Anaemia

Question 1

The World Health Organisation (WHO) defines anaemia by the following haemoglobin (Hb) concentrations:

Males < …
Females < …

Answer 1

The World Health Organisation (WHO) defines anaemia by the following haemoglobin (Hb) concentrations:

Males < 130 g/L (130-175 g/L)
Females < 120 g/L (120-155 g/L)*

Question 2

• In pregnancy, a Hb < … g/L is diagnostic for anaemia

Answer 2

• In pregnancy, a Hb < 110 g/L is diagnostic.

Question 3

Strictly speaking, anaemia is defined as a reduction in circulating red blood cell mass. However, in clinical practice, anaemia is defined by more measurable variables such as:

Answer 3

Red blood cell (RBC) count
Haemoglobin (Hb) concentration
Haematocrit

Question 4

The morphological approach categorises anaemia based on the size of RBCs (e.g. the mean corpuscular volume).

This approach arranges anaemia into three groups:

Answer 4

Microcytic (small RBCs)
Normocytic (normal sized RBCs)
Macrocytic (large RBCs)

Question 5

Symptoms - anaemia

Answer 5

Dyspnoea
Fatigue
Headache
Dizziness
Syncope
Confusion
Palpitations
Angina

Question 6

Signs - anaemia

Answer 6

Signs

Bounding pulse
Postural hypotension
Tachycardia
Conjunctival pallor
Shock

Question 7

A decrease in RBC production can occur due to two main mechanisms:

Answer 7

Insufficient production of RBCs

Ineffective production of RBCs

Question 8

Inherited haemolytic anaemias can be further classified based on the site of inherited defect:

Answer 8

Membrane abnormalities (e.g. hereditary spherocytosis)
Metabolic deficiencies (e.g. G6PD deficiency)
Haemoglobin abnormalities (e.g. alpha-thalassaemia, beta-thalassaemia, sickle cell disease)

Question 9

Acquired haemolytic anaemias can be divided into immune and non-immune:

Answer 9

Immune (e.g. warm and cold autoimmune haemolytic anaemia)

Non-immune (e.g. mechanical trauma, hypersplenism, infections, drugs)

Question 10

Blood loss is a common cause of anaemia, it may be obvious (e.g. trauma, haematemesis) or occult (e.g. gastrointestinal malignancy).

Answer 10

Erythrocytes form a major store of iron within the body. This means a loss of erythrocytes could lead to the development iron deficiency anaemia (IDA). Consequently, IDA commonly reflects blood loss from an unidentified source that requires further investigation.

Two common sources of blood loss include menstruation in young females and gastrointestinal bleeding in older populations.

Question 11

The MCV is a measure of the average volume of a RBC. The MCV is measured in femtolitres (fL) and usually resides between 82 and 99. RBCs that are > 99 fL are referred to as macrocytes, RBCs that are < 82 fL are referred to as microcytes. A normal RBC is approximately 7 microns in diameter.

Answer 11

The MCV is a measure of the average volume of a RBC. The MCV is measured in femtolitres (fL) and usually resides between 82 and 99. RBCs that are > 99 fL are referred to as macrocytes, RBCs that are < 82 fL are referred to as microcytes. A normal RBC is approximately 7 microns in diameter.

Question 12

Anaemia is described as microcytic when the MCV is < .. fL.

Answer 12

Anaemia is described as microcytic when the MCV is < 82 fL.

Question 13

Anaemia is described as microcytic when the MCV is < 82 fL.

Answer 13

Microcytic anaemia is commonly associated with a reduction in the mean corpuscular haemoglobin concentration (MCHC), which leads to the appearance of pale (hypochromic) RBCs.

The most common cause of microcytic anaemia is iron-deficiency anaemia (IDA). This may be evaluated with iron studies (transferrin and serum iron) and serum ferritin.

Other important causes of microcytic anaemia include:

Anaemia of chronic disease (predominantly causes normocytic anaemia)
Thalassaemia
Other haemoglobinopathies
Lead poisoning
Sideroblastic anaemia

Question 14

The most common cause of microcytic anaemia is…

Answer 14

The most common cause of microcytic anaemia is iron-deficiency anaemia (IDA). This may be evaluated with iron studies (transferrin and serum iron) and serum ferritin.

Question 15

Anaemia is described as normocytic when the MCV is within normal limits (…

Answer 15

Anaemia is described as normocytic when the MCV is within normal limits (82-99 fL).

Question 16

Normocytic

Anaemia

Answer 16

The causes of normocytic anaemia are extremely broad and it may reflect the early stages of either a microcytic or macrocytic anaemia.

Anaemia may be the first manifestation of a systemic disorder. One of the most common causes of a normocytic anaemia is ‘anaemia of chronic disease’.

Other common causes of a normocytic anaemia include blood loss, renal disease, cancer-associated anaemia and pregnancy.

Question 17

Anaemia is described as macrocytic when the MCV is > … fL.

Answer 17

Anaemia is described as macrocytic when the MCV is > 99 fL.

Question 18

Macrocytic

Anaemia is described as macrocytic when the MCV is > 99 fL.
CAUSES?

Answer 18

There are numerous causes of a macrocytic anaemia, but it is commonly secondary to folate and/or B12 deficiency. Folate and B12 deficiency cause a megaloblastic (immature) macrocytic anaemia and abnormal nucleic acid metabolism.

Drugs that interfere with nucleic acid metabolism may also cause a macrocytic anaemia (e.g. methotrexate).

Other important causes of a macrocytic anaemia include:

Alcohol abuse
Liver disease
Hypothyroidism
Haematological malignancies
Reticulocytosis

Question 19

There are numerous causes of a macrocytic anaemia, but it is commonly secondary to…

Answer 19

There are numerous causes of a macrocytic anaemia, but it is commonly secondary to folate and/or B12 deficiency. Folate and B12 deficiency cause a megaloblastic (immature) macrocytic anaemia and abnormal nucleic acid metabolism.