What Is Iron Deficiency Anaemia

Overview

Iron-deficiency anaemia (IDA) occurs due to the lack of iron in the body. The body consumes dietary iron in the form of haem or non-haem iron. Plant-based food has non-haem iron, whereas meat contains haem iron. Haem iron is bioavailable and plays an important role in haematopoiesis, oxygen transport, and neurotransmitter synthesis. In IDA, there is insufficient iron in the body for haemoglobin synthesis and to form normal red blood cells (RBC).^1,2,3

Globally, people assigned female at birth (AFAB) and children under the age of 5 years are more likely than people assigned men at birth (AMAB) to suffer from IDA. Targeted scrutiny of high-risk groups can help reduce the global burden of IDA. Despite IDA causing disabilities and chronic illnesses, it receives insufficient attention in many public forums and discussions.^4,5  It is the most common type of anaemia in middle-income and low-income countries. South Asia and West sub-Saharan Africa have the highest burden of IDA worldwide.⁴ 

Outlining the treatment and management of IDA can help people across all strata understand the disease better and seek timely help.

Stages of iron deficiency anaemia

The stages of IDA are as follows:^6,7

Stage 1: This initial stage has mild iron deficiency without anaemia. Although there is a depletion of iron stores, it does not affect the number and shape of RBCs.

Stage 2: There is a marginal iron deficiency of iron. New red blood cells have insufficient haemoglobin. Subtle symptoms of anaemia begin to appear.

Stage 3: This is a stage of iron-deficiency anaemia (IDA). RBCs are small, misshapen and pale. During this stage, clinical features become more pronounced.

It is crucial to note that as the disease progresses from stage 1 to stage 3, the symptoms may vary from person to person.^6,7

Causes of iron deficiency anaemia

Numerous causes contribute to IDA, and the causes tend to vary across patient age groups (children, people AFAB, and older people), geographical areas (developed and developing countries), and comorbidities.⁸

Haemoglobinopathies, chronic kidney disease, and gastrointestinal haemorrhages contribute more to the anaemia burden in high-income regions. Likewise, inadequate diet supplements and frequent infections are common causes of IDA in younger age groups and underdeveloped nations.^4,6,8  

The common causes of IDA are:

• Inadequate dietary intake: poverty, malnutrition, and a vegetarian diet may contribute to IDA due to insufficient intake of iron-rich food
• Blood loss: conditions such as heavy menstrual bleeding and chronic inflammation may deplete the iron level in the body. Similarly, certain drugs and interventions, such as bypass surgery and dialysis, can cause significant blood loss
• Malabsorption: despite sufficient iron intake, conditions such as coeliac disease, atrophic gastritis and surgical procedures like partial gastric removal may impair iron absorption
• Increased iron demands: iron requirement increases among children of growing ages. There is a demand for extra iron during foetal development and breastfeeding
• Infections: infections are the chief cause of anaemia in West sub-Saharan Africa. Commonly encountered infections are malaria, schistosomiasis, and hookworm infestations
• Haemoglobinopathies and other genetic conditions: thalassaemia, sickle cell disease, and glucose-6-phosphate dehydrogenase deficiency are the common genetic disorders leading to IDA

Signs and symptoms of iron deficiency anaemia

The individual may miss symptoms of mild anaemia. The clinical presentation becomes more prominent with the severity of this condition. Chronic deficiency, however, may cause less noticeable symptoms due to physiological adaptation.⁶

Common signs and symptoms of IDA are:

• Tiredness
• Shortness of breath
• Skin pallor
• Restlessness or palpitations
• Headache
• Inability to concentrate
• Poor productivity

Other less common symptoms are:

• Difficulty in swallowing
• Ulcers in the corners of the mouth
• Craving for non-food items (pica)
• Pruritus - itchy skin
• Tinnitus
• Sore tongue

The non-specific symptoms of IDA and overlapping aetiological factors have made diagnosing and treating the cause challenging. 

Management and treatment for iron deficiency anaemia

Management of the IDA involves addressing the issues related to the underlying cause, planning the treatment, and avoiding associated sequelae.

Treatment of IDA includes:^1,8

• Iron therapy: iron tablets or oral solution in various forms, such as ferrous sulphate, ferrous fumarate, and ferrous gluconate. Continuation of treatment is advised at least three months after the recovery. In case of intolerance to oral iron, intravenous iron is prescribed
• Intake of iron-rich food such as meat, green leafy vegetables, prunes etc. and avoiding coffee and tea in the diet
• Identifying and treating the underlying causes of iron deficiency is necessary to prevent recurrence
• Some cases may require blood transfusions
• Monitoring the patient for response to treatment

Diagnosis

After the physical examination, the clinician advises a series of tests. A single test cannot give a definite diagnosis or be the sole indicator of IDA. The tests are:^1,6,8,9

