SUN-423 Nonhemorrhagic Pituitary Apoplexy Following CABG Surgery

Abstract

Introduction: Pituitary apoplexy (PA) is a rare syndrome resulting from acute infarction, hemorrhage, or edema of the pituitary gland. Due to a wide variety of nonspecific symptoms and number of precipitating triggers, diagnosis can be challenging. Thus, a high level of suspicion must be maintained. Cardiac surgery with the utilization of cardiopulmonary bypass is a unique cause of PA that has an interesting pathophysiologic mechanism as an inciting factor. Knowledge of this is important as PA is a life-threatening condition with significant morbidity and mortality, especially in the perioperative period. Case: A 68-year-old male with a history of coronary artery disease status post recent coronary artery bypass graft presented on post-operative day 2 with acute blurry vision and visual field defects and remarkably no headache. MRI Brain revealed a heterogeneous intra- and suprasellar mass measuring 2.4 x 2.7 x 2.5 cm and expansion of the sella turcica with impingement of the optic chiasm, concerning for non-hemorrhagic PA in a previously undiagnosed pituitary macroadenoma. Laboratory workup was consistent with panhypopituitarism (except for central DI) for which he was immediately started on hormone replacement therapy with hydrocortisone and levothyroxine. Due to contraindication for surgery, fractionated intensity modulated radiation therapy was initiated delivering a total of 5400cGy of radiation in 30 fractions over 6 weeks. Serial post-radiation MRIs demonstrated dramatic decrease in pituitary macroadenoma size to 1.6 x 0.5 x 1.4 cm with complete resolution of sellar expansion, optic chiasm compression and his visual symptoms. Discussion: PA is a life-threatening syndrome that typically occurs in the setting of a pre-existing pituitary adenoma. Clinical diagnosis is made based upon sudden onset of symptoms within the syndrome of panhypopituitarism. Uniquely, cardiac surgery has been postulated as a cause of PA due to acute tumor expansion from cardiopulmonary bypass dynamics, which allow for infarction as a result of hemodilution, hypotension, and/or microembolism. PA is a clinical diagnosis which requires radiological confirmation with MRI with a sensitivity of 89-94%. Cases without signs of pituitary hemorrhage have a less severe clinical presentation and a better outcome. PA must be managed urgently by hormonal replacement. Definitive treatment is with surgical decompression and transphenoidal resection or radiotherapy. Radiotherapy is an option for refractory disease or non-surgical candidates showing excellent rates of local tumor control for non-functioning adenomas in particular. Due to its associated morbidity and mortality, it is important for clinicians to recognize PA as a rare perioperative complication of CABG that requires a high level of clinical suspicion to allow for prompt radiographic workup and treatment to ensure quality patient care.