Orthopedics - Oleksa A.P. 2006

Metabolic Bone Diseases
Endocrine Skeletal Disorders
Gigantism and Acromegaly

Pituitary hyperfunction, often associated with an Adenoma of the anterior lobe, results in excessive Growth Hormone secretion, leading to gigantism during youth and acromegaly in adulthood. Z.V. Bazylevska (1968) provides a schematic diagram (Fig. 87) illustrating body build in various endocrine disorders.

Gigantism is characterized by the disproportionate enlargement of certain body parts, particularly the limb bones, which are excessively long relative to the trunk. These bones overgrow not only in length but also in width, becoming thicker due to increased periosteal activity. After growth cessation, affected individuals develop more features characteristic of acromegaly. The jaws are also somewhat enlarged, with normal Teeth. The Skull and Brain remain unaffected because Tissues of ectodermal origin are less responsive to growth hormone.

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Fig. 87. Body build in various endocrine disorders, according to Z.V. Bazylevska: 1. Pituitary dwarf (aged 14). 2. Myxedema (female, aged 18). 3. Healthy male. 4. Gigantism.

N.A. Sherishevsky established the close relationship between gigantism and acromegaly, noting that they can sometimes be difficult to distinguish.

Acromegaly is typically caused by a slow-growing anterior pituitary adenoma, which results in gradually progressive clinical manifestations. Early signs of acromegaly are non-specific and include headaches, visual impairment, and a decrease or loss of libido. The Skin and mucous membranes thicken, and Hair growth increases. Signs of Optic nerve compression in the chiasmal region emerge, along with excessive bone growth. However, overgrowth predominantly affects the protruding PARTS OF THE body, whereas height and overall weight do not become excessive. Bone proliferation in acromegaly occurs via the periosteum, causing the thickening of long bones, prominent enlargement of the supraorbital ridges, and forward protrusion of the lower jaw (prognathism). The teeth develop normally and are therefore spaced apart. The bones and soft Tissues of the face and Nose also enlarge. Clinically, the "tall type" (gigantism) develops prior to epiphyseal fusion, whereas the "broad type" develops after fusion.

These clinical manifestations correspond to radiological findings. The cranial bones, particularly facial bones, are enlarged due to hyperostosis. The Mandible is elongated and projects forward. The supraorbital ridges are enlarged. The sella turcica is typically enlarged due to deepening toward the Sphenoid bone and posteriorly. The posterior clinoid process is posteriorly inclined and thinned, while the anterior process is thickened or pointed. Radiological Changes in the sella turcica are absent only in exceptional cases of acromegaly.

In cases of gigantism, radiographs reveal excessively long limb bones, whereas acromegaly is dominated by bone proliferation in width, particularly in the epiphyses and Muscle tendon attachment sites. The Phalanges of the fingers are thickened, especially the distals. Increased anteroposterior dimensions of the thoracic vertebrae resulting from proliferation, Kyphosis, degenerative changes in the spinal joints, and marginal exostoses may also be detected. Osteoporotic changes can occur in the thickened vertebrae.

Treatment. Attempts at conservative treatment for gigantism and acromegaly have proven ineffective and are therefore unjustified. The detection of pathological changes in the sella turcica via radiography or computed tomography in acromegaly indicates a pituitary adenoma. Consequently, the only effective treatment is surgical removal of the adenoma. Prompt surgical intervention is particularly crucial in cases of rapidly growing adenomas, as they threaten blindness due to optic chiasm compression.

Regarding gigantism (height exceeding 2 m), patients are generally not treated, although Kinscher reported at the 1st All-Union Congress of Orthopedist-Traumatologists (Moscow, 1961) that he shortened the femurs of a female artist by resecting a portion of the femoral diaphysis followed by intramedullary nailing using Küntscher rods.