ANEMIA

ANEMIA

INTRODUCTION

Anemia, also spelled anaemia is usually defined as a decrease in the total amount of red blood cells (RBCs) or hemoglobin in the blood. It can also be defined as a lowered ability of the blood to carry oxygen. When anemia comes on slowly, the symptoms are often vague and may include feeling tired, weakness,shortness of breath or a poor ability to exercise. Anemia that comes on quickly often has greater symptoms, which may include confusion, feeling like one is going to pass out, loss of consciousness, or increased thirst. Anemia must be significant before a person becomes noticeably pale. Additional symptoms may occur depending on the underlying cause.

There are three main types of anemia: that due to blood loss, that due to decreased red blood cell production and that due to increased red blood cell breakdown. Causes of blood loss include trauma and gastrointestinal bleeding, among others. Causes of decreased production include iron deficiency, a lack of vitamin B12,thalassemia, and a number of neoplasms of the bone marrow. Causes of increased breakdown include a number of genetic conditions such as sickle cell anemia, infections like malaria, and certain autoimmune diseases. It can also be classified based on the size of red blood cells and amount of hemoglobin in each cell. If the cells are small, it is microcytic anemia. If they are large, it is macrocytic anemia while if they are normal sized, it is normocytic anemia.^[4] Diagnosis in men is based on a hemoglobin of less than 130 to 140 g/L (13 to 14 g/dL), while in women, it must be less than 120 to 130 g/L (12 to 13 g/dL), Further testing is then required to determine the cause.

Certain groups of individuals, such as pregnant women, benefit from the use of iron pills for prevention. Dietary supplementation, without determining the specific cause, is not recommended. The use of blood transfusions is typically based on a person's signs and symptoms. In those without symptoms, they are not recommended unless hemoglobin levels are less than 60 to 80 g/L (6 to 8 g/dL). These recommendations may also apply to some people with acute bleeding.Erythropoiesis-stimulating medications are only recommended in those with severe anemia.

Anemia is the most common disorder of the blood, affecting about a quarter of the people globally. Iron-deficiency anemia affects nearly 1 billion. In 2013, anemia due to iron deficiency resulted in about 183,000 deaths – down from 213,000 deaths in 1990. It is more common in females than males, among children, during pregnancy, and in the elderly. Anemia increases costs of medical care and lowers a person's productivity through a decreased ability to work. The name is derived from Ancient Greek: ἀναιμία anaimia, meaning "lack of blood", from ἀν- an-, "not" + αἷμα haima, "blood". 

SIGNS AND SYMPTOMS

Anemia signs and symptoms vary depending on the cause of your anemia. They may include:

• Fatigue
• Weakness
• Pale or yellowish skin
• Irregular heartbeats
• Shortness of breath
• Dizziness or lightheadedness
• Chest pain
• Cold hands and feet
• Headache

CAUSES 

Anemia occurs when your blood doesn't have enough red blood cells. This can happen if:

• Your body doesn't make enough red blood cells
• Bleeding causes you to lose red blood cells more quickly than they can be replaced
• Your body destroys red blood cells
• Different types of anemia and their causes include:
  • Other anemias. There are several other forms of anemia, such as thalassemia and malarial anemia.
  • Iron deficiency anemia. This is the most common type of anemia worldwide. Iron deficiency anemia is caused by a shortage of iron in your body. Your bone marrow needs iron to make hemoglobin. Without adequate iron, your body can't produce enough hemoglobin for red blood cells.
    Without iron supplementation, this type of anemia occurs in many pregnant women. It is also caused by blood loss, such as from heavy menstrual bleeding, an ulcer, cancer and regular use of some over-the-counter pain relievers, especially aspirin.
  • Vitamin deficiency anemia. In addition to iron, your body needs folate and vitamin B-12 to produce enough healthy red blood cells. A diet lacking in these and other key nutrients can cause decreased red blood cell production.
    Additionally, some people may consume enough B-12, but their bodies aren't able to process the vitamin. This can lead to vitamin deficiency anemia, also known as pernicious anemia.
  • Anemia of chronic disease. Certain diseases — such as cancer, HIV/AIDS, rheumatoid arthritis, kidney disease, Crohn's disease and other chronic inflammatory diseases — interfere with thecan  production of red blood cells.
  • Aplastic anemia. This rare, life-threatening anemia occurs when your body doesn't produce enough red blood cells. Causes of aplastic anemia include infections, certain medicines, autoimmune diseases and exposure to toxic chemicals.
  • Anemias associated with bone marrow disease. A variety of diseases, such as leukemia and myelofibrosis, can cause anemia by affecting blood production in your bone marrow. The effects of these types of cancer and cancer-like disorders vary from mild to life-threatening.
  • Hemolytic anemias. This group of anemias develops when red blood cells are destroyed faster than bone marrow can replace them. Certain blood diseases increase red blood cell destruction. You can inherit a hemolytic anemia, or you can develop it later in life.

