Diagnosis of a Rare Case of Acromegaly Secondary to Pituitary Macroadenoma Debuting as Sudden DKA

Abstract

Acromegaly is an uncommon clinical syndrome that results from excessive secretion of growth hormone with an annual incidence of 6 to 8 cases per 1 million of individuals with a mean age of diagnosis between 40-45 years. Pituitary adenomas can be the principal reason for an overgrowth of the anterior pituitary somatotroph cells, and account for approximately one-third of all hormone-secreting pituitary adenomas with a prevalence of about 38-69 cases per 1 million and an incidence of 3-4 cases per 1 million individuals. The onset of acromegaly is insidious, and its progression is usually very slow. At the moment of diagnosis, approximately 75% of patients have presence of macro adenomas, but most cases are diagnosed after several laboratory workups and incidental brain imaging. A characteristic clinical presentation of pituitary adenomas could be secondary to mass effect. Metabolic presentation such as diabetes is one of the most common related conditions preceding the diagnosis of acromegaly. Clinical presentation with abrupt onset of DKA could be a determining factor on disease progression due to higher GH levels correlating with an increased prevalence of insulin resistance. We present a rare case of a 28y/o female G5P3A2 without previous PMHx who presented to ER with abdominal pain, general malaise, slurred speech, headache and gait difficulty of 3 days of evolution. Upon initial evaluation at ER patient was found with hyperglycemia of 317mg/dL, low central bicarbonate, high anion gap and positive serum ketones suggestive of DKA de novo. Based on neurological complaints, head CT performed showed an incidental parasellar/suprasellar/temporal hyperdense mass measuring 2.5cm x 2.6cm with optic chiasm compression features. Upon further specific questioning patient referred amenorrhea for the past 3 years, bitemporal hemianopsia, galactorrhea and marked facial feature changes, frontal bossing, weight gain, and acanthosis nigricans, for the past year. Pituitary adenoma workup revealed low prolactin levels (1.38), markedly increased growth hormone (501) and IGF-1 (893) suggesting diagnosis of acromegaly, most likely secondary to a functioning macroadenoma. Patient initially treated with Cabergoline, uncontrolled diabetes was managed and was referred to Neurosurgery service for further evaluation and tumor removal. Based on current literature, the incidence of acromegaly cases is low, more specifically when presenting with new onset diabetic ketoacidosis, insulin resistance and secondary to functioning macroadenomas. Medical awareness should be promoted to assess for careful consideration of signs and symptoms, workup, management and treatment to assess and minimize further health complications and physical burdens acromegaly and pituitary adenomas could pose for affected individuals.