Arguinchona, Joseph

Abstract Disclosure: J. Arguinchona: None. N. Allen: None. M. Vahidi Rad: None. K. Doshi: None. Background: Thyrotoxic periodic paralysis (TPP) is a distinct disorder characterized by episodic, generalized muscle weakness due to hypokalemia, occurring predominantly in young adult males (20-40 years) with hyperthyroidism, particularly Graves' disease. TPP is common in East Asian populations, affecting approximately 2% of individuals with hyperthyroidism, but is rare in Western populations (0.1-0.2%) and often underrecognized in the United States. Herein, we present three cases of TPP in young Hispanic and Caucasian males with Graves’ disease, underscoring the importance of diagnostic vigilance. Clinical Cases: Case 1: A 21 y.o. Hispanic male presented to endocrine clinic following multiple hospitalizations for severe hypokalemia and myopathy. During admission, labs showed a potassium (K) 1.2 mmol/L (3.6-5.2), undetectable thyroid stimulating hormone (TSH), and free thyroxine (FT4) 2.8 ng/dL (0.9-1.7). K was replaced and Graves’s disease was confirmed by positive TSH receptor antibodies. He was started on methimazole and subsequently underwent radioactive iodine (I-131) therapy. Following development of hypothyroidism, he was placed on levothyroxine replacement, with no further recurrence of paralysis. Case 2: An 18 y.o. Caucasian male with a history of Graves’ disease presented after multiple hospitalizations for hypokalemia and lower extremity weakness. Hospitalization labs showed a suppressed TSH, FT4 2.2 ng/dL, free triiodothyronine (FT3) 7.9 pg/mL (2.3-4.1), and K 2.8 mmol/L. His weakness improved with K replacement. Methimazole was initiated and the patient subsequently opted for total thyroidectomy for definitive therapy. No recurrence of TPP was observed after thyroidectomy. Case 3: A 29 y.o. Hispanic male with Graves’ disease, non-adherent to methimazole was hospitalized due to symptoms of diffuse upper and lower extremity weakness. Labs showed K 1.6 mmol/L, undetectable TSH, and T4 >7.7 ng/dL. Symptoms resolved with K replacement. He was restarted on methimazole as well as atenolol and advised on medical adherence. Unfortunately, he was lost to follow up, and re-hospitalized 7 months later with similar symptoms and labs, again due to nonadherence with thionamide medication. After aggressive K replacement and methimazole resumption, he was discharged with urgent endocrine follow-up for definitive management of Graves’ disease. Conclusion: These cases highlight the under recognition of TPP in non-Asian populations in the United States, leading to delayed diagnosis and recurrent hospitalizations. Clinicians should maintain a high index of suspicion for TPP in young males with hypokalemia, and generalized weakness, particularly in the setting of undiagnosed or untreated hyperthyroidism. Prompt recognition and definitive treatment of hyperthyroidism is critical to preventing recurrent episodes and associated morbidity. Presentation: Saturday, July 12, 2025

Abstract While adrenal androgen production is primarily regulated by ACTH, some data suggest a less common association between hyperprolactinemia and elevated dehydroepiandrosterone sulfate (DHEA-S). We describe 2 patients with this underrecognized connection. Patient 1, a 60-year-old male, was incidentally found to have bilateral adrenal masses on computed tomography during evaluation of gastrointestinal complaints. Further workup revealed elevated levels of DHEA-S and prolactin, with pituitary macroadenoma identified as the cause, given normalization of both prolactin and DHEA-S on cabergoline therapy. Patient 2, a 38-year-old male, presented with visual field defects, and subsequent pituitary magnetic resonance imaging confirmed a macroadenoma. He also had markedly elevated levels of DHEA-S and prolactin. Both patients were treated with cabergoline, leading to rapid normalization of both prolactin and DHEA-S levels. These cases demonstrate an association between hyperprolactinemia and elevated DHEA-S, supported by the normalization of levels with medical treatment of prolactinoma. Although hyperprolactinemia in the context of a prolactinoma is an uncommon cause of elevated DHEA-S, it should be considered once other etiologies have been excluded.