Sickle cell anemia. This inherited and sometimes serious condition is an inherited hemolytic anemia. It's caused by a defective form of hemoglobin that forces red blood cells to assume an abnormal crescent (sickle) shape. These irregular blood cells die prematurely, resulting in a chronic shortage of red blood cells.   

DIAGNOSIS

To diagnose anemia, your doctor may ask you about your medical and family history, perform a physical exam, and run the following tests:

• Complete blood count (CBC). A CBC is used to count the number of blood cells in a sample of your blood. For anemia your doctor will be interested in the levels of the red blood cells contained in the blood (hematocrit) and the hemoglobin in your blood.
  Normal adult hematocrit values vary from one medical practice to another but are generally between 40 and 52 percent for men and 35 and 47 percent for women. Normal adult hemoglobin values are generally 14 to 18 grams per deciliter for men and 12 to 16 grams per deciliter for women.
• A test to determine the size and shape of your red blood cells. Some of your red blood cells may also be examined for unusual size, shape and color                                Anemia is typically diagnosed on a complete blood count. Apart from reporting the number of red blood cells and the hemoglobin level, the automatic counters also measure the size of the red blood cells by flow cytometry, which is an important tool in distinguishing between the causes of anemia. Examination of a stained blood smear using a microscopecan also be helpful, and it is sometimes a necessity in regions of the world where automated analysis is less accessible.
  In modern counters, four parameters (RBC count, hemoglobin concentration, MCV and RDW) are measured, allowing others (hematocrit, MCH and MCHC) to be calculated, and compared to values adjusted for age and sex. Some counters estimate hematocrit from direct measurements.

  WHO's Hemoglobin thresholds used to define anemia(1 g/dL = 0.6206 mmol/L)

  Age or gender group	Hb threshold (g/dl)	Hb threshold (mmol/l)
  Children (0.5–5.0 yrs)	11.0	6.8
  Children (5–12 yrs)	11.5	7.1
  Teens (12–15 yrs)	12.0	7.4
  Women, non-pregnant (>15yrs)	12.0	7.4
  Women, pregnant	11.0	6.8
  Men (>15yrs)	13.0	8.1

Reticulocyte counts, and the "kinetic" approach to anemia, have become more common than in the past in the large medical centers of the United States and some other wealthy nations, in part because some automatic counters now have the capacity to include reticulocyte counts. A reticulocyte count is a quantitative measure of the bone marrow's production of new red blood cells. The reticulocyte production index is a calculation of the ratio between the level of anemia and the extent to which the reticulocyte count has risen in response. If the degree of anemia is significant, even a "normal" reticulocyte count actually may reflect an inadequate response. If an automated count is not available, a reticulocyte count can be done manually following special staining of the blood film. In manual examination, activity of the bone marrow can also be gauged qualitatively by subtle changes in the numbers and the morphology of young RBCs by examination under a microscope. Newly formed RBCs are usually slightly larger than older RBCs and show polychromasia. Even where the source of blood loss is obvious, evaluation of erythropoiesis can help assess whether the bone marrow will be able to compensate for the loss, and at what rate. When the cause is not obvious, clinicians use other tests, such as: ESR, ferritin, serum iron, transferrin, RBC folate level, serum vitamin B₁₂, hemoglobin electrophoresis, renal function tests (e.g. serum creatinine) although the tests will depend on the clinical hypothesis that is being investigated. When the diagnosis remains difficult, a bone marrow examination allows direct examination of the precursors to red cells, although is rarely used as is painful, invasive and is hence reserved for cases where severe pathology needs to be determined or excluded.                                                                                                                                                                                                                                                                                                   TREATMENT                                                                                                                                                                
 ANEMIA TREATMENT DEPEND ON THE CAUSE

