anaemia - presentation, diagnosis and treatment Flashcards
what is anaemia?
what is the haemoglobin range typically in an adult male?
what is the haemoglobin range typically in an adult female?
when the number of red blood cells or haemoglobin concentration is lower than typically normal
- For Hb typically in adult male = 135-175g/l
- For Hb typically in adult female = 120-155 g/l
define MCV
define MCH
define MCHC
define RDW
what equations would be used to calculate each of the above?
MCV - mean cell volume
- Haematocrit (Hct) (%) X10
RBC count (number as 1012/l)
MCH - mean cell Hb
- Hb
RBC
MCHC - mean cell Hb concentration
- Hb
Hct
RDW - red cell distribution width is a measure of spread of RBC size e.g retics/ transfusion
what are the symptoms relating to the cause of the anaemia? (5)
- “Tired all the time”- need to unpack this
- Symptoms relating to reduced O2 delivery eg:
- short of breath
- muscle pain on exertion
- dizzy
- angina
what are the clinical signs relating to the cause of anaemia?
- Pallor in skin and conjunctiva
- Tachycardia
- Rapid breathing
- Peripheral oedema if severe anaemia
how does anaemia cause adaption?
- cardiac output increases (rate and stroke volume) if anaemia present
- changes in distribution of blood flow
- changes in O2 dissociation curve (decreased 2,3-DPG when anaemia present)
mild anaemia is likely to cause no symptoms unless extreme exertion
in what four ways is anaemia classified?
define microcytic/normocytic/macrocytic/hypchromic MCVs
- there is either an underproduction or an increased loss of RBC
- it is either cogenital or acquired
- it is either acute or chronic
- it can also be classified by mean cell volume (MCV)
- Microcytic- MCV 60-80fl-iron def, thalassaemia
-
Normocytic- MCV 80-100fl- blood loss, anaemia
of chronic disease, renal impairment -
Macrocytic – MCV 100-120fl-megaloblastic
anaemia- B12/folate deficiency, myelodysplasia - (Hypochromic- MCH pg 22-26 iron def,
thalassaemia)
iron deficiency anaemia:
how common is iron deficiency anaemia?
how does it appear on a full blood count?
- commonest cause of anaemia worldwide
- it is typically a reduction in mCV (microcytic) to 65-80
(from For Hb typically in an adult male = 135-175g/l and in an adult female = 120-155 g/l))
iron deficiency anaemia:
what are the causes?
what are the clinical features?
what are the investigation methods for iron deficiency anaemia?
causes
- poor intake of iron
- blood loss through:
- menstrual
- GI tract: haematemesis (upper gut issues** causing vomiting of blood), melaena (upper gut issues** causing blood in feces)
- **peptic ulcer, cancer, angiodysplasia - abnormality with blood vessels in gut, hookworm - parasitic worm in intestine
clinical features
- pale
- tachycardia - increase heart rate
- koilonychia - nails which become thin and flat, even concave (aka. spoon nails)
- hair loss
- pica - affects person’s thinking and behaviour
- glossitis - soreness or inflammation of the tongue /angular stomatitis - inflammation of the corners of the mouth
- features relating to cause e.g: weight loss, abdominal pain, bowel change, heavy periods
investigation
- guided by history - recent and past clinical findings
- confirmed iron deficiency by low ferritin and typical FBC (full blood count)
- screen for coeliac disease (IgA tissue transglutaminase or tGA)
- upper and lower endoscopy for all except pre-menopausal women
- consider other imaging/capsule endoscopy
what are the two types of treatment options for ion deficient anaemia?
what are the side effects of each option?
treatment:
oral treatment
- Oral- replacement with sufficient iron for long enough period eg. ferrous sulphate 200mg 2 or 3 per day- 65mg elemental iron per dose
- Side effects- nausea/abdo pain/constipationdose related - may improve if changed to ferrous gluconate or fumarate
- Typically patients need 3 months of iron AFTER
correction of anaemia to build up iron stores - Treat the underlying cause
- Rise in Hb generally 10g/l per week if not bleeding
parenteral treatment
- Intramuscular- not used now- painful, multiple doses, stains skin
- Intravenous:
- Ferric carboxymaltose- ferinject- over 15-
30mins. Often needs 2 doses - Iron dextran- cosmofer- over 4-6 hours after a
test dose.
