Thrombocytopenia refers to lowering of the platelets, the blood cells that prevent us from bleeding. The medical term for a platelet is Thrombocyte. “Thrombo” stems from Greek word "Thrombos" which means clot. Term “Penia” stems from Latin and means reduction. Various medical conditions such as drugs (Chemotherapy drugs among them) and Radiation therapy as well as immune disorders can cause Thrombocytopenia. A serious reduction in the number of these cells can result in bleeding.
Under normal conditions Platelets have a life span of about ten days, meaning that every day 10% of Platelets are lost and same amount is produced by bone marrow to replace this loss. Thrombocytopenia has various causes, among which are both benign and malignant conditions. Please visit www.tirgan.com for more information about malignant illnesses and their treatments.
This pamphlet is intended to assist patients and their relatives to have a better understanding of this condition and hopefully result in a better treatment outcome. It is a difficult task to cover every single issue in relation to Thrombocytopenia, therefore I have chosen 10 important subjects that patients may face and have listed them with a brief description. Remember that you should discuss your medical problems with a physician and this pamphlet is not meant to substitute for seeking professional medical help from your doctor.Michael H. Tirgan, MD
10 Most common things to know about Thrombocytopenia are:
1- Role of Bone Marrow
2- Bone Marrow Suppression
3- Excessive Destruction of Platelets
5- Cancer and Thrombocytopenia
6- Monitoring Thrombocytopenia
7- Treatment of Thrombocytopenic patients
9- Other causes of Thrombocytopenia
10- Evaluation of patients with Thrombocytopenia
1- Role of Bone Marrow
Blood cells are produced in bone marrow. Bone marrow refers to the tissue that resides inside the inner cavity of most bones and is in charge of blood production. This tissue is widely spread throughout our bones with a higher concentration in flat bones like skull, sternum, pelvis and vertebrae. Bone marrow has different functions, among which is blood production. Almost all cells that circulate in blood are produced in bone marrow. There are various types of cells in bone marrow and in blood. Red Blood Cells carry oxygen, Platelets prevent us from bleeding and White Blood Cells or Leukocytes that maintain the immune system and fight infections. All these cells are produced from one group of primitive cells called Stem Cells. The bone marrow cells that produce platelets are called Megakaryocytes. They are the largest cells in the human bone marrow and are easily recognizable.
Bone marrow examination may be necessary in the course of evaluating patients with Thrombocytopenia. Bone marrow samples are obtained from the pelvic bone using special needles. Such a study is performed to evaluate the health and number of Megakaryocytes as well as presence or absence of systemic illnesses in bone marrow.
The following two images illustrate the Megakaryocytes in bone marrow and Platelets in peripheral blood.
Bone marrow Megakaryocytes Red Blood Cell and Platelets in Blood
2- Bone Marrow Suppressions
Some illnesses and certain treatments can suppress the bone marrow and reduce its capacity to produce blood cells. Cancer chemotherapy and radiation therapy are the two most common causes of Thrombocytopenia. The chemotherapy drugs not only attack cancer cells, they also attack normal cells, causing certain complications such as Thrombocytopenia. A large number of medicines have been linked to bone marrow suppression and a decline in production of platelets from bone marrow.
Severe infections and sepsis can also cause bone marrow suppression and Thrombocytopenia. Certain cancers in their advanced stage can spread to bone marrow and causes bone marrow suppression. Lymphoma, Leukemias are among such cancers. Certain bone marrow illnesses such as multiple Myeloma can also present with low platelet count. To confirm bone marrow suppression, a bone marrow test should be performed which will show reduction or absence of Megakaryocytes.
3- Excessive Destruction of platelets
Another mechanism that we commonly encounter is destruction of platelets by the immune system. In this situation, bone marrow is quite healthy and is producing enough platelets, however the disease process destroys the platelets at a very rapid rate. This type of Thrombocytopenia is commonly seen in children and young women. This condition may be due an immune condition and is referred to as Immune Thrombocytopenia or Idiopathic Thrombocytopenic Purpura or ITP. This condition can be seen in association with viral illnesses such as chronic hepatitis and AIDS.
