Classification of Anaemia by Cause

Introduction

Anaemia is a global health problem, particularly affecting young children, menstruating girls, pregnant women, and new mothers. According to WHO (World Health Organization), globally, an estimated 40% of children aged 6–59 months, 37% of pregnant women, and 30% of women aged 15–49 battle with anaemia. Anaemia is a condition where your body doesn’t produce enough healthy red blood cells, leading to a lack of oxygen in the blood. This is directed to fatigue, weakness, and various other symptoms. Understanding the underlying causes of anaemia is crucial in effectively managing and treating this condition. Let us explore the causes and impact of anaemia on different groups.^1,2

Definition of Anaemia

Anaemia is a medical condition characterized by a deficiency of red blood cells or a decreased concentration of haemoglobin. Haemoglobin is crucial for carrying oxygen throughout the body. When there is an insufficient number of red blood cells or inadequate haemoglobin levels, the blood’s capacity to deliver oxygen to the body’s tissues is compromised.^1,2.

Symptoms and Diagnosis of Anaemia

Symptoms:

• Chills
• Bleeding
• Weakness
• Shortness of breath
• Paleness 
• Headache
• Tiredness
• Jaundice
• Dizziness and fainting
• In severe cases, it can pose increased risks for maternal and child mortality. Additionally, iron deficiency anaemia can adversely affect cognitive and physical development in children and reduce productivity in adults.^3,4

When you don’t get enough vitamin B12 and/or vitamin B9 (folate), you might end up with megaloblastic anaemia, a kind of vitamin-deficiency anaemia. Hence, consumption of vitamin B12 and folate in moderation is recommended to keep megaloblastic anaemia at bay.

Dr. Siddharth Gupta, B.A.M.S, M.D (Ayu)

Diagnosis

To diagnose anaemia, healthcare professionals employ various methods to assess your condition. Here are methods of diagnosis of anaemia:

• Medical history and risk factors: Your doctor will inquire about your medical history, dietary habits, and family history of anaemia to understand potential causes and risk factors.
• Physical examination: A physical examination may be conducted to observe symptoms of anaemia, such as pale tongue or brittle nails.
• Blood tests: Blood tests, including a complete blood count (CBC), are commonly performed to evaluate different components of your blood, such as red blood cells, white blood cells, haemoglobin, and platelets.
• Hematocrit levels: Low hematocrit values could indicate anaemia, as it measures the proportion of red blood cells in your blood.
• Mean corpuscular volume (MCV): Higher or lower MCV levels may be indicative of anaemia, as it measures the average size of red blood cells.
• Referral to a hematologist: If anaemia is diagnosed, your doctor may refer you to a hematologist, a specialist in blood diseases, for further evaluation and management.⁵

Sickle cell anaemia is a type of inherited anaemia. In this condition, your red blood cells take an abnormal shape. Instead of being round and flexible discs, they become to rigid and sticky sickle-shaped cells that may obstruct blood flow. Fanconi’s anaemia is another hereditary but rare blood disorder. Diamond-Blackfan type of inherited anaemia makes your bone marrow unable to produce enough red blood cells. condition.

Dr. Rajeev Singh, BAMS

Different Types of Anaemia

Anaemia encompasses various types that can be categorized based on their underlying causes. Here are the types of anaemia based on their causes:

Classification of Anaemia by Cause

A. Nutritional Deficiencies

Nutritional deficiency anaemia is a condition caused by inadequate intake of essential nutrients, leading to impaired red blood cell production; it encompasses various types based on specific nutrient deficiencies. They are:

1. Iron deficiency anaemia

• Iron deficiency anaemia is the most common form of anaemia globally. It is identified by certain changes in the appearance of red blood cells under a microscope, showing them to be smaller and paler than normal.
• The primary cause of iron deficiency anaemia is inadequate iron levels in the body, which can result from factors such as insufficient iron intake, decreased absorption, or blood loss.
• Common symptoms of iron deficiency anaemia include fatigue and dyspnea on exertion, but they can be nonspecific.
• The specific cause of iron deficiency anaemia varies depending on age, gender, and socioeconomic status.
• Blood loss, especially in older patients, is a major contributor to iron deficiency anaemia.
• Other causes include low dietary iron intake, increased iron requirements during pregnancy, decreased iron absorption in conditions like celiac disease, and iron bioavailability differences between breast milk and cow’s milk in infants.
• In developing countries, parasitic infestations also play a significant role in causing iron deficiency anaemia.
• Dietary sources rich in iron, such as green vegetables, red meat, and iron-fortified milk formulas, can help combat iron deficiency anaemia.⁶

