Anaemia & Transfusion Flashcards by rachael a

what is anaemia?

reduced count of red blood cells in the body

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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

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what are the types of anaemia based on size?

microcytic anaemia (normally hypochromic too)
macrocytic anaemia
normocytic anaemia

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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

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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

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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

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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

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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

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what is hereditary spherocytosis?

inherited defect of red blood cell membrane, have abnormal shape and decreased flexibility
haemolytic anaemia

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symptoms of hereditary spherocytosis?

jaundice (UNconjugated bili)
gallstones
increased red cell fragility

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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

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what does high unconjugated bilirubin mean?

prehepatic cause of jaundice

caused by haemolysis

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what does high conjugated billirubin mean?

decreased bilirubin elimination by hepatocytes

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common complication of haemolytic anaemia

gallstones
increased breakdown of haemoglobin to bilirubin
can cause post hepatic jaundice (conjugated)

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treatment for hereditary spherocytosis

folic acid (increased demand)
splenectomy
blood transfusion

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name acquired causes of haemolytic anaemia

snake venom
malaria
drug induced
haemolytic uraemic syndrome
autoimmune
alloimmune (after blood transfusion)

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name hereditary causes of haemolytic anaemia

hereditary spherocytosis
sickle cell
g6pd deficiency (pentose shunt pathway defect)
pyruvate kinase deficiency (glycolytic pathway defect)

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how to confirm if haemolytic anaemia is immune or not

direct antiglobulin test DAT

positive = immune basis

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what is autoimmune haemolytic anaemia?

autoantibodies against own RBC via type II hypersensitivity reaction
idiopathic or associated w SLE, lymphoma etc

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clinical presentation of autoimmune haemolytic anaemia

DAT positive

normocytic anaemia with high bilirubin UNconjugated
high LDH, reticulocytes,
MCV borderline raised - not high

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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