Haematology Flashcards
Where is iron mainly absorbed in the intestine?
Duodenum and jejunum
Describe how iron is absorbed and how deficiency occurs?
Fe requires stomach acid → keeps iron soluble ferrous (Fe2+) form → less acid = changes to insoluble ferric (Fe3+) form.
What can affect iron absorption and cause iron deficiency?
Inadequate iron absorption → meds like PPI can interfere with Fe absorption, infl. of duodenum or jejunum like coeliac or Crohn’s disease.
Dietary insufficiency → MC in children.
Loss of iron → heavy menstruation.
What is ferritin? When is extra ferritin released?
The form that iron takes when it is deposited and stored in cells.
Extra ferritin is released from cells when there is inflammation, such as with infection or cancer.
Sx of Fe deficiency anaemia?
General anaemia sx +
Brittle hair and nails
Koilonychia (spoon shaped nails)
Angular stomatitis ( ulceration around mouth corners)
Atrophic glossitis (enlarged tongue)
Ix + results for Fe deficiency anaemia?
FBC - Low MCV
Blood film - target cells + Howell Jolly bodies
Fe studies - low: serum Fe, ferritin, transferrin
Colonoscopy/oesophagogastroduodenoscopy (OGD) for malignancy.
Tx of Fe deficiency anaemia?
Oral Fe → Ferrous sulphate or ferrous fumarate.
What are the SE of oral iron?
Constipation and black coloured stools.
Describe structure of haemoglobin
two alpha-globin and two beta-globin chains
What is thalassaemia?
Genetic defect in protein chains that make up Hb (defects in both alpha and beta - globin chains).
How does splenomegaly occur in thalassaemia?
Px w/thalassaemia → fragile RBCs → breakdown easily → haemolytic anaemia → spleen filters blood and removes old cells → therefore collects destroyed RBCs → splenomegaly
Sx of thalassaemia
Fatigue
Pallor
Jaundice
Gallstones
Splenomegaly
Poor growth and development
Ix of thalassaemia
FBC - low MCV
Raised ferritin - iron overload
Hb electrophoresis
How would iron overload occur in thalassaemia?
Inefficient production of RBCs due to low Hb levels leads to:
1. Increased iron absorption in the gastrointestinal tract
2. Blood transfusions → maintain adequate Hb levels
What kind of genetic inheritance are both alpha and beta thalassaemia?
Autosomal recessive
Which chromosome do gene mutations occur in alpha thalassaemia?
Chromosome 16 - has 4 alpha genes
In alpha thalassaemia mutation (gene deletion) occurs in one of the alpha genes.
What does each of the following stand for and what does it consist of?
1. HbA
2. HbA2
3. HbF
4. HbH
- Adult Hb (2 alpha, 2 beta)
- Minor component of HbA (2 alpha, 2 delta)
- Fetal Hb (2 alpha, 2 gamma)
- Abnormal Hb form where mutation of alpha Hb chains leads to excess beta chains (4 beta no alpha)
In alpha thalassaemia gene deletion occurs. What is the name when these occur + Sx:
1 gene deletion
2 gene deletion
3 gene deletion
4 gene deletion
1 - Silent carrier/ aSx
2 - Alpha thalassaemic trait - mild anaemia Sx
3 - HbH hemotetrameres - moderately severe anaemia
4 - Hb Bart’s - hydrops fetalis - in utero HF → baby dies in utero
At birth how much do HbF and HbA account for in Hb and when does the Hb mostly transition to HbA?
At birth:
HbF - 80%
HbA - 20%
By 6 months mostly HbA
Tx of alpha/beta thalassaemia?
Blood transfusions
Splenectomy may be performed
Bone marrow transplant
iron chelation - remove excess Fe from body
Which chromosome do gene mutations occur in beta thalassaemia?
Chromosome 11
In beta thalassaemia mutation occurs. What is the name when these occur + Sx:
1 normal + 1 reduced/absent beta
1 reduced + 1 absent or 2 reduced beta
2 absent beta (no functioning beta)
- Thalassaemia minor (trait) - aSx, carrier
- Thalassaemia intermedia - marked anaemia sx
- Thalassaemia major - abnormal features:
Frontal bossing (prominent forehead)
Enlarged maxilla (prominent cheekbones)
Depressed nasal bridge (flat nose)
Protruding upper teeth
What is sickle cell anaemia?
Genetic condition that causes sickle (crescent) shaped red blood cells.
Describe pathophysiology of sickle cell anaemia
Patients with sickle-cell disease → abnormal variant haemoglobin S (HbS). HbS results in sickle-shaped red blood cells → more fragile as S.A low → less efficient + causes clotting
