Acromegaly Flashcards
define acromegaly?
constellation of signs and symptoms caused by hyper secretion of GH in adults
Gigantism occurs with disease onset in childhood (prior to epiphyseal closure)
summarise the epidemiology of acromegaly?
rare
5/1000000
age affected 40-50 years
explain the aetiology/ risk factors of acromegaly?
most cases are caused by a GH- secreting pituitary adenoma
pro-lactin is co-secreted in about 25-30% of cases
rarely caused by excess GHRH causing somatotroph hyperplasia from hypothalamic ganglioneuroma ,bronchial carcinoid or pancreatic tumours
what are the presenting symptoms of acromegaly?
ring and shoes become tight
increased sweating
headaches
carpal tunnel syndrome
hypopituitary symptoms ( due to adenoma compressing normal pituitary)
- hypogonadism
- hypothyroidism
- hypoadrenalism
Visual disturbances ( due to compression of optic chiasm by tumour)
hyperprolactinaemia
- irregular periods
- decreased libido
- impotence
headaches
snoring
hypertension/ arrhythmia
increased appetite/ polyuria/ polydipsia
why can acromegaly cause increased appetite/polururia/ polydipsia?
impaired glucose tolerance or diabetes mellitus
these occur as a result of insulin resistance due to chronic GH excess
why can acromegaly cause arrhythmia/hypertension?
These findings may be associated with hypertrophic cardiomyopathy.
Excessive levels of GH/insulin-like growth factor 1 can cause major structural and functional cardiac changes that are associated with increased morbidity and premature mortality.
what are the signs of acromegaly on physical examination?
HANDS ○ Large spade-like hands ○ Thick greasy skin ○ Skin tags ○ Carpel tunnel syndrome signs Premature osteoarthritis
FACE ○ Prominent eyebrow ridge ○ Prominent cheeks ○ Broad nose bridge ○ Prominent nasolabial folds ○ Thick lips ○ Increased gap between teeth ○ Large tongue ○ Prognathism Husky resonant voice (due to thickening of vocal cords)
VISUAL FIELD LOSS
Bitemporal superior quadrantopia progressing to bitemporal hemianopia
NECK
Multinodular goitre
FEET
Enlarged
summarise the prognosis for patients with acromegaly?
GOOD with early diagnosis and treatment
Physical changes are irreversible
what are the appropriate investigations for acromegaly?
Serum IGF-1 - useful screening test but lacks specificity therefor does not confirm diagnosis
GH stimulates IGF-1 secretion – hence levels elevated
Oral Glucose Tolerance Test (OGTT) - CONFIRMATORY TEST
○ Positive result: failure of suppression of GH after 75 g oral glucose load
random serum growth hormone ( GH )- Because GH values vary significantly during the day for normal people, an isolated elevated value does not, in itself, provide evidence for the presence of acromegaly.
what other factors can alter IGF-1 secretion which make it a weaker investigation for acromegaly?
Malnutrition, hypothyroidism, systemic diseases with catabolic states, liver failure, and exogenous oestrogen alter IGF-1 concentrations.
What investigations should you consider for acromegaly?
• Pituitary Function Tests ○ 9am cortisol ○ Free T4 and TSH ○ LH and FSH ○ Testosterone ○ Prolactin
• MRI of Brain - visualise the pituitary adenoma
Visual field testing
outline the management plan for acromegaly?
- Surgical - trans-sphenoidal hypophysectomy -1st line (bromocriptine May be used to reduce the size before definitive treatment like surgery if the tumour is very big
- Radiotherapy - adjunctive to surgery
• Medical - if surgery is contraindicated or refused
○ Subcutaneous Somatostatin Analogues
▪ e.g. octreotide, lanreotide
▪ Side-effects: abdominal pain, steatorrhoea, glucose intolerance, gallstones
○ Oral Dopamine Agonists
▪ e.g. bromocriptine, cabergoline
▪ Side-effects: nausea, vomiting, constipation, postural hypotension, psychosis (RARE)
○ GH Antagonist (pegvisomant)
○ Monitor: GH and IGF1 levels can be used to monitor disease control
what somatostatin analogies can be used on medical treatment of acromegaly?
octreotide, lanreotide
side effects- abdominal pain, steatorrhea, glucose, intolerance, gallstones
what are the oral dopamine agonists that can be used in the medical treatment of acromegaly?
e.g. bromocriptine, cabergoline
Side-effects: nausea, vomiting, constipation, postural hypotension, psychosis (RARE)
what are the complications of acromegaly?
• CVS
○ Cardiomegaly
○ Hypertension
• Respiratory
○ Obstructive sleep apnoea => snoring
• GI
○ Colonic polyps
• Reproductive
○ Hyperprolactinaemia (in 30% of cases)
• Metabolic ○ Hypercalcaemia ○ Hyperphosphataemia ○ Renal stones ○ Diabetes mellitus ○ Hypertriglyceridaemia
• Psychological
○ Depression
○ Psychosis (from dopamine agonists)
• Complications of Surgery ○ Nasoseptal perforation ○ CSF leak ○ Meningitis ○ haemorrhage ○ Hypopituitarism ○ Adenoma recurrence
• Osteoarticular
Joint pain and dysfunction
