Red Cell Disorders (REVISE) Flashcards
What percentage of anaemias are from iron deficiency
95%
Is diet a significant cause of anaemia
No it is very rarely a cause
Different types of anaemias
Iron deficiency anaemia Megaloblastic anaemia Haemolytic anaemia Aplastic anaemia Sickle cell Thalassaemias
Symptoms of Anaemia
Shortness of breath
Weakness/Lethargy
Tachycardia
Does skin colour (not race; literal colour) indicate anaemia; what else/alternative
Skin colour not a reliable sign, as this is determined by blood flow. Nail bed and conjunctiva may be pale
What might severe anaemia cause in elderly
Angina
Oral manifestations of anaemia (REVISE)
Glossitis (painful red tongue)
Angular cheilitis (fissures at corner of mouth)
How might DPG levels change in anaemic patients
DPG may be elevated in RBCs so O2 more readily given up to tissues
Microcytic Anaemia
Anaemia caused by decreased MCV; type of iron deficiency
Why does iron deficiency anaemia cause microcytic anaemia
Body is starved of iron so RBCs are abnormally small as one of their main components is depleted
Label
Usual treatment for Iron Deficiency Anaemia
Usually Iron Sulfate (FeSO4)
Find and treat the underlying cause (e.g. GI Bleeding, menstrual problems)
REVISE
Normocytic Anaemia
Patient has normal-sized red blood cells, but a low number of them
Renal Anaemia
Kidney produces EPO, so in chronic kidney disease, RBC production is not stimulated which causes normocytic anaemia
REVISE MINORLY
How do pregnancies affect anaemia
Dilution and/or iron deficiency as the foetus is taking iron from the mother
Hormones of pregnancy increase MCV while iron reduces it causing normocytic anaemia
REVISE MINORLY JUST DOUBLE CHECK
Megaloblastic Anaemia
Abnormal RBC maturation due to defective DNA synthesis, out of step with cytoplasmic development; bone marrow contains megaloblasts
Macrocytic
Due to Vit B12 or folate deficiency - increased incidence in alcohol abuse
REVISE SIGNIFICANTLY, MAYBE EVEN MORE THAN ONE CARD
Folic Acid
Essential for thymidylate synthesis (Rate limiting step in DNA synthesis as thymidine is a pyrimidine base)
Obtained through foods
DNA Synthesis mechanism
B12 is relevant or something; folate is similar???
REVISE ASF
Methotrexate
Anti-cancer drug and immunosuppressant in rheumatoid arthritis and other diseases
Inhibits dihydrofolate reductase, therefore folate regeneration impaired
They are supplemented with occasional folate to avoid megaloblastic anaemia
Pernicious Anaemia
Lack of intrinsic factor for absorption of B12 due to autoimmune disease - treat with hydrocobalamin i.m
REVISE
Crohn’s Disease
IBD
Malabsorption of B12, folate or iron
Haemolytic Anaemias and causes
Increased rate of RBC destruction
Caused by:
Spherocytosis - genetic - abnormal reduction in RBC membrane protein (spectrin) - cells fragile
Acquired - Haemolytic transfusion reaction, malaria, drug-induced
Symptoms of Haemolytic anaemias
Jaundice (?) and enlarged spleen
Folate deficiency may occur due to increased erythropoiesis
Sickle cell anaemia
Single Nucleotide Polymorphism (Val -> Glu. Acid)
Abnormal Hb - insoluble forms crystals at low O2, causing RBC forming sickle shapes and potentially blocking microcirculation
Causes haemolytic anaemia
Clinical Features of Sickle Cell Anaemia
Vaso-occlusive crisis Pain Reduced life expectancy Risk of stroke Managed by transfusions
Ethnicity Bias of Sickle Cell Anaemia
Very common in sub-saharan africa as the trait has advantages against malaria
2% of Nigerian newborns are affected
8% of black population are carriers
Thalessaemias
Genetic disorder - reduced rate of alpha or beta globin units production many variations
Deletion of both alpha genes leads to death in uterus as Hb (γ4) produced
One alpha=gene deletion reduces RBC volume and haematocrit
Ethnicity of Thalassaemia
REVISE
Aplastic Anaemia
Insufficient production of RBCs, WBCs and platelets (pancytopenia); Although may just be RBCs (pure red cell aplasia)
Symptoms of aplastic anaemia
Decreased resistance to infections, increased bleeding, increased tiredness
How is aplastic anaemia acquired
Cytotoxic (anticancer) agents
Chloramphenicol
Sulphonamides
Insecticides
REVISE!!
Treatment of Aplastic Anaemia
Bone marrow transplant - with tissue match
Immunosuppressants - to prevent immune destruction of stem cells
Colony-stimulating factors - increase WBC count
REVISE!!
Polycythaemia
Opposite of Anaemia; Increased Hb content and haematocrit
Increased blood viscosity - poor tissue perfusion
Signs and Symptoms of Polycythaemia
Ruddy appearance Cyanosis Headaches Blurred vision Hypertension
Causes of Polycythaemia
Primary: Changes in bone marrow, stem cell defect
Secondary: Increased erythropoietin - altitude, smoking, renal carcinoma, COPD
Treatment of polycythaemia (primary and secondary)
Primary - Taking blood from patient regularly (venesection)
Giving patient radioactive phosphorus which causes bone marrow suppression (myelosuppression)
Cytotoxic Agents (myelosuppression)
Secondary polycythaemia is treated by treating the root cause
