Iron Deficiency Anaemia

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Definition Aetiology Pathophysiology Sign and Symptoms Investigations Management

Iron deficiency anaemia (IDA) is a common type of anaemia characterised by an insufficient amount of iron in the body. Anaemia occurs when the red blood cells are unable to carry enough oxygen to the body's tissues due to a low concentration of healthy red blood cells or inadequate haemoglobin production.

Inadequate Dietary Intake:

Insufficient dietary intake of iron is a primary cause of IDA. Iron is primarily obtained from food sources such as red meat, poultry, fish, and vegetables. Vegetarians, vegans, and individuals with poor dietary habits may be at a higher risk of developing IDA due to inadequate iron consumption.

Poor Iron Absorption:

Even with adequate dietary intake, certain conditions can impair iron absorption, leading to IDA. These include disorders affecting the small intestine, such as celiac disease or inflammatory bowel disease, which can disrupt the absorption of iron and other essential nutrients.

Increased Demand:

Certain life stages and medical conditions increase iron demand, making individuals more susceptible to IDA. Pregnancy, for example, necessitates a higher intake of iron to support foetal development and meet the increased red blood cell requirements. Additionally, rapid adolescent growth and lactation also increase iron demand, making these groups more vulnerable to developing IDA.

Blood Loss:

Chronic or excessive blood loss is a significant contributor to iron deficiency anaemia. Gastrointestinal bleeding caused by conditions such as peptic ulcers, colorectal cancer, or gastritis can result in iron depletion over time. Similarly, heavy menstruation in women and blood loss from trauma or surgery can lead to IDA in both genders.

Poor Iron Utilisation:

Even when iron intake is sufficient, certain factors can interfere with its utilisation within the body. Inflammatory conditions like chronic infections, autoimmune disorders, or certain cancers can disrupt iron metabolism, leading to an imbalance between iron supply and demand. Additionally, genetic disorders like thalassemias and sickle cell disease can negatively impact the body's ability to utilise iron effectively.

1. Iron Stores Depletion:
The initial stage of IDA involves the depletion of iron stores in the body, primarily in the form of ferritin. Ferritin serves as an intracellular storage protein for iron. Inadequate dietary intake, increased demand for iron (such as during pregnancy or periods of rapid growth), or chronic blood loss can lead to the depletion of iron stores. As a result, serum ferritin levels decline.

2. Iron-Deficient Erythropoiesis:
Iron-deficient erythropoiesis signifies a stage where there is a diminished supply of iron for the production of red blood cells. Iron is essential for the synthesis of heme, the pigment in haemoglobin that carries oxygen. In IDA, insufficient iron availability limits the production of heme, resulting in the impaired maturation of red blood cells.
As iron deficiency progresses, the body responds by releasing erythropoietin, a hormone that stimulates the bone marrow to produce more red blood cells. However, due to limited iron availability, erythropoietin's effect remains compromised. Consequently, the red blood cells produced are smaller in size (microcytic) and have a reduced concentration of haemoglobin (hypochromic).

3. Iron Deficiency Anaemia:
The final stage of IDA occurs when iron depletion becomes severe enough to impair normal red blood cell functioning. At this point, the number of red blood cells and their oxygen-carrying capacity decline significantly, leading to typical clinical manifestations of anaemia, such as fatigue, weakness, shortness of breath, and pale skin.

1. Fatigue and weakness: Feeling excessively tired and lacking energy is a prominent symptom of IDA. The insufficient iron levels make it difficult for your body to transport oxygen to cells and tissues, leading to fatigue and weakness.

2. Pale skin and nails: A paler complexion than usual is often noticeable in individuals with IDA. The lack of iron affects the production of haemoglobin, the protein responsible for the red colour in blood. Consequently, the skin and nails may appear noticeably paler or even borderline white.

3. Shortness of breath: When iron levels are low, the body struggles to oxygenate tissues efficiently, resulting in shortness of breath during physical activity or even at rest. This is a significant symptom to watch out for, especially if it occurs without any other apparent cause.

4. Rapid or irregular heartbeat: Inadequate iron levels can disrupt the normal functioning of the cardiovascular system. As a result, individuals may experience a rapid or irregular heartbeat, known as tachycardia or arrhythmia, respectively. This symptom may be accompanied by a feeling of heart palpitations or pounding in the chest.

5. Headaches and dizziness: Reduced oxygen supply to the brain can lead to frequent headaches and a feeling of lightheadedness or dizziness. These symptoms may worsen with physical activity or exertion.

1. Medical History:
The initial step in diagnosing iron deficiency anaemia involves gathering relevant information about the patient's medical history.

2. Physical Examination:
These may include pale skin, a rapid or irregular heartbeat, weakness, splenomegaly/hepatomegaly and brittle nails.

3. Laboratory Tests:
Specific laboratory tests are crucial in confirming the diagnosis of iron deficiency anaemia. The most common tests include:

• Full blood count (FBC): This test measures the number of red blood cells, haemoglobin levels, hematocrit, and other cell components in the blood. In iron deficiency anaemia, the number of red blood cells, haemoglobin, and hematocrit  levels tend to be lower than normal.

• Serum Ferritin Level: Ferritin is a protein that stores iron in the body. A low serum ferritin level typically indicates iron deficiency, as it reflects depleted iron stores.

• Iron Studies: This includes tests such as serum iron, total iron-binding capacity (TIBC), and transferrin saturation. These tests provide information about the body's iron levels, iron transport capacity, and the percentage of iron being transported.

4. Additional Tests:

Gastrointestinal investigations such as endoscopy, colonoscopy, or a FIT test may be performed to identify any sources of chronic bleeding.

1. Dietary Modifications:

• Encourage a diet rich in iron sources such as lean red meat, poultry, fish, legumes, dark leafy greens, and fortified cereals.

2. Iron Supplements:

• Prescribe oral iron supplements to individuals with moderate to severe iron deficiency anaemia. For example, if haemoglobin less than 70 g/L.

3. Blood Transfusion:

• Consider blood transfusion for individuals with severe iron deficiency anaemia who require immediate resolution of symptoms or have associated complications.

Follow local guidelines for management of patients with IDA. For example, Ferrous sulfate 200mg OD.

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