SYNOPSIS of "The Hospital Medicine Podcast: Immune thrombocytopenia Purpura" by Dr Gil Porat MD

This podcast was recorded on July 2, 2012 and can be found here: https://itunes.apple.com/us/podcast/hospital-medicine-podcast/id541752791


   This was a very interesting podcast, as are all of Dr. Porat's lectures. So lets start of by saying that platelets are non-nucleated cells that clot to prevent bleeding. Thrombin forms when coagulation proteins bind to the platelet surface. Platelets also secrete factors for platelet repair. They live for about 10 days and 30% of them are sequestered in the spleen.
     Thrombocytopenia is when the platelet count is below 150k. ITP is normally a chronic benign condition. Spontaneous remission is seen in 9% of adults and is even more common in children. The two ways that ITP occurs is through decreasing production of platelets  (by drugs and bone marrow diseases  and decreasing the survival of platelets ( by ITP, TTP sepsis, hypersplenism, etc).
    The type of ITP that Dr. Porat discusses in this podcast is autoimmune induced thrombocytopenia. It is commonly a diagnosis of exclusion after systemic illnesses and medication reactions are ruled out. ITP is commonly an incidental finding on a lab results, but petechiae, purpura, menstrual  mucosal and cutaneous bleeding my be seen.
     Treatment goals are hemostasis and to increase the platelet count to above 30k. If there is no bleeding and the platelet count is already above 30k, then treatment is typically not needed. Otherwise, the first line of therapy is corticosteroids. Improvement should be noted within one to two weeks, although re-occurrence will often be seen after the steroids are discontinued  Splenectomy is considered second line treatment. Patients should have the appropriate vaccinations prior to surgery (pneumovax, H. influenza, and meningococcal . This therapy is associated with a 60% remission rated although physicians should be diligent to watch for inherent side affect of this surgery (i.e, sepsis). Anabolic steroids have also been used for treatment, but may not be appropriate for female patients.
     Rituximab is a monoclonal antibody that decreases the production of B cells. It decreases the antibodies that are destroying the platelets. It has been shown to be effective, but immune suppressants such as this one have several restrictions and warnings as well.
     The newer medications affect thrombopoietin  Thrombopoietin is made in the liver and sent to the bone marrow to tell the megakaryocytes to increase production of platelets. Two thrombopoietin agonists (Romiplostim and Eltrombopag)  have shown to increase platelet counts to greater than 50K in 94% and 87%, respectively. These medications are very expensive, and continual use is needed for them to work. Some of the side effects are elevated LFT's, thromboembolism, and bone marrow fibrosis.
     Lastly , platelet transfusion in emergency situations, although the effect, is temporary. IVIG can be given along side the transfusion to help the effects.