Virginia Research Day 2025

Medical Resident Research Case Reports

13 Large Pericardial Effusion in Untreated Hypothyroidism

Kenton Kozel, PGY3; Kimberly Bird, MD Corresponding author: kenton.kozel@lpnt.net

Department of Medicine, Sovah Health, Danville, VA, United States

kidney disease stage 3. However, a CT scan of the chest revealed a large pericardial effusion (Figure 1). Upon further investigation, it was discovered that her thyroid medication was missing from the blister packs. A follow-up thyroid panel showed significantly deranged thyroid function, with a thyroid-stimulating hormone level of 179 µU/mL and a low Free T4 of 0.19 ng/dL, confirming untreated hypothyroidism. Cardiology was consulted, and an echocardiogram showed a normal ejection fraction and no evidence of tamponade. Levothyroxine therapy was promptly reinitiated, and the patient was stable for discharge the following day. She continued to follow up with cardiology and had serial echocardiograms, with the pericardial effusion resolving after 9 months. Discussion and Conclusion: Hypothyroidism is a known cause of pericardial effusion, especially in severe cases. In this patient, the diagnosis of untreated hypothyroidism was confirmed by lab findings of markedly elevated TSH and low Free T4, despite her reported adherence

to thyroid medication. This discrepancy highlights the importance of investigating potential causes of inadequate thyroid replacement, such as improper dosing or absorption issues, particularly after thyroidectomy. The management of pericardial effusion secondary to hypothyroidism is primarily conservative. By reinitiating levothyroxine therapy, the thyroid hormone deficiency was corrected, leading to the gradual resolution of the effusion without the need for invasive procedures.

Introduction: Pericardial effusion is a rare but significant complication of untreated hypothyroidism. Here is presented a case of a 66-year-old female with history of thyroidectomy, who developed a large pericardial effusion. This case highlights the importance of thyroid function monitoring, even in patients with reported medication adherence. Case Report: A 66-year-old African American female presented with worsening stabbing back pain radiating to the left mid-axillary line, along with fatigue and generalized weakness. Her past medical history includes hypothyroidism following a total thyroidectomy in 2017, fibromyalgia, arthritis, cirrhosis, and chronic kidney disease (stage 3). She reported complete adherence to her prescribed medications, which she took daily from three separate blister packs. On musculoskeletal examination, diffuse tenderness was noted, particularly in the left shoulder and upper back, which worsened by palpation. Initial laboratory workup in the emergency department was nonspecific, consistent with her known chronic

Figure 1

53

2025 Research Recognition Day