Microcytic Anaemia

Question 1

What causes microcytic anaemia

Answer 1

• iron deficiency
• thalassaemia
• sideroblastic anaemia
• anaemia of chronic disease
• GI cancer (increases with age)
• hookworm infestation in developing countries

Question 2

What is the main cause of iron deficiency anaemia

Answer 2

• iron deficiency anaemia usually occurs as a result of blood loss through the GI tract or through menesturation

Question 3

What drugs can cause iron deficiency anaemia

Answer 3

• NSAIDs and aspirin account for 10-15% of iron deficiency anaemia

Question 4

What does thalassaemia cause anaemia

Answer 4

• thalassaemias cause anaemia in the carrier state (trait) but people are usually only symptomatic when both parents are affected (thalassaemia major)

Question 5

What investigations do you carry out

Answer 5

• do a FBC and then repeat it to confirm the initial blood count and establish if abnormal results are stable or progressive
• if results are abnormal request an examination of a peripheral blood film
• test for coeliac disease (anti-tissue transglutaminase antibodies)
• upper and lower GI investigations
• autoimmune gastritis (gastrin and parietal cell antibodies)
• helicobacter pylori (urea breath test)

Question 6

What investigations distinguish between iron deficiency anaemia and thalassaemia trait

Answer 6

• Serum ferritin - decreases in iron deficiency anaemia but remains normal in thalassaemia trait
• haemoglobin A2 quantitation - increase in beta thalassaemia trait but normal in alpha thalassaemia trait

Question 7

what use can a reticulocyte count do

Answer 7

• differentiates anaemia due to underproduction (low if untreated iron deficiency anaemia) from that due to red blood cell loss or destruction (raised in haemolytic, bleeding and during treatment for iron deficiency)

Question 8

what should you do if someone has microcytic anaemia and is either a man or postmenopausal women

Answer 8

• need investigation of upper and lower GI tract unless there is bleeding from a non gastrointestinal source

Question 9

when should premenopausal women be investigated with microcytic anaemia

Answer 9

• premenopausal women with GI symptoms and iron deficiency anaemia
• all premenopausal women should be screened for coeliac disease
• aged over 50 have a family history of colon cancer need investigation of the lower GI tract

Question 10

when do you refer patients

Answer 10

• Refer patients to the gastrointestinal department whether or not they have gastrointestinal symptoms
• Refer women to a gynaecologist if there is a structural abnormality on pelvic ultrasonography, menorrhagia unresponsive to medical management, or postmenopausal bleeding
• Refer patients to a haematology service when the type of anaemia is in doubt, laboratory findings suggest iron deficiency anaemia but there has been a poor response to oral iron supplements, or when further haematological investigations, such as bone marrow examination or an investigation of bleeding state, cannot be carried out in primary care.

Question 11

what is the treatment for iron deficiency anaemia

Answer 11

Ferrous

sulphate 200 mg three times daily is effective

Question 12

What might thalassaemia trait coexist with

Answer 12

Thalassaemia trait may coexist with iron deficiency anaemia and should be considered (by repeating haemoglobin A2 quantitation) when a microcytic anaemia fails to respond to iron supplementation

Question 13

to avoid iron overload in patients what should you monitor

Answer 13

• monitor serum ferritin levels only when there is a dual cause for anaemia (as in iron deficiency anaemia with thalassaemia trait or with anaemia of chronic disease)

Question 14

what happens to 
- serum ferritin level 
- serum iron level 
- total iron binding capacity 
- transferrin saturation 
- haemoglobin electrophoresis and quantitation of haemoglobin A2 
in iron deficiency anaemia

Answer 14

• serum ferritin level = decreased
• serum iron level = decreased
• total iron binding capacity = increased
• transferrin saturation = decreased
• haemoglobin electrophoresis and quantitation of haemoglobin A2 = normal

Question 15

what happens to 
- serum ferritin level 
- serum iron level 
- total iron binding capacity 
- transferrin saturation 
- haemoglobin electrophoresis and quantitation of haemoglobin A2
in thalassaemia trait

Answer 15

• serum ferritin level = normal
• serum iron level = normal
• total iron binding capacity = increased
• transferrin saturation = normal
• haemoglobin electrophoresis and quantitation of haemoglobin A2 = increased haemoglobin A2 in beta thalassaemia trait, normal in alpha thalassaemia trait

Question 16

what happens to 
- serum ferritin level 
- serum iron level 
- total iron binding capacity 
- transferrin saturation 
- haemoglobin electrophoresis and quantitation of haemoglobin A2
in sideroblastic anaemia

Answer 16

• serum ferritin level = increased
• serum iron level = increased
• total iron binding capacity = normal
• transferrin saturation = normal
• haemoglobin electrophoresis and quantitation of haemoglobin A2 = normal

Question 17

Name features that could be found on blood film examination in microcytic anaemia

Answer 17

• anisocytosis
• dimorphism
• basophilic stippling
• pappenheimer bodies
• target cells
• hypochromia
• elliptocytes (pencil cells)

Question 18

What is anisocytosis

Answer 18

Increased variation in size of red blood cells

Present in
- Untreated iron deficiency anaemia and several other types of anaemia (except thalassaemia trait)

Question 19

What is dimorphism

Answer 19

Two distinct populations of red blood cells (in this case normocytic well haemoglobinised cells and small hypochromic cells)

Present in
- Iron deficiency anaemia on treatment or sideroblastic anaemia

Question 20

What is basophilic stippling

Answer 20

Multiple small blue dots inside red blood cells

Present in
- β thalassaemia or sideroblastic anaemia

Question 21

What is pappenheimer bodies

Answer 21

Iron containing inclusions in red blood cells

Present in
- Sideroblastic anaemia

Question 22

What are target cells

Answer 22

Red blood cells with an area of central darkness surrounded by a ring of pallor

Present in
- β thalassaemia, iron deficiency anaemia, or sideroblastic anaemia

Question 23

What is hypochromia

Answer 23

A reduction in staining of red blood cell

Present in
- Thalassaemia or iron deficiency anaemia

Question 24

What is elliptocytes (pencil cells)

Answer 24

Red blood cells with long axes more than twice their short axes

Present in
- Characteristic of iron deficiency anaemia but may be found in thalassaemia trait