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For further information, see CMDT Part 26-03: Acromegaly & Gigantism
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Essentials of Diagnosis
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Pituitary neuroendocrine tumor
Acromegaly: excessive growth of hands, feet, jaw, and internal organs
Gigantism if growth hormone (GH) excess before closure of epiphyses; acromegaly if after closure
Amenorrhea, hypertension, headaches, visual field loss, weakness
Soft, doughy, sweaty handshake
Elevated serum insulin-like growth factor 1 (IGF-1)
Serum GH not suppressed following oral glucose
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General Considerations
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GH exerts much of its effects by stimulating release of IGF-1
Nearly always caused by pituitary adenoma, usually macroadenomas (> 1 cm); may be locally invasive but < 1% are malignant
GH-secreting pituitary tumors usually cause hypogonadism by cosecretion of prolactin or direct pressure on pituitary
Usually sporadic, rarely familial with < 3% being due to multiple endocrine neoplasia (MEN) types 1 or 4
Rarely, acromegaly may be seen in McCune-Albright syndrome and Carney complex
Occasionally caused by ectopic secretion of GH-releasing hormone or GH secreted by lymphoma, hypothalamic tumor, bronchial carcinoid, or pancreatic tumor
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Tall stature
Head and neck
Facial features coarsen
Hat size increases, tooth spacing widens
Mandible becomes more prominent
Macroglossia and hypertrophy of pharyngeal and laryngeal tissue
Goiter may be noted
Hands
Feet grow, particularly as change in shoe width
Hypertension (50%) and cardiomegaly
Weight gain
Arthralgias, degenerative arthritis, and spinal stenosis may occur
Colon polyps common
Skin
Hyperhidrosis
Thickening
Cystic acne
Skin tags
Acanthosis nigricans
Symptoms of hypopituitarism
Hypogonadism: decreased libido, erectile dysfunction, irregular menses or amenorrhea common
Women who become pregnant have an increased risk of gestational diabetes mellitus and hypertension
Secondary hypothyroidism sometimes occurs, hypoadrenalism is unusual
Headaches and temporal hemianopia
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Differential Diagnosis
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Familial tall stature, coarse features, or large hands and feet
Physiologic growth spurt
Pseudoacromegaly (acromegaly features, insulin resistance)
Inactive ("burned-out") acromegaly (spontaneous remission due to pituitary adenoma infarction)
Myxedema
Isolated prognathism (jaw protrusion)
Aromatase deficiency or estrogen receptor deficiency causing tall stature
Other causes of increased GH level
Exercise or eating prior to test
Acute illness or agitation
Liver failure or kidney disease
Malnourishment
Diabetes mellitus
Drugs (estrogens, β-blockers, clonidine)
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