• Iron deficiency anemia. Treatment for this form of anemia usually involves taking iron supplements and making changes to your diet.
  If the underlying cause of iron deficiency is loss of blood — other than from menstruation — the source of the bleeding must be located and stopped. This may involve surgery.
• Vitamin deficiency anemias. Treatment for folic acid and B-12 deficiency involves dietary supplements and increasing these nutrients in your diet.
  If your digestive system has trouble absorbing vitamin B-12 from the food you eat, you may need vitamin B-12 shots. At first, you may receive the shots every other day. Eventually, you'll need shots just once a month, which may continue for life, depending on your situation.
• Anemia of chronic disease. There's no specific treatment for this type of anemia. Doctors focus on treating the underlying disease. If symptoms become severe, a blood transfusion or injections of synthetic erythropoietin, a hormone normally produced by your kidneys, may help stimulate red blood cell production and ease fatigue.
• Aplastic anemia. Treatment for this anemia may include blood transfusions to boost levels of red blood cells. You may need a bone marrow transplant if your bone marrow is diseased and can't make healthy blood cells.
• Anemias associated with bone marrow disease. Treatment of these various diseases can include medication, chemotherapy or bone marrow transplantation.
• Hemolytic anemias. Managing hemolytic anemias includes avoiding suspect medications, treating related infections and taking drugs that suppress your immune system, which may be attacking your red blood cells.
  Depending on the severity of your anemia, a blood transfusion or plasmapheresis may be necessary. Plasmapheresis is a type of blood-filtering procedure. In certain cases, removal of the spleen can be helpful.
• Sickle cell anemia. Treatment for this anemia may include the administration of oxygen, pain-relieving drugs, and oral and intravenous fluids to reduce pain and prevent complications. Doctors also may recommend blood transfusions, folic acid supplements and antibiotics.
  A bone marrow transplant may be an effective treatment in some circumstances. A cancer drug called hydroxyurea (Droxia, Hydrea) also is used to treat sickle cell anemia.
• Thalassemia. This anemia may be treated with blood transfusions, folic acid supplements, medication, removal of the spleen (splenectomy), or a blood and bone marrow stem cell transplant.

                                                                                                                                                                             PREVENTION       

How to Prevent Against This

Some types of anemia cannot be prevented. Sickle-cell disease is an example of this type of anemia. Sickle-cell anemia is a genetic condition, so the disease cannot be avoided if you inherit the genes.

Anemia due to blood loss is also difficult to prevent since accidents and injuries are unpredictable. If you do find yourself in a situation where you start to lose a significant amount of blood, you should try to stop or limit the bleeding as much as possible until you can get help.

For other types of anemia, supplements and vitamins can help prevent the condition and treat symptoms. A doctor might decide to put you on a diet that helps with the production of healthy red blood cells. You might even need to take regular supplements or medications to complement your diet.

To prevent becoming anemic, it can be helpful to eat foods that are rich in iron, vitamin B12, and foliate. For some people, these foods do not adequately prevent against anemia. A doctor might choose to put you on a regular vitamin and supplement regimen. Folic acid, iron, and vitamin B6 are supplements that the doctor might ask you to take. The type of supplements that you take is related to the type of anemia that you develop or are likely to develop. For example, a person who is iron deficient may not necessarily benefit from a vitamin B12 supplement.

If you have been diagnosed as anemic or borderline anemic, you should take precautions to stay up to date with your routine physicals and blood tests. Catching a problem or recurring condition early on can help to prevent severe anemia in the future. Take efforts to catch even the most subtle warning signs to prevent problems later on.

Keep track of your symptoms so that you can communicate with your doctor. You may be unaware of a potential underlying condition that is triggering your anemia. Your condition may be serious, so it is important that you follow your doctor's instructions for additional tests.

If you start to fail faint, nauseous, or dizzy, you should sit down immediately. Fold your upper body over your knees with your head between your legs until you start to feel stable once again.

If you are pregnant, make sure that you stay up to date with your regular exams and scans. You want to make sure that you and your baby are safe.