Diagnosis and management of acromegaly

Table 4: Monitoring of therapy for acromegaly

Assessment of disease activity

Serum IGF-I measurement (random blood specimen; significantly elevated level for age and sex indicates residual growth-hormone excess)

Oral glucose tolerance test for growth-hormone suppression (75 g glucose; growth hormone is suppressed to less than 2 µg/L throughout a 2-h test in normal subjects)

Further tests to assess the effects of a growth-hormone-producing tumour

Serum prolactin measurement

TRH or GnRH stimulation test to assess paradoxical growth-hormone response

Thyroid function tests (serum thyrotropin, FT4 or FT4 index test), and possibly TRH stimulation test

In men, serum total and free testosterone, FSH and LH levels

In postmenopausal women, serum FSH and LH levels

In premenopausal women with secondary amenorrhea, serum 17 ß-estradiol or progestational challenge

Assessment of the integrity of the hypothalamic-pituitary-adrenal axis (insulin tolerance, metyrapone or cortrosyn stimulation test)

Ancillary tests in patients with symptoms or signs of residual marked effect of pituitary mass

MRI or CT of the pituitary fossa

Assessment of visual field by perimetry to assess effect of tumour on the optic apparatus

Tests to assess effects of growth-hormone excess on other tissues

Full colonoscopy

Periodic stool screening for occult blood

Echocardiographic examination to assess left ventricular hypertrophy

Nerve conduction velocity study if entrapment symptoms warrant

Sleep apnea studies if excessive fatigue and daytime somnolence persist