Anaemia Flashcards
What is the main function of red blood cells
Circulate oxygen around the body and remove CO2
What is erythropoiesis
Synthesis of RBCs
steps of erythropoiesis
EPO secrete from kidneys, which stimulates stem cells in bone marrow to develop into a mature erythrocyte
What other things are required for erythropoiesis
Fe
Folate(B9- for DNA synthesis to produce cells)
What is anaemia
- Fewer RBCS than normal OR
- Less haemoglobin than normal in each RBC
What is anaemia in pregnant women reffered to as
Dilutational anaemia - as they have an expansion in blood volume and higher oxygen needs
What is the clinical definition of anaemia in quantity of haemoglobin IN MEN
Hb < 13g/dL
What is the clinical definition of anaemia in quantity of haemoglobin IN WOMEN
Hb <12g/dL
* lower due to menstrual cycle
What are the two main causes of Anaemia
- Increased haemoglobin loss
- reduced haemoglobin synthesis
what conditions cause an Increased haemoglobin loss
- Hemorrhage - injuries, trauma
- haemolysis(splitting of RBCs) - due to infections, medications and cancers, autoimmune disorders
What conditions cause reduced haemoglobin synthesis
- Reduced proliferation of precursors(i.e iron deficiencies, renal failure, aplastic anaemia)
- precursors not maturing effectively(iron. folate defiency, vitamin B12, disorders of globin synthesis/thalassemias )
What are 8 symptoms of anaemia
Fatigue
Increased HR
Shortness of breath
Headache
Dizziness
Chest pain
Paleness
Coldness
What is microcytic anaemia
Low mean corpuscular volume (smaller red blood cells)
What is the common cause of microcytic anaemia
iron deficiency
What 7 blood tests are there for anaemia
- Haemoglobin
- RBC
- Mean corpuscular volume
- Haematocrit - proportion of RBC in blood
- Ferritin (iron stores)
- Folate
- B12 levels
Where do we get iron from
Solely from diet
Where is iron absorbed
Duodenum and proximal jejunum
What the 3 causes of iron def anemia
- inadequate iron absorption (poor diet to malabsorption)
- increased blood loss (i.e menstruation, PUD)
- Increased requirement (i.e pregnancy)
What pregnancy complications of iron defiency anaemia
Pre-term delivery
Maternal post partum fatigue and depression
What would a blood test for iron deficiency anaemia show
Low hb
Low MCV
Low ferritin(<30mcg/L confirms diagnosis)
Low mean cell haemoglobin(hypochromia)
What should we exclude in iron deficiency anaemia
- Other anaemias,
- GI bleed,
- GI cancer
When should we refer those with iron defiency
- GI symptoms
- FIT test result of 10mcg Hb in feces
- Men and post-menoposal women, unless clearing no GI bleeding
- Pregnant women with hb<70g/L or advanced gestation 34 weeks+
- Unresponsive to tx
- positive coeliac seriology
- profound anaemia with symptoms of heart failure
What is tx of Iron def anemia
One tablet daily of either
- Ferrous sulfate
- Ferrous fumarate
- Ferrous gluconate(exc One tablet BD)
Which=65mg of elemental iron
What should you do initially if ferrous salt not tolerated/causes S/E for iron deficiency anaemia
Reduce to alternative daily dosing
or take with/ after food but this reduces efficacy
How long should you continue elemental iron supplementals for iron deficiency anaemia after corrected
3 months
How much should Hb rise by after 1 month of iron supplementation
20g/L or 10g/L(alternate day dosing)
What are side effects of elemental iron
Constipation.
Diarrhoea.
Epigastric pain.
Faecal impaction.
Gastrointestinal irritation.
Nausea.
What are iron rich foods
Dark green vegetables
Red meat
Apricots
Prunes
Raisins
When should you review patient on iron supplementation
3-4 weeks after initation
If no response(did not rise by 20g/L) then refer.
