clinical topic updates
Proper Clinical Diagnosis Is Essential in Primary Immune Thrombocytopenia
A diagnosis of immune thrombocytopenia (ITP) is commonly made by a thorough patient and family history, physical examination, complete blood count, and review of the peripheral blood smear. Patients frequently are diagnosed with ITP with minimal further testing. Although response to first-line treatment with corticosteroids or intravenous immunoglobulin (IVIg) supports the ITP diagnosis, further testing is needed to exclude secondary ITP. The peripheral blood smear must be carefully reviewed and the patient further examined to exclude any secondary causes of thrombocytopenia, such as myelodysplastic syndrome, pregnancy, or another chronic disorder. The International Working Group (IWG) on ITP recommends additional screening tests for adults with ITP to verify a proper diagnosis, including tests for Helicobacter pylori, HIV, and hepatitis C. In addition, some studies have demonstrated that a positive antinuclear antibody may be associated with increased risk of chronic or refractory disease in children, and a quantitative immunoglobulin level measurement should be considered in children with ITP as part of their evaluation.
Donald I Feinstein Chair in Medicine
A proper diagnosis is essential in ITP. This is a clinical diagnosis, not a laboratory diagnosis. Good clinical sense and following the recommendations of the IWG on how to do an assessment up front is really important to ensure that you are really diagnosing someone with ITP. Despite a lot of basic and translational research going on in this disease state, none of it has led to anything that can help clinicians to either predict who is going to respond to treatment and how they are going to respond or even tell us how to use new tests for the actual diagnosis of this disease. ITP is a diagnosis of exclusion, but the strongest indicator in diagnosis is that a patient responded to immune modulation. A good solid workup by a thoughtful clinician is really what you need to diagnose and properly manage patients with ITP, and there are more therapies available now than what we had just 20 years ago, with the main ones being the thrombopoietin receptor agonists (TPO-RAs). There are patients who improve their platelet counts on corticosteroids and IVIg, and patients will respond to a TPO-RA even if they don’t have ITP. I really like the concept that we’ve documented that the patient has ITP, and now we are trying to treat immune disease and not make the error of treating something else. We have had patients who came in with thrombocytopenia who have been diagnosed with a familial RUNX genetic abnormality for their thrombocytopenia. About 20% of treatment-refractory patients have secondary ITP, and that’s really an issue. They have lupus. There are patients who have immunodeficiency states. So, ITP is a very heterogeneous disease in this regard.
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