| Thrombocytopenia refers to an abnormally low number of platelets (blood cells produced in the bone marrow, that help form blood clots and stop bleeding). A reduction in the number of platelets may result in bleeding, especially from the smaller vessels.
Thrombocytopenia is a symptom of many conditions, not a disease. Its causes may be grouped into three categories: decreased platelet production in the bone marrow, increased platelet destruction, and abnormal platelet pooling in the spleen.
Decreased production of platelets can occur when bone marrow activity is impaired. This impairment may occur as the result of certain drugs, including ethanol and many antibiotics, or as the result of certain infections, such as HIV or infectious mononucleosis. Other causes of decreased production include vitamin B12 deficiency (pernicious anemia), folate deficiency, aplastic anemia, leukemia, and marrow infiltration (myelophthisic anemia).
Increased destruction is often related to a condition involving the immune system. In immune thrombocytopenia, platelets are destroyed by antibodies created by the individual's own immune system. In post-transfusion thrombocytopenia, platelets are destroyed by antibodies following a blood transfusion. Immune thrombocytopenia may be associated with certain connective tissue diseases, such as systemic lupus erythematosus (SLE); lymphoproliferative diseases, such as chronic lymphocytic leukemia; or infections, such as the tickborne infection Ehrlichiosis. Certain drugs, particularly the anticoagulant heparin, may also induce immune thrombocytopenia. Up to 10% of patients receiving heparin may develop thrombocytopenia (Schafer).
Nonimmune conditions that increase platelet destruction include mechanical damage, such as that caused by a mechanical heart valve or that caused by the use of certain drugs. Thrombotic thrombocytopenic purpura (TTP) is a serious nonimmune condition in which platelets clump together. It is accompanied by other abnormalities, such as hemolytic anemia and kidney dysfunction. It may be associated with infection. Hemolytic-uremic syndrome (HUS), a similar serious condition, is associated with E. coli infection. Although HUS is rare in adults, it also can cause thrombocytopenia and kidney dysfunction.
An enlarged spleen (hypersplenism) can result in thrombocytopenia, sequestering up to 90% of circulating platelets. A variety of conditions may cause hypersplenism, including liver disease.
Thrombocytopenia may develop during pregnancy, particularly in the third trimester. In many cases, it is believed to be a manifestation of pre-eclampsia or eclampsia.
In as many as 50% of cases, the cause of thrombocytopenia is never identified. This is called idiopathic thrombocytopenic purpura (ITP). ITP is considered an autoimmune disease in which the body's own defenses attack and destroy the platelets.Risk: ITP is most common in children where the sexes are affected equally. In adults, women are more likely to be diagnosed with this disease, and are twice as likely to acquire TTP ("Thrombocytopenia"; Allford). Incidence and Prevalence: ITP has an incidence of 1 out of 10,000 people; while the incidence rate of TTP is 4 in 100,000 ("Thrombocytopenia"). |
Source: Medical Disability Advisor
| History: Symptoms are dependent on the platelet count. Bleeding only becomes evident when the count drops to a certain point. Individuals usually report bruising, bleeding gums, nosebleeds, excessive bleeding from minor cuts, bloody stools, or prolonged or heavy menstrual bleeding. Headache and dizziness may indicate a risk of brain hemorrhage. Physical exam: The individual may have small capillary hemorrhages (petechia) or larger bruises (ecchymoses) under the skin. An enlarged spleen may be felt when the physician examines the abdomen by pressing on it with the fingers (palpation). Tests: A complete blood count (CBC) shows a decrease in the number of platelets. Immature platelets may be seen on a peripheral blood smear. Bone marrow aspiration and biopsy will confirm whether the marrow is involved. Coagulation tests to check platelet function and look for other clotting abnormalities include bleeding time, prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen, and platelet aggregation studies. Additional tests will be performed as needed and may include liver function tests, platelet antibody tests, and tests to identify infections, such as HIV and Ehrlichiosis, and connective tissue diseases, such as systemic lupus erythematosus. |
Source: Medical Disability Advisor
| Mild to moderate thrombocytopenia may not require treatment. General caution, however, dictates that individuals with thrombocytopenia avoid invasive procedures or injury and, if possible, avoid any drug that may affect platelets, such as aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs). Treatment may be needed only when the individual has had a traumatic injury or is preparing for surgery.
In more significant thrombocytopenia, treatment addresses the underlying cause of the thrombocytopenia. For possible drug-induced thrombocytopenia, all drugs that could reduce the numbers of platelets must be discontinued. Only medically necessary drugs should be continued. If the condition is life-threatening, intravenous immune globulin should be given. If infection is present, treatment must be directed primarily at clearing the infection. Malignancy-caused thrombocytopenia is treated with appropriate chemotherapy. Removal of the spleen (splenectomy) may be beneficial if the spleen is sequestering platelets.
