It is a disease of adult life characterized by the growth of bulk but not in the length of bone especially of the extremities from over-secretion of growth hormone after epiphyseal closure, due to adenoma of the anterior pituitary. Hypersecretion of growth hormone before puberty (before epiphyseal closure) produces gigantism. Most of the adenomas aremacroadenomas (> l cm in diameter).
Acromegaly is rarely caused by ectopic growth hormone-releasing hormone or growth hormone secreted by lymphoma, hypothalamic tumor, bronchial carcinoid, or a pancreatic tumor.
Growth hormone acts directly on some tissues, but most of its biological effects are because of stimulation of insulin-like growth factor (IGF-1) produced in the liver and other tissues.
DUE TO LOCAL EFFECTS OF ADENOMA
Headache & vomiting
• Bitemporal hemianopia
• Cranial nerve palsy
• Large spade-like hands & large feet.
• Enlargement of the lower jaw (prognathism)
• Prominent supraorbital ridges with large
• Increased hat size due to enlargement of
sinuses and skull bones.
• Spacing apart of teeth
• Over growth of vertebral bone can cause spinal
• Tongue enlarged with difficulty in articulation. Hypertrophy of pharyngeal and laryngeal tissue causing obstructive sleep apnea.
• Thickening of lips and nose
• Thickening of soft tissue of hands & feet
• Thickening of skin, increased sweating, acne.
• Moist handshake ( due to sweating of palm)
• Visceromegaly e.g. cardiomegaly, thyroid
goiter and hepatomegaly.
• Carpal tunnel syndrome.
• Colon polyps are common.
• Glucose intolerance (25%)
• Clinical diabetes mellitus (10%)
• Hypertension (50%)
• Weight gain due to increased mass of muscle and bone.
• Growth hormone secreting pituitary tumors usually cause hypogonadism due to secretion of prolactin or by suppression of normal pituitary tissue.
• Secondary hypothyroidism may occur.
• Hypopituitarism, hypertension, glucose intolerance or frank diabetes mellitus, cardiomegaly and cardiac
• Carpal tunnel syndrome, arthritis of hips, knees, and spine, spinal cord compression.
• Visual field defects.
• Acute loss of vision or cranial nerve palsy may occur if the tumor undergoes spontaneous hemorrhage and necrosis called pituitary
L Fasting serum prolactin and insulin – like growth factor 1 (IGF- 1).
IGF-1 is elevated while serum prolactin is also elevated in 30% of patients.
3. Growth hormone level: clinical diagnosis must be confirmed by measuring growth hormone levels during glucose tolerance test (GTT).
4. Pituitary function tests: show partial or complete hypopuitarism.
5. X-rays: X- ray skull shows enlarged pituitary fossa & double floor may be seen due to greater enlargement of the gland on one side. X-rays of hand and feet may also show tufting of the terminal phalanges of fingers and toes.
A lateral view of foot shows increased thickness of the heel pad .
5. CT Scan & MRI to detect tumor extent. MRI is superior to CT scan.
Untreated acromegaly results in markedly reduced survival with most of the deaths from heart failure, coronary artery disease, hypertension and colonic tumors. The aim of therapy is to reduce growth hormone level below 5mU/L.