Abstract Disclosure: D. Moreno Watashi: None. H.R. Alkaissi: None. M.B. Sharma: None. Introduction: Pituitary apoplexy (PA) results from sudden hemorrhaging and infarction of the pituitary gland, typically within a pituitary adenoma. The primary symptom is a sudden, severe headache, often followed by acute endocrine dysfunction, ophthalmoplegia and visual or neurological disturbances. Case Description: A 68-year-old male with a past medical history of hypertension presented to the emergency department with acute chest and upper back pain, beginning one day prior. No history of smoking, alcohol intake or drug use. Blood pressure (BP) on arrival was 180/95 mmHg. Initial labs revealed mild electrolyte abnormalities. Troponins were normal, but ECG showed diffuse T wave inversion and ST depression. CT angiography revealed a type B aortic dissection. He was managed in the critical care unit with continuous esmolol intravenous (IV) infusion and planned for endovascular repair. During his stay, he became disoriented and hypotensive. MRI from the brain incidentally discovered a pituitary macroadenoma measuring 2.9x2.2x3cm and recent infarcts, with a distribution concerning for hypoperfusion. Fundoscopy concerning for optic chiasm compression. Labs indicated secondary hypothyroidism and hypogonadism (TSH 0.3 uUI/ml, free T4 0.88 ng/dL, total testosterone 56.3 ng/dL). Neurosurgical intervention was deferred until after aortic repair. Endovascular aortic repair was performed with episodes of hypotension. Post-procedure, the patient developed fever (39.5°C) and worsening mental status. Head CT revealed an increased suprasellar extension of the pituitary macroadenoma and vasogenic edema, consistent with hemorrhage of the lesion. He was started on stress doses of hydrocortisone, levothyroxine 125mcg and managed conservatively due to a high surgical risk. Discussion: PA's extrinsic risk factors include angiographic procedures, endocrinological dynamic tests, anticoagulation therapy, exogenous estrogen administration, orthopedic and cardiac surgeries (due to BP fluctuations). The intrinsic risk factors are non-functioning adenomas, macroadenomas and suprasellar extension. Treatment is focused on immediate correction of endocrine derangements and relieving local compression. Stress dosage of corticosteroids should be administered IV as soon as the diagnosis is confirmed to prevent life-threatening corticotropic deficiency. Neurosurgical decompression via a transsphenoidal approach is the definitive therapy to relieve local compression with severe visual loss, obtundation or rapidly progressive course. The potential outcomes are based on the extent of hemorrhage, necrosis, and edema. PA should be treated as a medical emergency in the setting of hemodynamic changes from acute corticotropic deficiency and irreversible neurological damage from acute intracranial compression. The risk factors for PA should be known to assist in early diagnosis. Presentation: 6/1/2024