acromegaly Flashcards
acromegaly pathophysiology
- excess growth hormone
- commonly pituitary adenoma
- rarely cancer secreting ectopic growth hormone-releasing hormone or growth hormone - paraneoplastic syndrome
- excess GNRH
- GNRH > GH > high IGF-1
tumour pressing on local structure - vision loss
- optic chaiasm
- bitemporal hemianopia
presentation of acromegaly
- headaches
- visual field defects
- prominent forehead and brow
- coarse, sweaty skin
- large nose
- large tongue
- large hands and feet
- large protruding jaw
- hypertrophic heart
- hypertension
- type 2 diabetes
- carpal tunnel syndrome
- arthiritis
- colorectal cancer
investigations
insulin like growth factor 1 - raised
growth hormone supression test / oral glucose tolerance test - if GH not supressed
MRI - visualise adenoma
ideal treatment
trans-sphenoidal surgery - through
ectopic hormones from liver / pancreatic tumours invloves surgical removal or radiotherapy
medical options for when surgery is not available
pegvisomant - growth hormone receptor antagonist
somatostatin analogues - block GH release
dopamine agonists - block GH release
GH antagonist
radiotherapy
Acromegaly in children (3)
- Called gigantism
- Occurs before epiphyseal fusion
- Hypopituitarism causes inhibition of puberty as gonadotrophs cannot be released
Complications of acromegaly (6)
- T2DM caused by impaired glucose tolerance
- Obstructive sleep apnoea
- Cardiomyopathy
- Hypertension
- Arthropathy - joint disease eg arthiritis
- Carpal tunnel syndrome
Other symptoms suggesting active raised growth hormone (2)
- Development of new skin tags
- Profuse sweating
Why can acromegaly cause sleep apnoea?
Pressure around the neck due to enlargement
Signs of acromegaly to do with GH causing organ dysfunction (4)
- Hypertrophic heart
- Hypertension
- Impaired glucose tolerance
- Colorectal cancer
gold standard test for acromegaly
oral glucose tolerance test
Criteria for diagnosis of acromegaly
Acromegaly excluded if:
random GH <0.4 ng/ml and normal IGF-I
If either abnormal proceed to:
75 gm Glucose tolerance test (GTT)
Acromegaly excluded if:
IGF-I normal
and
GTT nadir GH <0.4 ng/ml
initial test
IGF-1
Acanthosis nigricans is characterised by hyperpigmented velvety plaques in skin folds/posterior neck. It may also affect the vulva, tongue, and lips as papillary lesions that are not pigmented. cause?
insulin resistance
Prognathism
an extension or bulging out (protrusion) of the lower jaw
frontal bossing
the development of an unusually pronounced forehead which may also be associated with a heavier than normal brow ridge
symtpoms of tingling and sweating in the index finger and thumb of hand
carpal tunnel syndrome is very common in acromegaly
when would you use oral glucose tolerance test and when would you use serum IGF-1 test
IGF-1 serum levels are used to monitor acromegaly. OGTT can be used in the diagnosis, not monitoring, of Acromegaly
what is the ultimate decider test to confirm a diagnosis and not just to investigate
OGTT
MEN Type 1 (Wermer Syndrome)
Glands Involved: Parathyroid, pituitary, pancreas.
Gene: MEN1 (menin gene mutation).
Other Features: May also affect the thymus and duodenum.
MEN Type 2A (Sipple Syndrome)
Glands Involved: Thyroid, parathyroid, adrenal glands.
Common Tumors: Medullary thyroid cancer (MTC), pheochromocytomas (adrenal),
hyperparathyroidism.
Gene: RET (RET proto-oncogene mutation).
MEN Type 2B
Glands Involved: Thyroid, adrenal glands, mucosal tissues.
Common Tumors: Medullary thyroid cancer (MTC), pheochromocytomas (adrenal), mucosal neuromas, marfanoid appearance.
Gene: RET (RET proto-oncogene mutation).
if someone cant have surgery what happens
somatostatin receptor ligand (SRL’s)
result of oral glucose tolerance test to confirm acromegaly
normal levels - should be suppressed
somatostatin analogues
block GH production
is sleep apnoea common?
yes lots of patients can present with it
can present with tiredness
due to upper airway obstruction from macroglossia
OGTT preformed
The most common glucose tolerance test is the oral glucose tolerance test (OGTT).
Before the test begins, when you have had nothing to eat or drink for at least 8 hours, a sample of blood will be taken.
You will then be asked to drink a liquid containing a certain amount of glucose (usually 75 grams). Your blood will be taken again every 30 to 60 minutes after you drink the solution.
The test may take up to 3 hours.
