Acromegaly with Normal Insulin-Like Growth Factor-1 Levels and Congestive Heart Failure as the First Clinical Manifestation

Abstract

The leading cause of morbidity and mortality in patients with acromegaly is cardiovascular complications. Myocardial exposure to excessive growth hormone can cause ventricular hypertrophy, hypertension, arrhythmia, and diastolic dysfunction. However, congestive heart failure as a result of systolic dysfunction is observed only rarely in patients with acromegaly. Most cases of acromegaly exhibit high levels of serum insulin-like growth factor-1 (IGF-1). Acromegaly with normal IGF-1 levels is rare and difficult to diagnose. Here, we report a rare case of an acromegalic patient whose first clinical manifestation was severe congestive heart failure, despite normal IGF-1 levels. We diagnosed acromegaly using a glucose-loading growth hormone suppression test. Cardiac function and myocardial hypertrophy improved 6 months after transsphenoidal resection of a pituitary adenoma.

Impact of Glucose Metabolism Disorders on IGF-1 Levels in Patients with Acromegaly

“…In this study, normal IGF-1 level was not observed in any of the patients. This may be due to majority of the patients in our study presented with macroadenoma on the contrary to the case reports in the literature [17][18][19][20].…”

“…However, to the best of our knowledge this is the first comparative study investigating impact of hepatic insulin resistance on IGF-1 levels in patients with acromegaly. Only low or normal IGF-1 levels are reported in patients with acromegaly with unregulated type 2 DM as case reports [17][18][19][20]. Increase in IGF-1 levels are reported with the improvement of glycemic regulation in these patients.…”

“…reports. Improvement of glucose metabolism leads to increase in IGF-1 levels in all and decrease in GH levels in some of these patients [17][18][19][20][21][22][23]. Therefore, GH and IGF-1 levels may not reflect actual levels in patients with acromegaly accompanying DM or prediabetes.…”

Hypopituitarism after gamma knife radiosurgery for pituitary adenoma

“…A number of factors have been evaluated in order to assess the risk of hypopituitarism after GKRS. The studies published so far showed that the prescription dose of radiation and the tumor volume size are major risk factors for new pituitary hormone insufficiency [25,26]. It was shown that the 5-year risk of developing new pituitary deficits was higher for tumors with a volume higher than 4 cm 3 (58% vs 18%) [16].…”

“…Median patients' age was 56 years . GKRS was performed using the Leksell gamma knife Model C. The median prescription radiation dose was 20 Gy (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) and the median tumor volume size was 3.4 cm 3 (0.06-16.81). New onset hypopituitarism was defined as a new deficit of one of the three hormonal axes (corticotroph, thyreotroph or gonadotroph) ≥3 months following GKRS.…”