65 yr old man underwent tests for acromegaly because of his facial features. IGF1 was elevated 3 times upper limit of normal for age. GH failed to suppress on OGTT. MRI pituitary normal. No abnormality of the rest of the pituitary functions. This case was discussed by another physician.
The questions: are these results compatible with false positive elevation of GH as this pt has underlying type 2 diabetes and CRF with GFR 25. Can IGF1 level be falsely elevated in pts with low GFR? < firstname.lastname@example.org >
Failure of GH suppression to an OGTT is recognised in patients with severe renal impairment. However in CRF serum IGF-I levels tend to be normal or only slightly raised. The 3-fold elevation in this patient together with his clinical symptoms would point towards the diagnosis of acromegaly. A normal MRI is not uncommon although it would be prudent to have it reviewed by a specialist neuroradiologist if not already done.
A theraputic trial of somatostatin analogue might be considered both in terms of biochemical and clinical response. Paul Jenkins, MD