Hypothyroidism Associated Hyponatremia, A Complicated Presentation

Authors

Gary Lee, HCA HealthcareFollow
Spencer Steinberg, HCA HealthcareFollow
Samiuallh Shahid, HCA HealthcareFollow
Evangelista Ezenduka, HCA HealthcareFollow
Edgardo Flores

Files

Division

North Texas

Hospital

Medical City Arlington

Specialty

Internal Medicine

Document Type

Poster

Publication Date

2025

Keywords

hypothyroidism, hyponatremia, euvolumic hyponatremia

Disciplines

Endocrine System Diseases | Internal Medicine | Medicine and Health Sciences | Nutritional and Metabolic Diseases

Abstract

Introduction: Hypothyroidism is a well known text-book cause of euvolumic hyponatremia that is a rare occurrence in clinical practice in the absence of other potential etiologies of hyponatremia. We review a case of a 48 year old female presenting with profound generalized weakness found to have severe hyponatremia, later found to have severe hypothyroidism during admission. We review the potential mechanisms whereby hypothyroidism results in hyponatremia and whether or not hypothyroidism-induced hyponatremia truly exists and the current evidence supporting these views Case Presentation: 48 year old female with history of hypothyroidism, breast cancer post right lumpectomy and radiation presented for a few day history of generalized malaise and weakness found to be hypothermic and bradycardic with a notable sodium level of 109. Patient eu-volumic on physical exam. Further history reviewed that she only took “supplements” for her hypothyroidism and not any pharmacological thyroid replacement. Patient brought to ICU where hyponatremia was corrected. TSH and T4 were obtained and had a value of 39.160 uIU/mL and .16 ng/dL, respectively. Thyroid hormone replacement initiated as well as IV steroids. Other potential causes of hyponatremia including depleted intra-vascular volume and medications were ruled out. Patient’s clinical course was complicated with rhabdomyolysis resulting in compartment syndrome necessitating fasciotomy of the lower extremities. Patient did well in the end with sodium normalizing and previous presenting symptoms resolved. Patient was sent home on levothyroxine with close PCP follow up Conclusion and Learning points: Hypothyroidism-induced hyponatremia remains a known, but rare, entity in everyday clinical practice. Proposed mechanisms include, but are not limited to, the activation of anti-diuretic hormone in the face of decreased glomerular-filtration rate, baroreceptor mediated release of vasopressin, and reduction of Na-K-ATPase activity leading to reduced tubular sodium reabsorption. Evidence regarding these mechanisms is conflicting. It remains that there is no absolute causal relationship between hypothyroidism and hyponatremia. Therefore, it is imperative to evaluate for other causes of hyponatremia in hypothyroid patients in the clinical setting

Original Publisher

HCA Healthcare Graduate Medical Education

Recommended Citation

Lee, Gary; Steinberg, Spencer; Shahid, Samiuallh; Ezenduka, Evangelista; and Flores, Edgardo, "Hypothyroidism Associated Hyponatremia, A Complicated Presentation" (2025). North Texas Research Forum 2025. 33.
https://scholarlycommons.hcahealthcare.com/northtexas2025/33