PSAT331 A Rare Case of Thrombocytopenia in Concurrence With Severe Hypothyroidism: Are We Still Missing Something?
Authors: Dunn Sandi , Alsamman Mrhaf , Abdelmasih Randa , Ashraf Bilal 
Published: November 2022

Introduction

Hashimoto thyroiditis as an etiology of secondary thrombocytopenia is a very rare phenomenon but has been reported in literature. The concurrence of hypothyroidism and immune thrombocytopenia is not clearly understood. The theory to this association involves a metabolic process in which hypothyroidism induces a shorter life span in platelets through increased phagocytosis, and an immunologic process in which antibodies are formed against platelets and thyroid tissue. Literature suggests that achievement of a euthyroid state corrects the immune imbalance which subsequently improves thrombocytopenia. Although this association is still debatable, we present a case of severe thrombocytopenia in concurrence of severe hypothyroidism that responded to steroid and levothyroxine treatment.

Case presentation

An 85-year-old female presented to our facility with complaint of diffuse abdominal pain. Abdominal imaging revealed extensive stool throughout the colon. Labs were significant for hemoglobin of 9.1, as well as marked thrombocytopenia, with a platelet count of 9000. She was transfused one unit of platelets. A peripheral blood smear revealed markedly decreased platelets and further workup revealed an elevated TSH level of 62.5 with free T4 less than 0.25. HIV, HCV, B12 and folic acid levels were all within normal limits. Platelet antibody test for HLA class I, IA/IIA, IB/IX and IIB/IIIA antibodies were all negative. Serum protein electrophoresis and immunoglobulin levels of A, G, M, Kappa/lambda results were within normal limits. Patient was started on Levothyroxine, and received steroids which subsequently led to improvement in platelet count.

Discussion

Immune thrombocytopenia (ITP) is defined as low platelet count due to autoimmune destruction of platelets. Primary ITP also known as idiopathic, is ultimately a diagnosis of exclusion. Secondary ITP may be due to many underlying conditions such as HCV, HIV, DIC, SLE, sepsis, malignancies or drugs [1]. Our patient presented with marked thrombocytopenia without any of the aforementioned definite etiologies. However, the patient was noted to have profound hypothyroidism. Association of thyroid disorders have been described in few case reports and retrospective studies but still a debatable topic. A retrospective study by Shoko et al reviewed 248 patients with newly diagnosed ITP in for whom we had thyroid function data at diagnosis. Of the 248 patients with ITP, 74 patients also had thyroid disease, including 36 with overt thyroid disease (13 Graves’ disease and 23 Hashimoto's thyroiditis) and 38 with subclinical thyroid disease (3 hyperthyroidism and 35 hypothyroidism). Treatment for thyroid disease in 22 patients improved thrombocytopenia in 21 patients, especially in 4 patients who were not treated for ITP [2].

Conclusion

Hashimoto thyroiditis is an uncommon etiology for the development of thrombocytopenia, and very few cases have been reported thus far. Hence, clinicians should be aware of this association in the appropriate clinical context when common etiologies are exhausted.

Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.