Pituitary Tumors Flashcards
What are the most common causes of pituitary hormone hypersecretion and hyposecretion syndromes in adults?
Pituitary adenomas
Pituitary adenomas are benign tumors that affect hormone levels.
How are pituitary tumors classified?
According to the hormones they produce and their size:
* Microadenomas (less than 10 mm)
* Macroadenomas (more than 10 mm)
* Macroadenomas with extrasellar extension.
What is the relationship between tumor size and hormone levels in pituitary adenomas?
The levels of hormones produced by the tumors generally parallel the size of the tumors.
Are pituitary adenomas typically malignant?
No, they are very rarely malignant but can be locally invasive.
What hormone does a somatotroph adenoma produce and what disorder does it cause?
Growth hormone; causes acromegaly/gigantism
Prevalence: 10–15%.
What is the prevalence of lactotroph (prolactinoma) adenomas and what disorder do they cause?
25–40%; causes hypogonadism and galactorrhea.
What disorder is caused by corticotroph adenomas and what hormone do they produce?
Cushing’s disease; produces adrenocorticotropic hormone
Prevalence: 10–15%.
What hormones are produced by gonadotroph adenomas, and what are their effects?
Follicle-stimulating hormone and luteinizing hormone; causes mass effects and hypopituitarism
Prevalence: 15–20%.
What is the prevalence of thyrotroph adenomas and what disorder do they cause?
<3%; causes hyperthyroidism.
What do nonfunctioning/null cell adenomas cause and what is their prevalence?
Mass effects and hypopituitarism; prevalence: 10–25%.
What are common clinical manifestations of pituitary adenomas?
Signs and symptoms related to mass effects, such as headaches and visual field abnormalities.
What is the most common visual field abnormality associated with pituitary adenomas?
Bitemporal hemianopia.
What can cause sudden onset of severe headache in patients with pituitary adenomas?
Hemorrhagic infarction with sudden enlargement of a pituitary adenoma.
What is a common cause of hypopituitarism in patients with pituitary adenomas?
Compression of the hypothalamic-pituitary stalk.
What is the primary mode of therapy for most pituitary tumors that warrant intervention?
Surgical removal.
What is the transsphenoidal route used for?
It is the surgical approach used for most pituitary tumors.
What is the role of radiation therapy in the treatment of pituitary tumors?
It is usually used as adjunctive therapy after surgery or in combination with medical therapy.
What is the gamma knife technique in radiation therapy?
A technique that delivers radiation as a single dose through multiple ports using computerized matching of irradiation to tumor geometry.
What role do dopamine agonists play in the management of prolactinomas?
They induce a rapid fall in PRL levels and decrease tumor size.
Name two somatostatin analogues and their role in treatment.
Octreotide and lanreotide; they suppress the secretion of certain hormones, including GH and TSH.
What is the primary medical therapy for Cushing’s disease aimed at?
Inhibition of steroid biosynthesis.
Name three drugs used for inhibiting steroid biosynthesis in Cushing’s disease.
- Ketoconazole
- Metyrapone
- Aminoglutethimide.
