11. Anaemia Flashcards
What is anaemia
defined as a low level of haemoglobin in the blood
an- means without
-aemia refers to blood
what does mean cell volume tell you (MCV)
the size of the RBC
what does the mean corpuscular haemoglobin (MCH) tell you
the average mass of Hb per RBC
what does mean corpuscular haemoglobin concentration (MCHC) tell you
the concentration of Hb in a given volume of packed red blood cells
What are the main causes of microcytic anaemias (mnemonic tails)
Thalassaemia Anaemia of chronic disorders Iron deficiency anaemia Lead poisoning Sideroblastic anaemia
What are the main causes of normocytic anaemia (3A and 2H)
acute blood loss anaemia of chronic disease aplastic anaemia haemolytic anaemia hypothyroidism
what is macrocytic megaloblastic anaemia
this is a result of impaired DNA synthesis preventing the cell from deciding normally and so it keeps growing into a larger, abnormal cell
Folate or B12 deficiency
what are some causes of normoblastic microcytic anaemia
alcohol reticulocytosis hypothyroidism liver disease drugs such as azathioprine (immunosuppressant)
what are the generic symptoms of anaemia
tiredness SOB headaches dizziness palpations worsening of other conditions such as angina, heart failure or peripheral vascular disease weakness
what are the symptoms/signs specific to IDA
PICA which is dietary craving for abnormal things such as dirt Hair loss headache, especially with activity sore or smooth tongue brittle nails or hair loss spoon shaped nails angular chelitiis
what are the generic signs of anaemia
pale skin
conjunctival pallor
tachycardia
raised RR
in what kind of anaemia does jaundice occur in
haemolytic anaemia
in what kind of anaemia does bone deformities occur in
Thalassaemia
in what kind of anaemia does koilinychia, angular chelitis, atrophic glossitis and brittle hair and nails occur in
iron deficiency anaemia
Define and describe hypochromia
the red blood cells are paler than normal ad this can be evaluated by the mean corpuscular haemoglobin (MCH)
note that in hypochromia the area of central pallor is increased
true or false: microcytic anaemias are associated with hypothermia ie they have less Hb in them than normal
true
Is adult dietary iron deficiency common
no, it is uncommon
why does normocytic anaemia from blood loss take several hours to be detected
the loss of blood volume will be replaced by either non-red cell containing fluids or by natural plasma expansion
note that it could be that there has been only limited fluid replacement
Why does rapid blood loss not immediately affect the Hb levels
the Hb is measured as a concentration of red cells in plasma and is not an absolute value
If you loose 1000ml of blood, this represents what amount of iron loss
500mg
B12 information:
Tell me about transcobalamin (TCN1), aka heptocorrin, R factor and R. protein
it is a glycoprotein produced by the salivary glands of the mouth protects cobalamin (vitamin B12) form acid degradation in the stomach by binding to it
B12 information:
what happens to the B12-transcobalamin when it reaches the duodenum
pancreatic proteases degrade haptocorrin aka transcobalamin
free B12 bids to intrinsic factor (IF)
B12 information:
where is intrinsic factor produced from
stomach parietal cells
B12 information:
why do you need intrinsic factor
needed to be able to bind to enterocyte (cubulin receptors in the terminal ileum)
IDA:
in what scenarios are iron stores used up, making the patient iron deficient
insufficient dietary iron
iron requirements increase (for example pregnancy)
iron is being lost (for example slow bleeding from a colon cancer)
inadequate iron absorption
name 2 GI diseases that can affect the absorption of iron
coeliac disease
chron’s disease
IDA
what is the most common cause in adults
blood loss
- (consider menorrhagia in women of childbearing age
- in men and post menopausal women the most common cause is GI tract cancer
- note that oesophagitis and gastritis are the most common causes of GI tract bleeding
- IBD should also be considered
IDA:
how does iron travel around the blood
ferric ions (Fe3+) bound to a career protein called transferrin
IDA
What is total iron binding capacity (TIBC)
the total space on the transferrin molecule for the iron to bind
IDA
how do you calculate transferrin saturation and what does this tell us
the proportion of transferrin molecules that are bound to iron
