Red cells 3 (anaemia) Flashcards
Factors influencing the normal range for haemoglobin
- Age
- Sex
- Ethnicity
- Time of day sample is taken
- Time to analysis
Normal haemglobin range for males
- 12-70 = 140-180
- >70 = 116-156
Normal haemoglobin range for females
- 12-70 = 120-160
- >70 = 108-146
Clinical features of anaemia due to reduced O2 delivery to tissues
- Tiredness/pallor
- Breathlessness
- Ankle oedema
- Dizziness
- Chest pain
Clinical features of anaemia related to underlying cause
-Evidence of bleeding
Menorrhagia, PR bleeding, Dyspepsia
-Symptoms of malabsorption
Diarrhoea, Weight loss
- Jaundice
- Splenomegaly/Lymphadenopathy
What causes destruction/loss of blood leading to anaemia
- Haemorrhage (blood loss)
- Haemolysis
- Hypersplenism (overactive spleen)
What problems with RBCs themselves can lead to anaemia
- Membrane
- Haemoglobing
- Enzymes
What is MCV + MCH
- MCV = Mean Cell Volume (size)
- MCH = Mean Cell Haemoglobin
- Can give morphological discription of anaemia
3 types of anaemia
- Hypochromic Microcytic Anaemia
- Normochromic Normocytic Anaemia
- Macrocytic Anaemia
What investigations are used to distinguish between types of anaemia
- Red cell indices
- Blood film
What investigation is done when Hypochromic Microcytic anaemia is diagnosed
Serum ferritin
What investigation is done when Normochromic Normocytic anaemia is diagnosed
Reticulocyte count
What investigation is done when Macrocytic anaemia is diagnosed
- Serum B12 + Folate assay
- ?Bone marrow biospy?
If serum ferritin is high or low in Hypochromic Microcytic anaemia what is the cause
- Low = Iron deficiency
- High = Thalassaemia/Secondary anaemia/?sideroblastic anaemia?
How does Iron move around the blood
- In haemoglobin
- Bound to Transferrin
How is iron stored in most cells
Ferritin
How is iron transported from enterocytes + macrophages
Ferroportin
What is hepcidin and where is it made
- Synthesised in Hepatocytes
- Responds to inflammation (and increased Fe levels)
- Blocks ferroportin, so reduces intestinal Fe absorption
What do high + low levels of hepcidin cause
- High = Anaemia
- Low = Haemochromatosis
What is ferroportin
- Transmembrane portein
- Transports iron from inside a cell to outside (i.e. out of gut cells into blood)
Commonest cause of anaemia worldwide
Iron deficiency anaemia
DISCRIPTION, NOT A DIAGNOSIS, MUST ESTABLISH A CAUSE
Hx for iron deficiency anaemia
- Dyspepsia, GI bleeding
- Other bleeding, e.g. menorrhagia
- Diet (N.B. children + elderly)
- Increased requirement e.g. pregnancy
Signs of iron deficiency
- Koilonychia
- Angular stomatitis
- Atrophic tongue (smooth + glossy can be tender/painful)
Causes of iron deficiency anaemia
- GI blood loss (worms)
- Menorrhagia
- Malabsorption (Gastrectomy, coeliac disease)
Management of iron deficiency anaemia
Correct cause
- Diet
- Ulcer therapy
- Surgery if bleeding
- ?COC pill if menorrhagia?
Correct anaemia
- Oral iron supplement ussually adequate
- Possible need of transfusion
If reticulocyte count is high or low in Normochromic Normocytic anaemia what is the cause
- High = Acute blood loss or Haemolysis
- Low = Secondary anaemia, hypoplasia, marrow infiltration
Causes of haemolytic anaemia
Congenital
- Hereditary spherocytosis (HS)
- G6PD deficiency
Acquired
-Auto-immune haemolytic anaemia (extravascular)
Intravascular (also acquired)
- Mechanical (artificial valve)
- Severe infection
- Drugs
2 ways of categorising acquired haemolytic anaemia
- Immune (mostly extravascular)
- Non-mmune (mostly intravascular)
How to test for auto-immune haemolytic anaemia
- Direct antiglobin test
- Casuses agglutination in vitro
(if -ve suggests the haemolytic anaemia is not immune mediated)
What is seen on a blood film in intravascular haemolysis
Shcistocytes (red cell fragments)
Management of haemolytic anaemia
-Folic acid (support marrow function)
Correct cause
-Immunosupression if autoimmune (?Prednisolone?)(treat trigger CLL, lymphoma)
-Remove site of destruction (splenectomy)
-Treat sepsis, leaky prosthetic valce, malignancy etc
-Consider transfusion
Describe secondary anaemia
- “Anaemia of chronic disease”
- 70% normochromic normocytic, 30% hypochromic microcytic
- Defective iron utilisation
- Identifiable underlying disease (infection, inflammation, malignancy)
If there is megaloblastic changes or no megaloblastic changes in bone marrow in Macrocytic anaemia what is the cause
- Megaloblastic change = B12 + Folate deficiency
- Non-megaloblastic = Marrow infiltration, Myelodysplasia, Drugs
Causes of B12 deficiency
- Pernicious anaemia
- Gastric/ileal disease
Causes of folate deficiency
- GI disease (coeliac disease)
- Increased requirement (haemolysis)
- Dietary
What happens to the skin in megaloblastic anaemia
Lemon yellow tinge
What causes pernicious anaemia
Antibodies against intrinsic factor (auto-immune)
Rx for megaloblastic anaemia
Replace vitamin
- B12 deficiency = B12 IM injection, loading dose then 3 monthly maintenance
- Folate deficiency = Oral folate replacement
