SUN-583 Immune Thrombocytopenic Purpura Associated with Stiff Person Syndrome and Polyglandular Autoimmune Syndrome Type 2

Abstract

Background Idiopathic thrombocytopenic purpura (ITP) is an acquired autoimmune disease caused by antibodies against platelet glycoproteins. Stiff person syndrome (SPS) is a progressive neurological disorder characterized by axial muscle rigidity and involuntary spasms associated with anti-glutamic acid decarboxylase (GAD) antibodies. Polyglandular autoimmune syndrome type 2 (APS-2) is defined by the occurrence of Addison disease with thyroid autoimmune disease and/or Type 1 diabetes mellitus (T1DM). SPS has been associated with APS-2 as well as to T1DM and autoimmune thyroid disease alone. ITP has been linked T1DM in rare cases as well as autoimmune thyroid disease, yet SPS and ITP have not previously been associated. We present the first reported case to our knowledge of a patient with ITP subsequent to Graves disease, SPS and T1DM. Clinical Case The patient is a 35-year-old female evaluated in endocrinology clinic for follow up of Graves disease treated with RAI ablation 5 years prior. She presented with fluctuating muscle rigidity and spasms involving the axial muscles leading to gait disturbance and frequent falls. She displayed the classic “wooden-man” appearance when ambulating first described by Moersch and Wotmann which lead to the name of SPS. She was treated with diazepam due to clinical suspicion for SPS. Neurology was consulted, both the referring physician and neurologist agreed with the diagnosis of SPS. Her symptoms gradually improved yet they have proven to be relapsing and remitting in nature requiring modification of dosing depending on response. 7 years later she was diagnosed with T1DM, presenting to the ED with generalized weakness and fatigue. Initial laboratory work was consistent with DKA. During her hospitalization routine laboratory work showed incidental thrombocytopenia with a platelet count of 15,000. Over the next few days her platelet count dropped to 5,000 prompting diagnostic bone marrow aspiration and biopsy which revealed a hypercellular marrow and adequate megakaryopoiesis. ITP was the working diagnosis and patient was discharged with prednisone. A favorable response to therapy was noted and prednisone was tapered accordingly. 2 years later she presented with a relapse of ITP with a platelet count of 6,000; treatment was initiated with intermittent prednisone and IVIG. At this time T1DM and thyroid disease were well controlled. Serum GAD-antibodies tested after presentation of ITP were >250 IU/ml (0-5.0 IU/ml). Conclusion To our knowledge ITP has not previously been documented in a patient with SPS. Our goal is to create physician awareness regarding the association between these disorders as well as the need for regular monitoring of patients with an endocrine autoimmune disease. SPS has been linked to APS-2; yet is it possible that SPS can independently be associated with ITP?