MON-071 - Pituitary Apoplexy Presenting with Severe Hyponatremia and Absence of Neuro-Ophthalmologic Deficits

Background: 
Pituitary apoplexy classically presents with sudden headache, visual field deficits, ophthalmoplegia, and varying degrees of acute hypopituitarism. In some cases, pituitary hemorrhage may present predominantly with endocrine dysfunction in the absence of neuro-ophthalmologic findings, creating diagnostic and management challenges.

Clinical

Case: 
A 32-year-old woman presented to an outside hospital emergency department with two days of nausea, emesis, and mild headache. Patient had a known 1.6 cm pituitary adenoma with mass effect on right optic nerve and cavernous sinus invasion, discovered during workup for fatigue and amenorrhea. She started cabergoline 0.25 mg twice a week about 3 months prior, with initial prolactin level 226 ng/mL.

On admission, serum sodium was 112 mmol/L without seizures, altered mentation, or visual changes. Brain MRI demonstrated acute hemorrhage within the known macroadenoma, concerning for pituitary apoplexy. She received hypertonic saline and was transferred to our institution. Other outside labs were not immediately available. On arrival she was alert and oriented, hemodynamically stable, and without significant neurologic deficits. Endocrinology initiated stress-dose hydrocortisone. Labs showed TSH 1.15 mIU/L, Free T4 0.85 ng/dl, FSH 3.6 mIU/ml, LH 2.4 miU/ml, Prolactin 11.0 ng/mL, cortisol 25 ug/dl (drawn after hydrocortisone was administered). Hypertonic saline was stopped and patient was evaluated by neurosurgery and ophthalmology. No gross visual field deficits were noted. No surgical intervention was recommended. Sodium level improved over time and patient was discharged with maintenance dose hydrocortisone and outpatient follow up. Upon later review of outside hospital labs, initial ACTH was < 1.5 pg/ml.

Discussion:
Although pituitary apoplexy classically presents with severe "thunderclap" headache, visual impairment, and cranial nerve symptoms, the clinical presentation may vary depending on the size of hemorrhage and compression on surrounding structures. In this otherwise young and healthy female patient, steroids were delayed at the outside hospital because she was well-appearing with only mild symptoms. However, the patient clearly had adrenal insufficiency, as indicated by the low ACTH level and severe hyponatremia. The patient's symptoms and sodium level improved after stress dose steroids.

Conclusion:
Clinicians should be aware that pituitary apoplexy can have a variable clinical presentation. Recognizing deficiencies of pituitary hormones is essential to facilitate timely glucocorticoid therapy.

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