= serum iron/ total iron binding capacity
IDA
what is the form that iron takes when it is deposited and stored in cells
ferritin
IDA
in what. situation would extra ferritin be released from cells
inflammation, such as with infection or cancer
IDA
in IDA what would you expect the TIBC and transferrin levels to be
increased
IDA
what two things can increase the values of all the iron testing results, giving the impression of iron overload
supplementation with iron
acute liver damage (lots of iron is stored in the liver
IDA
what are the treatment options that are considered to treat this
a blood transfusion will immediately correct the anaemia
iron infusion eg cosmofer
oral iron eg serous sulphate 200mg TD
what is the main side effect with iron supplements
causes constipation and black coloured stools
when correcting IDA you can. expect the Hb to rise by around _____ g/L a week
10
what is a hematinic and what are the main 3
a hematinnic is a nutrient that is required for the formation of blood cells in the process of haematopoiesis
iron, B12 and folate
why do a lot of babies have iron deficiency
milk affects the ability of the body to absorb iron
in post-menopausal women or older male, what conditions can you not miss when someone has anaemia
cancer of the GI system
Thalassaemia:
what is a normal Hb molecules consisting of
2 alpha and 2 beta globin chais (A1)
Thalassaemia:
what is beta Thalassaemia minor and how is it diagnosed
have one abnormal beta globin gene and diagnosed by having a raised HbA2 which is the normal variant off Hb in which you have 2 alpha chains and 2 delta chains
Thalassaemia:
what is beta Thalassaemia major
2 abnormal genes and so you have no adult Hb (HbA) only HbF (foetal)
Thalassaemia:
describe what happens in alpha Thalassaemia depending on how many genes are deleted (note there are 4)
o 1 gene deleted- clinically silent
o 2 gene deleted- alpha thalassaemia trait
o 3 gene deleted- haemoglobin H disease (moderately severe anaemia develops due to reduced formation of alpha globin chains)
o 4 genes deleted- barts hydrops fetalis (foetus usually dies)
name some causes of IDA
Rapid growth, menarche, pregnancy
prematurity, low birth weight
cows milk in toddlers
GIT: GI bleed (could be taking a lot of NSAIDs)
menorrhagia
• Misc causes: renal tract bleeding, idiopathic pulmonary haemosiderosis, bleeding diathesis
True or false: a low ferritin at times of rapid growth (infancy, adolescence) does not necessarily mean that there is iron deficient erythropoiesis
true
why does ferritin give falsely high values in infections and patients with long term inflammatory conditions such as rheumatoid arthritis
ferritin is an acute reactant protein
name some causes of B12 deficiency
nutritional: vegan, poor diet, pregnancy
Malabsorption: gastro causes are surgery or pernicious anaemia (IF and gastric parietal cell antibodies). Intestinal causes are iliac resection,
Get malabsorption but not deficient in chrons, coeliac and CF
Name some common causes of folate deficiency
nutritional: poor diet, goat milk only drinkers (this has iron but no folate)
coeliac disease or jejunal resection
excessive requirement during pregnancy, prematurity
increased turnover: in chronic Haemolysis, severe skin conditions
Drugs: methotrexate, anticonvulsants
Excess loss during dialysis
alcohol (although beer is a good source of folate)
What are some of the main signs in someone with B12 deficiency
Incidious onset (comes on slowly at first and doesn’t have obvious symptoms at first)
neuropathy
mild jaundice and anaemia
glossitis (inflammation of the tongue)
angular cheilitis (inflammation of the corners of the mouth)
what is one of the main symptoms of folate deficiency
similar to b12 deficiency but more often a sensory peripheral neuropathy only
Name some other causes of macrocytosis (large red blood cells) that isn’t Vitamin B12 and folate deficiency
alcohol pregnancy chemotherapy, anti-HIV drugs liver disease raised reticulocyte count hypothyroidism aplastic anaemia (fails tp produce red blood cells in sufficient quantities) hypoxia Myeloma
When you tell a patient to take iron supplements, what advice should you give them
take it on an empty stomach with orange juice (ascorbic acid), don’t take it with tea, coffee, eggs or milk products and be aware that your stools may turn black
True or false: folate alone may exacerbate neuropathy symptoms
true
