Acromegaly presenting with low insulin-like growth factor-1 levels and diabetes: a case report

Abstract

IntroductionAcromegaly is an endocrine disorder arising from excessive serum growth hormone levels in adulthood and is characterized by progressive somatic enlargement. Biochemical confirmation is achieved by demonstration of elevated baseline serum growth hormone levels which are not suppressed during an oral glucose tolerance test, and by increased levels of serum insulin-like growth factor-1. The serum insulin-like growth factor-1 level provides an assessment of integrated growth hormone secretion and is recommended for diagnosis, monitoring, and screening of acromegaly. We report a case of a patient with acromegaly secondary to a pituitary microadenoma who presented with low insulin-like growth factor-1.Case presentationAn 83-year-old Sinhalese woman presented to our hospital with an enlarging multinodular goiter. She was observed to have macroglossia, thickened coarse skin, acral enlargement, and newly detected, uncontrolled diabetes. A diagnosis of acromegaly was suspected. She did not complain of recent headaches, vomiting, visual difficulties, or galactorrhea and was clinically euthyroid. Her pulse rate was 84 beats/min, and her blood pressure was 150/90 mmHg. A visual field assessment did not reveal a defect. Her random growth hormone levels were 149 mU/L (<10 mU/L), and her oral glucose tolerance test was supportive of acromegaly with a paradoxical rise of growth hormone. Her serum age-specific insulin-like growth factor-1 level was below normal at 124.7 ng/ml (normal range 150–350 ng/ml). Her serum insulin-like growth factor-1 level, measured after glycemic control was achieved with metformin and insulin, was elevated, which is characteristic of acromegaly. Magnetic resonance imaging of her pituitary revealed a pituitary microadenoma. Acromegaly secondary to a growth hormone–secreting pituitary microadenoma was confirmed.ConclusionsSystemic illnesses, including catabolic states, hepatic or renal failure, malnutrition, and diabetes mellitus, are known to decrease insulin-like growth factor-1 levels and may result in false-negative values in patients with acromegaly A low insulin-like growth factor-1 level does not exclude acromegaly in a patient with supportive clinical features and poorly controlled diabetes.

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.…”

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.…”

Early Predictors of Remission in Acromegaly Patients after Pure Endoscopic Endonasal Transsphenoidal Surgery

“…On the basis of this physiopathology, two case studies report challenges in diagnosing acromegaly due to poor glycemic control resulting in low or normal IGF-1 levels. 56 57 Similarly to “wild-type” type 2 DM, IGF-1 levels also increase after insulin treatment in secondary DM. 58 On the other hand, ACROSTUDY data show that diabetic patients need higher doses of pegvisomant (PEGV) to regulate IGF-1 levels.…”

“…As a result of that, serum GH levels increase while IGF-1 concentrations stay within normal or low levels. On the basis of this physiopathology, two case studies report challenges in diagnosing acromegaly due to poor glycemic control resulting in low or normal IGF-1 levels 56,57 . Similarly to 'wild-type' type 2 DM, IGF-1 levels also increase after insulin treatment in secondary DM 58 .…”

Secondary diabetes mellitus in acromegaly: Case report and literature review

“…However, reports of blood glucose normalization postsurgery are comparatively infrequent. [8][9][10][11][12][13] The primary pathophysiological processes through which acromegaly contributes to diabetes mellitus involve heightened lipolysis and modified fat distribution, leading to increased insulin resistance. [9] The pivotal factor is the mutual antagonism in insulin action by GH and IGF-1: GH promotes insulin resistance, while IGF-1 increases insulin sensitivity.…”

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.…”

Early Predictors of Remission in Acromegaly Patients after Pure Endoscopic Endonasal Transsphenoidal Surgery

“…On the basis of this physiopathology, two case studies report challenges in diagnosing acromegaly due to poor glycemic control resulting in low or normal IGF-1 levels. 56 57 Similarly to “wild-type” type 2 DM, IGF-1 levels also increase after insulin treatment in secondary DM. 58 On the other hand, ACROSTUDY data show that diabetic patients need higher doses of pegvisomant (PEGV) to regulate IGF-1 levels.…”

“…As a result of that, serum GH levels increase while IGF-1 concentrations stay within normal or low levels. On the basis of this physiopathology, two case studies report challenges in diagnosing acromegaly due to poor glycemic control resulting in low or normal IGF-1 levels 56,57 . Similarly to 'wild-type' type 2 DM, IGF-1 levels also increase after insulin treatment in secondary DM 58 .…”

Secondary diabetes mellitus in acromegaly: Case report and literature review

“…However, reports of blood glucose normalization postsurgery are comparatively infrequent. [8][9][10][11][12][13] The primary pathophysiological processes through which acromegaly contributes to diabetes mellitus involve heightened lipolysis and modified fat distribution, leading to increased insulin resistance. [9] The pivotal factor is the mutual antagonism in insulin action by GH and IGF-1: GH promotes insulin resistance, while IGF-1 increases insulin sensitivity.…”

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.…”

Early Predictors of Remission in Acromegaly Patients after Pure Endoscopic Endonasal Transsphenoidal Surgery

“…On the basis of this physiopathology, two case studies report challenges in diagnosing acromegaly due to poor glycemic control resulting in low or normal IGF-1 levels. 56 57 Similarly to “wild-type” type 2 DM, IGF-1 levels also increase after insulin treatment in secondary DM. 58 On the other hand, ACROSTUDY data show that diabetic patients need higher doses of pegvisomant (PEGV) to regulate IGF-1 levels.…”

“…As a result of that, serum GH levels increase while IGF-1 concentrations stay within normal or low levels. On the basis of this physiopathology, two case studies report challenges in diagnosing acromegaly due to poor glycemic control resulting in low or normal IGF-1 levels 56,57 . Similarly to 'wild-type' type 2 DM, IGF-1 levels also increase after insulin treatment in secondary DM 58 .…”

Secondary diabetes mellitus in acromegaly: Case report and literature review

“…However, reports of blood glucose normalization postsurgery are comparatively infrequent. [8][9][10][11][12][13] The primary pathophysiological processes through which acromegaly contributes to diabetes mellitus involve heightened lipolysis and modified fat distribution, leading to increased insulin resistance. [9] The pivotal factor is the mutual antagonism in insulin action by GH and IGF-1: GH promotes insulin resistance, while IGF-1 increases insulin sensitivity.…”