What patients can take ongoing iron supplementation for prophylaxis
Recurrent anaemia where further investigations not indicated,
Plant-based diet,
Malabsorption disease,
Menorrhagia,
Pregnant women (continue throughout pregnancy)
Should you refer pregnant women with iron deficiency anaemia
Yes if they have significant symptoms and or/severe anaemia(Hb<70g/L) OR if pregnancy at advanced gestation(34 weeks)
What level of ferritin would confirm Iron deficiency anaemia diagnosis
30mcg/L
When is parenteral iron necessary
- oral therapy unsucessful
- Continuing blood loss or malabsorption
How is parenteral dose calculated
According to body weight and iron need(Hb deficit)
Check SPC for products dosing
what is the risk of parenteral iron
Iron overload
Severe Hypersensitivity reactions(Anaphylaxis)
What is ferinject
Parenteral Iron
How much ferinject can be given in a single week
1,000 mg
How do you calculate dose of ferinject?
- Patient weight and Hb - then look at table for dose
- Calculate maximum cumulative dose(to ensure it dose not exceed)
- if over 1000mg then split administration by 7 days
- how much diluent is need and how long is infusion(check table in SPC)
How many tablets of ferrous gluconate should be taken for iron deficiency anaemia
Two (300mg) tablets daily
300mg is equivalent to 35mg of elemental iron
aside from iron deficiency anaemia, what are two other microcytic anaemias
- Anaemias of chronic diseases
- Sideroblastic anaemia
What conditions cause anaemia of chronic disease
Inflammatory conditions such as Crohns, UC, Rheumatoid arthritis
Cancers( + cytotoxic agents also impact this)
Renal disease
What happens in anaemias of chronic inflammatory diseases
Inflammatory cytokines cause the liver to produce hepcidin which decreases iron absorption from the gut and reduces the release of iron from body stores
What happens in anaemias of chronic renal disease or heart failure
decreased production of EPO –> leads to anaemia
How do you treat anemia of chronic disease
- Treat the underlying condition- anaemia should resolve.
- Do NOT treat these patients with iron – functional disorder, not actual deficiency (and reduced absorption of iron)
How do you treat anaemia of chronic kidney disease (Hb falls to <10-11g/dL and patient has symptoms)
- ESAs (erythropoietic stimulating agents) i.e Epoetin
- Give SC Once weekly - if they also have iron deficiency give IV iron therapy. Serum ferritin levels should not rise above 800mcg/L
What is sideroblastic anaemia caused by
abnormal utilisation of iron during heme production in erythropoiesis.
Are iron stores(ferritin) low in anaemia of chronic diseases
Normal ferritin but iron is not circulation (low serum iron)
What are sideroblast
Erythroblasts which contain excessive iron granules arranged in a distinct ring around the nucleus
Are iron stores low in sideroblastic anaemia
No they are normal
What causes sideroblastic anaemia
- myeloproliferative disorders i.e myeloma/leukemia
- hereditary
- drugs - TB drugs isoniazid/pyrazinamide, Chloramphenicol, alcohol
- Copper deficiency
Treatment of sideroblastic anaemia
Discontinue the drugs/toxins
X-linked sideroblastic anaemia - Trial pyridoxine 50-200mg daily - takes several months to see results, if severe: Blood transfusion may be required to move oxygen around the body.
Idiopathic sideroblastic anaemia - Pyridoxine high dose 100-400mg daily
What does megaloblastic anaemias mean
They are macrocytic having a raised MCV >100fL
what are the two main causes of megaloblastic anaemias
Vitamin B12 deficiency
Folate deficiency
What is Pernicious Anaemia
an Autoimmune condition causing gastric atrophy of parietal cells which secretes intrinsic factor
Intrinsic factor is required for B12 absorption from the gut –> anaemia
what is the role of Vitamin B12 and Folate
Essential co-factors in the synthesis of DNA precursors purine and pyrimidines.
