Anemia is a common disease, affecting more than 600 million people globally, with more than 100,000 cases per year in India alone. It is a condition that results in the decreased oxygen-carrying capacity of red blood cells which may be due to decreased amount of red blood cells and/or decreased levels of haemoglobin in the blood. Anemia may be a result of varied causes. In fact, there are about 400 different types of Anemia! Most commonly, however, Anemia is a result of decreased iron levels in the blood, although other cases of Anemia due to vitamin B12 deficiency and folate deficiency have been reported. Anemia can also be genetic, as seen in the case of sickle-cell Anemia and thalassemia. It can also be a result of faulty erythropoiesis in the bone marrow. Anemias can also be classified based on the size of the erythrocytes in the blood. While its occurrence is quite common, the effects of Anemia can sometimes be lethal. In this article, we attempt to address the causes, symptoms, and risk factors of Anemia and also discuss different types of Anemia based on the size of erythrocytes.
Anemia is a condition that leads to the loss of red blood cells in the blood. Additionally, Anemia can also be a result of low haemoglobin levels in the blood. Both cases directly lead to a deficiency of oxygen in the body. While its occurrence is quite common, the effects of Anemia can sometimes be lethal.
As we know, the erythrocytes in the blood are tasked with the very important function of carrying oxygen to every part of the body. They can do this because they contain haemoglobin a protein that contains iron in its structural composition. Hence, iron is an essential component of oxygen transportation by haemoglobin across the body. Naturally, decreased levels of reserved iron in the body directly affect the amount of oxygen carried to the body. As the haemoglobin production itself is affected, the transport of oxygen to various parts of the body also decreases consequently.
There are several different types of Anemia, but broadly they can be a result of −.
Increases destruction of red blood cells that surpasses their production.
Decreased production of red blood cells or abnormal red blood cells.
Increased blood loss.
Nutrient deficiencies include iron deficiency and those related to iron levels in the body, such as vitamin B12 deficiency (pernicious Anemia), and folic acid deficiency (folate-deficiency Anemia).
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Symptoms of Anemia include −.
Dizziness/ faintings.
Shortness of breath.
Nausea.
Rapid pulse rates and enlargement of the heart as a compensatory action of reduced oxygen supply.
Paleness of the skin.
Enlarged spleen or liver.
Brittle nails.
Anemia can develop in women during pregnancy due to the increased nutrient requirements of the mother and fetal requirements of iron.
Anemia is seen in patients who suffer from diseases such as Sickle Cell Anemia, Glucose 6-phosphate dehydrogenase deficiency, spherocytosis, etc.
A condition known as erythroblastosis fetalis causes the destruction of the fetal RBCs by the maternal antibodies, leading to Anemia in the fetus.
Bone marrow disorders can lead to conditions like aplastic Anemia.
Poor dietary habits can cause a deficiency in iron, vitamin B12, and folate, all of which are linked with reduced amounts of haemoglobin and abnormal development of erythrocytes, leading to Anemia.
Exposure to hemolytic substances like sulfanilamide, primaquine and naphthalene can cause hemolytic Anemia.
Obesity.
Although some forms of Anemia are rare genetic conditions, most of them, such as iron-deficiency Anemia or folate-deficiency Anemia can be prevented by an improved dietary routine.
Intake of foods rich in iron help maintain healthy levels of haemoglobin in the blood. These include.
Red meats and poultry, fish, and seafood. The liver is a highly recommended organ meat, which supplies the daily required intake of iron to the body.
Green leafy vegetables such as spinach and collard greens, and other vegetables like cabbage and broccoli.
Fruits with high iron content (figs, raisins, dates); or Vitamin C content (vitamin C facilitates iron uptake), such as oranges, grapefruits, strawberries.
Nuts like cashew nuts and walnuts,.
Legumes like kidney beans, black beans, and lima beans.
Iron-fortified food such as bread and pasta, etc.
Iron supplements can be taken to increase the levels of iron in the body as a preventive measure against the development of anaemic conditions.
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Macrocytic hyperchromic Anemia, as the name suggests, is a result of larger than normal RBCs, with a high mean corpuscular volume (MCV) and with decreased mean corpuscular haemoglobin concentration (MCHC) per cell.