what is pernicious anaemia
autoimmune condition where antibodies form against the parietal cells or intrinsic factor
a lack of IF prevents the absorption of B12
What neurological symptoms can B12 deficiency cause
peripheral neuropathy with numbness or paraesthesia (pins and needles)
loss of vibration sense or proprioception
visual changes
mood or cognitive changes
TOM TIP:
in exams you should remember to test for what if someone presents with peripheral neuropathy, particularly with pins and needles
vitamin b12 deficiency and pernicious anaemia
If there is a folate deficiency as well as a B12 deficiency, why is it important to treat the B12 deficiency first. I.E why should you not give someone folic acid when they have a b12 Deficiency
can lead to subacute combined degeneration of the cord
what is haemolytic anaemia
anaemia as a result of increase in destruction of red blood cells (Haemolysis)
in haemolytic anaemia what is the main thing on the FBC that would be raised
increased reticulocyte
Name some inherited haemolytic anaemias
- Hereditary Spherocytosis
- Hereditary Elliptocytosis
- Thalassaemia
- Sickle Cell Anaemia
- G6PD Deficiency
Name some acquired haemolytic anaemias
- Autoimmune haemolytic anaemia
- Alloimmune haemolytic anaemia (transfusions reactions and haemolytic disease of newborn)
- Paroxysmal nocturnal haemoglobinuria
- Microangiopathic haemolytic anaemia
- Prosthetic valve related haemolysis
- Copper deficiency (Wilson’s disease)
AS a result of the destruction of red blood cells, what symptoms would you expect to see in someone with haemolytic anaemia
anaemia due too reduction in circulating red blood cells
splenomegaly as the spleen becomes filled with destroyed red blood cells
jaundice as bilirubin is released during the destruction of red blood cells
What is hereditary spherocytosis
autosomal dominant condition which causes a share shaped red blood cell that are fragile and easily break down when passing through the spleen
how does hereditary spherocytosis present
jaundice, gallstones, splenomegaly and notably aplastic crisis
what is the treatment for hereditary spherocytosis
foliate supplementation and splenectomy
removal of gallbladder (cholecystectomy) may be required if gallstones are a problem
TOM TIP: The key piece of knowledge for G6PD deficiency relates to triggers. In your exam look out for a patient that presents in what way
turns jaundice and becomes anaemia after eating broad beans, developing an infection or being treated with antimalarials.
What is G6PD deficiency and what triggers a crisis
a condition where there is a defect in the red blood cell enzyme G6PD
more common in Mediterranean and African patients ad is X linked recessive
Causes crisis that are triggered by infections, medications or lava beans
what is autoimmune haemolytic anaemia (AIHI)
occurs when antibodies are created against the patients red blood cells
what is the usual cause of warm type autoimmune haemolytic anaemia
it is idiopathic
what is the usual cause of cold type autoimmune haemolytic anaemia
often secondary to other conditions such as lymphoma, leukaemia, systemic lupus erythematous and infections such as mycoplasma, EBV, CMV and HIV
what is the management of autoimmune haemolytic anaemia
blood transfusion
prednisolone steroid
rituximab (a monoclonal antibody against B cells)
Splenectomy
What is the haemoatocrit
the percentage of red blood cells in blood
what is mean cell volume
MCV is the size of the red blood cells
What does the reticulocyte count tell you
measures the number of new red blood cells being produced (high reticulocyte count may mean that they are being destroyed prematurely and low reticulocyte means not enough is being produced
Around 6 weeks of age what is fetal Hb replaced with
Hb A
patients with sickle cell disease have an abnormal variant of Hb known as
HbS which causes the red blood cells to be an abnormal sickle shape
what kind of genetic inheritance is sickle cell disease
autosomal recessive
why is there no need for sickle cell patients to receive constant blood transfusion
the oxygen dissociation curve of sickle Hb is shifted to the right and oxygen is more readily. released to the tissues which makes the anaemia well tolerated
what do anti globulin tests look for
antibodies to red blood cells
what medication is used in sickle cell patients which switches back on the production of fetal Hb
hydroxyurea
