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
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