- Ferric carboxymaltose- ferinject- over 15-
- All IV iron preparations can cause ‘flu like symptoms and a small risk of hypersensitivity reaction or anaphylaxis
how does B12 deficiency anaemia appear on a blood count?
what can B12 deficiency anaemia also cause?
what are the three main causes?
what are the two options of treatment?
- typically a macrocytic anaemia - MCV 100-120 and later pancytopenia (reduced RBCs, WBCs and platelets) and a raised bilirubin and LDH raised
- can also cause peripheral neuropathy - demyelination and posterior column damage
causes
- B12 result can be falsely low in pregnancy/oral contraceptive/on metformin
- can be caused by pernicious anaemia - in which gastric atrophy and auto antibodies to parietal cells and intrinsic factor preventing absorption
- can also be caused by strict vegan diets or terminal ileas disease (lack of movement in intestine)
treatment
- Hydroxocobalamin 1mg IM alternate days for 5 doses then 3 monthly if confirmed ongoing need eg pernicnious anaemia
- Cyanocobalamin available orally but not available on prescription
how does folate deficiency appear? and how does its full blood count appear?
how can folate deficiency develop?
what are the causes?
what is the treatment?
- Blood count and film appearance same as
B12 def: a **macrocytic anaemia - MCV 100-120 and later pancytopenia (reduced RBCs, WBCs and platelets) and a raised bilirubin and LDH raised** - Limited stores of folate so deficiency can develop in weeks
causes
- Poor intake, increased use eg pregnancy/haemolysis, malabsorption, drugs eg anti-epileptics or trimethoprim
treatment
- Replacement with oral folic acid 5mg per day
- Pre-conception folic acid reduces neural tube defects - UK plan to add folic acid to flour
anaemia through blood loss:
what are Hb levels like immediately after blood loss and then after fluid replacement?
how long does the retic response take?
what is used to replace blood loss?
how is blood lost?
- Hb concentration immediately after blood loss will be normal and then there is a drop after fluid replacement
- each 500 ml loss gives approximately drop of Hb by 10-15g/l
- retic response within hours/days
- a blood transfusion is needed to replace loss
- blood loss can be due to trauma, GI bleed, around delivery
anaemia of chronic disease:
what is normocytic anaemia associated with? (Normocytic- MCV 80-100fl- blood loss, anaemia of chronic disease, renal impairment)
what are the contents of blood like?
how is anaemia of chronic disease investigated?
- Typically a normocytic anaemia associated with chronic inflammatory disease
- Plentiful iron stores but poor transfer to RBC due to hepcidin and cytokines
- History of chronic disease, inflammatory markers increased eg CRP/ESR/plasma viscosity, exclusion of other causes
Anaemia of renal failure:
what are the contents of blood like in a patient with anaemia of renal failure?
what is renal failure due to?
what is the treatment?
- Drop in Hb once creatinine clearance drops below 20-30 ml/min chronically
- Mainly due to lack of erythropoietin as well as a contribution from blood loss at dialysis, inflammatory disease
- Responds well to erythropoietin eg weekly or alternate weeks s/c
anaemia by haemolysis:
what is haemolysis?
in what two ways can anaemia be classified?
what are the issues which cause anaemia by haemolysis?
- Increased or premature RBC destruction, marrow can increase production 5-10 fold
- Can be acute or chronic, congenital or acquired
- Issues to do with:
- RBC membrane
- RBC enzymes
- Globin chains in Hb
-
****RBC membrane****
- Congenital spherocytosisautosomal dominant defect in spectrin causing spherical cells to be less able to deform so shortened
survival
- Auto-immune haemolysis - auto antibodies against RBC surface antigens - Fc portion recognised by macrophages in spleen.- Treated with steroids/splenectomy/rituximab
-
**********RBC membrane and enzymes************
- Prosthetic heart valve- mechanical
- Disseminated intravascular coagulation (DIC)- eg in sepsis, prostate cancer causing RBC fragmentation by fibrin
- RBC enzyme def eg G6PD or pyruvate kinase can cause shortened RBC survival
