Endocrine Abstracts

Introduction: Elevated levels of growth hormone (GH) and insulin-like growth factor-1 (IGF-1) are a recognised cause of dilated cardiomyopathy in patients with acromegaly. Presentation with acute heart failure suggests late-stage disease with left ventricular (LV) systolic dysfunction being a rare consequence of the underlying acromegaly.

Case Report: A 45-year-old man presented to the emergency department with dyspnoea and was found to have acute decompensated heart failure with no prior background of cardiac disease. Echocardiogram showed LV systolic dysfunction with an ejection fraction of 27%. After cardiology review, he was commenced on heart failure medication. Cardiac MRI showed non-ischaemic dilated cardiomyopathy, significant LV dilatation, severe LV systolic impairment and mid-wall/subepicardial fibrosis. From facial features, a diagnosis of acromegaly was suspected and he was referred to endocrinology. Examination revealed acromegalic facies, with diastema, prominent nasolabial folds and prognathism. Investigations showed IGF-1 of 640 μg/L (74-227) and lack of GH suppression during oral glucose tolerance testing with a nadir value of 1.4 μg/L (<0.3). Pituitary MRI showed a 6 mm hypo-enhancing lesion in the left lateral aspect of the pituitary gland in keeping with a microadenoma. Considering his heart failure, he was started on lanreotide 60 mg monthly prior to surgery with improvement of IGF-1 levels to 273 μg/L eight weeks after treatment initiation and he reported marked improvement in exercise tolerance. He is being assessed by the neurosurgical team for transsphenoidal resection surgery.

Discussion: Despite the cardiac manifestations of acromegaly usually indicating a late diagnosis, cardiac improvement can be achieved with normalisation of IGF-1. Successful treatment with somatostatin analogues can reduce circulating levels of GH and IGF-1 and result in the reversal of cardiac fibrosis. Even greater cardiac recovery is seen with definitive transsphenoidal surgery. Ultimately, the early diagnosis and treatment of acromegaly is key to improving cardiac outcomes.