Anaemia (CH) Flashcards
Define anaemia.
Anaemia is a Hb level two standard deviations below the mean for the age and sex of the patient
A decrease in the [Hb] in circulating blood
What are the general blood results for anaemia?
Reduced RBC, reduced Hct, reduced PCV (packed cell volume)
What can be used to distinguish the mechanism of anaemia?
Reticulocyte count
- increased = haemolytic anaemia, recent blood loss, recent treatment with iron, B12/folate
- decreased = reduced output of RBC from bone marrow
What are the causes of anaemia? (4 types + examples of each)
- reduced production of RBC by bone marrow
- iron deficiency anaemia
- anaemia of chronic disease
- megaloblastic anaemia (B12 deficiency)
- blood loss from body (normocytic)
- reduced survival of RBC in circulation
- hereditary spherocytosis
- autoimmune haemolytic anaemia
- G6PD deficiency
- increased pooling of RBC in enlarged spleen (sickle cell anaemia)
What are the general symptoms of anaemia? (5)
- tiredness
- lethargy
- malaise
- dyspnoea
- pallor
What are some general investigations for anaemia?
- FBC - low Hb
- iron studies - IDA
- blood film - reticulocytes, abnormalities
- electrophoresis - haemoglobinopathies
- DAT/Coomb’s Test
- LFTs, bilirubin - haemolytic anaemia
What are the three types of anaemia?
- microcytic
- normocytic
- macrocytic
Define microcytic anaemia.
- insufficient Hb production
- MCV < 80 fL
What are the types of causes of microcytic anaemia?
- defective haem synthesis
- iron deficiency anaemia
- anaemia of chronic disease (may also be normocytic)
- defective globin synthesis
- thalassaemia
- sideroblastic anaemia
- lead poisoning
- anaemia of chronic disease
How does microcytic anaemia present?
- brittle hair and nails
- pallor
- koilonychia (spoon-shaped nails in IDA)
- glossitis
- angular stomatitis (red patches in corner of mouth in IDA)
- signs of thalassaemia
- ankle swelling
- palpitations
- tachycardia
- post-cricoid webs
- exacerbation of ischaemic conditions
What investigations are done for microcytic anaemia?
- FBC - MCV<80, reticulocytes
- blood film - microcytes, increased area of central pallor, hypochromic, basophilic stippling
- iron studies
- CRP, ESR - elevated in ACD
- serum lead - elevated in lead poisoning
- Hb electrophoresis - thalassaemia, SCA
Iron studies - what would be suggestive of iron deficiency anaemia?
- low iron and ferritin
- raised transferrin
- increased TIBC (total iron binding capacity)
Iron studies - what would be suggestive of anaemia of chronic disease?
- low/normal iron and ferritin
- low transferrin
- low TIBC
- increased hepcidin
Iron studies - what would be suggestive of sideroblastic anaemia?
- high iron
- high ferritin
- high transferrin saturation
Iron studies - what would be suggestive of thalassaemia?
Mentzer index (MCV/RBC) <13
What is the difference in blood count results between iron deficiency anaemia vs anaemia of chronic disease?
- MCV: low vs low/normal
- ferritin: low vs high
- transferrin: high vs low/normal
- transferrin saturation: low vs normal
- ESR: may be high (due to low Hct) vs high
What are the causes of iron deficiency anaemia?
- increased blood loss
- hookworm
- menstrual
- GI (aspirin/NSAIDs, cancers, ulcers, coeliac, gastrectomy, H.pylori, angiodysplasia)
- insufficient intake
- dietary
- malabsorption - coeliac, gastritis
- increased requirement
- pregnancy
- infancy
What investigations are done for iron deficiency anaemia?
- FBC
- iron studies (high transferrin/TIBC, low serum iron/ferritin)
- blood film (poikilocytosis, anisocytosis, microcytosis hypochromia)
- if >40yrs OR post-menopausal women OR male with unexplained IDA: upper GI endoscopy, colonoscopy
- if Hb<10 - refer within two weeks
How do we manage iron deficiency anaemia?
- iron supplements
- oral ferrous sulfate/fumarate/gluconate, continue for 3 months after IDA correction to allow stores to replenish
- if oral iron not tolerated, IV iron
- iron-rich diet (dark leafy veg, meat, iron-fortified bread)
- address underlying causes (e.g. treat menorrhagia, stop NSAIDs)
What are some causes of anaemia of chronic disease?
- no unrelated cause except for a different unrelated pathology (hepcidin production increased in inflammation –> reduced iron supply by blocking absorption from gut/release of storage iron)
- infections: TB and HIV
- autoimmune disorders (inflammatory): RA, SLE, Crohn’s/UC, CKD
- cancer, lymphomas/leukaemia
What investigations are done for anaemia of chronic disease?
FBC - increased ferritin, low/normal transferrin
What is the pathophysiology of anaemia of chronic disease?
- involvement of pro-inflammatory cytokines
- IL1, TNF-a, IL6
- all decreased EPO production
- increase hepcidin production = decreased release of storage iron
How do we manage anaemia of chronic disease?
Treat the underlying cause
What is sideroblastic anaemia?
Inability to form haem in mitochondria –> deposits of iron in mitochondria form a ring around nucleus called a ring sideroblast
What is a congenital cause of sideroblastic anaemia?
Delta-aminolevilinate synthase-2 deficiency
What are the acquired causes of sideroblastic anaemia?
MALA
- myelodysplasia
- alcohol
- lead
- anti-TB medications
What is seen on a blood film of sideroblastic anaemia? (3)
- basophilic stippling of RBCs
- dimorphic blood film
- hypochromic microcytes
- (bone marrow film: Prussian blue staining shows ring sideroblasts)
How do we manage sideroblastic anaemia?
- supportive
- if secondary - treat the cause
- pyridoxine
- iron chelation if not treatment