MON-460 - Rare Complication of Toxic Multinodular Goiter as Right Sided Chylothorax

Introduction/

Background:
Toxic multinodular goiter (MNG) is a common thyroid disorder characterized by the presence of multiple autonomously functioning thyroid nodules that produce excessive thyroid hormones, often leading to clinical thyrotoxicosis. Chylothorax, on the other hand, is a rare but serious condition defined by the accumulation of chyle in the pleural space. It typically results from disruption or obstruction of the thoracic duct, due to trauma, malignancy, or, less commonly, non-malignant causes. Herein, we present a very rare complication of MNG.

Case Presentation:
An 82-year-old female with a history of hypertension presented with progressively worsening shortness of breath, dysphagia, unintentional weight loss of 30 pounds, hand tremors, and palpitations over a 6-months period. Initial evaluation revealed a large right-sided pleural effusion, for which a PleurX catheter was placed. Fluid analysis confirmed chylothorax. Work up revealed clinical evidence of severe hyperthyroidism, with an undetectable TSH level. Imaging showed a large multinodular goiter with retrosternal extension, causing distal intrathoracic duct obstruction. She was initiated on high dose methimazole, atenolol and saturated solution of potassium iodide (SSKI) as part of preoperative thyroid suppression. Total parenteral nutrition (TPN) was started, pleural drainage was performed three times weekly. The patient underwent a total thyroidectomy. Postoperatively, she experienced marked improvement in obstructive symptoms, including dysphagia and dyspnea. The chylous drainage significantly decreased, eventually resolving. Postoperative thyroid panel was consistent with TSh 4.93 mIU/L ( 0.5-5.0 mIU/L) , fT4 0.5 ng/dl (0.8 to 1.8 ng/dl), T3 total 42 ng/dl (60-180 ng/dl), patient was commenced on 50 mcg daily levothyroxine.

Conclusions/

Discussion:
This case highlights a rare presentation of toxic multinodular goiter complicated by right-sided chylothorax, with resolution following thyroidectomy without involving sternotomy or thoracic duct ligation for management of chylothorax. Non traumatic chylothorax associated with MNG is reported very rarely in the literature. This case underscores the importance of considering structural thyroid disease in the differential diagnosis of chylothorax and illustrates how definitive surgical management can lead to both metabolic, anatomical recovery and prevent sternotomy or thoracic duct ligation for management of chylothorax.

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