Purpose: Patients with hypothyroidism are increasingly enquiring about the benefit of using combination therapy of levothyroxine (LT4) and liothyronine (LT3) as a potential treatment for hypothyroidism. Combination therapy, however, remains controversial. The purpose of this study was to systematically review available hypothyroidism treatment recommendations from clinical practice guidelines from around the world to identify the consensus regarding combination therapy.Source: Clinical practice guidelines were obtained from searches of PubMed, EMBASE, and MEDLINE, using several combinations of MeSH terms. The search was limited to clinical guidelines in English-language publications, published between January 1, 1990 and May 1, 2015. A quantitative approach was utilized for data synthesis.Principal Findings: Thirteen guidelines were identified, including three regarding pregnancy, two regarding pediatric populations and eight regarding adult populations. There were six guidelines from North America, four guidelines from Europe and three guidelines from South America. Twelve of the guidelines were published after 2010. Nine guidelines addressed combination therapy of LT4 plus LT3, and all nine concluded that LT4 therapy alone is the standard of care, with insufficient evidence to recommend widespread combination therapy. Only the 2012 ETA Guidelines and the 2015 BTA Guidelines concluded that combination therapy could be used, although only in certain circumstances and as an experimental treatment.
Conclusion:This systematic review illustrates that clinical practice guidelines worldwide do not recommend and do not support routine use of combination LT4 and LT3 therapy to treat hypothyroidism.
Objective:We report a case of cerebral venous thrombosis (CVT) associated with Graves hyperthyroidism in order to increase awareness of this association in the literature. CVT entails significant morbidity and mortality, and awareness of its risk factors may assist both with expediting its diagnosis and completing an appropriate workup.Methods: A 62-year-old female with a 3-week history of symptoms of hyperthyroidism secondary to Graves disease, and a 2-week history of treatment with methimazole, presented with sudden onset of severe headache, right-sided weakness, and generalized seizure.Results: A computed tomography scan of her head identified extensive CVT, located within the superior sagittal sinus and extending into the right transverse sinus. She remained biochemically hyperthyroid at the time of her presentation (thyroid-stimulating hormone = 0.10 mIU/L; free thyroxine = 32.8 pmol/L; free triiodothyronine = 10.0 pmol/L). A thrombotic workup revealed normal antithrombin, protein C, and protein S levels; normal platelet count, international normalized ratio, and activated partial thromboplastin time; and negative cytoplasmic antineutrophil cytoplasmic antibodies (ANCA), perinuclear-ANCA, antinuclear antibody, and extractable nuclear antigen antibod-ies. Factor VIII concentration was abnormally elevated at 3.63 IU/mL (normal, 0.50 to 1.50 IU/mL). Conclusion: Our case highlights the risk of CVT with Graves hyperthyroidism likely related to coagulopathy from Factor VIII elevation. Patients presenting with stroke and hyperthyroidism should be investigated for possible CVT, and if the diagnosis is confirmed, should receive prompt initiation of anticoagulation. (AACE Clinical Case Rep. 2017;3:e70-e73) Abbreviations: CVT = cerebral venous thrombosis; FT4 = free thyroxine
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