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Pituitary Disorders/Neuroendocrinology

(21.04) A case of heat stroke precipitating hypopituitarism

Saturday, May 11, 2024
12:30 PM – 12:45 PM CDT
Location: ePoster Showcase, Empire Ballroom Foyer, Level 2
Introduction : Hypopituitarism is an endocrine illness characterized by the total or partial lack of pituitary hormones. Main causes include pituitary tumors, apoplexy, infiltrative disease, and others. We present an uncommon case of Hypopituitarism precipitated by watershed ischemia from heat stroke. 

Case(s) Description :

A 67-year-old woman was admitted to the hospital after being found unconscious on the street with sun burns on bilateral upper and lower extremities. On arrival, she was hyperthermic and hypotensive. She was diagnosed with heat stroke. When she became more responsive, it was noted that she had right sided hemiparesis and paresthesia. A computerized tomography (CT) head Angiography showed atheromatous occlusion of the left internal carotid artery (ICA) at the origin through the supraclinoid segment, with reconstitution of flow distally via collaterals and prominent atherosclerotic calcifications in the bilateral cavernous ICAs. Magnetic Resonance Imaging (MRI) of the brain showed asymmetric hyperintense signal abnormality centered in the left-sided white matter, reflective of watershed ischemia given the vascular findings. She was outside the therapeutic window for tissue type plasminogen activator (tPA) and was not an endovascular candidate. 



During her hospitalization, she had sinus bradycardia and hyponatremia. She was euvolemic on physical examination. Hyponatremia workup demonstrated a low serum osmolality, and a high urine sodium and urine osmolality. Workup showed low thyroxine (T4) levels, an inappropriately normal Thyroid-stimulating hormone (TSH), low prolactin level, and inadequately normal levels of cortisol under stress(burns). The patient was diagnosed with hypopituitarism secondary to acute on chronic ischemia from acute hypotension in the setting of bilateral internal carotid artery atherosclerosis. 


Discussion :

About 70 to 90% of the pituitary gland is irrigated by the superior hypophyseal artery (from the Supraclinoid segment of the ICA) and the rest by the short hypophyseal vessels and the inferior hypophyseal artery (from the cavernous segment of ICA). 



In this case, the patient had atherosclerotic plaques in the cavernous and supraclinoid portions of the ICA, leaving the pituitary gland vulnerable to acute changes in blood flow. The heat stroke with consequent severe dehydration contributed to an abrupt decrease in perfusion of the pituitary gland causing ischemia and resultant hypopituitarism. 



Hyponatremia is a rare manifestation of hypothyroidism and adrenal insufficiency, caused by various mechanisms affecting kidney perfusion and impaired water excretion. It is important to recognize that ischemic stroke, especially that affecting the deeper segments of the ICA may be associated with hypopituitarism and needs prompt attention to workup and management.