Anemia - causes, symptoms and treatment

What is Anemia and Definition

A reduced ability of the BLOOD to meet the body’s oxygenation needs arising from either a diminished volume of erythrocytes (red blood cells) in the blood or from reduced HEMOGLOBIN content in the erythrocytes. Though the common perception of anemia is that it is itself a health condition, doctors consider anemia an indication of other health conditions. Diagnosis and treatment target those underlying conditions. Anemia affects about 3.5 million people in the United States. Anemia can affect people of any age though is most common among menstruating women and during PREGNANCY.

Causes of Anemia

Anemia may be acute (come on suddenly) or chronic (continue over an extended time). Anemia may also result from medication interactions or ADVERSE REACTIONS, CHEMOTHERAPY, RADIATION THERAPY, and numerous health conditions. In general, anemia results from three circumstances, individually or in combination:

excessive blood loss drains erythrocytes from the body
the SPLEEN destroys (hemolyzes) too many erythrocytes
the BONE MARROW produces too few defective erythrocytes

Causes of Anemia: Blood loss

Blood loss, either in large quantity suddenly or through chronic bleeding, has a twofold consequence on the blood’s ability to carry oxygen. First, the bleeding reduces the number of erythrocytes in the blood, making fewer erythrocytes and thus less hemoglobin available. Second, old erythrocytes, which the spleen culls from the circulation to dismantle and recycle, are a key source of ingredients such as iron and hemoglobin for the production of new erythrocytes. Traumatic hemorrhage, GASTROINTESTINAL BLEEDING, and heavy menstrual bleeding are among the causes of anemia related to blood loss.

Causes of Anemia: Erythrocyte destruction or deformity

One of the spleen’s roles is to filter erythrocytes from the blood that are old or defective, a normal process called HEMOLYSIS that maintains an appropriate balance of erythrocytes in the blood. The spleen may inappropriately sequester and destroy healthy erythrocytes, sometimes without apparent reason. SICKLE CELL DISEASE is a complex genetic disorder that results in malformed erythrocytes, causing anemia among other symptoms. In THALASSEMIA, another genetic disorder, erythrocytes are normal but hemoglobin is defective.

Causes of Anemia: Inadequate erythropoiesis

Nutritional deficiencies and renal failure are the leading causes of diminished erythropoiesis. The bone marrow requires vitamin B12, iron, and folic acid to manufacture erythrocytes. Pernicious anemia results when the STOMACH fails to produce intrinsic factor, a substance necessary to absorb vitamin B12 from ingested foods. When these vital NUTRIENTS are lacking, the bone marrow cannot generate new erythrocytes. Iron deficiency anemia is the most common type of anemia in the United States.

Kidney disease and RENAL FAILURE also affect erythropoiesis because the KIDNEYS secrete ERYTHROPOIETIN (EPO), the HORMONE that stimulates the bone marrow to produce erythrocytes. Bone marrow disorders such as myelofibrosis and MULTIPLE MYELOMA also disturb HEMATOPOIESIS. Aplastic anemia is a life-threatening type of anemia that results when the bone marrow completely shuts down blood cell production.

COMMON CAUSES OF ANEMIA
adverse DRUG reactions	CHEMOTHERAPY
chronic HEPATITIS	CIRRHOSIS
DYSMENORRHEA	environmental toxins
folic acid deficiency	GALLBLADDER DISEASE
GASTROINTESTINAL BLEEDING	HEMOLYSIS
hemorrhage	HIV/AIDS
INFLAMMATORY BOWEL DISEASE (IBD)	iron deficiency
LEUKEMIA	lymphoma
MALABSORPTION syndromes	MULTIPLE MYELOMA
MYELODYSPLASIA SYNDROME	MYELOFIBROSIS
PREGNANCY RADIATION	THERAPY
RENAL FAILURE	SICKLE CELL DISEASE
SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)	THALASSEMIA
vitamin B12 deficiency

Symptoms of Anemia and Diagnostic Path

Many people do not have symptoms of anemia but instead find out they have anemia through blood tests conducted for other reasons, such as during ROUTINE MEDICAL EXAMINATION or screening for BLOOD DONATION. When symptoms are present, they are generally the same regardless of the underlying cause and commonly include

tiredness and fatigue
breathlessness, especially with physical exercise
HEADACHE
chronically cold or tingling hands and feet
PALPITATIONS or ARRHYTHMIA (irregular or rapid heartbeat)
irritability
paleness of the SKIN, nail beds, and gums

Hemolytic anemia may also cause JAUNDICE. Severe anemia can be debilitating, preventing an individual from participating even in everyday activities. Such severe anemias generally result from serious underlying health circumstances. Diagnostic blood tests including complete blood count (CBC), hemoglobin, and hematocrit often provide the initial diagnosis. Further tests might include bone marrow biopsy to determine whether the bone marrow is adequately producing erythrocytes or whether the erythrocytes are normal. The doctor may choose to perform other diagnostic procedures, depending on the findings. Whether or not the anemia causes symptoms, it is important to find its cause.

Anemia Treatment Options and Outlook

Most types of anemia are curable or treatable. Treatment targets the underlying cause of the anemia. Supplemental iron, vitamin B12, and folic acid can improve many types of anemia. Pernicious anemia requires lifetime injections of vitamin B12. Aplastic anemia or anemia due to chronic health conditions may require BLOOD TRANSFUSION or BONE MARROW TRANSPLANTATION. Doctors may treat chronic anemia or transient anemia due to cancer treatment with EPO supplementation. Anemia resulting from GENETIC DISORDERS such as sickle cell disease or thalassemia requires ongoing treatment. Successful treatment of the underlying cause nearly always eliminates the anemia. Most anemias are curable or treatable.

Risk Factors and Preventive Measures

A number of factors can create risk for developing anemia. People who are at greatest risk for anemia are those who

consume a diet low in iron, folic acid, and vitamin B12, nutrients the bone marrow requires to manufacture erythrocytes
have gastrointestinal conditions that interfere with nutrient absorption, notably INFLAMMATORY BOWEL DISEASE (IBD), MALABSORPTION disorders, and CELIAC DISEASE
menstruate or are pregnant
have chronic health conditions that strain the body’s resources, such as AUTOIMMUNE DISORDERS or INFECTION (for example, HEPATITIS or HIV/AIDS)
have blood disorders; LEUKEMIA, LYMPHOMA, or multiple myeloma; or who are undergoing CHEMOTHERAPY or RADIATION THERAPY for other types of CANCER

People at risk for anemia should have their blood tested regularly and any time they develop symptoms of anemia. Though it is not always possible to prevent anemia, early treatment can minimize the adverse effects of anemia on overall health as well as intervene in the underlying condition at an early stage.