Microcytic Anaemia Flashcards
What is microcytic anaemia caused by?
Deficient Hb synthesis
How does microcytic anaemia work?
One of the building blocks of haemoglobin is lacking, so Hb is underdeveloped
What are the main causes of microcytic anaemia?
TAILS-
Thalassemia
Anaemia of chronic disease
Iron deficiency
Lead poisoning
Sideroblastic anaemia
Which anaemias are caused by Haem deficiency?
Anaemia of chronic disease, IDA, lead poisoning, sideroblastic anaemia
Which anaemias are caused by globin deficiency?
Thalassaemia
What is the most common cause of microcytic anaemia?
Iron deficiency anaemia
What causes iron deficiency anaemia?
Insufficient intake-
Higher likelihood in women and children due to greater requirement
Diet
Pregnancy
Too much loss (bleeding)-
menorrhagia
GI ie ulcers and tumours
Haematuria
Malabsorption-
Coeliac disease
What is iron used for in the body?
Essential in oxygen transport and electron transport
What are Ferritin and Transferrin?
FERRITIN-
Iron storage molecule, most found in cells and some circulates in blood
Low serum ferritin -> sign of iron deficiency
Stored to prevent toxicity
TRANSFERRIN-
Chaperone molecule for iron transport.
Produced in liver, rate can be adjusted depending on iron levels in body
Explain the metabolic pathway of iron
Primary source is dietary- absorbed in the duodenum
Circulating iron carried by transferrin to bone marrow macrophages
These macrophages deliver iron to premature RBCs
Extra iron is taken up via ferritin and stored in the liver
System is closed so only a little can be absorbed at a time, and only small amounts moves around
What is the source of iron?
Dietary
Can get heme and non-heme, heme found in meats and non-heme in plant sources
Heme is absorbed directly, non-heme requires reduction before absorption
How does IDA present?
Anaemia- breathlessness, fatigue, headaches, palpitations, faintness, pallor
In longstanding disease-
Koilonychia
Tongue papillae atrophy
Angular stomatitis
Brittler hair
Dysphagia
How will red cells appear on blood film and other investigations?
Microcytic, so MCV <80, and hypochromic
poikilocytosis (variation in shape)
anisocytosis (variation in size)
Serum ferritin may be low
What is the pathophysiology of anaemia of chronic disease?
Chronic disease -> IL6 -> inc hepicidin production
Elevated hepicidin inhibits ferroportin which mediates release of iron
Inflammatory cytokines result in increased ferritin
(Less is released, more is stored)
What is sideroblastic anaemia?
Where iron is unable to be properly incorporated into Hb
