Acromegaly Flashcards
what is this due to
increased secretion of growth hormone from pituitary tumour or hyperplasia
where could ectopic GH releasing hormone come from
carcinoid tumour
what does GH stimulate bone and soft tissue growth via
insulin like growth factor-1
symptoms
acroparaesthesia (of digits), amenorrhoea, decr libido, headache, incr sweating, snoring, arthralgia, backache
signs
incr growth of hands, jaw and feet; coarsening face, wide nose; big supraorbital ridges; macroglossia; widely spaced teeth; puffy lips, eyelids and skin; scalp folds; skin darkening; acanthosis nigricans; laryngeal dyspnoea; OSA; goitre; proximal weakness and arthropathy; carpal tunnel signs
complications
may present with CCF or ketoacidosis. impaired glucose tolerance; vascular- incr bp, LVH, cardiomyopathy, arrhythmias, IHD, stroke. neoplasia- incr colon cancer risk, colonoscopy
tests
incr glucose, incr calcium, incr phosphate.
why can you not rely on random GH
because secretion is pulsatile and during peaks there is overlap
when can GH increase
stress, sleep, puberty, pregnancy
what happens normally with a high glucose
suppression of GH and GH hardly detectable. in acromegaly GH fails to suppress
when is an oral glucose tolerance test needed
if basal GH >0.4ug/L and/or IGF-1 incr
when is acromegaly confirmed with oral glucose tolerance test
if lowest GH during the test is >1ug/L then acromegaly is confirmed
what is the method in OGTT
collect samples for GH glucose at 0,30,60,90,120,150 min
when can you get false positives
pregnancy, puberty, hepatic and renal disease, anorexia nervosa, DM
other tests
MRI of pituitary fossa, look for hypopituitarism, visual fields and acuity, ECG, echo