Another group of illnesses that can cause Thrombocytopenia are the autoimmune disorders such as Lupus and Rheumatoid Arthritis. These conditions cause production of antibodies against Platelets, which eventually will lead to demise of Platelets.
Among rare conditions that deserve being mentioned here is Thrombotic Thrombocytopenic Purpura or TTP. TTP is a very aggressive disease with very high complication rate. Patients are extremely sick and are almost always hospitalized.
Examination of bone marrow in this type of illnesses shows abundance of Megakaryocytes.
Thrombocytopenic patients are at risk for bleeding. When the platelet count is extremely low, bleeding can occur in almost any organ. Skin of lower legs is the most common site to see the earliest signs of bleeding. The appearance is of multiple small bleeding spots that are purple color. Bleeding can also take place in oral cavity. Patients may bleed from their gums as they brush their teeth. In cases of severe persistent Thrombocytopenia, patients will develop more severe bleedings such as stomach bleeding or bleeding in the guts or brain.
Bleeding is more sever in cases of bone marrow suppression as opposed to increased destruction of Platelets. When Platelets are destroyed, bone marrow is most likely healthy and is constantly producing large number of Platelets. Therefore all the existing Platelets in blood are young and healthy. In cases of marrow suppression, the Platelets in blood are rather aged and not as functional as younger Platelets.
Normal Platelets count is about 200,000-400,000 per cubic millimeter of blood. When this number falls below 50,000, patients will be prone to bleeding if they sustain a trauma. Levels below 20,000 carry higher risk for bleeding and levels below 10,000 carry a very high risk for spontaneous life threatening bleeding. This is true for patients whose Thrombocytopenia is due to bone marrow suppression.
Patients with peripheral destruction of Platelets can tolerate very low levels of Thrombocytopenia much better and are at lower risk for bleeding as compared to those with marrow suppression.
5- Cancer and Thrombocytopenia
Thrombocytopenia is most commonly seen in cancer patients undergoing treatment. Chemotherapy and radiation therapy are quite damaging to the bone marrow and can cause severe marrow suppression and result in lowering of the Platelets as well as white and red blood cells. Higher dosage and intensity of chemotherapy or radiation can cause and is associated with a more severe Thrombocytopenia. Radiation to any part of body can cause Thrombocytopenia, especially radiation to pelvis area. There is significantly more bone marrow tissue in the pelvic bones than in any other bones. There are other occasions that cancer patients develop Thrombocytopenia. Involvement of bone marrow with cancer is not a rare condition. This complication is seen more often in patients with Lymphoma and Leukemia, however there are many other cancer types that can spread to bone marrow.
Disseminated Intravascular Coagulopathy (DIC) is a complication of certain advanced cancers. This condition is due to over activation of coagulation system and secondary consumption of Platelets. DIC can also be seen in patients with overwhelming sepsis and severe infections.
6- Monitoring Thrombocytopenia
Once Thrombocytopenia is diagnosed, one has to monitor the Platelet count carefully. The frequency of performing Platelet count depends on the seriousness and severity of Thrombocytopenia and its underlying cause.
Thrombocytopenia is a common and dangerous complication for most chemotherapy regimens. Such patient should have regular blood tests to assess the level of Platelets, white blood cells and neutrophils. Patients should also have a baseline blood count prior to initiation of cancer treatments. Severity of Thrombocytopenia depends on the type of treatment as well as the underlying illness and overall condition of the patient. The oncologists should consider these factors in scheduling blood tests. For example, in patients with acute leukemia who is undergoing chemotherapy, the blood tests may need to be done on a daily basis, however a patients with breast cancer who is receiving chemotherapy may require a weekly blood test. Some patients may be managed by monthly blood tests.