2. Vitamin B12 deficiency anaemia

• Vitamin B12-deficiency anaemia is a condition where the body lacks sufficient vitamin B12 to produce healthy blood cells.
• Vitamin B12 is necessary for the production of red blood cells, white blood cells, and platelets.
• Causes of vitamin B12-deficiency anaemia include problems with gut absorption and conditions like pernicious anaemia.
• Symptoms of vitamin B12-deficiency anaemia initially include fatigue, paleness, shortness of breath, headaches, and dizziness.
• Risk factors for developing vitamin B12 deficiency include inadequate dietary intake, lack of intrinsic factor production, certain medications, lifestyle habits like excessive alcohol consumption, and various medical conditions.
• Prevention involves maintaining a diet rich in vitamin B12 through consumption of foods such as lean red meat, fish, dairy products, fortified cereals, and eggs.⁷

3. Folate deficiency anaemia

• Folate-deficiency anaemia occurs when there is a lack of folate (B vitamin), leading to a decrease in red blood cells.
• Causes of folate-deficiency anaemia include inadequate folate intake, hemolytic anaemia, long-term alcoholism, and certain medications.
• Risk factors for this type of anaemia include alcoholism, consuming overcooked food, poor diet lacking fresh fruits and vegetables, pregnancy, and weight loss diets.
• Folic acid is crucial during pregnancy for proper fetal growth, and insufficient folate intake can increase the risk of birth defects in the baby.⁸

B. Hemolytic Anaemia

• Hemolytic anaemia is a condition characterized by the rapid destruction of red blood cells and leads to the reduction of red blood cells in the body. 
• Anaemia occurs when there are fewer red blood cells, resulting in insufficient oxygen supply to the body.
• Hemolytic anaemia disrupts the normal balance of red blood cells production and destruction.
• Insufficient oxygen levels can negatively impact the overall functioning of the body. 
• Hemolytic anaemia is caused by an accelerated breakdown of red blood cells, a process known as hemolysis.⁹

1. Inherited hemolytic anaemia

• Inherited hemolytic anaemia occurs when the condition is passed from parents to their children through genetic inheritance.
• Two common forms of inherited hemolytic anaemia are sickle cell anaemia and thalassemia.
• These conditions result in the production of abnormal red blood cells that have a shorter lifespan than normal red blood cells.⁹

2. Acquired hemolytic anaemia

• Acquired hemolytic anaemia is a condition that develops later in life and is not present at birth.
• It occurs when the body produces normal red blood cells that are later destroyed.
• Several factors can contribute to acquired hemolytic anaemia, including infections (viral or bacterial), certain medications, blood cancers, autoimmune disorders, an overactive spleen, mechanical heart valves, and severe reactions to blood transfusions.
• Some forms of acquired hemolytic anaemia are temporary and resolve within months, while others can be chronic and have episodes of remission and recurrence.⁹

C. Aplastic Anaemia

• Aplastic anaemia, also known as bone marrow failure, is a rare and serious blood condition where the bone marrow fails to produce enough new blood cells.
• It is more than just anaemia and can affect the production of red blood cells, white blood cells, and platelets.
• This can be caused by damage to the stem cells in the bone marrow, often due to an autoimmune response where the immune system attacks and destroys these cells. Other causes include certain medications, exposure to toxins or chemicals, and rare cases of inheritance.
• Treatments for aplastic anaemia may include blood and bone marrow transplants, blood transfusions, medications to suppress the immune system, medications to stimulate blood cell production, and avoiding environmental toxins.
• Without treatment, aplastic anaemia can lead to complications such as bleeding, leukaemia, irregular heartbeat, and heart failure. Regular monitoring and precautions are necessary to manage the condition effectively.¹⁰

D. Anaemia of Chronic Disease

• Anaemia of chronic disease, also known as anaemia of inflammation or ACD, is a type of anaemia that occurs in individuals with conditions causing inflammation, such as infections, autoimmune diseases, cancer, and chronic kidney disease (CKD).
• It is characterized by a lower amount of red blood cells and haemoglobin in the blood, which can lead to insufficient oxygen supply to the body.
• This type of anaemia is more prevalent in older adults who have chronic diseases associated with inflammation.
• Severe anaemia of chronic disease can pose risks, including fatigue, shortness of breath, and may be potentially life-threatening.
• In individuals with CKD, severe anaemia can increase the likelihood of developing heart problems.
• Symptoms of anaemia of chronic disease may be mild or absent, often overshadowed by the symptoms of the underlying disease causing the anaemia.
• Common symptoms of anaemia, such as rapid heartbeat, body aches, fatigue, pale skin, and shortness of breath, can occur.
• Anaemia of chronic disease is thought to be caused by immune system-related changes that affect iron storage and utilization, reduced production of erythropoietin (EPO) by the kidneys, inadequate response of the bone marrow to EPO, and accelerated breakdown of red blood cells.¹¹

