1b// Anaemia & Transfusion Flashcards
what is anaemia?
reduced count of red blood cells in the body
what are the broad causes of anaemia
reduction in production of red cells/haem in bone marow
reduced survival of red cells in the circulation
loss of blood from the body
pooling of cells in the spleen
what are the types of anaemia based on size?
microcytic anaemia (normally hypochromic too)
macrocytic anaemia
normocytic anaemia
what are the causes of microcytic anemia?
defect in haem synthesis - iron deficiency, anaemia of chronic disease
defect in globin synthesis - a thalassemia, b thalassemia
how do blood results help you differentiate anaemia of chronic disease and iron deficiency anaemia?
AoCD - high ferritin, low/norm transferrin, high ESR
ID- low ferritin, high transferrin, may have high ESR
how can you differentiate iron deficiency anaemia from thalassemia trait?
ID- low Hb, MCV, MCHC, RBC, normal electrophoresis, low ferritin
TT - normal Hb, lower MCV, MCH, relatively preserved MCHC increased RBC, HbA2 raised in b-trait, normal ferritin
what are the common causes of macrocytic anaemia?
lack of vit B12/folic acid
drugs interfering with DNA synthesis
liver disease, ethanol toxicity
haemolytic anaemia
what are the causes of haemolytic anaemia?
all result in shortened erythrocyte survival
damage to RBC membrane - hereditary spherocytosis, autoimmune
loss of haem structure and function - sickle cell
cellular metabolism - G6PD deficiency
what is hereditary spherocytosis?
inherited defect of red blood cell membrane, have abnormal shape and decreased flexibility
haemolytic anaemia
symptoms of hereditary spherocytosis?
jaundice (UNconjugated bili)
gallstones
increased red cell fragility
what are the clinical test results for hereditary spherocytosis
increased red cell fragility in osmotic fragility test
blood film - spherocytes, increased reticulocytes (polychromatic cells)
high UNconjugated bilirubin
blood results - high LDH, hyperbilirubinaemia (UNconju), increased MCV, reduced haptoglobins, high reticulocyte count
what does high unconjugated bilirubin mean?
prehepatic cause of jaundice
caused by haemolysis
what does high conjugated billirubin mean?
decreased bilirubin elimination by hepatocytes
common complication of haemolytic anaemia
gallstones
increased breakdown of haemoglobin to bilirubin
can cause post hepatic jaundice (conjugated)
treatment for hereditary spherocytosis
folic acid (increased demand)
splenectomy
blood transfusion
name acquired causes of haemolytic anaemia
snake venom malaria drug induced haemolytic uraemic syndrome autoimmune alloimmune (after blood transfusion)
name hereditary causes of haemolytic anaemia
hereditary spherocytosis
sickle cell
g6pd deficiency (pentose shunt pathway defect)
pyruvate kinase deficiency (glycolytic pathway defect)
how to confirm if haemolytic anaemia is immune or not
direct antiglobulin test DAT
positive = immune basis
what is autoimmune haemolytic anaemia?
autoantibodies against own RBC via type II hypersensitivity reaction
idiopathic or associated w SLE, lymphoma etc
clinical presentation of autoimmune haemolytic anaemia
DAT positive
normocytic anaemia with high bilirubin UNconjugated
high LDH, reticulocytes,
MCV borderline raised - not high
what is G6PD deficiency
deficiency of glucose-6-phosphate dehydrogenase deficiency, x linked recessive
increased sensitivity to oxidative stress (pentose shunt pathway is normally protective)
acute haemolytic anaemia (usually triggered)
clinical presentation of G6PD deficiency
jaundice - unconjugated
recticulocytosis and high MCV
blood film - ghost cells, hemighosts, heinz bodies, irregularly contracted cells
what are heinz bodies?
oxidised and precipitated haemoglobin embedded in membrane on RBCs
(weird dark spots on membrane)
what are ghost cells and hemighost cells?
present in G6PD deficiency
ghost - translucent cells
hemighost - half white half normal cells (irregularly contracted)
what advice should be given to G6PD deficiency patients?
avoid oxidant drugs
avoid broad beans
avoid naphthalene
awareness that infection may cause haemolysis
what is iron deficiency anaemia?
insufficient iron for haemoglobin synthesis
can be insufficient intake/uptake, blood loss, increased requirements
increased blood loss iron deficiency causes
most common in adults
hookworm
menstrual
gastrointestinal bleed - often occult
insufficient intake /uptake causes iron deficiency anaemia
dietary - veggies
malabsorption - coeliac, h.pylori gastritis
increased iron requirements anaemia causes
pregnancy
infancy
symptoms of iron deficiency anaemia
fatigue weakness pallor shortness of breath headache dizziness spoon nails glossitis pallor of eyelid inside
what are the FBC results for iron deficiency anaemia?
low Hb, MCV, MCHC and MCH
low ferritin, serum iron
high transferrin
no HbA2 increase
blood film for iron deficiency anaemia
microcytosis
hypochromia
pencil cells/elliptocytes
target cells
questions to ask someone with iron deficiency anaemia
diet gastrointestinal symptoms - dysphagia, malaena, change in bowel habits, dyspepsia menstrual history weight loss medication history - aspirin, NSAIDs
investigations for someone with iron deficiency anaemia, weight loss, abdo pain
blood in stool - faecal immunochemical test
GI investigations - upper endoscopy, colonoscopy
coeliac antibody testing
what is anaemia of chronic disease?
anaemia resulting from chronic inflammation
common causes of anaemia of chronic disease?
TB, HIV,
rheumatoid arthiritis
malignancy
what is the FBC results of anaemia of chronic disease?
low Hb, MCV
low transferrin and ferritin
high ESR
blood film for anaemia of chronic disease?
hypochromia
microcytosis
rouleaux
pathophysiology of anaemia of chronic disease?
hepcidin blocks absorption and release of iron stores
hepcidin increased by inflammation (IL6, TNFa)
proinflammatory cytokines interfere with action and release of erythropoetin
what is megaloblastic anaemia?
large nucleated red blood cell with immature nucleus compared to cytoplasm
common causes of megaloblastic anaemia?
vit B12, folate deficiency
agents impairing DNA synthesis - azathioprine chemotherapy, folate antagonists, bone marrow cancers
pathophysiology of megaloblastic anaemia?
failed DNA synthesis leads to asynchronous maturation of nucleus and cytoplasm in RBCs
what is vitamin B12 required for?
DNA synthesis
integrity of nervous system
what is folate required for?
DNA synthesis
homocysteine metabolism
FBC results for megaloblastic anaemia?
low Hb, high MCV
high LDH, reticulocytosis
low B12 /folate
blood film results for megaloblastic anaemia?
poikilocytosis
hypersegmented neutrophils
causes of B12 deficiency
reduced intake - veganism, dieting
GI issues - gastrectomy, pernicious anaemia, h.pylori
bowel issues - crohns, ileal resection, tapeworm, coeliac
mechanism of pernicious anaemia
lack of intrinsic factor from parietal cells
therefore B12/IF complex not absorbed in distal ileum
causes of folate deficiency
diet
malabsorption - jejunal resection, coeliac
increased demand - pregnancy, lactation, haemolysis (cell turnover)
treatment of B12 and folate deficiency
oral supplements
B12 hydroxycobalamin IM injections
neurological defects associated with megaloblastic anaemia?
B12 - dementia, subacute combined degeneration of spinal cord
folate - neural tube defects
