The condition of having a lower-than-normal number of red blood cells or quantity of hemoglobin. Anemia diminishes the capacity of the blood to carry oxygen. Patients with anemia may feel tired, fatigue easily, appear pale, develop palpitations, and become short of breath. Children with chronic anemia are prone to infections and learning problems. The main causes of anemia are bleeding, hemolysis (excessive destruction of red blood cells), underproduction of red blood cells (as in bone marrow diseases), and underproduction of normal hemoglobin (as in sickle cell anemia and in iron deficiency anemia). Women are more likely than men to have anemia because of menstrual blood loss. In children, anemia is most commonly due to insufficient iron in the diet. Anemia is also often due to gastrointestinal bleeding caused by medications, including such common drugs as aspirin and ibuprofen.
There are more than 400 types of anemia, which are divided into three groups:
- Anemia caused by blood loss
- Anemia caused by decreased or faulty red blood cell production
- Anemia caused by destruction of red blood cells
Anemia Caused by Blood Loss
Red blood cells can be lost through bleeding, which often can occur slowly over a long period of time, and can go undetected. This kind of chronic bleeding commonly results from the following:
- Gastrointestinal conditions such as ulcers, hemorrhoids, gastritis (inflammation of the stomach), and cancer
- Use of nonsteroidal anti-inflammatory drugs (NSAIDs) such asaspirinor ibuprofen, which can cause ulcers and gastritis
- Menstruation and childbirth in women, especially if menstrual bleeding is excessive and if there are multiple pregnancies
The physiologic response to anemia varies according to acuity and the type of insult. Gradual onset may allow for compensatory mechanisms to take place. With anemia due to acute blood loss, a reduction in oxygen-carrying capacity occurs along with a decrease in intravascular volume, with resultant hypoxia and hypovolemia. Hypovolemia leads to hypotension, which is detected by stretch receptors in the carotid bulb, aortic arch, heart, and lungs. These receptors transmit impulses along afferent fibers of the vagus and glossopharyngeal nerves to the medulla oblongata, cerebral cortex, and pituitary gland.
In the medulla, sympathetic outflow is enhanced, while parasympathetic activity is diminished. Increased sympathetic outflow leads to norepinephrine release from sympathetic nerve endings and discharge of epinephrine and norepinephrine from the adrenal medulla. Sympathetic connection to the hypothalamic nuclei increases antidiuretic hormone (ADH) secretion from the pituitary gland. ADH increases free water reabsorption in the distal collecting tubules. In response to decreased renal perfusion, juxtaglomerular cells in the afferent arterioles release renin into the renal circulation, leading to increased angiotensin I, which is converted by angiotensin-converting enzyme (ACE) to angiotensin II.
Angiotensin II has a potent pressor effect on arteriolar smooth muscle. Angiotensin II also stimulates the zona glomerulosa of the adrenal cortex to produce aldosterone. Aldosterone increases sodium reabsorption from the proximal tubules of the kidney, thus increasing intravascular volume. The primary effect of the sympathetic nervous system is to maintain perfusion to the tissues by increasing systemic vascular resistance (SVR). The augmented venous tone increases the preload and, hence, the end-diastolic volume, which increases stroke volume. Therefore, stroke volume, heart rate, and SVR all are maximized by the sympathetic nervous system. Oxygen delivery is enhanced by the increased blood flow.
In states of hypovolemic hypoxia, the increased venous tone due to sympathetic discharge is thought to dominate the vasodilator effects of hypoxia. Counterregulatory hormones (eg, glucagon, epinephrine, cortisol) are thought to shift intracellular water to the intravascular space, perhaps because of the resultant hyperglycemia. This contribution to the intravascular volume has not been clearly elucidated.
Common symptoms of anaemia include:
- feeling tired
- feeling short of breath
- feeling your heart racing or thumping, which is called palpitations
To diagnose anemia, your doctor may recommend:
- Physical exam. During a physical exam, your doctor may listen to your heart and your breathing. Your doctor may also place his or her hands on your abdomen to feel the size of your liver and spleen.
- 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. Doing so can help pinpoint a diagnosis.
For example, in iron deficiency anemia, red blood cells are smaller and paler in color than normal. In vitamin deficiency anemias, red blood cells are enlarged and fewer in number.
Treating anemia entails treating the condition of low haemoglobin and red blood cells in blood as well as detecting and treating the disease process that has led to the anemia.
Unless the underlying cause of anemia, which may be continuous blood loss, haemolytic anemias, iron deficiency or increased demand states like pregnancy, are assessed and managed, the treatment remains incomplete.
Types of treatment for anemia
Treatment of anemia may depend on what type of anemia the patient has. (1-6)–
Iron deficiency anemia treatment
This usually involves taking iron supplements to replace the lack of intake of iron in diet or excess loss of iron.
The most commonly prescribed supplement is ferrous sulphate. It is taken as pills two or three times a day.
Oral iron preparations come with a host of side effects that include nausea, vomiting, abdominal pain, heartburn, constipation, diarrhea, black stool and blackening of teeth, gums and tongue.
Taking ferrous sulphate along with food or shortly after eating helps to reduce the side effects.
Another alternative is ferrous gluconate.
Iron can be replaced by taking diet rich in iron. This includes dark-green leafy vegetables, iron-fortified bread and cereal, beans, meat, nuts, apricots, prunes, raisins, dates etc.
Tea, coffee, calcium, found in dairy products such as milk, antacids etc. reduce the iron absorption from the gut and should be avoided.
Vitamin C supplements helps absorb iron better. Patient is checked up after two to four weeks to see if there is a response.
Vitamin B12 deficiency anaemia treatment
This can be treated by injections of vitamin B12. The vitamin is in the form of a substance known as hydroxocobalamine. The injections are given on alternate days for two weeks.
If there is a dietary lack of the vitamin, tablets may be prescribed. Vitamin B12 can be found in meat, milk, eggs, salmon etc.
Vegetarians or vegans may need supplementation as tablets or fortified cereals or soy products.
Anemia due to folate deficiency
For folate deficiency anemia daily folic acid tablets are prescribed.
Folate tablets are usually prescribed along with Vitamin B12 supplements. This is because folic acid treatment can sometimes improve the symptoms masking an underlying vitamin B12 deficiency.
If a vitamin B12 deficiency is not detected and treated at this stage there could be severe damage to the brain, nerves and spinal cord due to vitamin B12 deficiency.
Folate is found in broccoli, green cabbage, wheatgerm, pulses, nuts, green leafy vegetables etc.
Treatment for severe anemia
When the anaemia is more severe, a blood transfusion is often necessary.
Sickle cell anemia treatment
Patients with sickle cell anemia need a healthy diet, supplements of folic acid, vitamin D and zinc and avoid triggers for crises.
This includes smoking, alcohol, overexertion, dehydration, cold and hot temperatures, constricting clothes etc.
There is no cure for sickle cell anaemia, but the frequency and severity of crises and their complications can be reduced. They need complete vaccinations against flu, pneumococcus meningitis, Hepatitis B and other diseases to prevent infections.