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ALL / Endocrinology
Acromegaly: investigations
Acromegaly: investigations
Growth hormone (GH) levels vary during the day and are therefore not diagnostic.Serum IGF-1 levels have now overtaken the oral glucose tolerance test (OGTT) with serial GH measurements as the first-line test. The OGTT test is recommended to confirm the diagnosis if IGF-1 levels are raised.
The Endocrine Society guidelines suggest the following:
1.1 We recommend measurement of IGF-1 levels in patients with typical clinical manifestations of acromegaly, especially those with acral and facial features.
...
1.5 In patients with elevated or equivocal serum IGF-1 levels, we recommend confirmation of the diagnosis by finding lack of suppression of GH to < 1 µg/L following documented hyperglycemia during an oral glucose load.
Serum IGF-1 may also be used to monitor disease
Oral glucose tolerance test
- in normal patients GH is suppressed to < 2 mu/L with hyperglycaemia
- in acromegaly there is no suppression of GH
- may also demonstrate impaired glucose tolerance which is associated with acromegaly
A pituitary MRI may demonstrate a pituitary tumour.
+PassMedicine Notes
Growth hormone (GH) levels vary during the day and are therefore not diagnostic.
Serum IGF-1 levels have now overtaken the oral glucose tolerance test (OGTT) with serial GH measurements as the first-line test. The OGTT test is recommended to confirm the diagnosis if IGF-1 levels are raised.
The Endocrine Society guidelines suggest the following:
1.1 We recommend measurement of IGF-1 levels in patients with typical clinical manifestations of acromegaly, especially those with acral and facial features. ... 1.5 In patients with elevated or equivocal serum IGF-1 levels, we recommend confirmation of the diagnosis by finding lack of suppression of GH to < 1 µg/L following documented hyperglycemia during an oral glucose load.Serum IGF-1 may also be used to monitor disease
Oral glucose tolerance test- in normal patients GH is suppressed to < 2 mu/L with hyperglycaemia
- in acromegaly there is no suppression of GH
- may also demonstrate impaired glucose tolerance which is associated with acromegaly
A pituitary MRI may demonstrate a pituitary tumour.
