Thyroid Troubles: A Case of Hypothyroidism-Associated Recurrent Massive Pleural Effusion

Pleural effusions can be secondary to several different etiologies. Sometimes, they can be related to hypothyroidism. We present a case of massive pleural effusion resulting from hypothyroidism. A 75-year-old male with a history of liver cirrhosis, hypothyroidism, and medication non-adherence presented to the emergency department (ED) with shortness of breath and altered mental status. Physical exam and chest imaging were consistent with right-sided pleural effusion. Effusion was exudative. Multiple recurrences complicated the hospitalization despite thoracentesis and pleurodesis. Labs revealed hypothyroidism, and finally, the patient was started on hormone replacement, resulting in the resolution of the effusion. Pleural effusion is a rare manifestation of hypothyroidism, thought to be mediated by vascular endothelial factors. Pleural fluid analysis shows both exudative and transudative patterns. Hormonal replacement is the mainstay of treatment. Clinicians need to be aware of the rare etiologies of pleural effusion. Depending on the patient's presentation, due work-up should be done to ensure a timely diagnosis and management.