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Disease Definitions
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Please Choose from the list below:
- Antiphospholipid Antibody Syndromes (APS)
- Heparin-induced Thrombocytopenia (HIT)
- Catastrophic Antiphospholipid Antibody Syndrome (Thrombotic Storm)
- Thrombotic Thrombocytopenic Purpura (TTP)
- Paroxysmal Nocturnal Hemoglobinuria (PNH)
Antiphospholipid Antibody Syndromes (APS)
Antiphospholipid Antibody Syndrome (APS) is an autoimmune disease. In this disorder antibodies, which are found in the blood and normally fight off infections, are instead turning against the body's own normal clotting mechanisms. These antibodies make people more prone to certain problems, such as clots in the deep veins in the arms and legs, known as Deep Vein Thrombosis (DVT) or in the lung, known as Pulmonary Embolism (PE). People with APS can also develop clots in their arteries, known as heart attacks or strokes. In certain women, these antibodies can cause recurrent pregnancy loss.
Physicians use a combination of clinical symptoms, such as blood clots, and specific laboratory tests to diagnose the presence of APS. Laboratory studies used in the diagnosis of APS include tests for lupus anticoagulants and anticardiolipin antibodies. Although many patients with APS have lupus, most patients don't (referred to as primary APS).
The treatment of choice for patients with APS who have had a blood clot is anticoagulant therapy ('blood thinner'). For women with APS and recurrent miscarriages who have not had a prior blood clot, the use of anticoagulant therapy during the pregnancy may increase the likelihood of a successful outcome. Some individuals may have elevated antiphospholipid antibodies but have no clinical manifestations of the syndrome. These individuals do not need anticoagulant therapy, but studies are ongoing to evaluate whether an aspirin a day might be beneficial for these individuals.
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Heparin-induced Thrombocytopenia (HIT)
Heparin is a medicine that is frequently used for the treatment of blood clots. Approximately 1-3% of all patients receiving heparin develop an allergic complication known as Heparin-Induced Thrombocytopenia ("HIT"). Many drugs can cause a patient's platelet count to drop low, resulting in an increased risk for bleeding complications. When heparin causes a patient's platelet count to drop, however, it can paradoxically lead to an increased risk for a patient to develop a blood clot.
Physicians diagnose a patient with "HIT" when his or her platelet count drops after 5-7 days of therapy with heparin. As many as 30% to 50% of patients who develop "HIT" will also develop a blood clot, referred to as Heparin-Induced Thrombocytopenia and Thrombosis ("HITT"). If untreated, "HITT" can be fatal in a third of the patients who are affected.
Treatment of "HIT". An important aspect in the identification of patients with "HIT" is early recognition that the platelet count is falling. In a patient who is receiving heparin and who has a dropping platelet count, heparin must be stopped and an alternative therapy started to treat or prevent blood clots. These new medications include the 'direct thrombin inhibitors', which should be administered under the supervision of a physician who is experienced in their use.
Importantly, once a patient is diagnosed with "HIT", the diagnosis needs to be confirmed with a specific antibody test, and the patient should not be exposed to heparin in the future. In most cases, the antibody will go away over time (usually within 3-4 months), but, in general, the patient should not be re-exposed to heparin.
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Catastrophic Antiphospholipid Antibody Syndrome (Thrombotic Storm)
Catastrophic Antiphospholipid Syndrome
The catastrophic antiphospholipid syndrome is a very rare complication encountered in a subset of patients with antiphospholipid antibody syndrome. This rare syndrome is characterized by the development of multiple blood clots that block small blood vessels in several organs in the body. The organs most commonly affected by these small blood clots include the heart, lungs, nervous system, and kidneys. In many ways, this syndrome is similar to another rare disease, thrombotic thrombocytopenic purpura.
Many patients who develop this rare complication have lupus, and infections have been reported to potentially increase a patient's risk to develop the syndrome. Even with the best treatment, as many as half the patients who develop this syndrome do not survive.
Treatment includes anticoagulation (blood thinners), steroids, and a procedure called 'plasma exchange'. Plasma exchange refers to a process whereby a patient's plasma (the liquid part of the blood) is removed and replaced with plasma from blood donors. Patients who survive this life-threatening complication are generally maintained on long-term anticoagulant therapy.
Thrombotic Storm
Thrombotic storm is characterized by the rapid development of multiple thromboses (blood clots) in a patient with an underlying hypercoagulable state. The catastrophic antiphospholipid syndrome is one type of thrombotic storm, but patients may have other risk factors for forming blood clots. Treatment is similar to the approach used for patients with catastrophic antiphospholipid syndrome.
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Thrombotic Thrombocytopenic Purpura (TTP)
Thrombotic thrombocytopenic purpura ("TTP") is a rare blood condition characterized by a low platelet count and the widespread formation of small blood clots throughout the circulation. Platelets are the smallest of the cells in the blood, and they function as tiny corks that form a plug to stop bleeding. In general, a very low platelet count, referred to as 'thrombocytopenia', is associated with bleeding problems, and these patients may present with large bruises, or 'purpura'. These patients also develop clotting complications, however, involving the brain, kidneys, and virtually any organ in the body. These small clots are referred to as 'thrombi'.
TTP may occur in one to three people per million every year and appears to occur more frequently in women than in men. There is a very rare inherited form, but most cases of TTP appear to develop spontaneously. In some cases, the development of TTP may be associated with certain medicines or other clinical conditions, such as during pregnancy or with lupus or cancer. Symptoms of TTP can be subtle, and may include fever, fatigue, headache or bruising. Some patients may present with kidney failure or stroke-like symptoms, and the disease can be fatal if it is not quickly diagnosed.
TTP is diagnosed by the clinical presentation and certain associated laboratory findings. In particular, what distinguishes this disorder from the many other disorders that cause a low platelet count is that the patient's red blood cells will look torn or fragmented under the microscope. These damaged red blood cells are referred to as "schistocytes".
Treatment of TTP requires specialist care at a Medical Center. The primary treatment for TTP is a process called "plasma exchange", during which a patient's plasma (the liquid part of the blood) is removed and replaced with plasma from blood donors. This treatment is very effective and life-saving in the majority of patients. Other treatments that have been used include steroids, aspirin, and certain chemotherapy agents. In a subset of patients, the TTP may recur after stopping treatment. These patients may require treatment to be restarted, or a different type of therapy may become necessary.
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Paroxysmal Nocturnal Hemoglobinuria (PNH)
Paroxysmal Nocturnal Hemoglobinuria (PNH) is a rare but potentially serious disorder that can affect people of any age, any gender, and any race. PNH is not an inherited disorder, but it occurs following an acquired mutation in a specific gene in the DNA, or genetic material, of a particular type of cell (stem cells) in the bone marrow. Stem cells are responsible for forming all the cell types in the blood, including white blood cells, red blood cells, and platelets. The mutation results in making the red blood cells more susceptible to being destroyed, referred to as hemolysis, and can also result in a defect in the production of all blood cells in the bone marrow, referred to as marrow failure.
Symptoms of PNH include anemia, due to the destruction of the red blood cells, and an increased risk for blood clots, occasionally affecting veins in unusual locations, such as in the abdomen. Marrow failure can lead to an increased risk for infections and other problems. A characteristic sign of PNH is a dark discoloration of the urine, most commonly in the morning, which gives the disorder its name. In some patients, PNH may occur in association with aplastic anemia, or a myelodysplastic syndrome.
Conservative treatment modalities include management of hemolytic episodes, treatment of anemia, and anticoagulation for treatment of blood clots. Bone marrow transplantation can be used in selected patients to cure the disorder.
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