Acromegaly - Diagnosis
The diagnosis of Acromegaly is confirmed by Growth Hormone Suppression Test. Other tests like Insulin-like Growth Factor-1 levels, X-rays, MRI and CT scan can also be used to detect acromegaly.
The diagnosis of the disease is often delayed due to the slow onset of many of the signs and symptoms. Diagnosis can be established using the following:
The disease can be diagnosed by comparing serial photos taken over the years to observe physical changes in the patient.
- Growth Hormone (GH) and Insulin-like Growth Factor-1 (IGF-I) measurement in blood: In this test, the patient fasts overnight and gives a blood sample the next day morning to measure the levels of GH and IGF-I. In case of acromegaly, the levels are elevated.
- Growth Hormone Suppression Test: This is a confirmatory method for verifying acromegaly. The blood levels of GH are measured before and after a drinking 75 gms of glucose (sugar). In normal people there is suppression of growth hormone. GH levels are suppressed below 1 µg/L. Inability to sufficiently suppress serum growth hormone levels after glucose ingestion confirms acromegaly.
Remember in a pregnant woman, IGF-1 levels are two to three times higher than normal. Similarly, IGF-1 levels decline in aging people. It also may be abnormally low in patients with poorly-controlled diabetes mellitus.
- X-rays are taken to detect bone thickening.
- An MRI scan of the brain, which delineates the pituitary and the hypothalamus and helps in locating the tumor can be done.
- Computerized tomography (CT) scans can also be done to detect tumors. Presence of non-pituitary tumors in the chest, abdomen, or pelvis can be detected by measuring GHRH in the blood and by a CT scan of possible tumor sites.