Haematology 1 Flashcards
What is haematopoiesis?
A process through which all blood cells are derived.
What is the haematopoietic system composed of?
Bone marrow, spleen, liver, lymph nodes and thymus.
Why do all cells in blood start as?
What does this cell then differentiate into (2 options)?
Haemopoietic stem cell
Lymphoid progenitor cells and myeloid progenitor cell
What normal haemoglobin level does an adult male have?
130-170mg
What normal haemoglobin level does an adult female have?
120-155mg
What happens to red blood cells in anemia?
They have a reduction level in haemoglobin below normal.
less oxygen to body
What are the symptoms and what are the signs for anemia?
Symptoms:
- Fatigue
- Dizziness
- Palpitations
- Headaches
- Chest pain
Signs
- Pale appearance
- Tachycardia
- Wide pulse pressures
- Systolic flow murmors
- Congestive cardiac failure
What are the 4 reasons why anemia can develop?
1) Reduced red blood cell production
2) Increased red blood cell destruction (haemolytic anaemia)
3) Loss of red blood cells from the circulation
4) Dilutional effect from increased blood plasma
What are the 3 classifications of anemia cells?
1) Microcytic
2) Normocytic
3) Macrocytic
What is microcytic anaemia mainly caused by and how do we manage this?
- IRON DEFICIENCY
3 ways:
- Poor intake in diet
- Malabsorption
- Increased loss (through peptic ulceration, inflammatory bowel disease)
Management:
- Treat underlying cause
- Oral supplementation
- Blood transfusion if severe
What is normocytic anemia and how it is caused?
Abnormal RBC due to other diseases
- Chronic inflammatory condition (arthritis)
- Chronic infections e.g. TB
- Chronic renal disease
- Malignancies
What is macrocytic anemia and what are the two types?
Enlarged RBC.
- Megaloblastic erythopoiesis
- Normoblastic erythropoisis
What is megaloblastic anaemia?
folate cause
- Associated with folate deficiencies
- Derived from many food sources
CAUSES OF DEFICIENCY:
- Inadequate intake (elderly, alcoholism)
- Malabsorption (Coeliac disease, Crohn’s disease, resection)
- Increased requirement (pregnancy)
- Increased loss (dialysis, liver disease, congestive heart failure)
- Drugs (methotrexate, phenytoin, trimethoprism)
Explain megaloblastic anaemia in terms of Vitamin B12
Vitamin B deficiency:
Can be due to…
- Inadequate intake
- Inadequate section of intrinsic factor
- Inadequate release from food
- Diversion of dietary B12
- Malabsorption
What are clinical features of folate and B12 deficiencies in megaloblastic anaemia?
Folate and Vitamin B12
- Generic symptoms of anemia
- Occasionally mild jaundice
- Glossitis
- Oral ulceration
Vitamin B12
- Periphery neuropathy
- Demyelination with subacute combined degeneration of spinal cord
- Dementia
What is the management for megaloblastic anemia (folate and B12 deficiency)?
- Address underlying cause
- Oral supplementation (for B12 and folate)
- Parenteral vitamin B12
What are normoblastic macrocytosis anaemia causes?
- Alcohol excess
- Liver dysfunction
- Hypothyroidism
- Drugs
What are the two types of haemolytic anaemia (due to decreased RBC lifespan) ?
- Congenital
- Acquired
In terms of congenital haemolytic anaemia, what are the 3 types?
1) Membrane defects - problems with RBC membrane integrity. Mutation leads to increases fragility
2) Enzyme defects - deficiency in glucose-6-phosphate dehydrogenase - leading to reduced glucose metabolism
3) Globin defects
For acquired hemolytic anemia, what are the two classifications?
- Immune
(IgG coated red cells interacting with macrophages leading to phagocytosis)
(Autoimmune processes with antibodies against RBC)
(Autoimmune results from transfusion and production of antibodies) - Non-immune
(Mechanical trauma, burns, infections or drugs)
Explain the structure of haemoglobin
- 2 alpha and 2 beta chains
- Each globin group is associated with a haem group
Why does haemoglobin have high oxygen affinity in high oxygen tension areas?
Oxygen does not need to be released as the surroundings already has enough oxygen.
What is the name of congenital haemolytic anaemia - globin disorder?
Thalassaemia
Either alpha or beta thalassemia (depending on what globin chain is affected).
- Excess chains precipitate in the pre-cursor blood cells leading to premature death of cell
- Precipitated in the pre-cursor blood cells leading to premature death
What is the difference between the alpha and beta thalassemia in terms of what happens to the globin chains when in disease?
Alpha = deletion of genes
Beta = mutation of genes
What is the clinical presentation of thalasseamia?
- Bony deformities
- Growth retardation
- Enlargement of maxilla
- Spacing and migration of upper teeth
What happens in sickle cell anaemia?
Mutation in the B-globin gene leading to interaction of sickle-B globin chinas with normal A globin chains.
Leads to a variant of haemoglobin called HbS.
Results in deformation of the cell into a sickle shape.
What are the clinical manifestations of sickle cell anaemia?
- Chronic haemolytic anaemia
- Hyposplenism
- Acute chest syndrome
- Stokes
- Bone infarction
- Chronic leg ulcers
- Chronic renal disease
What is the management of sickle cells anaemia?
- Give transfusions when necessary
- Avoid vaccinations to prevent hyposplenism
- Prophylactic penicillin
Is it safe to treat patients with sickle cell anemia dental?
Yes!
Can be treated under LA.
What is the ABO system?
This released to the antigen on the RBC cell membrane.
A or B allele leads to antigen modification but O leads to no modifications.
O = universal doner
AB = universal receiver
What is the Rh system of classifying RBC?
- Encoded by 2 genetic loci on one chromosome
- D antigens are relevant here
- Rhd NEGATIVE person is at risk of developing anti-D antibodies after transfusion of Rhd POSITIVE blood
- Main relevance is to Rhd negative mothers as the fetus may be rhd + and have an adverse reaction (need to give mother anti-D drugs)
What are the two types of transfusion reactions that can occur?
1) Acute (within 24h)
Includes:
- Allergy
- Acute haemolytic reaction (destruction of all RBC - fatal)
2) Delayed (days to weeks)
- Delayed haemolytic transfusion reactions
- Transfusion associated graft vs host disease
How do we manage any reactions to a transfusion?
- Stop transfusion!
- Paracetamol
- IV fluids
- Look for signs of anaphylaxis
What is the dental relevance of anaemia?
Oral features of anaemia
- Angular cheilitis
- Glossitis
- Oral ulceration
- Peripheral neuropathies
Can sometimes complicate treatment
Sickle cell anemia can also lead to oral pain, osteomyelitis, trigeminal neuropathy.
How can anemia complicate dental treatment?
1) Bleeding - risk may be increased esp if the patient has liver disease
2) Anesthesia
- Avoid prilocaine
- Avoid GA with thalassemia and sickle cell disease