E. Other Causes of Anaemia

Other causes of anaemia may include:

• Family history: Having a family history of inherited types of anaemia increases the risk.
• Medications: Certain medications can cause anaemia.
• Immune System Problems: Problems with the immune system can lead to the destruction of red blood cells causing anaemia.
• Inherited Conditions: Anaemia can be caused by inherited conditions such as thalassemia or sickle cell anaemia.
• Pregnancy: Anaemia can occur during pregnancy.
• Bone Marrow Problems: Conditions like lymphoma, leukaemia, myelodysplasia, multiple myeloma, or aplastic anaemia can affect bone marrow function and result in anaemia.
• Slow Blood Loss: Gradual blood loss from heavy menstrual periods or stomach ulcers can cause anaemia.
• Sudden Heavy Blood Loss: Anaemia can result from episodes of significant acute blood loss.
• Aging: The risk of anaemia increases with age.
• Excessive Blood Loss: Anaemia can occur due to bleeding from inflammation, surgery, serious injury, or frequent blood donations.^11,12,13

Conclusion

In conclusion, the classification of anaemia by cause is essential for accurate diagnosis and appropriate treatment.  By understanding the underlying cause, healthcare professionals can develop tailored treatment plans and improve patient’s quality of life. Early detection and intervention are crucial in preventing complications. Overall, the classification of anaemia by cause plays a crucial role in providing personalized care and promoting optimal health outcomes.

Frequently Asked Questions (FAQs)

References:

1. Anaemia [Internet]. World Health Organization; [cited 2023 May 17]. Available from: https://www.who.int/health-topics/anaemia#tab=tab_1 
2. What is anemia? [Internet]. U.S. Department of Health and Human Services; [cited 2023 May 17]. Available from: https://www.nhlbi.nih.gov/health/anemia 
3. Symptoms [Internet]. U.S. Department of Health and Human Services; [cited 2023 May 17]. Available from: https://www.nhlbi.nih.gov/health/anemia/symptoms 
4. Anaemia [Internet]. World Health Organization; [cited 2023 May 17]. Available from: https://www.who.int/health-topics/anaemia#tab=tab_2
5. Diagnosis [Internet]. U.S. Department of Health and Human Services; [cited 2023 May 17]. Available from: https://www.nhlbi.nih.gov/health/anemia/diagnosis  
6. Warner MJ, Kamran MT. Iron Deficiency Anemia. [Updated 2022 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448065/ 
7. Vitamin B12–deficiency anemia [Internet]. U.S. Department of Health and Human Services; [cited 2023 May 17]. Available from: https://www.nhlbi.nih.gov/health/anemia/vitamin-b12-deficiency-anemia#:~
8. Folate-deficiency anemia: Medlineplus medical encyclopedia [Internet]. U.S. National Library of Medicine; [cited 2023 May 17]. Available from: https://medlineplus.gov/ency/article/000551.htm#:~ 
9. Hemolytic anemia [Internet]. 2021 [cited 2023 May 17]. Available from: https://www.hopkinsmedicine.org/health/conditions-and-diseases/hemolytic-anemia#:~ 
10. Aplastic anemia [Internet]. U.S. Department of Health and Human Services; [cited 2023 May 17]. Available from: https://www.nhlbi.nih.gov/health/anemia/aplastic-anemia#:~ 
11. Anemia of inflammation or chronic disease – NIDDK [Internet]. U.S. Department of Health and Human Services; [cited 2023 May 17]. Available from: https://www.niddk.nih.gov/health-information/blood-diseases/anemia-inflammation-chronic-disease#:~ 
12. What is Anemia? [Internet]. [cited 2023 May 17]. Available from: https://www.pennmedicine.org/for-patients-and-visitors/patient-information/conditions-treated-a-to-z/anemia 
13. Causes and risk factors [Internet]. U.S. Department of Health and Human Services; [cited 2023 May 17]. Available from: https://www.nhlbi.nih.gov/health/anemia/causes 

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