Diagnosis of acromegaly
- Shlomo Melmed, MD
Shlomo Melmed, MD
- Senior Vice President and Dean
- Cedars Sinai Medical Center
- Professor of Medicine
- University of California at Los Angeles School of Medicine
Acromegaly results from persistent hypersecretion of growth hormone (GH). Excess GH stimulates hepatic secretion of insulin-like growth factor 1 (IGF-1), which causes most of the clinical manifestations of acromegaly.
The clinical diagnosis is often delayed because of the slow progression of the signs of acromegaly over a period of many years. GH excess that occurs before fusion of the epiphyseal growth plates in a child or adolescent is called pituitary gigantism and is discussed separately.
The diagnostic approach to acromegaly will be reviewed here. GH excess in children and adolescents and the causes, clinical manifestations, and treatment of acromegaly are discussed separately. (See "Pituitary gigantism" and "Causes and clinical manifestations of acromegaly" and "Treatment of acromegaly".)
Acromegaly has been considered to be a rare disease, with an estimated prevalence in Europe of 30 to 70 individuals per million [1,2]. However, current estimates are considerably higher [2-4]. In one report, seven new cases of acromegaly were identified among 6773 unselected adults in a primary care population who underwent plasma insulin-like growth factor 1 (IGF-1) screening; this suggests a population prevalence as high as 1000 per million individuals . A similar uncontrolled IGF-1 screening study in over 2000 individuals with type 2 diabetes found a prevalence of approximately 480 per million individuals .
WHEN TO SUSPECT ACROMEGALY
The diagnosis of acromegaly should be suspected in individuals who present with the typical clinical features of growth hormone (GH) excess, which include the enlargement during adulthood of the jaw (macrognathia), hands, and feet, which result in increasing shoe and glove size and the need to enlarge finger rings. The facial features become coarse, with enlargement of the nose and frontal bones as well as the jaw, and the upper incisors may become spread apart. Despite the prominence of these findings at the time of diagnosis, the rate of change is so slow that few patients seek care because their appearance had changed. Other features include cardiovascular disease, sleep apnea, type 2 diabetes, arthropathies, carpal tunnel syndrome, and problems directly related to the pituitary tumor size (headache, visual loss).
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- Carmichael JD, Bonert VS, Mirocha JM, Melmed S. The utility of oral glucose tolerance testing for diagnosis and assessment of treatment outcomes in 166 patients with acromegaly. J Clin Endocrinol Metab 2009; 94:523.
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- WHEN TO SUSPECT ACROMEGALY
- Trends in timing of diagnosis
- DIAGNOSTIC EVALUATION
- Biochemical testing
- - Serum IGF-1 concentration
- - Oral glucose tolerance test
- - Limitations of random serum GH measurements
- - Other dynamic tests
- - Serum IGFBP-3 concentration
- Determining the source of excess GH
- - Pituitary MRI
- - Other studies
- INFORMATION FOR PATIENTS
- SUMMARY AND RECOMMENDATIONS