How low (K+)an you go: a case report of thyrotoxic periodic paralysis and concomitant renal tubular acidosis in a young patient successfully treated with electrolyte replacements and antithyroid medications
Year: 2025
Type: article
Study design: Case Report
Abstract: Background: Thyrotoxic periodic paralysis (TPP) is a rare and dangerous complication of thyrotoxicosis that has been well-documented in East-Asian patients. However, its incidence outside of this population is unknown. Additionally, type 1 distal renal tubular acidosis (RTA) is a complication of TPP not well-described in the literature. Here we report a case of TPP with concurrent RTA in a non-Asian patient. Case Description: A 37-year-old Ghanaian male with no past medical history presented to the emergency department with four episodes over the last year of sudden muscle weakness and cramping that self-resolved after 6 hours. Over the same period, he had also experienced heat intolerance, weight loss, and diplopia. Vitals were notable for tachycardia and hypertension; the physical exam was significant for reduced strength in the bilateral lower extremities, tremors in his hands on extension, and thyromegaly with a positive bruit. Labs showed K <2 mEq/L, hemoglobin A1c (HbA1c) 5.8%, thyroid-stimulating hormone (TSH) <0.05 µIU/mL, free T4 >5 ng/dL, and anti-TPO >1,000.0 IU/mL. A diagnosis of Graves’ disease was made. Venous blood gas analysis revealed a non-anion gap metabolic acidosis, and urine studies demonstrated alkaline urine. Computed tomography imaging of the spine was done to rule out cord pathology, which was normal. He was admitted to the intensive care unit and was started on propranolol and methimazole. Due to persistent tachycardia, undetectable TSH, and high free thyroxine (FT4), therapy was escalated to atenolol and a higher dose of methimazole. Potassium, magnesium, and phosphate were replaced via a central line, and sodium bicarbonate tablets were started for suspected distal RTA. The patient was discharged on day 3 of hospitalization with improved weakness and thyroid hormone levels, with plans for close follow-up with an endocrinologist. Conclusions: TPP should be considered in any patient with lower extremity weakness and signs of hyperthyroidism. It is a reversible muscle weakness if diagnosed and treated appropriately. Treatment should focus on electrolyte repletion, symptomatic control, and antithyroid therapies. Distal RTA was likely secondary to the autoimmunity associated with Graves’ disease.
Authors: Cyrus W. Hadavi, Nicholas S. Samel, Maneesh Gaddam, Aman Shaikh, Maneesha D. Bangar
Language: English
Subfield: Endocrinology, Diabetes and Metabolism
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W4414136012