Author: V. Dimov, M.D., Assistant Professor, University of Chicago
Reviewer: S. Randhawa, M.D.
A 44-year-old African Americal male (AAM) with a past medical history (PMH) of HIV/AIDS, non-compliant with his Highly Active Antiretroviral Therapy (HAART), was admitted with upper gastrointestinal (GI) bleeding to the intensive care unit (ICU).
Initially, his hemoglobin (Hgb) was 5.9 mg/dL and he was transfused 2 units of packed red blood cells (2 U PRBC). His platelet count came back as 1/mm3.
Platelet count = 1/mm3 (click to enlarge the image).
What would you do?
He was transfused with 10 untis of platelets with little effect: Platelet count increased to 4/mm3. There were petechiae on the soft palate but no other evidence of bleeding.
No GI specialist would be willing to do an esophagogastroduodenoscopy (EGD) with a platelet count of 1/mm3. The patient was "lucky" that the bleeding stopped on its own.
He gradually developed oral petechiae and mild mucosal bleeding.
How was his platelet count before this admission?
When we asked the patient if he was ever told that his platelet count was low, he answered that it was "always OK." The ID specialist checked with the HIV clinic that was following the patient and they told us that his platelets were never above 10 .
Why are the platelets low?
The HemOnc consultant made the diagnosis of idiopathic thrombocytopenic purpura (ITP), and prednisone 1 mg/kg PO QAM was started. HIV can cause thrombocytopenia as well.
What if the platelet count does not increase?
If prednisone is ineffective, you have to start IVIG, or even better, anti-Rh Ab.
Should we do splenectomy without a bone marrow biopsy in ITP?
No. Splenectomy will help only if the bone marrow is working. ITP is a clinical diagnosis. You do not need antiplatelet antibodies to make the diagnosis.
However, a bone marrow biopsy is recommended in this patient. If he has ITP, the biopsy will show a lot of megakarioblasts because the bone marrow is working hard to produce the platelets which are destructed in the periphery. On the other hand, if the thrombocytopenia is due to bone marrow failure (i.e. not ITP), the splenectomy will be useless.
In this particular patient the reticulocyte count was 6% which indicated a good BM response.
Is anti-Rh Ab better than IVIG for treatment of ITP?
Anti-Rh antibody is more effective and is also less expensive. Win-Rho (anti-Rh Ab) cost is 1/3 of the cost of IVIG. Actually, it more cost effective to do a splenectomy rather than to give IVIG.
How does anti-Rh (anti-D) work?
Anti-D antbody can be used only in Rh-positive patients. Out patient's blood group was B positive.
Antibodies cover the RBCs and when they go to the spleen, they keep the Fc receptors there "busy," thus preventing the spleen from destructing platelets. The problem is that anti-D Ab can cause hemolytic anemia, therefore its use is relatively contraindicated in patients with severe anemia.
The patient refused a bone marrow biopsy. His platelet count increased to 7 and then drecreased again to 1 while taking Prednisone.
He developed hematuria and further oral mucosa bleeding.
12 units of platelets were transfused and IVIG was started. He refused his anti-HIV medications and left the hospital AMA.
What did we learn from this case?
It is always good practice to believe your patient but always double check the information they provide.
Examine the oral cavity of patients with thrombocytopenia daily. This is where the bleeding often first starts.
Immune Thrombocytopenic Purpura - Let the Treatment Fit the Patient. NEJM 8/03
Initial Treatment of ITP with High-Dose Dexamethasone. NEJM 8/03
Systematic Review: Efficacy and Safety of Rituximab for Adults with Idiopathic Thrombocytopenic Purpura. Annals of Int Med, 2 January 2007, Volume 146 Issue 1, Pages 25-33.
FDA approves Amgen's blood platelet booster (Nplate, romiplostim). Reuters, 08/2008.