• Full blood count: it measures haemoglobin (Hb), RBC count, mean cell haemoglobin concentration (MCHC), and mean cell volume (MCV). All these parameters are reduced in IDA patients
• Serum ferritin: there is a reduction in serum ferritin level. However, interpreting IDA is sometimes challenging in chronic inflammation due to raised or normal serum ferritin levels
• Total iron-binding capacity (TIBC): raised TIBC is a good indicator of iron deficiency
• Transferrin saturation: it is low in IDA and an important marker for confirming IDA in chronic conditions with raised serum ferritin
• Peripheral blood smear examination: it helps to identify the morphology of RBCs. The microcytic hypochromic RBC in the smear is suggestive of IDA
• Additional investigations such as stool examination, endoscopy and colonoscopy to identify the cause of IDA

Risk factors

The known risk factors for IDA include:^2,6,8

• Age: infants, children, people AFAB at reproductive age and the elderly age group are more susceptible to IDA
• Gender: people AFAB are at a higher risk of developing IDA due to menstrual bleeding, pregnancy and breastfeeding
• Dietary factors: a vegetarian diet population has a greater risk of developing IDA
• Frequent blood donors are more prone to IDA
• People on anti-inflammatory drugs have the risk of developing IDA
• Patients with chronic conditions: increased risk of IDA in patients with underlying chronic infections, gastrointestinal or renal diseases

Complications

Untreated and improperly managed IDA can have a wide range of clinical outcomes.

The potential consequences of IDA are:^6,8,10,11

• Impairment of cognitive functions: iron deficiency can affect the brain's intellectual and cognitive functions, such as the inability to concentrate, delayed learning, and executive functioning
• Negative impact on routine activities: the quality of life deteriorates due to tiredness, fatigue, and physical weakness associated with IDA
• Increased susceptibility to infections: poor immunity and reduced oxygen to tissue can lead to frequent infections
• Increased risk of pregnancy-associated complications: in mothers with IDA, babies are at risk of premature birth and low birth weight. Severe IDA is also associated with increased newborn and maternal death
• Disease progression: there is an increased risk of hospitalisation and decreased survival in patients with chronic heart diseases. Additionally, IDA can increase the possibility of advancement to end-stage kidney disease in patients undergoing dialysis
• Restless leg syndrome (RLS): it is a neurological disorder characterised by an uncontrolled urge to move the legs. A low ferritin level in cerebrospinal fluid can impair dopamine function, leading to secondary RLS

The IDA must therefore be diagnosed as soon as possible, treated, and followed up regularly in high-risk groups to prevent complications.

FAQs

How can I prevent iron deficiency anaemia?

Healthy lifestyle changes and dietary modifications can help in preventing IDA. The following approaches can help to prevent the development of IDA:^2,4,5,8

• Dietary modification: one must consume a diet that consists of meat and iron-rich food
• Iron supplementation: high-risk and susceptible individuals can benefit from iron supplementation
• Food-fortification: in countries with an increased incidence of IDA, enrichment of food such as rice can help reduce the incidence of IDA
• An iron absorption modifier: including enhancers such as vitamin C and avoiding inhibitors such as calcium and tannins can help prevent iron deficiency
• Public health measures and integrated school packages in African and Asian countries with a high burden of IDA are constructive approaches
• Early identification of the region-specific aetiological factors to prevent the IDA and its complications

How common is iron deficiency anaemia?

The key facts regarding the prevalence of IDA are:^4,12

• Roughly one-quarter of the world's population is affected by anaemia, and IDA is known to be the most common type
• The leading cause of IDA varies significantly by region, age and sex
• Compared to Europe and North America, the prevalence of IDA in Africa and South Asia is a cause of concern due to its long-term complications

What can I expect if I have iron deficiency anaemia?

One can expect a range of symptoms based on the severity of anaemia. The common presentations include:^1,4

• Weakness
• Pale skin and mucous membrane
• Tiredness
• Increased heartbeat
• Shortness of breath
• Lack of concentration

When should I see a doctor?

It is essential to consult a doctor if someone suspects anaemia or experiences any symptoms suggestive of anaemia. Pregnant women and women planning to conceive should also seek medical advice about IDA. A doctor can guide regarding the available treatment options and iron therapy that suits the individual after necessary investigations. 

Summary

Iron-deficiency anaemia is the leading cause of anaemia worldwide. It is a key health problem that can directly impact physical performance and cognitive functions. The symptoms may differ with the degree of anaemia and other underlying diseases. Therefore, a multifaceted approach is needed to address this preventable nutritional deficiency anaemia. In geographic areas with a high prevalence of IDA, food fortification and nutrition programs can help reduce the disease.

Supplementing iron in high-risk groups and checking serum iron levels in the early trimester can help reduce the incidence of IDA. Also, region-specific epidemiological studies to identify the factors responsible for IDA can help in its prevention. A better understanding of the prevalence, causes and risk factors of IDA can aid early detection and management.

The cost-effectiveness of blood tests and iron therapy makes them accessible to people all across the globe. A vital aspect of raising awareness is educating consumers about iron-rich foods and providing information about IDA's symptoms, complications, and socioeconomic outcomes.