Platelets

Platelets or thrombocytes are cell fragments found in the blood with an average life span of about 5- 9 days. Typically a healthy adult has about 150,000 to 450,000 platelets per micro liter of blood. Platelets are crucial for the clotting process since they are involved in hemostatis. If the platelet count is too high or low, it can be indicative of some disorders. Abnormally high platelet count can lead to myocardial infarction, pulmonary embolism or a stroke. Very low platelet count can lead to excessive bleeding. Low platelets can happen due to medications, leukemia, hemolytic anemia or chemotherapy. Abnormally high platelet count can be due to anemia, thrombocythemia or recent spleen removal.

Pheresis

The term 'Pheresis' is of Greek origin and it means 'to take away' or 'separate'. Pheresis is a special kind of blood donation. The specific components of blood namely the plasma, erythrocytes, platelets, granulocytes, agranulocytes are separated. In this procedure, the blood component needed to diagnose a suspected abnormality or treat a known disease is separated and the remaining blood is returned to the donor. Pheresis can also be described as a blood purification process.

During pheresis, whole blood is collected from one arm of the donor and this goes into a machine called 'cell separator'. The blood is spun in the machine and components separated and after the desired component is collected into a special bag, the red cells and other components are returned to the donor. As most blood is returned to the donor, pheresis facilitates a donor to donate more of a specific component. There are two main types of pheresis. One is removal of platelets - platelet pheresis and removal of plasma - plasmapheresis.

Plateletpheresis: This is especially used in patients who have leukemia or aplastic anemia and are receiving chemotherapy. They need platelets as cancer and cancer treatments can deplete the body of platelets. Platelets are necessary to prevent potentially fatal bleeding problems. Platelet is a very precious component of blood that can be stored only for five days and only about one tablespoon of platelet can be collected from one unit.

Plasmapheresis: Otherwise known as therapeutic plasma exchange, in plasmapheresis, the cells from the straw colored liquid portion of the blood which contains the clotting factors, infection fighting antibodies and other proteins are removed. Plasma is necessary to regulate blood pressure and maintain the mineral balance in the body. Fresh frozen plasma is also administered to control disseminated intravascular coagulation.

A flexible tube is inserted into the donor's arm. Blood is slowly drawn into a sophisticated machine which separates various components of blood. Each pheresis donation is typed and marked for a specific patient. Both plasmapheresis and plateletpheresis can be conducted in a hospital or blood donation center. There are certain preparatory procedures that a donor needs to follow before undergoing pheresis. He/she should get a good night's sleep, eat a balanced diet, drink plenty of caffeine-free liquids. A donor is also advised not to consume aspirin within 72 hours or ibuprofen within 24 hours before undergoing pheresis. After the donation, the pheresis donor may feel tired for a few hours. The donor should not plan on driving home after the procedure. Heavy lifting or strenuous exercise need be avoided until the following day.

Thrombocytosis

Thrombocytosis refers to a hematological condition in which the accumulation of platelets causes many medical emergencies such as stroke and cardiac complications. Platelets are responsible for regulating and facilitating the mechanism of blood clot formation, also known as thrombus. The elevated level of platelets is associated with disorders of blood or bone marrow in which blood cells are produced. The abnormalities can lead to many hematological disorders, Thrombocytosis being one of the most noticed.

Classification and Clinical manifestations

Thrombocytosis can be classified in to two types depending upon the origin of its occurrence:

Primary thrombocytosis: Primary thrombocytosis is caused by abnormalities associated with bone marrow or blood. It is commonly known as essential thrombocythemia. This disorder is predominantly noticed in women and adults above the age of 55. The clinical symptoms associated with disease include erythromelalgia where there is redness of the arms and legs with burning sensation and pain. In addition to this, lightheadedness, nausea, weakness, lethargy, dizziness, frequent nosebleeds and bloody stools follow depending upon the stage of the thrombocytosis. Pathological smears usually indicate the presence of megakaryocytic cells in the blood smear, which are produced by the bone marrow in excess. Studies indicate the genetic evidence of the Janus kinase 2 (JAK 2)mutation in thrombocytic patients, which also associate, with neoplasms of proliferative origin leading to ischemia and heart attack.

Secondary Thrombocytosis: This form of thrombocytosis is reactive in nature and it is caused by the excessive production of the pro-inflammatory interleukins such as IL-1 and IL-6. In this condition, C reactive protein is noticed in excess in the serum and typically indicating the onset of inflammatory disease. It is one of the common conditions in the United States and the complications associated with it are related to vascular obstructions. Secondary thrombocytosis is caused because of various underlying conditions such as infections, trauma, splenectomy, malignancy and anemia associated with iron deficiency.

Diagnosis and Treatment

Thrombocytosis is diagnosed by blood tests to determine the amount of megakaryocytic in the blood film. Complete blood count with platelet amount evaluation along with C protein reactivity is studied. Splenomegaly is noticed in nearly 25% of patients. Abnormal platelet values may be over 2,000,000/mcL. The common medications prescribed for thrombocytosis are hydroxyurea, anagrelide and introns. Some of the noticed side effects are associated with leukemia and hence the dosage is very important to avoid additional complications such as dizziness, diarrhea and vomiting.