anticoagulant treatment with WARFARIN.
- The blood test looks to see how well your blood clots
What should a persons INR be if they are taking a blood thinner?
- Between 2 and 3
What is a pulmonary embolism?
- When a blood clot gets caught in the arteries in the lungs
What is an APPT test?
- Activates Partial Thromboplastin Time test
What are 2 examples of local haemostatic measures?
- Pack socket with haemostatic material that will produce a meshwork to control the clot
- Cover with stitches to close the wound
