Acromegaly is predominantly caused by a pituitary adenoma, which secretes an excess of GH resulting in increased IGF-I levels. Most of the GH assays used currently measure only the 22 kDa form of GH. In theory, the diagnostic sensitivity may be lower compared to the previous assays, which used polyclonal antibodies. Many GH-secreting adenomas are plurihormonal and may co-secrete prolactin, TSH and α-subunit. Hyperprolactinemia is found in 30-40% of patients with acromegaly and hyperprolactinemia may occasionally be diagnosed before acromegaly is apparent.Although trans-sphenoidal surgery of a GH-secreting adenoma remains the first treatment at most centres, the role of somatostatin analogues, octreotide LAR and lanreotide Autogel, as primary therapy is still the subject of some debate. While normalization of GH and IGF-I levels is the main objective in all patients with acromegaly, GH and IGF-I levels may be discordant, especially during somatostatin analogue therapy. This discordance usually takes the form of high GH levels and an IGF-I level towards the upper limit of the normal range.Pasireotide, a new somatostatin analogue, may be more efficacious in some patients, but the drug has not yet been registered for acromegaly. Papers published on pasireotide have reported an increased risk of diabetes mellitus due to a reduction in insulin levels.Pegvisomant, the GH receptor antagonist, is indicated - alone or in combination with a somatostatin analogue - in most patients who fail to enter remission on a somatostatin analogue. Dopamine-D2-agonists may be effective as monotherapy in a few patients, but it may prove necessary to apply combination therapy involving a somatostatin analogue and/or pegvisomant.
Journal review article
European Journal of Endocrinology, 2014, Vol 170, Issue 1
Acromegaly/blood/*diagnosis/*drug therapy/etiology Antineoplastic Agents/therapeutic use Chemotherapy, Adjuvant Dopamine Agonists/*therapeutic use Drug Therapy, Combination Growth Hormone-Secreting Pituitary Adenoma/drug therapy/genetics/physiopathology/*surgery Human Growth Hormone/analogs & derivatives/antagonists & inhibitors/blood Humans Hyperprolactinemia/etiology Insulin-Like Growth Factor I/analysis Intracellular Signaling Peptides and Proteins/genetics Mutation Somatostatin/*analogs & derivatives/therapeutic use