Abstract Patients with newly diagnosed Graves disease often elect for treatment with the drug methimazole (MMI) over alternative therapies. However, MMI can commonly result in skin allergy that in severe cases can lead to discontinuation of therapy. We present a case of Graves thyrotoxicosis with a delayed hypersensitivity reaction while on MMI. The patient was successfully treated with a novel, individualized, 27-day desensitization protocol that resulted in tolerance of MMI with subsequent improvement in thyroid indices. Previous literature has offered various rapid desensitization protocols to MMI for immediate type hypersensitivity reactions. However, in nonimmediate, delayed hypersensitivity reactions, a slower desensitization protocol can be considered. As demonstrated in this case, desensitization to MMI is a reasonable alternative in patients who wish to avoid definitive therapy who develop an initial adverse reaction to MMI, as this can occur in up to 13% of treated cases.

Abstract Disclosure: J. Arguinchona: None. A. Mahajan: None. A. Gonzalez-Estrada: None. E. De Filippis: None. Introduction: Patients with newly diagnosed Graves’ disease often choose treatment with methimazole (MMI) over traditional ablation therapies. However, MMI can result in adverse reactions including skin rash, pruritus, and urticaria. We present a case of Graves’ thyrotoxicosis with a type IV hypersensitivity reaction while on MMI. The patient was successfully treated with a novel, individualized, 27-day desensitization protocol which resulted in tolerance of MMI with subsequent improvement in thyroid indices. Clinical Case: A 42-year-old female presented for abnormal thyroid studies with associated insomnia, heat intolerance, palpitations, resting tremor, and weight loss. Lab work revealed a thyroid-stimulating hormone <0.005 (0.450-4.500 μIU/mL), free thyroxine 3.28 (0.82-1.77 ng/dL), triiodothyronine 310 (71-180 ng/dL), thyroid peroxidase antibody (Ab) 62 (0-34 IU/mL), thyroid-stimulating immunoglobulin 0.67 (0.00 -0.55 IU/L), and thyrotropin receptor Ab of 6.00 (0.00-1.75 IU/L). She was started on MMI, 10 mg daily for Graves’ disease. Three weeks later, T3 and T4 remained elevated prompting an increase in MMI dose to 10 mg twice daily. Two weeks later, she developed a diffuse, pruritic maculopapular exanthema over her trunk, neck, and extremities. Methimazole was discontinued while prednisone was initiated that subsided her rash. Unfortunately, the patient’s symptoms recurred upon repeat MMI exposure. The patient declined propylthiouracil due to concerns of hepatotoxicity and elected to avoid ablation therapy with iodine or surgery. With the assistance of an allergist, a novel, 10-step, 27-day desensitization protocol was developed specifically for her reaction to MMI with plans to taper prednisone once desensitization was completed. The patient underwent desensitization with development of mild lower extremity exanthema that was successfully treated with high dose antihistamines. Three months later, she was tolerating MMI at 15 mg daily without further adverse reactions and tapered off prednisone. While on MMI, her immune titers normalized with euthyroid clinical and biochemical restoration. Conclusion: Many patients and clinicians initially prefer medical management over definitive ablation therapies in the treatment of Graves’ disease. This case demonstrates with the assistance of an allergist, desensitization to MMI is a viable option in the setting of a known hypersensitivity reaction when it is the first line treatment and no equally efficacious alternatives exist. In addition, patient’s preferences should also be considered during medical decision making. Previous literature has offered various rapid desensitization protocols for MMI for immediate type hypersensitivity reactions. However, in non-immediate, type IV hypersensitivity reactions, a slower desensitization protocol can be considered, as demonstrated in this case. Presentation: Thursday, June 15, 2023