At a Glance
Acromegaly is a rare chronic endocrine disorder caused by the hypersecretion of growth hormone (GH) from the anterior pituitary gland in adults. A GH-secreting adenoma of the pituitary gland is the most common cause of acromegaly. Rarely, GH may be secreted by some malignancies.
Acromegaly is indolent with symptoms often preceding diagnosis by several years. Visual field defects and persistent headaches are common complaints caused by expansion of the adenoma. The tumor may also compromise normal pituitary tissue leading to deficiencies of other pituitary hormones.
Because GH stimulates the hepatic synthesis of insulin-like growth factor 1 (IGF-1), other symptoms of acromegaly are related to the excess GH and IGF-1 secretion and include:
Enlargement of the extremities
Increase in ring and/or shoe size
Coarsening of facial features
Prognathism (growth of mandible)
Acromegalics have an increased risk of developing diabetes mellitus, hypertension, cardiovascular disease, and congestive heart failure. They also show a greater incidence of premalignant colon polyps that increases the risk of colon cancer.
What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?
GH and IGF-1 testing is indicated for individuals with headaches and musculoskeletal growth. Because GH secretion is pulsatile, its concentration in acromegaly may be within the established reference interval. In contrast, serum concentrations of IGF-1 are relatively constant and are usually elevated in acromegaly. Thus, IGF-1 is the best single test for diagnosis. Acromegaly is excluded, if the GH concentration is less than 0.3 ng/mL in conjunction with a concentration of IGF-1 within the established reference interval.
GH secretion is inhibited by glucose. Individuals with active acromegaly are unable to suppress GH concentration after an oral glucose tolerance test. After administering 75 grams of glucose, samples are obtained over 120 minutes. Failure to suppress GH (<0.3 ng/mL) at 120 minutes is diagnostic of acromegaly. If GH is suppressed, then acromegaly is excluded.
Are There Any Factors That Might Affect the Lab Results? In particular, does your patient take any medications - OTC drugs or Herbals - that might affect the lab results?
Age- and gender-specific reference intervals are required for accurate interpretation of IGF-1. Starvation, obesity, and diabetes mellitus decrease and pregnancy increases concentrations of IGF-1.
Copyright © 2017, 2013 Decision Support in Medicine, LLC. All rights reserved.
No sponsor or advertiser has participated in, approved or paid for the content provided by Decision Support in Medicine LLC. The Licensed Content is the property of and copyrighted by DSM.
The Cardiology Advisor Articles
- Class 1 Device Recall: Endologix AFX Device Recalled Due to Type III Endoleaks
- Harvard: Fraudulent Data Found in Publications of Heart Researcher
- Traumatic Life Events May Increase Risk for Atrial Fibrillation in Older Women
- No Differences Between Bivalirudin, UFH Post-PCI After Ticagrelor Pretreatment
- Rivaroxaban Approved to Reduce Risk of Major Cardiovascular Events in CAD, PAD
- Coenzyme Q10 Supplementation May Reduce Statin-Induced Myopathy
- Long-Term Exposure to Elevated BP Associated With AS and AR
- Risk Factors for Atherosclerotic Cardiovascular Disease in the South Asian Population
- Takotsubo Syndrome Associated With Substantial Morbidity, Mortality
- Bariatric Surgery Reduces Macrovascular Complications in Obesity, T2D
- Metformin May Improve Vascular Health in Adolescents With Type 1 Diabetes
- Improved Cardiovascular Event Reporting Needed in Leukemia Clinical Trials
- Psoriasis Associated With Clinical Signs of Accelerated Atherosclerosis
- Can Dermatoscope Magnets Be Used With CV Implanted Electronic Devices?
- The Striking Effects of Diversity in Health Care: Improving Patient Outcomes