7- Treatment of Thrombocytopenia
Severe Thrombocytopenia must be treated urgently. Treatment depends on the cause of Thrombocytopenia. Immune Thrombocytopenias and ITP are treated with steroids and medicines that can suppress the immune system.
In secondary Thrombocytopenia due to infections or DIC, the underlying cause of Thrombocytopenia must be treated aggressively.
In severe Thrombocytopenia due to bone marrow suppression, the goal of therapy is to treat the underlying cause of marrow suppression. Additionally, patients may also require transfusion of Platelets.
Length of Thrombocytopenia depends on its underlying cause. In cases that are secondary to cancer, the nature of cancer, the type of chemotherapy and the overall health of the patient are among most important factors that will determine the time to recovery from Thrombocytopenia.
Another important step in treatment of Thrombocytopenia due to bone marrow suppression is proper usage of medicines that can stimulate bone marrow to produce more Platelets. The only commercially available medicine at this time is “Neumega”.
Most patients with mild to moderate Thrombocytopenia are treated in out patient settings. Patients with severe Thrombocytopenia may need to be admitted to a hospital for treatment with intravenous medicines or Platelets transfusions.
This medicine has been available for a few years and hematologists and oncologists are most familiar with it. It can be used either to prevent Thrombocytopenia or alternatively shorten the period of Thrombocytopenia. Neumega is well tolerated and its most noticeable side effect is retention of fluids. In patients who suffer from heart disease this side effect may worsen their condition and result in congestive heart failure. Neumega may have to be stopped if the fluid retention poses a problem. Additionally, there are a number of medicines, such as Lasix, that can increase fluid excretion from body.
Neumega is an injection and is given once daily under the skin, in the upper arm area. The length of time that patients may need this medicine is quite variable and ranges between 7-14 days. The injections are either given at the doctor’s office or by the visiting nurses at home. Best and most convenient method may be for the patients to learn how to self-inject. Response to Neumega is very slow and it may take up to two weeks to see a rise in Platelet count.
9- Other causes of Thrombocytopenia
Thrombocytopenia is most commonly seen in patients undergoing cancer treatment. There are numerous other causes to Thrombocytopenia, among which are immune disorders like ITP as well as Viral illnesses such as HIV disease, chronic hepatitis. Thrombocytopenia can be seen as an adverse reaction to drugs.
Thrombocytopenia due to HIV infection and its treatment with antiviral drugs are seen quite frequently. Many drugs, including those used to treat HIV infection are notorious to bone marrow and in the same token, the virus itself is very harmful to the marrow. Other infections can also cause Thrombocytopenia. Many viral and bacterial illnesses can cause lowering of Platelets and result in Thrombocytopenia. Certain drugs such as anti-inflammatory medicines, cardiac medicines, antibiotics, Pepsid, etc. are known to cause Thrombocytopenia. Although the chance of developing a reaction to these drugs is low, they should be considered as a cause of Thrombocytopenia in patients who are taking them. In such cases, if the patient has been on a medicine, that medicine should be considered as the cause of Thrombocytopenia and be stopped if possible.
An enlarged spleen can cause Thrombocytopenia as well. In this situation, the enlarged spleen traps and destroys Platelets. Immune system illnesses, such as Lupus and Rheumatoid disease can also cause Thrombocytopenia.
10- Evaluation of patients with Thrombocytopenia.
If the cause of Thrombocytopenia is not obvious, the physician who is caring for the patient should take a rational and systematic approach to this condition. Most importantly, such patients should be seen by a hematologist/oncologist and undergo a comprehensive evaluation. A complete history and physical examination can reveal certain causes of Thrombocytopenia. A complete blood count must be obtained along with other chemistry, immune system and HIV tests. Some patients will undergo bone marrow examination. If the cause of Thrombocytopenia remains unclear, further tests should be performed to look in to genetic or other forms of Thrombocytopenia, which are rather rare.
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