A brief about blood and its components
Blood is a connective tissue, which accounts for about 7 to 10 percent of the body weight. Apart from delivering nutrients and oxygen to cells and transporting waste from cells, it plays an important role in maintaining homeostasis and regulating the body’s systems.
It has four main components, as follows:
Red blood cells (erythrocytes) account for about 40-45% volume of the blood. They carry oxygen from lungs to the body tissues and the carbon dioxide from the tissues to lungs with the help of a special protein called as hemoglobin. They are formed in the bone marrow.
White blood cells (leukocytes) are essential components of immune system, which defend the body against infections and foreign bodies. They account for about one percent of the blood volume. Like other blood cells, they are primarily produced in the bone marrow.
Platelets (thrombocytes) are small cell fragments that stop or prevent bleeding through formation of blood clots, through process known as coagulation. The ideal platelet range is 150,000 to 400,000 per microliter.
Plasma refers to the liquid component of the blood that accounts for about 55% of its volume. It is the mixture of sugar, fats, protein, salts, and water. It helps to carry blood cells and nutrients throughout the body. It also carries electrolytes to the muscles and helps to maintain pH balance in the body, thereby supporting cell function.
Blood disorder is an umbrella term for all problems that involve one or more components of the blood. While many of such disorders do not cause symptoms or affect life expectancy, others could be life-threatening. Anemia, thalassemia, thrombocytopenias, and idiopathic thrombocytopenic purpura (ITP) are some of the common blood disorders discussed below.
Anemia is a common blood disorder caused by low number of red blood cells, and its worldwide prevalence is about 24.8%. Typically, anemia is a symptom of a condition rather than a disease itself. It could be caused due to nutritional deficiencies or arise because of other chronic or severe conditions. There are many types of anemia depending how it occurs. Often, they are mild and treatable conditions, while others can be severe and life-threatening.
Symptoms of anemia
The symptoms of anemia may vary from person to person. In its mild state, anemia may not cause any symptoms. The severe state may cause symptoms, which may include:
- Paleness of the skin
- Irregular heartbeat
- Feeling cold
- Shortness of breath
- Sore or swollen tongue
- Impaired wound and tissue healing
Causes of anemia
The most common causes for anemia may include:
- Nutritional deficiencies
- Inherited, autoimmune or cancerous conditions
Diagnosis of anemia
The diagnosis includes obtaining the medical and family history, followed by physical examination to evaluate the overall health. Complete blood count (CBC) is the primary test recommended for patients with anemia, which provides information about the number of red blood cells along with their shape and size. Other tests may be recommended to identify the cause of anemia. Rarely, a bone marrow biopsy that involves obtaining sample of bone marrow is recommended to look for defects that may lead to anemia.
Treatment of anemia
The treatment for anemia varies according to the underlying cause. Typically, it involves recommending dietary modifications and medications to improve the red blood cell count. Other treatments may involve treating the underlying diseases causing anemia. Blood transfusions or bone marrow transplantation may be required to treat certain types of anemia.
Thalassemia is an inherited (passed from parents to children) blood disorder, where the body makes lesser or abnormal form of hemoglobin. This leads to shortage of red blood cells, depriving the cells of oxygen. It is estimated that about 1.5% of the global population are carriers of beta-thalassemia, with about 60,000 symptomatic individuals are born each year.
Depending on the specific genetic changes causing thalassemia, it is divided into two types, namely alpha thalassemia (mutation in HBA1 and/or HBA2 genes) and beta thalassemia (mutation in HBB gene). Thalassemia may cause mild anemia that may not have adverse effects on health; the severe form of the same can damage organs and could turn fatal.
Symptoms of Thalassemia
People with mild form of thalassemia have small red blood cells causing no symptoms. People with intermediate and severe forms of thalassemia can have mild to severe anemia and may experience the following symptoms.
- Yellow discoloration of skin (jaundice)
- Bone problems
- Growth failure
- Enlarged heart or liver
Causes of Thalassemia
Hemoglobin, a protein that helps to carry oxygen in the blood is made of two subunits known as beta globulin and alpha globulin. The defects (mutations) in the genes that provide instructions for making respective subunits leads to reduced levels of alpha or beta globulins causing thalassemia.