Immune thrombocytopenia is initially treated with immunosuppressant glucocorticoid drugs until platelet counts return to normal. At that time the glucocorticoids should be tapered off. Individuals with chronic thrombocytopenia may need additional treatment cycles to maintain an adequate platelet count. Individuals with severe bleeding are hospitalized and treated with intravenous glucocorticoids plus high-dose immune globulin (immune globulin increases platelet survival time). If the bleeding is life-threatening, platelet transfusions may also be given. Splenectomy is beneficial for individuals who do not respond to steroid therapy or require unacceptably high doses to maintain adequate platelets. Although in immune thrombocytopenia the spleen does not sequester platelets, it does produce the antibodies that attack the platelets. Removing the spleen removes the source of the destructive antibodies.
Thrombotic thrombocytopenic purpura, severe thrombocytopenia in pregnancy, and post-transfusion thrombocytopenia are treated with plasma exchange (plasmapheresis). Immune globulin is also given when needed. |
Source: Medical Disability Advisor
| Many cases of thrombocytopenia resolve when the offending agent is removed. For example, thrombocytopenia caused by ethanol responds within 10 to 14 days after the removal of ethanol. Once a viral infection is cleared, the platelet count generally rises immediately. In pregnancy, thrombocytopenia resolves following delivery.
In immune thrombocytopenia, immunosuppressant glucocorticoid treatment usually reduces bleeding within 1 day and raises platelet counts within 1 to 3 weeks. Most individuals respond to this treatment, but many will relapse once the treatment has stopped and will require additional treatment cycles. Approximately 90% of individuals with immune thrombocytopenia develop a chronic condition and require ongoing treatment. Splenectomy will bring about partial or complete remission in 80% of individuals with immune thrombocytopenia. Thrombotic thrombocytopenic purpura has a 90% response rate to timely plasma exchange therapy. |
Source: Medical Disability Advisor
| If the individual's platelet counts drop to a dangerously low level, severe, even life-threatening, bleeding can occur, particularly inside the brain (intracranial hemorrhage). Splenectomy carries a risk of infection. |
Source: Medical Disability Advisor
| Individuals who have significantly decreased platelet counts need a safe work environment that reduces the risk of personal injury, which could trigger an acute bleed. Where indicated, protective gear, especially for the head, should be worn. Office work or sedentary work would probably be more appropriate than strenuous work involving heavy lifting or other physical exertion. The treating physician might advise the employer of how to provide the appropriate level of care quickly in the event of an on-the-job injury. Once the individual's platelet counts have returned to normal, no work restrictions should be needed. Time off will be needed if splenectomy or hospitalization is required. |
Source: Medical Disability Advisor
| If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case. Regarding diagnosis:
- Does individual have an underlying condition that is causing thrombocytopenia?
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Does individual have idiopathic thrombocytopenic purpura?
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Does individual have bruising, bleeding gums, or nosebleeds? Do minor cuts bleed excessively?
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Are stools bloody?
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Have menstrual cycles been prolonged or heavy?
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Any headaches or dizziness?
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On physical exam, were petechia or ecchymosis found?
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Was the spleen enlarged on palpation?
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Did individual have a CBC? Bone marrow biopsy? Coagulation studies?
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Were other diseases such as HIV, Ehrlichiosis, and lupus ruled out?
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Have conditions with similar symptoms been ruled out?
Regarding treatment:
- Does individual have mild to moderate thrombocytopenia? Is individual avoiding drugs that may affect the platelets?
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Does individual try to avoid injury or invasive procedures?
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Is the underlying cause of the thrombocytopenia being treated?
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Which type of thrombocytopenia does individual have? Is the treatment appropriate to the type?
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Does individual respond appropriately to treatment?
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Have platelet transfusions been necessary?
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Has immune globulin been given?
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Did splenectomy become necessary?
Regarding prognosis:
- Is individual's employer able to accommodate any necessary restrictions?
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Does individual have any conditions that may affect the ability to recover? Has life-threatening bleeding occurred? Has individual had multiple infections?
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Source: Medical Disability Advisor
| Allford, Sarah, and Samuel Machin. "Thrombotic Thrombocytopenic Purpura (TTP)." NetDoctor.co.uk. 5 Dec. 2004 <http://www2.netdoctor.co.uk/diseases/facts/ttp.htm>.Schafer, Andrew I. "Thrombocytopenia and Disorders of Platelet Function." Internal Medicine. Ed. Jay H. Stein. 5th ed. St. Louis: Mosby, Inc., 1998. 610-617. "Thrombocytopenia." HealthCentral.com. HealthCentral.com. 5 Dec. 2004 <http://www.healthcentral.com/mhc/top/000586.cfm>. |
Source: Medical Disability Advisor
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