Anaemia

Original Editor - Lucinda Hampton

Top Contributors - Lucinda hampton, Franca Ebomah and Kim Jackson  

What is Anaemia?

Anaemia(also spelled as anemia) is a condition in which the oxygen-carrying cells (referred to as the red blood cells) are not enough to meet up with the physiological demands of the body. Usually it signals the presence of an underlying disease . Anaemia often results from diseases in the liver or gastrointestinal tract.

Causes of Anaemia

• Globally, shortage of iron in the system has been considered to be the most common cause of anaemia.
• Other causes include:
  • Nutritional deficiencies e.g. folate, vitamin B12 or vitamin A deficiencies.
  • Acute or chronic inflammations
  • Parasitic infections
  • Inherited or acquired disorders that affect haemoglobin synthesis, red blood cell production or red blood cell survival e.g. sickle cell disease.

Epidemiolgy

Anaemia affects one-third of the world's population. Oftentimes, it is mild and asymptomatic, requiring no management.

It is a global health concern affecting majorly pregnant women and young children. According to WHO, 42% of children less than 5 years of age and 40% of pregnant women globally are anaemic

• The prevalence is more than 20% of individuals who are older than the age of 85: incidence of anemia 50%-60% in the nursing homes; in the elderly, approximately 33% of patients have a nutritional deficiency as the cause of anemia e.g. iron, folate or vitamin B12; 33% of patients, there is evidence of renal failure or chronic inflammation.
• Other at-risk groups include alcoholics, the homeless population, and those experiencing neglect or abuse.
• New-onset anemia, especially in those over 55 years of age, needs investigating and should be considered cancer until proven otherwise (especially true in men of any age who present with anemia).
• Race is also an important determinant of anemia, with the prevalence increasing in the African American population from e.g. Thalassemia
• In 2010, it was found that Sub-Saharan Africa, South Asia, the Caribbean, and Oceania had the highest anemia prevalence across all age groups and both sexes

Biological Mechanism of Anaemia

Physiologically, anaemia results from a disproportionate loss of red blood cell compared to production .This can occur for two reasons:

1. Deficient erythropoiesis: Erythropoiesis is the process of red blood cell formation in a living tissue.
2. Excessive loss of erythrocytes e.g. in hemolysis or blood loss or both

Symptoms

In mild cases there would be no presentation of symptoms. In severe cases, symptoms generally include:

• Dizziness, light-headedness, or feeling like you are about to pass out
• Fast or unusual heartbeat
• Headache
• Pain, including in your bones, chest, belly, and joints
• Problems with growth, for children and teens
• Shortness of breath
• Skin that’s pale or yellow
• Cold hands and feet
• Tiredness or weakness

Symptoms depend on factors such as: the etiology of anemia, the acuity of onset, and the presence of other comorbidities e.g. cardiovascular disease. The normal haemoglobin(Hb) ranges are as follows: 13.5 to 18.0 g/dL in men; 12.0 to 15.0 g/dL in women; 11.0 to 16.0 g/dL in children. In pregnancy, range is varied and depends on the trimester, but generally greater than 10.0 g/dL. Anaemia is observed when Hb level is below 7.0g/dl.

Signs

• Cool skin on palpation
• Tachypnea
• Hypotension (Orthostatic)
• Jaundice
• Lymphadenopathy

Types

There are over 400 types of anaemia. However, this article will focus on just 7 types

1. Iron Deficiency Anemia

• Iron deficiency anemia is the most common type of anemia. 
• Accounts for approximately 50-percent of the diagnosed cases of anemia. 
• Can result from inadequate iron intake, decreased iron absorption, increased iron demand, or increased iron loss. 
• Blood tests such as a complete blood count (CBC) and serum ferritin level are useful for the diagnosis of iron deficiency anemia. A CBC can help determine red blood cell size, hematocrit (percentage of blood volume made up by red blood cells), and hemoglobin. Ferritin reflects iron stores and is the most accurate test to diagnose iron deficiency anemia.  All of these blood tests would be decreased in iron deficiency anemia. Iron deficiency anemia is treated with iron supplementation.

