- DYSMENORRHEA (abnormal MENSTRUATION) in
women and ERECTILE DYSFUNCTIONin men - weakness and fatigue
Headaches and visual disturbances occur when
the pituitary adenoma grows large enough to cre-
ate pressure against structures of the BRAIN. Often
this pressure affects the OPTIC NERVE, which passes
near the pituitary gland, causing an array of vision
disturbances. The excessive GH causes the SWEAT
GLANDSto enlarge and increase production, caus-
ing the unpleasant body odor and excessive
sweating. The overgrowth of BONEin the jaws dis-
places the teeth, often first apparent as a shift in
bite (the way the teeth meet when chewing).
There are no definitive tests to diagnose
acromegaly, requiring the endocrinologist to com-
pile a picture of clinical and observational find-
ings. About a third of people who have
acromegaly have elevated GH levels in the blood
an hour after they drink an oral GLUCOSEsolution.
Because of the constant interactivity between GH,
insulin, and glucose, GH stays in the blood circula-
tion for only a short time, and its levels vary
widely in a healthy person. The level of IGF-1 is
more indicative of excessive GH secretion because
IGF-1 stays in the circulation for an extended
time. However, IGF-1 levels naturally diminish
with age and in conditions such as OBESITYand
diabetes.
Because endocrine functions are so tightly inte-
grated, often the endocrinologist will measure the
blood levels of other hormones, such as those the
THYROID GLAND, ADRENAL GLANDS, and sex glands
produce. Other diagnostic procedures may include
imaging studies such as X-rays to identify changes
in bone structure and MAGNETIC RESONANCE IMAGING
(MRI) to determine whether a pituitary adenoma is
present. The endocrinologist also may ask to see
photographs of the person taken over the preced-
ing 5 to 10 years to evaluate changes in physical
structure and appearance.
Treatment Options and OutlookThe optimal treatment is an OPERATIONto remove
the pituitary adenoma. The surgeon reaches the
tumor from an incision made inside the NOSE,
entering the brain from the nasal cavity (called
transsphenoidal resection). Therapies such as
medications or radiation therapy may be neces-
sary to shrink tumors larger than 10 centimeters
(4 inches) or to treat tumors when surgery is not a
viable option or cannot remove all of the tumor.
In most people the surgery results in immediate
relief of pressure-related symptoms such as
HEADACHE and VISION IMPAIRMENT as well as a
prompt return to normal levels of GH in the
bloodstream. Many of the other symptoms then
improve, though some of the changes the exces-
sive GH has caused, such as bone overgrowth,
remain.MEDICATIONS TO TREAT ACROMEGALY
bromocriptine (Parlodel)
octreotide (Sandostatin)
pegvisomant (Somavert)About a third of people who develop
acromegaly also develop hypertension, resulting
from the altered hormonal environment in the
body, and HEART FAILURE, a consequence of
the enlargement of the HEARTin response to the
excessive GH. Many also develop chronic
OSTEOARTHRITIS, resulting from the overgrowth of
CARTILAGEat the bone ends and the joints, and
peripheral NEUROPATHY, resulting from overgrown
tissues compressing the nerves. Often, these prob-
lems are what cause people to seek medical atten-
tion.
In health the interactions among GH, insulin,
and SOMATOSTATINregulate the hormonal balance
that allows appropriate growth. In acromegaly, the
excessive GH throws the equilibrium of this
matrix out of kilter. As a result, people who have
acromegaly are also likely to develop type 2 dia-
betes as a consequence of hormonal disturbances
within the insulin–glucagon–somatostatin matrix.
Diabetes and other consequential conditions may
require ongoing therapy even after treatment for
the acromegaly restores normal GH secretion.
People who have acromegaly have an increased
risk for developing COLORECTAL CANCER, which
arises from adenomas of the intestinal wall (intes-
tinal polyps).Risk Factors and Preventive Measures
There are no known risk factors or preventive
measures for acromegaly. Early diagnosis providesacromegaly 105