This is essential for rapidly dividing cells such as red blood cells
What drugs can cause megaloblastic anaemias
Medications which modulate purine metabolism (e.g. azathioprine, MMF, allopurinol) or interfere with pyrimidine synthesis (e.g. hydroxyurea, trimethoprim), or both (e.g. MTX)
What food contain B12
animal products such as fish, eggs and dairy products
What the Blood tests results indicative of megaloblastic anaemia
Hb reduced,
MCV Increased,
Bilirubin increased – as cells haemolyse,
Serum B12 (cobalamin) and Folate will be reduced (One or both are low),
Serum autoimmune antibodies (parietal cell and IF),
Bone marrow examination
LFTs, TFTs to identify underlying cause
What the further features of megaloblastic anaemias
Glossitis(smooth/ pale tongue)
Anorexia
Mild jaundice
Sterility
Altered bowel habits
What is a serious distinctive feature of B12 deficiency
neurological involvement
- Loss of sensation(symmetrical neuropathy)
- Visual disturbances
- Muscle weakness
- Loss of mental or physical drive
What is the level of folate described in folate deficiency
<3mcg/L
what causes folate defiency
- deficient intake of folate foods
- Alcoholism
- GI disorders (i.e coeliac disease impairs absorption)
- Pregnancy (preferential to foetus- deficiency in utero increases risk of neural tube defects in child)
- Haematological disorders
- Medications
What foods contain folate
leafy geen vegetables(spinach, cabbage, kale)
Beans and legumes
Fortified breads and cereals
What drugs cause folate deficiency
Phenytoin
Barbiturates
Sulfasalazine
Oral contraceptives
Methotrexate
Trimethoprim
How do you manage folate deficiency
- Assess their dietary intake
- Check for coeliac disease(antibodies)
- Replace with folic acid - 5mg daily
- Replace B12 deficiency first or concurrently(check B12 in patients with folate deficiency as folate can mask symptoms of B12 deficiency)
What level is B12 deficiency diagnosed
<200ng/L
What drugs cause B12 deficiency
Tb drugs
Metformin
5-ASAs
Colchicine
PPI
What drug treatment should you use for unknown cause of B12 deficiency without neurological involvement
IM hydroxocobalamin 1mg every 2-3 months for life
PO cyanocobalamin large doses 500-1000mcg daily
How is B12 given
- Initial replacement
- Maintenance doses
if there is neurological involvement in B12 deficiency what should you do
Start IV hydroxycolabalamin
Refer to specialist
Treatment for B12 deficiency of a dietary cause
- Dietary advice
- Oral Cyanocobalamin between meals
- if poor adherence(IM hydroxocobalamin 1mg/3 weeks)
- Stop tx when corrected or possibly life long if vegan diet
What are the 4 haemolytic anaemias
- Autoimmune
- Sickle cell
- Thalassemia
- G6PD deficiency
What is sickle cell anaemia
Structural abnormality of red blood cells, resulting in deformed sickle shaped cells.
These cells cannot pick up oxygen well or flow through the body well
Is haemoglobin low in sickle cell anaemia
Yes
What is a sickle cell crisis
- blood vessels to part of body become blocked due to sickle shape.
- Extremely severe pain lasting days or weeks
Why might sickle cell patients also be on folic acid 5mg
Increased cell breakdown, so compensatory increased erythropoiesis (overactive bone marrow), increased demand for folate
What other treatments are sickle cell patients on
- Blood transfusions or hydroxycarbamide(specialist)
- Iron transfusion
- Prophylactic antibiotics (spleen damage)
How do they treat sickle cell crisis
IV fluids, Analgesia, antibiotics if infection
What is G6PD?
Glucose 6-phosphate dehydrogenase is an enzyme helps protect RBC from damage and premature destruction.
what is G6PD deficiency and its relevance to anaemia
without the enzyme, these patients have a susceptibility to develop acute haemolytic anaemia when taking certain drugs, when they have infection or when eating fava beans.
What drugs have a definite risk of causing haemolytic anemia in someone with G6PD deficiency
Nitrofurantoin
Fluroquinolones (ciprofloxacin)
Rasburicase
Sulfonamides
What drugs have a possible risk of causing haemolytic anemia in someone with G6PD deficiency
Aspirin(acceptable up to 1g daily)
Chloroquine (acceptable for malaria)
Menadione(vit K3)
Quinine - (acceptable for acute malaria)
Sulfonylureas
What is thalassaemias
it is an inherited autoimmune recessive disorder in which there is little to no haemoglobin production.
What is the most severe type of thalassaemias and what can it cause
Beta-thalassaemia and can serious organ damage/ life-threatening complications.
How do you manage thalassemias
Manage with regular blood transfusions.
What is the cure of thalassaemias
Stem cell or bone marrow transplant
