2. A
C DEFINITION
R
O Chronic metabolic disorder in which there is
M too much growth hormone and the body
E
tissue gradually enlarge
G
A
L
Y
4. PATHOPHYSIOLOGY
Acromegaly is characterized by hypersecretion of growth hormone (GH),
which is caused by the existence of a secreting pituitary tumor in more than
95% of acromegaly cases. Pituitary tumors are benign adenomas and can be
classified according to size (microadenomas being less than 10 mm in
diameter and macroadenomas being greater than 10 mm in diameter).3,4 In
rare instances, elevated GH levels are caused by extra pituitary disorders. In
either situation, hypersecretion of GH in turn causes subsequent hepatic
stimulation of insulin-like growth factor-1 (IGF-1).1
6. SYMPTOMS ( cont… )
Headdache
Hoarseness
Joint pain
Limited joint movement
Sleep apnea
Swelling of bony areas around a joint
Thickening of skin, skin tags
Widely spaced teeth
Excess hair growth in females
Weight gain
7. DIFFERENTIAL DIAGNOSIS
Pseudoacromegaly
Presence of similar acromegaloid features in the absence of elevated GH or IGF-I
levels
Physiologic growth spurt during puberty
Familial tall stature or large hands and feet
Myxedema
8. INVESTIGATION
Visual field tests
Assessment of other pituitary hormones: prolactin, adrenal, thyroid, and
gonadal hormones
MRI scan of pituitary and hypothalamus: more sensitive than CT scan
CT scan: for lung, pancreatic, adrenal or ovarian tumours that may secrete
ectopic growth hormone or GHRH
Total body scintigraphy with radio-labelled OctreoScan® (somatostatin) to aid
localisation of the tumour
Cardiac assessment: electrocardiogram, echocardiogram
9. PROGNOSIS
Pituitary surgery is successful in most patient, depending on the size of the
tumor and the experience of the surgeon
Without treatment the symptoms will get worse,and the risk of cardiovascular
disease increase
12. G
I
DEFINITION
G Abnormally large growth due to an excess of
A growth hormone during childhood, before the
N bone growth plates have closed.
T
I
S
M
14. CAUSES
The most common cause of too much growth hormone release is a noncancerous
(benign) tumor of the pituitary gland. Other causes include:
Carney complex
McCune-Albright syndrome (MAS)
Multiple endocrine neoplasia type 1 (MEN-1)
Neurofibromatosis
If excess growth hormone occurs after normal bone growth has stopped, the
condition is known as acromegaly.
15. SYMPTOMS
Delayed puberty
Double vision or difficulty with side (peripheral) vision
Frontal bossing and a prominent jaw
Headache
Increased sweating
Irregular periods (menstruation)
Large hands and feet with thick fingers and toes
Release of breast milk
Thickening of the facial features
Weakness
16. EXAMS & TESTS
CT or MRI scan of the head showing pituitary tumor
Failure to suppress serum growth hormone (GH) levels after an oral glucose
challenge (maximum 75g)
High prolactin levels
Increased insulin growth factor-I (IGF-I) levels
Damage to the pituitary may lead to low levels of other hormones, including:
Cortisol
Estradiol (girls)
Testosterone (boys)
Thyroid hormone
17. TREATMENT
Medical treatments of gigantism
Medications may be used to reduce GH release, block the effects of GH, or prevent
growth in stature. They include:
Dopamine agonists, such as bromocriptine mesylate (Cycloset, Parlodel) and cabergoline
(Dostinex), which reduce GH release
GH antagonist, pegvisomant (Somavert), which blocks the effects of GH
Sex hormone therapy, such as estrogen and testosterone, which may inhibit the growth of
long bones
Somatostatin analogs, such as octreotide (Sandostatin) and long-acting lanreotide
(Somatuline Depot), which reduce GH release
18. TREATMENT ( cont… )
Other treatments of gigantism
Radiation of the pituitary gland to regulate GH. This is generally
considered the least desirable treatment option because of its limited
effectiveness and side effects that can include obesity, emotional
impairment, and learning disabilities
Surgery to remove a pituitary tumor, which is the treatment of choice
for well-defined pituitary tumors
20. COMPLICATIONS
Delayed puberty
Difficulty functioning in everyday life due to large size and unusual features
Diminished vision or total vision loss
Embarrassment, isolation, difficulties with relationships, and other social
problems
Hypothyroidism
Severe chronic headaches
Sleep apnea