Diagnosis of Thalassemia
Diagnostic tests may include blood tests such as complete blood count to look for anemia and laboratory analysis of blood samples to detect abnormalities in the size and shape of red blood cells. Certain specific genetic mutations in the genes can be identified through mutational analysis. As thalassemia is an inherited condition, family genetic studies can help in diagnosis of the condition.
Treatment of Thalassemia
Majority of people have mild thalassemia causing no symptoms and require no treatment. However, severe forms of thalassemia require regular blood transfusions, folic acid supplements, and spleen removal or bone marrow transplantations.
Thrombocytopenia is a condition in which the body does not produce enough platelets. It may occur as a side effect of certain medications or due to other conditions such as bone marrow or immune system disorders. It may not cause any symptoms in its mild form, but when the platelet counts are severely low, it may cause internal bleeding. It can be seen in both adults and children.
Symptoms of thrombocytopenia
The signs and symptoms of thrombocytopenia may include:
- Easy bruising
- Pinpoint-sized red or purple spots called petechiae, usually on the lower legs
- Prolonged bleeding from cuts
- Nosebleeds or bleeding from gums
- Blood in urine or stools
- Heavy menstrual flows
- Enlarged spleen
Causes of thrombocytopenia
Thrombocytopenia can occur due to many reasons. The common causes of the condition may include:
- Cancers such as leukemia or lymphoma
- Cancer treatments such as chemotherapy and radiation therapy
- Antibodies that may act against healthy platelets
- Exposure to toxic chemicals or certain viruses such as HIV, Epstein-Barr virus, cytomegalovirus, or hepatitis
In rare cases, people with prostrate or breast cancer may develop thrombocytopenia, as the cancer spreads to bone. People with spleen cancer may also develop the condition.
Diagnosis of thrombocytopenia
Diagnostic tests for thrombocytopenia include obtaining medical history and family history of the patient and history of the medications taken by the patient. During physical exam, the skin may be examined for signs of bleeding and the abdomen is palpated to check for enlargement of liver or spleen. Blood tests such as complete blood count and clotting tests are ordered and specialized tests such as bone marrow biopsy is recommended to look for bone marrow abnormalities.
Treatment of thrombocytopenia
Treatment primarily involves treating the underlying disease or condition that is causing the thrombocytopenia. Blood transfusions may be required when the platelet count is severely low. In certain cases, the spleen may be removed to reduce further damage to the platelets.
Idiopathic thrombocytopenic purpura (ITP)
ITP is a bleeding disorder caused by persistently low platelets in the blood. In adults, the annual incidence of ITP is approximately 66 cases per every 1,000,000 cases. In children, the incidence is about 50 cases per 1,000,000.
There are two forms of ITP- acute and chronic thrombocytopenic purpura. The acute form is often seen in young children that may last less than six months, and does not require any treatment. Chronic thrombocytopenic purpura is predominantly seen in adults and may last for at least six months. It has higher chances to recur and requires regular follow-up care.
Symptoms of ITP
The symptoms of ITP may vary from person to person. The common symptoms may include:
- Red or purple colored tiny dots beneath the skin
- Excessive bruising
- Bleeding in the mouth or gums
- Heavy menstrual periods
- Blood in the vomit
- Blood in urine or stool
Causes for ITP
In most of the cases, ITP is linked to an autoimmune response that attacks body’s own platelets by mistake, leading to low platelet counts. Certain viral or bacterial infections such as HIV, Helicobacter pylori or hepatitis C may also lead to ITP. Especially, in children with short-term ITP, recent infections have been found to trigger immune reactions against platelets.
Diagnosis of ITP
The diagnosis starts with obtaining a complete medical history and physical examination. Blood tests such as complete blood count to measure platelet numbers along with their size and maturity are recommended. Additional blood or urine tests are recommended to determine the possible cause of the condition. Rarely, bone marrow aspiration may be used to rule out other possible causes of the condition.
Treatment of ITP
People with mild ITP may not require any treatment other than regular follow-up, and the disease often resolves by its own. Children with short-term ITP also do not require any treatment unless they have bleeding symptoms. Adults with chronic or long-term ITP or ITP with very low platelet counts often require treatment. The treatment may involve using medications that can improve platelet counts or to treat infections that may cause low platelet counts. Patients with severe bleeding may require platelet transfusions or surgery if the condition persists even after the conventional treatments.
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