Acromegaly Flashcards
What is gigantism?
Excessive growth hormone production in children before the fusion of the epiphyses of the long bones
What is acromegaly?
Excess growth hormone production in adults
What are the two hormones secreted by the hypothalamus that control growth hormone production?
- Growth hormone releasing hormone
- Somatostatin
Aside from the hormones produced from the hypothalamus, what other factors can influence GH production?
- High glucose inhibits the release of GH
- Ghrelin stimulated the release of GH
How does growth hormone have indirect effects?
It induces insulin-like growth factor which is synthesised in the liver and other tissues.
What does ILGF do?
- Promotes cellular metabolism
- Prevents cell death
- Helps cells divide and differentiate in the body
How does GH impact tissues directly?
Induces metabolic changes in the liver muscle, bone etc.
- Stimulates osteoclasts for example
What is acromegaly caused by in almost all cases?
Benign pituitary GH-producing adenoma
Apart from the release of excessive growth hormone what else other effect can a benign pituitary GH-producing adenoma have?
Tumour expansion can result in compression of surrounding structures causing headaches and visual field loss
What are some signs of acromegaly?
- Skin darkening
- Coarsening face with a wide nose
- Prognathism
- Big supraorbital ridge
- Deep voice
- Carpel tunnel syndrome
- Large tongue
- Interdental separation
What are the symptoms of acromegaly?
- Headaches
- Acral enlargement
- Excessive sweating
- Visual deterioration
- Snoring
- Wonky bite
- Increased weight
- Decrease labido
- Amenorrhea
- Arthralgia and backache
- Acroparaesthesia
- Fatigue
What investigations would you do in Agcromegaly?
- Plasma GH levels - not diagnostic as pulsatile throughout the day
- Glucose tolerance test - Normally glucose would inhibit GH release
- Insulin-like growth factors - this fluctuates less and is always elevated in someone with acromegaly = DIAGNOSTIC
What co-morbidities are associated with acromegaly?
- Impaired glucose tolerance
- Diabetes mellitus
- Sleep apnea
- Hypertension
- Colon cancer
- Arthritis
What is the first line treatment in acromegaly?
Trans-sphenoidal surgery - to remove the tumour and correct any compression around surrounding structure - e.g optic chiasm
What three types of drugs can be used if surgery fails to treat the increase in GH?
- Somatostatin analogues - Inhibits GH release
- GH receptor antagonists - stops GH binding to target tissues
- Dopamine agonists