In such a condition, the MCV is >100 fL, and the MCHC levels are less than 30gHb/ 100 ml.
The haemoglobin levels are less than 12 g/dL in females and less than 13 g/dL in males.
There are two kinds of macrocytic Anemia, namely, megaloblastic Anemia which is a result of folate or vitamin B12 deficiencies, and non-megaloblastic Anemia which can be caused due to liver diseases and alcohol consumption. Hyperthyroidism may also be responsible for non-megaloblastic macrocytic Anemia.
Example− Pernicious Anemia.
As the name suggests, microcytic hypochromic Anemia is a form of Anemia attributed to smaller than normal size of blood RBCs and a reduced concentration of haemoglobin in the blood, leading to decreased intensity of the red blood colour. It is the most common form of Anemia.
It is a result of decreased levels of iron reserves in the body, which directly affect haemoglobin production, causing a decrease in the newly formed red blood cells (MCV <80 fL) and also, a reduction in their size.
Microcytic hypochromic, deficiency of vitamin C, acute or chronic blood loss, and situations like pregnancies and some trauma may lead to increased blood loss.
It is a more common form of Anemia in premenopausal women (30%) and pregnant women (41%).
Iron-deficiency Anemia− it is the most common form of Anemia, accounting for ~50% of all cases.
It can result from poor dietary habits, malabsorption of iron by the body (may be due to underlying infections such as the H. pylori infection in the gut), intake of non-steroidal anti-inflammatory drugs (NSAIDs), and acute or chronic blood loss due to ulcers, hernia or cancer in the colon.
Thalassemia− Thalassemia is an inherited disorder wherein the body can not make haemoglobin due to mutations in the required genes.
Anemia of Chronic Disease(ACD) is a result of an underlying chronic disease.
This type of Anemia is a result of smaller MCV red blood cells (<80 fL) and a higher MCHC (>30gHb/ 100mL).
In such cases of Anemia, the amount of haemoglobin per red blood cell is well within normal levels, but the size of individual erythrocytes is less than 80 fL
An example of normochromic microcytic Anemia is Anemia of Chronic Disease (ACD). ACD can be a result of chronic diseases like cancer; infectious diseases like tuberculosis; chronic kidney disease; Auto-immune diseases like Rheumatoid arthritis, lupus, etc.; conditions like obesity, etc.
Anemia is a blood disorder that is caused by reduced RBC count or low haemoglobin levels.
Iron deficiency Anemia is the most common type of Anemia globally.
Cladogenesis is the branching off of two or more new species from an ancestral species and leads to speciation.
Anemia can also be caused by vitamin deficiencies .
Anemia can be of different types depending on the MCV and MCHC of the RBCs- there are macrocytic, microcytic, normocytic and hyperchromogenic, hypochromogenic and normogenic Anemias.
Anemia can be genetic such as SCA and Thalassemia.
Anemia can be prevented by a healthy dietary routine.
High-risk factors include pregnancy, family history, vitamin deficiencies, and bone marrow disorders.
Q1. What is spherocytosis?
Ans. A condition in which the shape of the blood RBCs changes from being concave to spherical. This leads to mild conditions of Anemia.
Q2. How does Anemia affect infants and children?
Ans. Iron deficiency and consecutive Anemia in infants and children can delay cognitive abilities and psychomotor development in affected individuals.
Q3. How is Anemia of chronic diseases treated?
Ans. Although Anemia of chronic diseases is untreatable, its effects can be mildened by taking iron supplements and undergoing routine blood transfusions. Synthetic EPO therapy is the treatment of choice in chronic kidney diseases (CKD).
Q4. What are hemoglobinopathies?
Ans. Hemoglobinopathies include all the genetic diseases that are related to haemoglobin- its structure or its function. Examples include sickle cell Anemia, thalassemia, cyanosis, etc.
Q5. What is aplastic Anemia and how can it be treated?
Ans. Aplastic Anemia is a condition wherein the bone marrow is unable to make erythrocytes, leading to decreased levels of RBC and haemoglobin in the blood. It can be treated by a bone marrow transplant.