acromegaly Flashcards
define acromegaly
Excess GH production, usually due to GH-secreting pituitary adenoma
what is a growth hormone- ( GH/somatotropin)?
is a peptide hormone secreted by the anterior pituitary gland.
what are the causes of acromegaly?
-Primary GH-secreting pituitary adenoma
-Ectopic GH-secreting tumours
e.g. Pancreatic-Islet Cell Tumours and Lymphoma.
-Iatrogenic GH
-Excessive GHRH (Rare)
e.g. Hypothalamic Hamartomas, Bronchial Carcinoid Tumours, Small cell lung cancer.
what does the secretion of GH lead to and what does it stimulate?
-GH leads to increased Insulin Growth Factor –1 (IFG1) secreted by the liver, which stimulates protein synthesis, cell division, lipolysis etc… for growth.
what can excessive GH cause?
Excess GH however causes excessive enlargement and growth of bone and soft tissue; Acromegaly
what are the signs of acromegaly?
-Acral Enlargement (Clubbing/Enlargement of hands and feet)
-Big tongue and widely spaced teeth
-Deep voice
-Prominent Superior Orbital fissure
-Puffy Lips, Thick Eyelid, Big Nose
what are the symptoms of acromegaly?
-Joint Pain
-Wrist Pain and Numbness (Carpal Tunnel Syndrome)
-Sleep/Snoring disorders (Sleep Apnoea)
-Headache and visual disturbance
-Erectile Dysfunction/Low libido
describe the epidemiology of acromegaly
Occurs in adults after the epiphyseal plates have fused; characterised by enlarged features
describe the epidemiology of giantism
Occurs in children before fusion of EP; have tall height
what are the risk factors for acromegaly?
Familial condition – Multiple Endocrine Neoplasia Type 1
what are the two types of treatment/ management of acromegaly?
- surgical
- medical
describe the surgical treatment/ management of acromegaly
-Endoscopic Transsphenoidal Surgery – Removes GH-secreting pituitary adenoma
-Surgical Removal of Ectopic cause
describe the medical treatment/ management of acromegaly
-Somatostatin Analogues (Octreotide, Lanreotide)
-Dopamine Agonists (Cabergoline, Bromocriptine)
-GH Antagonists (Pegvisomant)
what is the first line test of suspected acromegaly?
Measure serum IGF-1 levels NOT GH (as GH varies throughout the day).
what is the gold standard test for acromegaly?
ORAL GLUCOSE TOLERANCE TEST: 75g of oral glucose (Glucose suppresses GH).If after 2 hours GH conc. is >1ng/mL, Acromegaly is diagnosed.