Does a Male Sheehan’s Like Syndrome Exist?

Introduction:
Panhypopituitarism is defined as a condition in which secretion of most or all hormones from the pituitary gland is inadequate or absent. Deficiency of pituitary hormones such as Adrenocorticotropic Hormone (ACTH) and Thyroid Stimulating Hormone (TSH) impairs the ability of the adrenal glands and thyroid gland to secrete hormones that are vital for survival. Hypopituitarism is a rare condition, and its incidence is approximately 4.2 per 100,000 per year. Sheehan syndrome is a form of pituitary necrosis secondary to infarction in setting of severe postpartum hemorrhage. Hemorrhagic pituitary apoplexy of pre-existing pituitary adenomas in setting of hypotension has been reported. We describe a unique case of hypopituitarism in a man without known pituitary adenoma after liver transplantation.

Case Description:
A 48-year-old male underwent liver transplantation for cirrhosis. A few years after the transplant the patient developed dizziness, lightheadedness, polyuria, polydipsia, decreased libido, loss of muscle mass and fatigue. Post transplant he was on maintenance dose of Prednisone which was discontinued several years after the surgery. Testosterone replacement therapy with testosterone gel for fatigue was initiated by primary care provider, and he was referred to endocrinology for further evaluation. Hormonal profile revealed TSH 0.724 mcIU/mL (0.450-4.500), free T4 1.13 ng/dL (0.82-1.77), AM cortisol 5.2 mcg/dL (6.2-19.4), ACTH stimulated cortisol 11.4 mcg/dL after 30 min, 14.8 mcg/dL after 90 min, morning total testosterone 104.8 ng/dL (264-916), free testosterone 4.1 pg/mL (6.8-21.5), prolactin 2.1 ng/mL (4.0-15.2), LH 1.2 mIU/mL (1.7-8.6), IGF-1 26 ng/mL (75-216), FSH 1.6 mIU/mL (1.5-12.4), ACTH 19.6 pg/mL (7.2-63.3). Sodium was 143 mmol/L with urine osmolality 1135 mOsm/kg after overnight water deprivation so DI was successfully ruled out. An MRI of the brain demonstrated a very small pituitary gland within a small pituitary fossa. This was a significant change compared to the MRI performed soon after transplantation - it was unremarkable with normal sella and parasellar structures. The findings of empty sella on MRI and blood work consistent with hypogonadism, central adrenal insufficiency, hypoprolactinemia and growth hormone deficiency indicated a diagnosis of panhypopituitarism. Since ACTH stimulation test demonstrated partial adrenal insufficiency Hydrocortisone 20 mg daily was initiated. Patient was switched from gel to injectable testosterone with significant improvement in testosterone concentration. During a follow up visit patient reported feeling better but still endorsed fatigue and tiredness. Trial of growth hormone therapy resulted in resolution of his symptoms and improved wellbeing.

Discussion:
This case describes a unique presentation of hypopituitarism after major surgery in a patient with intact pituitary gland possibly secondary to hypotension during surgery and the pathophysiology may be analogous to Sheehan syndrome. Early diagnosis of hypopituitarism is crucial as deficiency in ACTH and TSH can cause adrenal insufficiency and hypothyroidism, respectively, which could be life-threatening.