2. Thalassemia

• Thalassemia is a group of inherited blood disorders characterized by the body making an abnormal form of hemoglobin.
• Results in hemolysis, or the destruction of red blood cells.
• More common in individuals of Mediterranean, African, and Asian descent.

3.Anemia in older persons

• Mounting evidence that low hemoglobin levels are a significant marker of physiologic decline.
• Prevalence increases with age (approx. 50% in chronically ill patients living in nursing homes).
• Evidence that even mild anemia is associated with increased morbidity and mortality.
• About one third of persons have anemia secondary to a nutritional deficiency, one third have anemia caused by chronic inflammation or chronic kidney disease, and one third have unexplained anemia.
• Nutritional anemia is effectively treated with vitamin or iron replacement. Iron deficiency anemia often is caused by gastrointestinal bleeding and requires further investigation in most patients.
• Anemia of chronic inflammation or chronic kidney disease may respond to treatment of the underlying disease and selective use of erythropoiesis-stimulating agents.

4. Aplastic Anaemia

• Aplastic anaemia refers to a deficiency of all types of blood cells (red cells, white cells, and platelets) caused by bone marrow failure. 
• Rare and serious condition that can develop at any age and can be fatal. 
• Develops when a person’s bone marrow is injured eg from from radiation and/or chemotherapy treatments, exposure to toxic chemicals, certain medications (antibiotics), autoimmune disorders (lupus and rheumatoid arthritis), and certain viral infections (hepatitis, Epstein-Barr, cytomegalovirus, parvovirus B19, and HIV).

5. Hemolytic Anaemia

• Hemolytic anaaemia is a disease in which red blood cells are destroyed and removed from the bloodstream before their lifespan is over. 
• Average lifespan of a red blood cell is 120-days. 
• Hemolytic anemia can be inherited or acquired. 

6. Sickle Cell Anemia

• Sickle cell anemia is an inherited disorder of red blood cells. 
• People with the disease have inherited two hemoglobin S genes, one from each parent.  The condition is termed hemoglobin SS and leads to sickle cell anemia. 
• In this disease, red blood cells assume a crescent, or sickle shape.  Under normal circumstances red blood cells are disc shaped. 
• The sickle shaped red blood cells can slow or block the flow of blood to body tissues and organs leading to attacks of sudden, severe pain (pain crises).

7. Pernicious Anaemia

Pernicious anaemia is a decrease in red blood cells that occurs when the intestines cannot properly absorb vitamin B12. 

• The body needs vitamin B12 to make red blood cells. 
• The intestines cannot properly absorb vitamin B12 due to a deficiency of a special protein called intrinsic factor in the stomach. 
• The disease is more common in individuals of Celtic (English, Irish, or Scottish) or Scandinavian origin.  In adults, symptoms of pernicious anemia are not seen until after age 30 and the average age at diagnosis is 60. 
• Can lead to irreversible nerve damage if treatment is not initiated within 6-months of developing symptoms.

Patient Education

• Patients with nutritional anaemia due to iron deficiency should be educated on food which is rich in iron. Foods such as green leafy vegetables, tofu, red meats, raisins, and dates contain a lot of iron. Vitamin C helps to increase dietary iron absorption.
• Patients must be advised to avoid excess tea or coffee, as these can decrease iron absorption.
• Patients on oral iron supplementation must be educated that there is an increased risk of constipation and of the risk of passing black tarry stools.
• Vegan and vegetarian patients, who may be deficient in B12 must be advised to consume food fortified with vitamin B12, such as certain plant and soy products.
• Patients who had gastric sleeve operations and sleeve gastrectomies are at an increased risk of vitamin B12 and folate deficiency, due to the loss of absorptive surface at the terminal ileum.

Concluding Remarks

• Anaemia is a condition in which the body lacks enough healthy red blood cells to carry adequate oxygen to your body's tissues.
• There are numerous forms and causes of anaemia.
• Anaemia can be temporary or long term, and it can range from mild to severe.
• Anaemia can be an indication of serious illness.
• Treatments for anaemia range from taking supplements to undergoing medical procedures.
• Some types of anaemia can be prevented by eating a healthy, varied diet.