Diffuse Idiopathic Skeletal Hyperostosis

Diffuse idiopathic skeletal hyperostosis, also called Forestier’s disease is characterized by unique, flowing (wave like in shape) calcification along the sides of the vertebrae of the spine. It is also commonly associated with inflammation and calcification of tendons at their attachments points to bone, a condition called enthesitis. Enthesitis can frequently lead to bone spurs such as heel spurs.

Usually the disease occurs after fifth decade of life.

Diagnostic Criteria

• Flowing calcifications and ossifications along the anterolateral aspect of at least 4 contiguous vertebral bodies, with or without osteophytes
• Preservation of disc height in the involved areas and an absence of excessive disc disease
• Absence of bony ankylosis of facet joints and absence of sacroiliac erosion, sclerosis, or bony fusion.

Unlike ankylosing spondylitis, DISH does not involve the sacroiliac joint.

Most commonly involved spine is lower thoracic spine involvement which is also is typical of DISH, but the lumbar and cervical spine also can be affected. The right side of spine is more commonly involved. The lesser involvement of left side of spine is attributed to pulsation of aorta on this side.

Etiology

The etiology of diffuse idiopathic skeletal hyperostosis (DISH) is not certain. Metabolism and increased uric acid have been implicated but no confirmed role has been defined.

It affects 6-8% people.

Presentation

DISH is only slowly progressive. Calcifications between the vertebrae occur over many years. This calcification can lead to limitation of motion of the involved areas of the spine.

Back pain with a stiff back is most common complaint. Rarely, kyphosis is present. Dysphagia may occur due to an indenting osteophyte.

Chronic pneumonia, hyperextension injuries of spine, airway obstruction, vocal cord paralysis, compression of the inferior vena cava, spinal canal stenosis and  heterotopic ossification have been reported to occur in patients of DISH.

Complaints are intermittent. Stiffness is worse in the morning and is relieved with mild activity.

Investigations

Radiograph of the thoracic and lumbar spine  is usually enough to make a diagnosis. Computed tomography  may be performed to evaluate complications, such as fracture, or  to conform  pressure effects on the trachea, esophagus, and veins.

Radiographs   demonstrate typical changes in spine as discussed earlier in this article. Other findings in other regions may be

• Ossification of the nuchal ligaments in skull
• Enthesopathy at the ischial tuberosities, ossification of the sacrotuberous ligament and symphysis pubis in pelvis
• Ossification of the quadriceps and infrapatellar tendons
• Ossification of the Achilles tendon and the plantar aponeurosis
• Ossification of the triceps tendon
• Subcutaneous calcification

There is no associated threat to any internal organs with this disorder.

Treatment

There is no specific treatment and the patients are treated symptomatically with anti inflammatory drugs, local heat and physical therapy. Any complication is treated accordingly.