Key Points
Î Acromegaly is a chronic disorder caused by growth hormone (GH)
hypersecretion.
Î Over 95% of patients with acromegaly harbor a GH-secreting pituitary
adenoma arising from somatotroph cells.
Î In less than 5% of cases, excess growth hormone-releasing hormone
(GHRH) secretion from a hypothalamic tumor or a neuroendocrine tumor
(usually from lung or pancreas origin) may lead to somatotroph hyperplasia
and acromegaly.
Î More rarely, ectopic GH production by an abdominal or hematopoietic tumor
may cause acromegaly.
Î Hereditary conditions include multiple endocrine neoplasia-1 (MEN1),
Carney complex, and McCune-Albright syndrome. Germline aryl
hydrocarbon receptor interacting protein (AIP) mutations have been
described in familial acromegaly with more aggressive tumors.
Î Hypersecretion of GH leads to excess production of insulin-like growth
factor-1 (IGF-1), leading to a multisystem disease characterized by somatic
overgrowth, multiple comorbidities, premature mortality, and physical
disfigurement.
Î A multidisciplinary approach is critical for the management of acromegaly.
Diagnosis
Î The Endocrine Society (ES) recommends measurement of IGF-1 levels in
patients with typical clinical manifestations of acromegaly, especially those
with acral and facial features. (1|⊕⊕⊕
)
Î ES suggests the measurement of IGF-1 in patients without the typical
manifestations of acromegaly, but who have several of these associated
conditions: sleep apnea syndrome, type 2 diabetes mellitus, debilitating
arthritis, carpal tunnel syndrome, hyperhidrosis, and hypertension.
(2|⊕⊕
)
Î ES recommends measuring serum IGF-1 to rule out acromegaly in a patient
with a pituitary mass. (1|⊕⊕⊕
)
Î ES recommends against relying on the use of random GH levels to diagnose
acromegaly. (1|⊕⊕⊕
)
Î In patients with elevated or equivocal serum IGF-1 levels, ES recommends
confirmation of the diagnosis by finding lack of suppression of GH to
<1 mcg/L following documented hyperglycemia during an oral glucose load.
(1|⊕⊕⊕
)