Abstract
Introduction: Isolated adrenocorticotropic hormone (ACTH) deficiency is a rare pituitary hormone deficiency defined by secondary adrenal insufficiency and normal secretion of all other pituitary hormones. Patients present with fatigue, weakness, weight loss, anorexia, nausea, low cortisol levels and low ACTH levels. Isolated ACTH deficiency is more common in males and usually presents in the fifth decade of life. Main mechanisms involved in the pathogenesis are genetics and autoimmune causes, traumatic brain injury and infarction of the pituitary postpartum, known as Sheehan’s syndrome. Sheehan’s syndrome is characterized by postpartum hemorrhage, failure to lactate and menstrual irregularities and it can occur from immediate postpartum period to years after delivery. The most common hormone deficiencies are prolactin and growth hormone. Empty sella is the most common finding on brain MRI. We are reporting a case of a woman in her third decade with isolated ACTH deficiency due to Sheehan’s syndrome two years postpartum, able to lactate, with normal menses and normal brain MRI. Clinical Case: A 33-year-old woman G3P3A0 with hypothyroidism who was referred to Endocrinology clinics due to tiredness, fatigue and weakness. She reported postpartum hemorrhage requiring 4 PRBC transfusions and IV steroids after last pregnancy 5 years ago. Patient was able to lactate after pregnancy and continued in her usual state of health until 3 years ago when she referred loss of consciousness with traumatic head injury due to hypoglycemia. At Endocrinology office physical examination and vital signs were unremarkable, including no blood pressure or heart rate variations with positional changes. Despite hypothyroidism being adequately controlled, she continued with extreme fatigue and weakness affecting her quality of life, for which cortisol and ACTH levels were ordered. Laboratories showed normal electrolytes, negative autoantibodies, cortisol 0.20 μg/dL (5-25 μg/dL) and ACTH 22 pg/mL (10-60 pg/mL) suggesting partial isolated ACTH deficiency. ACTH stimulation test was done and noted with suboptimal response. Evaluation of other anterior pituitary hormones was normal. Brain MRI showed normal pituitary gland. She was started on hydrocortisone in AM and PM and symptoms resolved. Conclusion: Immediate recognition of isolated ACTH deficiency due to Sheehan’s syndrome is necessary due to the availability of effective treatment and morbidity and mortality associated with this serious condition. To our knowledge isolated ACTH deficiency due to Sheehan’s syndrome in which the patient was able to lactate and normal findings on brain MRI has not previously been reported.References: Shivaprasad C. Sheehan’s Syndrome: Newer advances. Indian J Endocrinol Metab. 2011 Sep; 15(3): S203-207. DOI:10.4103/2230-8210.84869.