Hypersecretion of Anterior Pituitary Hormones Flashcards
What is the usual cause of hypersecretion of anterior pituitary hormones?
Pituitary adenoma
What visual defect is associated with pituitary adenoma?
Bitemporal hemianopia
State the disease resulting from hypersecretion of:
a. Corticotrophin
b. Thyrotrophin
c. Gonadotrophin
d. Prolactin
e. Somatotrophin
a. Cortictrophin Cushing’s disease b. Thyrotrophin Thyrotoxicosis c. Gonadotrophins Precocious puberty in children d. Prolactin Hyperprolactinaemia e. Somatotrophin Gigantism/Acromegaly
What is the usual cause of hyperprolactinaemia?
Prolactinoma
Most commonly microadenomas (< 1cm)
State the symptoms of hyperprolactinaemia.
Loss of libido Infertility Galactorrhoea (rarely occurs in males as well) Oligomenorrhoea/amenorrhoea Impotence (in men) Bitemporal hemianopia Gynaecomastia
State two physiological causes of hyperprolactinaemia.
Pregnancy
Breast feeding
What does excess growth hormone cause in children and in adults?
Children – gigantism
Adults – acromegaly
What are the most serious complications of excess growth hormone?
Cardiovascular problems (majority) and respiratory problems This is mainly due to organ growth
State some common clinical manifestations of acromegaly.
Prognathism Enlarged supraorbital ridges Enlarged soft tissue Carpal tunnel syndrome (due to excessive cartilaginous growth) Hypertension Kyphosis Polydipsia and polyuria from TDDM
What are the metabolic effects of acromegaly?
Increased insulin response to oral glucose leading to insulin resistance
What type of test is used to diagnose a hyperpituitary disorder?
Suppression test
What test is used to diagnose acromegaly and how are the results interpreted?
Glucose-induced suppression of growth hormone secretion
Giving glucose should cause a decrease in growth hormone release in a normal individual
In someone with acromegaly, giving glucose will cause a paradoxical rise in growth hormone release
State some of the treatments for acromegaly.
Transsphenoidal Hypophysectomy Radiotherapy Chemotherapy: Octreotide (somatostatin analogue) Bromocriptine and Cabergoline (dopamine receptor agonists)
What are the clinical uses of octreotide?
It can be used short-term before surgery to shrink the size of the pituitary adenoma
It can be used long-term if it can’t be controlled by other means
State some of the side effects of octreotide.
GI tract disturbance (because somatostatin is produced by the small intestine as well)
Initial reduction in insulin secretion causing hyperglycaemia (octreotide inhibits the production of insulin by the beta cells)
Rarely gallstones
