6556 Does Autoimmune Hashimoto’s Hypothyroidism Mask the Diagnosis of Ehlers-Danlos-Syndrome?

Abstract Disclosure: S. Azmat: None. U. Rafat: None. J.L. Gilden: None. Does Autoimmune Hashimoto’s Hypothyroidism Mask the Diagnosis of Ehlers-Danlos Syndrome? Background: Hypothyroidism is well-known to be associated with muscle weakness and fatigue. There are other etiologies for decreased muscle tone such as Ehlers-Danlos syndrome (EDS) which is group of connective tissue disorders characterized by joint hypermobility, skin hyperextensibility and tissue fragility. Other rheumatological and cardiac conditions associated with this syndrome can pose diagnostic challenges. We present case of 32-year-old female presenting with facial muscle weakness and newly diagnosed Hashimoto’s hypothyroidism. We highlight importance of keeping EDS as another differential in patients with muscle weakness allowing for accurate, prompt diagnosis and treatment to be done in timely manner. Case Description: A 32-year-old female professional musician was referred to Endocrine for mouth muscles weakness and decreasing ability to play her French Horn wind instrument with vocal dystonia and the question of whether these were symptoms of hypothyroidism. She was noted to have mild thyroid enlargement and abnormal thyroid function tests with positive thyroid antibodies. Initial TSH was 7.506 uIU/mL(0.55-4.78), free T4 0.9 ng/dL (0.76-1.46), peroxidase antibody = 96,061U/mL (0-60) and thyroglobulin of 134.9 U/mL (0-60). She also reported low energy, intermittent difficulty swallowing and decreased muscle strength. There was no prior personal and family history of hypo/hyperthyroidism or any other disorders. VS were normal, physical exam showe d no thyromegaly, reflexes revealed objective decrease but normal muscle strength. The skin was noted to be hyperextensible with passive hyperextension of fifth metacarpophalangeal joint beyond 90 degrees, thumb to flexor aspect of forearm and elbows bilaterally with positive Beighton criteria for EDS. She later admitted to intermittent palpitations and easy bruising. Subsequent lab tests were negative ANA, anti-mitochondrial, PCEL and striated muscles antibodies. Additionally she had normal IGA, PTH, AM cortisol- ACTH, vitamin B12 levels with negative 21 hydroxylases antibodies and celiac titers. She was started on levothyroxine 25 mcg and recommended for Cardiology evaluation and genetic testing. Physiotherapy was started. Upon six months follow-up she clinically felt better with improved muscle strength, swallowing and energy level. Repeat lab testing showed improved TSH of 2.67 uIU/mL(0.55-4.78) with free T4 of 1.0 ng/dL (0.76-1.46). Conclusion: This case demonstrates that although muscle weakness can be symptom of hypothyroidism one must evaluate all patients for other possible causes. We highlight importance of keeping EDS as a differential especially in female patients with muscle weakness. Though history and physical exam is crucial allowing for prompt diagnosis and treatment for other conditions. Presentation: 6/1/2024