Orthopedics - Oleksa A.P. 2006

Metabolic Bone Diseases
Endocrine Skeletal Disorders
Cushing's Disease

This disease was first described in 1925 by N. M. Itsenko, and later in 1932 by H. Cushing, who indicated that its underlying cause is a basophilic Adenoma of the adenohypophysis.

This rare condition can develop at any age, though it is most frequently observed in women after Puberty (Fig. 88).

The Etiology of the disease is most commonly associated with a basophilic adenoma of the anterior Pituitary Gland or its basophilic hyperplasia.

In pituitary basophilism, the decisive factor is ACTH hyperfunction, which leads to excessive steroid production by the adrenal cortex. The heightened secretion of glucocorticosteroids accelerates Gluconeogenesis. As a consequence, the body breaks down protein from all available sources—including the skeletal bones—to meet the increased demand for carbohydrate synthesis. Furthermore, these corticosteroid Hormones disrupt not only Protein METABOLISM but also mineral Homeostasis, ultimately resulting in generalized Osteoporosis.

Patients commonly complain of headaches, eye pain, lower back pain, profound weakness, and rapid fatigability. Female patients additionally report menstrual irregularities, facial Hair growth, obesity, and other related symptoms.

X-ray Examination of the Skeleton reveals systemic osteoporosis, particularly in chronic cases. Osteoporosis serves as a crucial diagnostic indicator, as radiological manifestations sometimes precede clinical symptoms. These osteoporotic changes typically appear first in the Skull, spine, and Ribs, whereas the long BONES OF THE extremities remain relatively unaffected for some time.

According to Reinberg, the osteoporosis associated with Cushing's disease presents on radiographs as a diffuse, homogeneous, fine-grained pattern, somewhat mimicking similar bone changes seen in hyperparathyroidism or Osteomalacia. However, unlike these conditions, Cushing's disease does not involve bowing of the long bones.

Spinal radiographs reveal a wide-meshed Structure OF THE vertebral bodies or even an apparent loss of their spongy architecture. The superior and inferior endplates of the vertebral bodies are gently depressed, causing the vertebrae to resemble fish vertebrae ("fish vertebrae" sign). Conversely, the intervertebral discs appear tall and swollen.

Class="center">

Fig. 88. Cushing's disease in a 12-year-old girl.

American radiologists consider the marginal Condensation sign to be a vital diagnostic marker specific to Cushing's disease. This sign appears on radiographs as a dark, band-like "frame" surrounding the radiolucent vertebra. Pathognomonic for Cushing's disease, this feature is absent in spinal osteoporosis of other etiologies.

Osteoporosis frequently leads to compression fractures of several thoracic or thoracolumbar vertebrae—specifically in the regions experiencing the highest mechanical load from an obese torso.

The length of the extremities remains proportional to the torso for a considerable time, though it may appear altered due to vertebral compression fractures and the resulting loss of trunk height.

Osteoporosis and zones of restructuring in the long tubular bones and ribs are occasionally complicated by pathologic fractures. These fractures occur with minimal physical effort and cause relatively little pain, which can be attributed to the analgesic effect of high circulating levels of corticosteroids. Healing occurs with The formation of a large, poorly structured callus.

It is worth noting that children and adolescents with basophilic pituitary adenoma may exhibit delayed skeletal development and somewhat retarded epiphyseal-metaphyseal fusion.

Once Cushing's disease is promptly diagnosed, patients should be referred to an endocrinologist for comprehensive evaluation and management. Conservative Treatment or surgical removal of the adenoma is known to improve the condition of the Skeletal System, reduce the severity of osteoporosis, and can even lead to the complete resolution of its radiological signs.