Bilateral phrenic nerve palsy associated with benign thyroid goiter.

Phrenic nerve palsy secondary to benign thyroid enlargement is a previously unreported complication. Large goiters, particularly substernal, may impinge upon adjacent structures, often leading to significant symptoms such as dysphagia or dyspnea due to airway compression. The phrenic nerve may be stretched by a large goiter along its course in the neck, but the more likely site of injury is the point at which it enters the thoracic cavity adjacent to the first rib. Such an injury, caused by compression, may go unrecognized if unilateral, as symptoms would be uncommon. However, bilateral phrenic nerve palsy can cause significant dyspnea due to pulmonary insufficiency, particularly in an elderly patient with cardio-pulmonary disease. Early operative treatment of the goiter may prevent this complication or limit its severity, thus avoiding permanent nerve injury.