Glossary

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G

• Gadolinium: a contrast agent given intravenously; often used when performing an MRI to help localize tumors; it is quite safe and does not contain iodine unlike the iodinated contrast agent used for CT scans (computed tomography.
• Galactorrhea: a milky breast discharge occurring at anytime other than during normal breast feeding. Galactorrhea is most often seen in women with hyperprolactinemia (high blood levels of prolactin), especially in those with prolactinoma or other pituitary-related tumors. Galactorrhea often occurs in association with amenorrhea (absence of menstrual periods) because of the effect of high prolactin on LH and FSH release from the pituitary gland. Rarely men may also experience galactorrhea. Learn more.
• Gigantism: the condition of extreme body height and excessive growth typically occurring in adolescence as a result of a growth hormone secreting pituitary adenoma (acromegaly). The typical physique is of enlarged head and jaw with “frontal bossing” as well as large hands and feet. Learn more.
  
• Glioblastoma Multiforme (GBM): the most common and most malignant type of glioma. This fast growing (Grade IV) astroctymoa typically occurs in adults and may arise anywhere in the central nervous system. The diagnosis of a GBM is best made by a brain MRI with and without contrast. Treatment involves surgical debulking, radiotherapy and chemotherapy. Learn more.
• Glioma: the most common type of brain tumor. They can occur at any age and in any part of the brain or spinal cord where glial cells (the support of the nervous system) are located. There are several types of gliomas and they range from the low grade to high grade (glioblastoma multiforme – GBM). Learn more.
  
• Growth Hormone (GH): the principle pituitary hormone that regulates growth and metabolism. Its action is primarily carried out by IGF-1 which is made in the liver. GH also has direct actions on the blood vessels both extra-cranially and in the brain. GH is essential for normal growth and development but is also important as an adult for muscle mass, exercise capacity and general quality of life. GH deficiency is treatable by a daily injection of GH. Learn more.