acromegaly Flashcards
def acromegaly
signs and symptoms caused by hypersecretion of GH in adults
aetiology acromegaly
GH secreting pituitary adenoma
rare: excess GHRH from hypothalamic ganglioneuroma, bronchial carcinoid or pancreatic tumours = somatotroph hyperplasia
GH stimulates bone and soft tissue growth through increased secretion of insulin like growth factor 1 (IGF-1)
genetic predisposition is rare
epi acromegaly
men = women
40-50yrs
rare
incidence 3/million/yr
approx 5% associated with MEN-1
sx acromegaly
gradual progression of symptoms over years - detected on photos
rings and shoes become tight
increased sweating, headache, carpal tunnel syndrome
snoring
arthralgia
backache
curly hair
wonky bite - malocclusion
symptoms of hypopit - hypogonadism, hypothyroidism, hypoadrenalism
visual disturbance - optic chiasm compression
hyperprolactinaemia - irregular periods, reduced libido, impotence
Acroparaesthesia
signs acromegaly
increased growth of hands (spade like), jaw and feet - sole may encroach on the dorsum
premature osteoarthritis
coarsening face, wide nose, prominant cheeks, nasolabial folds, thick lips
big supraorbital ridges
macroglossia
widely spaced teeth
prognathism
puffy lips, eyelids and skin (oily and large pored), skin tags
thick skin
scalp folds - cutis verticis gyrata sue to expanding but tethered skin
skin darkening
acanthosis nigricans
laryngeal dyspnoea (fixed cords) - husky resonant voice
obstructive sleep apnoea
goitre - increased thyroid vascularity
prox weakness and arthropathy
carpel tunnel signs in 50%
signs form any pit mass - hypopit +- local mass effect = Bitemporal superior quadrantanopia progressing to bitemporal hemianopia, reduced vision, fits
multi-nodule goitre in neck
feet enlarged
ix acromegaly
serum IGF-1: screening, GH stimulates IGF-1 secretion (IGF-1 varies with age of patient and increases during pregnancy and puberty).
Pituitary function tests: 9 a.m. cortisol, free T4 and TSH, LH, FSH, testosterone (in men) and prolactin (to test for hypopituitarism).
MRI of the brain: To image the pituitary tumour and effect on the optic chiasm
high glucose, Ca, phosphate
ECG
Echo
not just GH - pulsatile and increases in stress, sleep, puberty, pregnancy
serum IGF-1 acromegaly
If basal serum GH is >0.4mcg/L (1.2mIU/L) and/or if increase in IGF-I, an oral glucose tolerance test (OGTT) is needed
oral glucose tolerance test: failure of suppression of GH after 75g oral glucose load (false-positive results are seen in anorexia nervosa, Wilson’s disease, opiate addiction). Normally GH decreased by glucose
If the lowest GH value during OGTT is above 1mcg/L (3mIU/L), acromegaly is confirmed.
With general use of very sensitive assays, it has been said that this cut-off be decreased to 0.3mcg/L (0.9mIU/L)
Collect samples for GH glucose at: 0, 30, 60, 90, 120, 150min.
mx acromegaly
surgery = trans-sphenoidal hypophysectomy only curative treatment
radiotherapy - adjunctive treatment to surgery
medical
monitor:
- GH and IGF1 levels aim to reduce to <2mcg/L
- pit func tests
- echo
- colonoscopy
- blood glucose
- visual fields
- vascular assessment
- BMI
- photos
med mx acromegaluy
if surgery CI or refused
subcut somatostatin analogues (octerotide monthly IM, lanreotide)
- SE: abdo pain, steatorrhoea, flatulence, glucose intolerance, gallstones, irritation at the injection site
oral dopamine agonists (bromocriptine, cabergoline)
- SE: nausea, vomiting, constipation, postural hypotension, psychosis
GH antagonist - pegvisomant - suppresses GH to normal in 90%, GH levels may rise, and rarely tumour size may increase - monitor carefully
complications acromegaly
may present with CCF or ketoacidosis
impaired glucose tolerance in approx 40%, DM in 15%
obstructive sleep apnoea
increased BP, LVH +- dilatation/CCF, cardiomyopathy, arrhythmias, IHD, stroke (?due to increased BP ± insulin resistance and GH-induced increase in fibrinogen and decrease in protein S)
neoplasia - increased colon cancer risk, colonoscopy may be needed
acromegaly in pregnancy (Subfertility is common.) Pregnancy may be normal; signs and chemistry may remit. hyperprolactinaemia Monitor glucose
Metabolic: Hypercalcaemia, hyperphosphataemia, renal stones, diabetes mellitus,hypertriglyceridaemia.
Psychological: Depression, psychosis (resulting from dopamine agonist therapy).
complications of acromegaly surgery
Nasoseptal perforation, hypopituitarism, adenoma recurrence, CSF leak, infection (meninges, sphenoid sinus).
Px acromegaly
Good with early diagnosis and treatment, although physical changes are irreversible.
16% get diabetes with SSAs vs ~13% after surgery
