Week 2 - Anaemia Flashcards
What is anaemia
A decrease in O2 carrying capacity due to decrease in haemoglobin conc. in blood
Results in less O2 reaching tissues
What are the 4 deficiency causes (aetiology) of anaemia
- Iron deficiency
- Fe is required for haemoglobin (Hb) - Folate deficiency
- folic acid is required for DNA synthesis - Vitamin B12 deficiency
- required for DNA synthesis, amino acid metabolism and fatty acid metabolism - G6PD deficiency
- produces glutathione which protects RBC from oxidising agents / form being oxidised
- oxidation leads to RBC being destroyed quicker
What are other causes of anaemia
- Reduced RBC production
- Renal failure (EPO is not released)
- Deficiency (e.g. Fe, Folate, B12) - Increased requirements
- Pregnancy, breastfeeding (lactation) - Excessive RBC destruction
- sickle cell anemia
- G6PD deficiency - Blood loss
- acute - trauma
- chronic - GIT bleeding
- menstruation
What are the effects of anaemia (pathology)
What are the signs & symptoms of anaemia
- Fatigue
- Breathlessness
- Reduced exercise tolerance
- Pale appearance (pallor)
Other Symptoms:
- Dizziness
- Headache
- Insomnia
- Palpitations
- Tachycardia
What are the 3 classifications of anaemia
- Microcytic
- RBCs are smaller than normal
- CAUSE: Fe deficiency - Macrocytic
- RBCs are larger than normal
- CAUSE: B12 or folic acid deficiency
- e.g. mesoblastic anaemia - Normocytic
- RBCs are normal sized
- anaemia due to blood loss
Classification by colour:
1. Hypochromic = pale cells
2. Hyperchromic = darker cells
3. Normochromic = normal coloured cell
What is the cause of Iron (Fe) deficiency anaemia & how do you manage it (microcytic anaemia)
CAUSE:
- Reduced intake; e.g. poor diet, reduced absorption of fat from small intestines
- Increased requirements; e.g. pregnant, breastfeeding
- Blood loss; e.g. mensustartion, GI bleeding, trauma
TREATMENT - Iron therapy:
1. Oral Iron therapy (1st line treatment)
- administer before food, will have greater Fe absorption
- e.g. Feospan (1-2 daily) OR Ferrograd (1 daily) ~ both MR
- 100-200mg daily to treat deficiency
- 60-130mg for prevention / mild deficiency
- Haemoglobin ↑ after 3-4 weeks, when reach desired level continue taking for 3 months
- many different formulations, e.g. salts, mixtures, diff. doses, combinations
- vitamin C is used in paediatric dose to prevent oxidation of Fe2+ into Fe3+
- Fe plus folic acid (in pregnancy)
- Fe plus vitamin B or ascorbic acid NOT recommended
SIDE EFFECTS: nausea, diarrhoea, constipation, dark stool
- Parenteral (non-oral) Iron Therapy
- ONLY used if oral route not possible
- e.g. unable to tolerate oral Fe, malabsorption (incomplete absorption from SI), renal failure (less EPO produced = less RBC produced)
ISSUES: painful to inject, stains skin, anaphylaxis risk, is slower than oral route,
- ONLY used if oral route not possible
What is the cause of folate / folic acid deficiency anaemia and how do you manage it (macrocytic anaemia)
CAUSE:
- Diet
- folic acid is in polyglutamate form found in food
- polyglutamate is converted into monoglutamate which is absorbed into body + converted into dihydrofolate
- dihydrofolate is converted into active form tetrahydrofolate which is used to produce new RBC
- Malabsorption
- Pregnancy
- Alcohol (ethanol effects conversion of polyglutmate into monoglutatmate)
- Drugs (e.g. methotrexate can affect pathway leading to tetrahydrofolate production)
TREATMENT:
- Oral folic acid
- 5mg daily for 4 months
- recommended in females planning to get pregnant (0.4 to 5mg daily)
What is the cause of vitamin B12 deficiency anaemia and how do you manage it (macrocytic anaemia)
CAUSE:
- Strict veganism (B12 is ONLY found in animal products, can take supplements or in yeast)
- GI surgery (may not have enough gut left to absorb B12)
- Bacterial overgrowth or tape worm (will use up B12 = not enough left for DNA synthesis)
- Lack of intrinsic factor (factor is needed to absorb B12 from stomach)
TRAETMENT:
- Hydroxycobalamin (I/M)
- 1mg alternate days THEN 1mg every 3 months
- life long treatment
How do you manage anaemia due to G6PD deficiency
G6PD = Glucose-6-phosphate dehydrogenase
- G6PD produces glutathione which protects RBC from oxidising agents / being oxidised
- Deficiency = RBC prone to oxidation = RBCs will be destroyed quicker
- Patients with deficiency can develop haemolytic anaemia in response to some drugs e.g. aspirin
TREATMENT:
- identify + stop oxidising agent
- keep patient well hydrated
- blood transfusion if severe
Explain the types of clinical / lab monitoring required for anaemia
Require multiple tests, single test doest give all answers
Tests will indicate if anaemia is microcytic, macrocytic or normocytic
- RBC (red blood count)
- ↓ for all 3 types of anaemia - MCV (mean cell volume)
- gives indication to size e.g. microcytic, macrocytic, normocytic
- vol. ↓ in microcytic, remain same in normocytic etc. - Haemoglobin
- ↓ for all 3 types - MCHC (mean cell haemoglobin conc.)
- ↓ in microcytic and normocytic - Serum FE (amount of iron bound to transferrin)
- ↓ in microcytic and normocytic (due to lack of Fe)
- absorbed ion is transported in plasma attached to transferrin - TIBC (total iron binding capacity)
- ↑ in microcytic and ↓ in normocytic
- TBIC = serum Fe + unsaturated Fe sites - Reticulocyte (is a premature RBC) count
- in all 3 the value will be low in beginning but when treatment is started it starts to ↑ - Serum folate
- NOT clear indicator as levels vary depending on diet / consumption
- i.e. if fasting levels are much lower, if eat a meal rich in Fe levels are higher - Red cell folate
- PREFERRED over serum (is less dependant on diet)
- difficult to measure but gives better indication - Total B12 and Active B12
- Active B12 is PREFERRED over total B12
- Active B12 gives indication of ow much B12 is usable by body, total B12 gives no indication - Methylmalonic Acid
- Levels are elevated in B12 deficiency ONLY
- It is an enzyme which processes B12, if have deficiency = acid builds up
List the adv. and disadv. of the different formulations used to treat iron deficiency anaemia
- Oral iron therapy
- Parenteral iron therapy
What patient advice should be given when dispensing oral iron preparations
- Administer before food, better Fe absorption
- COMBINATION DRUGS: Fe plus vitamin B or ascorbic acid NOT recommended
SIDE EFFECTS: nausea, diarrhoea, constipation, dark stool
