HEAM Flashcards
ANAEMIA:
def
• Present when there is a decrease of haemoglobin in the blood below the reference
level for the age and sex of the individual
Red blood cell’s (RBC) lifespan is
120 days
There are three major types of aneamia:
- Hypochromic (pale) MICROCYTIC - low MCV
- Normochromic NORMOCYTIC - normal MCV
- MACROCYTIC - high MCV
MICROCYTIC ANAEMIA:
- Main causes:
- Iron deficiency anaemia - the MOST COMMON CAUSE WORLDWIDE
- Anaemia of chronic disease
- Thalassaemia (see inherited red cell disorders)
Iron deficiency anaemia Tx:
- Find and treat cause
- Oral iron e.g. FERROUS SULPHATE
• Side effects; nausea, abdominal discomfort, diarrhoea/constipation
and black stools
• FERROUS GLUCONATE if side effects are bad - Parenteral iron e.g IV iron or deep IM iron in extreme cases e.g. severe malabsorption
NORMOCYTIC ANAEMIA:
- Main causes:
• Acute blood loss • Anaemia of Chronic Disease • Endocrine disorders such as hypopituitarism, hypothyroidism and hypoadrenalism • Renal failure • Pregnancy
MACROCYTIC ANAEMIA:
Main causes:
Sub-types
• Megaloblastic: delayed nuclear maturation because of delayed DNA synthesis - these are megaloblasts, they are large (i.e. high MCV) and have no nuclei - Vitamin B12 deficiency (known as COBALAMIN) - Folate deficiency • Non-megaloblastic: erythroblasts are normal i.e. normoblastic - Alcohol - Liver disease - Hypothyroidism - Haemolysis - Bone marrow failure (aplastic anaemia) - Bone marrow infiltration - Antimetabolite therapy - Myeloma
Pernicious anaemia Tx
- If a low B12 is due to malabsorption then injections are required
- If cause is dietary then give oral B12
- Replenish B12 stores by giving IM HYDROXOCOBALAMIN
Folate deficiency:
Treat underlying cause
- Give FOLIC ACID TABLETS daily for 4 months - NEVER WITHOUT B12 as
well (unless the patient is known to have NORMAL B12) since in low B12
states it may precipitate/worsen subacute combined degeneration of the spinal cord
HAEMOLYTIC ANAEMIA:
Main causes:
RBC types (2)
• RBCs can be either NORMOCYTIC or if there are many young RBC’s (which are
larger) due to excessive destruction of old RBCs then MACROCYTIC
- RBC membrane defects:
• Hereditary spherocytosis
- Enzyme defects:
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency
- Haemoglobinopathies:
• B Thalassaemia
• A Thalassaemia
• Sickle cell disease
- Autoimmune haemolytic anaemia
HAEMOGLOBIN: • Normal Hb (HbA) = Haem +?chains • Foetal Hb (HbF) = • Hb delta (HbA2) = • In an adult: - HbA = % - HbA2 = - HbF =
• Normal Hb (HbA) = Haem + 2 alpha chains + 2 beta chains
• Foetal Hb (HbF) = Haem + 2 alpha chains + 2 gamma chains
• Hb delta (HbA2) = Haem + 2 alpha chains + 2 delta chains
• In an adult:
- HbA = 97%
- HbA2 = 2%
- HbF = 1%
THE THALASSAEMIAS - DEF + types
disorders of quantity (reduced production):
Beta Thalassaemia = Reduced B chain synthesis
• Alpha Thalassaemia = Reduced A chain synthesis
BETA THALASSAEMIA:
Tx:
Regular (every 2-4 weeks) life-long transfusions to keep Hb above 90g/L and to suppress the ineffective extramedullary haematopoiesis and to allow normal growth
- Iron-chelating agents to prevent iron overload; oral DEFERIPRONE & SC
DESDERRIOXAMINE:
• Side effects; pain, deafness, cataracts and retinal damage
• Decrease iron loading when having infusions
• Iron overload is a big problem
- Large doses of ASCORBIC ACID to increase urinary excretion of iron
SICKLE CELL ANAEMIA - DEF
Tx:
A disorder of quality (abnormal molecule or variant haemoglobins):
FOLIC ACID to all haemolysis patients
Oral HYDROXYCARBAMIDE:
- Increases HbF concentrations
APLASTIC ANAEMIA DUE TO BONE MARROW FAILURE:
Immunosuppressive therapy with ANTITHYMOCYTE GLOBULIN (ATG) and
CICLOSPORIN in those:
• Over 40
• Below 40 with severe disease who do not have a HLA identical sibling donor
• Those who are transfusion dependent