What Is Thrombocytopenia?
Thrombocytopenia is a condition in which one has a low blood platelet count. Platelets, also known as thrombocytes, are the blood cells that help in blood clotting. The average platelet count is between 150,000 and 450,000 per microliter. Platelets stop bleeding by clumping together and forming plugs in the injured blood vessels. It is one of the most common hematological disorders. Thrombocytopenia can occur due to bone marrow disorders such as leukemia, immune system problem, or side effects of certain medications. It affects both children and adults. It can be mild, causing few signs or symptoms, such as fever, loss of appetite, rashes, or spontaneous bleeding. However, in rare cases, the platelets number can decrease so much as to cause internal bleeding, which can be fatal.
What Causes Thrombocytopenia?
Thrombocytopenia occurs when the platelet count is lesser than 150,000 platelets per microliter of blood. Each platelet cell lives for ten days, so the body continuously renews the platelet supply by producing new platelets in the bone marrow. The condition is rarely inherited and can be caused by several medications or conditions. The platelets are reduced by one or more of the following processes: trapping platelets in the spleen, decreasing platelet production, or increasing the destruction of platelets.
1. Trapped Platelets:
The spleen is a small organ located just below the rib cage on the left side of the abdomen. The spleen fights infection and removes waste from the blood. An enlarged spleen, caused by several disorders, can harbor many platelets within it, thus decreasing the number of platelets in circulation.
2. Decreased Platelets Production:
The platelets are produced within the bone marrow. A decreased platelet production can be caused by cancer, such as -
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Leukemia or blood cancer.
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Certain anemias.
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Viral infections.
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Chemotherapy drugs and radiation therapy.
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Heavy alcohol intake.
3. Increased Breakdown of Platelets:
Certain conditions can break down the platelets faster than production, leading to decreased platelets in the bloodstream.
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Pregnancy - Pregnancy can cause thrombocytopenia that is mild and improves immediately after childbirth.
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Immune Thrombocytopenia - Autoimmune diseases, like lupus and rheumatoid arthritis, cause this thrombocytopenia. The body's immune system attacks and destroys its platelets. If this condition's exact cause is unknown, it is referred to as idiopathic thrombocytopenic purpura, affecting children quite often.
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Bacteremia - The presence of bacteria in the blood (bacteremia) can cause infections, thus destroying the platelets.
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Thrombotic Thrombocytopenic Purpura - This rare condition occurs when several blood clots suddenly form within the body, using a lot of platelets.
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Hemolytic Uremic Syndrome - This is a rare disorder causing a drop in the number of platelets, destruction of red blood cells, and decreased kidney function.
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Medications - Certain medications can decrease the number of platelets in the blood, such as Heparin, Quinine, sulfa-containing antibiotics, and anticonvulsants.
How To Manage Thrombocytopenia in Emergency?
The first line of treatment is to treat the cause of thrombocytopenia, such as stopping the medication, treatment of the infection, immunoglobulin G (IgG) replacement, or chemotherapy for chronic lymphocytic leukemia. In the case of severe bleeding, if the cause is unknown but is not immunologic, platelet transfusion can lead to an immediate platelet increase.
In contrast, if the underlying cause is immunologic, the effect obtained from the platelet transfusion may be less and short-lived and should be reserved only for life-threatening bleeding.
1. Inherited Thrombocytopenia.
In the past, patients with inherited thrombocytopenia have been treated with platelet transfusions. In addition, allogeneic stem cell transplantation is used for inherited thrombocytopenias with a high risk of marrow failure or acute leukemia.
2. Immune Thrombocytopenia (ITP).
Many cases of immune thrombocytopenia can be left untreated. However, counts of under 50 x 109 /L are usually monitored with blood tests, and those with counts of under 10 to 20 × 109 /L are usually treated because the risk of spontaneous bleeding, especially intracranial hemorrhage, is significantly higher with lower platelet counts. Any patient experiencing severe bleeding symptoms secondary to thrombocytopenia can also be treated.
The first line of treatment is generally corticosteroids, with a dose of 1 mg/kg/day orally for up to 21 to 28 days depending upon the individual's response, followed by gradually reducing the dose. Intravenous immunoglobulin can also be used as an initial treatment with or without steroids. However, most adult patients relapse after the initial treatment and require second-line therapy.
The second-line treatment option is splenectomy or spleen removal. Additional second-line treatment options include Azathioprine, Cyclosporine, Cyclophosphamide, Danazol, Dexamethasone, Vinca alkaloids, Mycophenolate mofetil, Rituximab, thrombopoietin-receptor agonists.
Thrombopoietin-receptor agonists are an effective and safe second-line treatment. Two thrombopoietin-receptor agonists were approved for treating chronic immune thrombocytopenia in adults by the US Food and Drug Administration (FDA) in 2008 and are now being used for treating chronic immune thrombocytopenia in relapsed patients. These were Romiplostim, a thrombopoietin mimetic formed from peptides, and Eltrombopag.
3. Thrombotic Thrombocytopenic Purpura.
Thrombotic thrombocytopenic purpura is a medical emergency since untreated patients' mortality rate is very high because of disseminated intravascular thrombosis (DIC). Disseminated intravascular thrombosis is a condition in which the blood clots within the blood vessels throughout the body, thus causing ischemic injury and multiple organ failure. Ischemic organ injury can affect all organs, but the brain and heart are primarily affected. Ischemia is the reduced supply of blood to the organs. Acute kidney injury requiring dialysis leading to chronic kidney disease is rare. Central nervous system involvement is often manifested by neurologic abnormalities resulting from small strokes in the brain, which may cause neurologic deficiencies.
The primary treatment involves plasmapheresis with plasma replacement. Plasmapheresis is the process that removes the blood plasma from the body by withdrawing blood, separating it into plasma and cells, and transfusing the cells back into the blood. Other treatment modalities for individuals not responding to plasmapheresis include immune suppression, high-dose steroids, and B-cell-depleting agents. In addition, platelet transfusion is given to patients with clinically significant bleeding.
Conclusion
The successful treatment of thrombocytopenia in an emergency requires knowledge of the underlying pathophysiological processes causing the disease. Prompt investigation and identification are essential and life-saving. A thorough history and physical investigation can disclose information regarding possible underlying diseases and medical treatments. New treatment options for thrombocytopenia patients have been developed. Along with Rituximab and the thrombopoietin agents, combinations of different diagnostic and treatment modalities are the main strategies for adequately managing the condition.
