Investigation and management
Med student UniSZA
1) Assessment of GH:
Random GH: often not diagnostic because of
episodic secretion and short half-life of the
Glucose tolerance test: GH is normally inhibited by
glucose. If the glucose load fails to suppress the
GH level below 1 mU/L and the IGF-1 level is
elevated then the diagnosis of acromegaly can be
• long half-life and so is a useful measurement to
assess GH secretion and therefore screen for
acromegaly and monitor the effect of therapy.
• A normal IGF-1 together with GH < 5 mU/L (2.5
ng/L) may be taken to exclude acromegaly if the
diagnosis is clinically unlikely
IGF-binding protein-3 (IGFBP-3): is the main
binding protein for circulating IGF and is
increased in acromegaly. Can be useful in the
diagnosis of acromegaly.
2) Visual field examination – defects are common, e.g.
bitemporal hemianopia (partial blindness where vision is
missing in the outer half of both the right and left visual
3) MRI scan of pituitary if above tests abnormal. This will
almost always reveal the pituitary adenoma.
4) Pituitary function – partial or complete anterior
hypopituitarism is common.
5) Prolactin – mild to moderate hyperprolactinaemia occurs in
30% of patients. In some, the adenoma secretes both GH
• Pictures show the normal eyes view and
bitemporal hemianopia view
6) chest and abdominal radiology:
– to detect an ectopic source of growth hormone
– may detect cardiomegaly due to cardiomyopathy
7) hands radiology reveals:
– tufting of terminal phalanges
– increased joint spaces due to cartilage
Complication of acromegaly
• Heart disease
acromegaly increases the risk of ischemic
heart disease leading to a worsening of risk of
heart attacks and angina.
Risk of heart failure also rises with
enlargement of the heart and imbalance
between demands of the body to the capacity
of the heart to pump blood.
• The risk of diabetes mellitus rises to a great
extent among those with acromegaly.
• Pregnant women with acromegalyhave a
heightened risk of developing gestational
diabetes and pregnancy induced
hypertension. This may raise the risk of
preterm birth or still birth.
• Those with acromegaly are at risk of arthritis
and joint pains as well. This is called
Acromegalic arthropathy and affects up to
70% of patients. Both the axial and peripheral
skeleton may be affected. This involves the
spine as well as the joints of the limbs. Due to
compression of nerves of the hand, patient
may develop Carpal tunnel syndrome.
• Due to overgrowth of structures of the back of
the throat and tongue, there may be
development of obstructive sleep apnoea and
this leads to interrupted sleep.
• There is a high risk of development of colonic
polyps. These polyps, if not detected early and
removed, may go on to form adenocarcinoma of
the colon or bowel cancer. Those with
acromegaly thus require early and regular
screening for bowel cancer.
MANAGEMENT OF ACROMEGALY
Aim= to achieve a mean growth
hormone level below
5 mU/L (or 2.5 ng/L)
Siti hamidah mahbud 030480
Trans-sphenoidal surgery is the appropriate firstline therapy. It will result in clinical remission
in a majority of cases (60–90%) with pituitary
Very high pre-operative GH and IGF-1 levels are
also poor prognostic markers of surgical cure.
Transfrontal surgery is rarely required except
for massive macroadenomas.
External radiotherapy is normally used after
pituitary surgery fails to normalize GH levels
oftencombined with medium-term treatment
with a somatostatin analogue or a dopamine
agonist because of the slow biochemical
response to radiotherapy.
Stereotactic radiotherapy is used insome
• three receptor targets for the treatment
of acromegaly pituitary somatostatin
receptors, dopamine (D2) receptors and
growth hormone receptors in the
• Somatostatin receptor agonists.
Octreotide and lanreotide are synthetic
analogues of somatostatin
used as a short-term treatment but now are
sometimes used as primary therapy. They
reduce GH and IGF levels in most patients.
Both drugs are typically administered as
monthly depot injections and are generally
well tolerated but are associated with an
increased incidence of gallstones
• Dopamine agonists.
act on D2 receptors and can be given to shrink
tumours prior to definitive therapy or to control
symptoms and persisting GH secretion;
most effective in mixed growth-hormone-producing
and prolactin producing tumours.
The doses are bromocriptine 10–60 mg daily or
cabergoline 0.5 mg daily which should be started
Given alone they reduce GH to ‘safe’ levels (only a
minority of cases) but they are useful for mild
residual disease or in combination with
• Growth hormone antagonists
Pegvisomant (a genetically modified analogue of
GH) is a GH receptor antagonist which has its
effect by binding to and preventing dimerization
of the GH receptor.
does not lower growth hormone levels or reduce
tumour size but has been shown to normalize
IGF-1 levels in 90% of patients.
main role = treatment of patients in whom GH and
IGF levels cannot be reduced to safe levels with
somatostatin analogues alone, surgery or