HAEM: Anaemia I - Microcytic Anaemia Flashcards
What is anaemia?
- Haemoglobine level below the lower limit of normal for the age and sex of the patient
- A symptom, NOT a diagnosis
What are the clinical features of anaemia?
- Pallor
- Impaired oxygen delivery:
- weakness, fatigue, lethargy
- dizziness
- headaches
- Cardiac compensation:
- tachycardia
- increased pulse pressure
- cardiac flow murmurs
- In older patients:
- cardiac failure
- angina
- claudication (leg cramp during exercise)
- confusion
What are the causes of anaemia, using a pathophysiological classification?
(comprehensive list yuck)
- Decreased red cell production
- stem cell abnormalities (aplastic anaemia)
- decreased erythropoietin (renal failure)
- defective DNA synthesis (megaloblastic anaemia)
- defective haemoglobin synthesis (iron deficiency, thalassaemia)
- displacement of normal haemopoietic progenitors (bone marrow fibrosis, haemotologic and metastatic malignancies)
- multifactorial (anaemia of chronic disease)
- Increased red cell loss
- blood loss (trauma, GI bleeding e.g. polyps)
- haemolysis
What are 3 causes of hypochromic microcytic anaemias (low MCV, low MCH)
- Iron deficiency
- Anaemia of chronic disease
- Thalassaemia
What are the causes of macrocytic anaemia? (high MCV)
- Megaloblastic anaemia
- Liver disease
- Alcohol
- Pregnancy
- Hypothyroidism
- Myelodysplasia
- Reticulocytosis
What are the causes of normochromic normocytic anaemia? (normal MCV and MCH)
- Anaemia of chronic disease
- Renal failure
- Acute blood loss (diagnosis of exclusion)
- Some haemolytic anaemias
What is the primary cause of microcytic anaemia and how do we mainly measure it?
Iron deficiency
Measure ferritin - the major storage protein for iron
What are 3 causes of iron deficiency?
- Excess blood loss
- Menorrhagia
- haematuris
- GI bleeding
- ulcer or malignancy
- Decreased absoption
- coeliac disease
- achlorhydia (autoimmune or Helicobacter pylori gastritis)
- Increased utilisation
- pregnancy and lactation
What are the clinical features?
- general features of anaemia (see other card)
- pica
- painless smooth glossitis
- angular stomatitis
- brittle nails
- koilonychia (spoon nails)
What are the features of a full blood picture typical of mycrocytic anaemia e.g. iron deficiency?
What would you expect to see in a blood film?
- Hypochromic microcytic red cells
- Pencil cells
What are the typical results for iron studies?
- Low ferritin
- Low or normal serum iron
- High transferrin
- Low transferrin saturation (ratio of iron to transferrin)
Is iron deficiency a fine diagnosis?
NO - not a diagnosis in its own right. Underlying cause should always be established.
Explain the management of iron deficiency and when would expect to see response
- Oral iron therapy
- safe, cheap, effective
- Iron best absorbed as salt (Fe2+)
- ascorbic acid (vitamin c) enhances absorption
- typical dose - 150-200mg daily
- adverse effects: GI disturbance
Response: reticulocytosis (new young red cells) seen by 5-7 days following. Hb should normalise within 6-8 weeks
- Parenteral iron therapy
- indicated by:
- unable to tolerate oral iron
- non-compliant with oral iron
- malabsorption GI
- iron carboxymaltose (Ferinject) or polymaltose (Ferrosig)
- indicated by:
What are blood transfusions indicated for iron deficiency?
Only when patient are haemodynamically unstabl or who have ischaemic symptoms secondary to severe iron deficiency.
What is anaemia of inflammation/anaemia of chronic disease?
- Diagnosis of exclusion
- Common, found patients with inflammatory or malignant disease
- Multifactorial pathogenesis, including:
- reduced erythropoietin response to anaemia
- decreased red cell survival
- impaired iron absorption in liver due to hepcidin release during inflammation
Describe the FBP, Iron studies and management of typical of Anaemia of Chronic Disease
- FBP:
- shows mild anaemia
- MCV normal or reduced
- Iron studies - typical results (pic)
Management:
- correction of underlying condition
- doesn’t respond to oral iron therapy
What is thalassaemia?
- Genetic disorder of globin gene (alpha or beta)
- Deletions or point mutations which result in decreased production of one of the globin chains
Explain the differences between Beta thalassaemia trait and Beta thalassaemia major
Beta thalassaemia trait (heterozygotes)
- Asymptomatic clinically
- Detected as result family studies or FBP done
Beta thalassaemia major (homozygotes)
- cannot produce any beta globin
- leads to severe transfusions dependent anaemia
What are the typical results of FBC and blood smear for thalassaemia?
What are the clinical features of beta thalassaemia major?
- Severe transfusion dependent anaemia
- Expansion of haemopoietic tissue
- bony deformities
- marrow mass expands
- facial bones increase in size to increase marrow capacity
- hepatosplenomegaly
- bony deformities
- Can get iron overload from excessive infusions
Explain α thalassaemia
Alpha thalassaemia = most common monogenic disorder
Most commonly occurs as result of deletions of various size in the alpha globin locus.
Clinical features depend on degree of reduction in alpha globin synthesis.
- Silent/Thalassaemia trait: α α / α -
- Thalassaemia trait: α α / - -
- HbH Disease: α - / - -
- Hb Barts/Hydrops fetalis: - - / - - (fatal)
What are the laboratory features of α thalassaemia trait?
- “Thalassaemic Red Cell Indices”
- Hb level is normal/midly reduced
- Microcytosis is disproportionate to the Hb level
- RCC is often elevated
- Hb studies are normal
- Require molecular studies to confirm the diagnosis
- Iron studies usually normal in uncomplicated cases
- But can developed iron deficiency also!!
Why is it important to recognise α thalassaemia trait?
