Acromegaly and Gigantism
Chronic, progressive diseases, acromegaly and gigantism are marked by hormonal dysfunction and startling skeletal overgrowth. Acromegaly occurs after epiphyseal closure, causing bone thickening and transverse growth and visceromegaly. Gigantism begins before epiphyseal closure and causes proportional overgrowth of all body tissues. Although the prognosis depends on the causative factor, these disorders usually reduce life expectancy unless treated in a timely way.
Causes
Typically, oversecretion of human growth hormone (HGH) produces changes throughout the entire body,
resulting in acromegaly and, when oversecretion occurs before puberty, gigantism. Somatotrope adenomas and, rarely, extrapyradimal pituitary lesions or other tumors may cause this oversecretion, but the cause of the tumors themselves remains unclear. Elevated HGH levels in more than one family member suggest a genetic cause.
resulting in acromegaly and, when oversecretion occurs before puberty, gigantism. Somatotrope adenomas and, rarely, extrapyradimal pituitary lesions or other tumors may cause this oversecretion, but the cause of the tumors themselves remains unclear. Elevated HGH levels in more than one family member suggest a genetic cause.
The earliest sign of acromegaly is soft-tissue swelling of the extremities, which causes coarsening of the facial features. This rare form of hyperpituitarism occurs equally among men and women, usually between ages 30 and 50.
Age AlertIn gigantism, proportional overgrowth of all body tissues starts before epiphyseal closure. This causes remarkable height increases of as much as 6 ″ (15.2 cm) per year. Gigantism affects infants and children, causing them to attain as much as three times the normal height for their age. As adults, they may ultimately reach a height of more than 80 ″ (203.2 cm).
Signs and symptoms
Acromegaly develops slowly, whereas gigantism develops abruptly.
Acromegaly
Acromegaly commonly produces hyperdidrosis, arthropathy, carpal tunnel syndrome, proximal muscle weakness and fatigue, acanthosis nigricans and skin tags, and oily skin.
Hypersecretion of HGH produces cartilaginous and connective tissue overgrowth, resulting in a characteristic hulking appearance, with an enlarged supraorbital ridge and thickened ears and nose. Prognathism, projection of the jaw, becomes marked and may interfere with chewing. Laryngeal hypertrophy, paranasal sinus enlargement, and thickening of the tongue cause the voice to sound deep and hollow. Also, the fingers are thickened.
Coronary artery disease, cardiomyopathy with arrhythmias, left ventricular hypertrophy, decreased diastolic function, and hypertension occur in 30% of patients; upper airway obstruction with sleep apnea, in 60% of patients. Generalized visceromegaly occurs, including cardiomegaly, macroglossia, and thyroid gland enlargement.
Full access? Get Clinical Tree
