A

acromegaly A condition in which the PITUITARY
GLANDsecretes excessive GROWTH HORMONE (GH),
causing the bones to thicken and become over-
grown. This excessive growth is most apparent in
the facial features and the extremities, especially
the jaw, brow, hands, and feet. Most commonly
acromegaly develops in midlife. When acromegaly
occurs before the growth plates in the long bones
of the arms and legs have fused, excessive height
results. Doctors call this gigantism rather than
acromegaly, though it is the same disease process.
When excessive secretion of GH takes place after
the growth plates have fused (generally after
PUBERTY), the bones enlarge by thickening and
spreading. This pattern of overgrowth results in
the distortions characteristic of the disorder.

A BOND ACROSS TIME

Some medical historians believe the biblical

giant Goliath and the sixteenth president of the

United States, Abraham Lincoln (1809–1865),

had in common the disorder of acromegaly. Both

were exceedingly tall for the time in which they

lived. Descriptions of Goliath and photographs

of Lincoln suggest the characteristic features of

acromegaly: overgrown facial features, excessive

height, and unusually large hands and feet. Lin-

coln’s headaches and fatigue, widely known,

also were indications of acromegaly.

Though the small number of people doctors
diagnose with acromegaly gives the perception
this condition is rare, endocrinologists believe
acromegaly is much more common than those
numbers suggest. Acromegaly typically develops
over years to decades, with symptoms emerging
slowly and often nonspecifically. Many people
learn they have acromegaly during evaluation for

other conditions that could account for their

symptoms, such as HYPERTENSION(high BLOOD PRES-

SURE) or DIABETES.

The most common cause of acromegaly is an

ADENOMA(noncancerous tumor) in the anterior

lobe of the pituitary gland, increasing the quantity

of cells that secrete GH. Occasionally an adenoma

or, rarely, an ADENOCARCINOMA(an adenoma that

has turned cancerous) that secretes GH and is

located elsewhere in the body, such as the gas-

trointestinal tract (notably the PANCREAS) or the

LUNGS, is responsible. Growth hormone does not

itself cause growth but instead stimulates the LIVER

and other structures to produce other hormones,

known collectively as insulinlike growth factors,

or IGFs (sometimes called somatotropin mediators

or somatomedins), that increase the rate at which

cells divide. The most prominent of these is INSULIN

growth factor 1 (IGF-1). High GH secretion results

in excessive IGF-1 circulating in the BLOOD, which

becomes one of the clinical markers for making

the diagnosis.

Symptoms and Diagnostic Path

Often the earliest symptoms of acromegaly are

gradual changes in the hands and feet, especially

swelling of the palms and soles. A person may

need larger sizes of shoes or gloves than usual and

find that rings or watches no longer fit. Other

symptoms include

• frequent headaches and vision disturbances


• excessive sweating and body odor


• thickened, often darkened, SKINand NAILS
  
  
  • increasing space between the TEETH
  
  
  • PAINin the joints
  
  
  
  

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