Acromegaly

Acromegaly, also known as gigantism when seen in children, is a disorder in which the overproduction of growth hormone causes excessive growth.

Growth hormone is responsible for the growth of muscles, bones and internal organs. An excess of the hormone thus affects all of these tissues, causing them all to grow abnormally.

Overproduction of growth hormone is usually due to a non-cancerous tumour in the pituitary gland.

Symptoms and disease pathway

In children, the growth (epiphyseal) plates between joints are still open, facilitating longitudinal bone growth. Excessive growth hormone production will cause the bones to lengthen enormously, and the child will grow to a great stature.

In most cases, however, the overproduction of growth hormone occurs during adulthood; long after the growth plates have turned to bone. In this case, bones become deformed, rather than elongated. Meanwhile, muscles and organs grow and thicken. Signs of this include:

·         Deepening of the voice, due to thickened cartilage in the voice box;

·         Enlargement of the tongue;

·         Darkening and thickening of coarse body hair; and

·         Excessive perspiration due to enlarged sweat glands.

The effect on internal organs also has serious implications. Enlargement of the heart may cause its function to become impaired, and may culminate in heart failure. Increased pressure on the brain may result in severe headaches, and compression of nerves may result in coordination difficulties. Joint pain is a common symptom; crippling arthritis is often associated with acromegaly.

Diagnosis

Due to the slow nature of changes to the body, the outward signs of acromegaly may not be immediately apparent, especially in children. When symptoms do become discernible, the diagnosis is confirmed by blood tests, which should indicate high levels of growth hormone, and radiographic imaging, to locate the tumour.