What is Diffuse Idiopathic Skeletal Hyperostosis?
What is Diffuse Idiopathic Skeletal Hyperostosis (DISH)?
DISH is a condition where ligaments and tendons become calcified (hyperostosis), forming bone spurs, which are tiny pointed bone outgrowths. Most of these calcified ligaments are found in the upper spine, but may also affect the lower spine and neck. Other tendons and ligaments throughout the skeletal system may also be affected, and spurs may be found diffusely, even occurring on the heel, ankle, hand, knee, shoulder and hips.
About 19% of men and 4% of women older than 50 years of age are afflicted with this condition. It is a form of degenerative arthritis which also affects many mammals and even dinosaurs, as was found in paleontological and zoological records. Like arthritis it is a progressive condition that slowly develops with age but is rarely associated with complications or death.
Symptoms of DISH
Pain is not a prominent symptom although there may be marked stiffness of joints. Stiffness is most noticeable in the morning, upon getting up, with a limitation of motion and loss of lateral flexion. Pain may be felt when pressure is applied on the affected area. The upper back is most commonly involved. Back pain and neck pain are possible but not severe.
A rare complication may be the growth of spurs in the neck vertebrae, and these may impinge on internal structures like the esophagus causing difficulty in swallowing, or on the trachea, causing hoarseness of voice.
Causes and Risk Factors for DISH
The exact cause of DISH is unknown. Some risk factors have been associated with the condition, such as:
- The use of certain medications like Accutane, a retinoid similar to vitamin A
- Males are more prone to develop the condition
- Age greater than 50 years
- Diabetes type II
- Obesity, high blood sugar levels and high insulin levels
Diagnosis of DISH
Diagnosis is sometimes made from unexpected findings on X-ray studies because of the lack of symptoms. The thoracic (upper back) vertebrae (spine segments) are always involved, followed by findings of bony growths in the lumbar (lower back) area and then the neck. When evidence of diffuse bony growths is found throughout the body especially in the hips, knees and heels, the diagnosis of diffuse idiopathic skeletal hyperostosis is made.
Treatment of Bony Spurs
Although bony spurs may cause stiffness and discomfort they do not lead to major complications, except for possible vertebral fracture due to its loss of flexibility. Pain is experienced mostly when the areas involved are pressed. Medical treatment is not indicated except when pain is persistent.
Physical therapy to mobilize joints and increase their range of motion may be helpful. This should be done with a doctor’s supervision or with the help of a physical therapist.
Other measures that can help relieve pain and discomfort are the application of cold and hot packs over the area and doing regular exercises such as walking and swimming.
Indications for Surgery in DISH
In rare cases where bony spurs grow in the neck near the esophagus and cause difficulty in swallowing, surgery may be done to remove these obstructing structures. Another internal structure in the neck that may be affected is the large airway, or trachea, which when compressed by spurs, may cause hoarseness of the voice and difficulty in breathing.
Although rare, bony spurs can also cause pressure on the spinal cord, and loss of sensation and paralysis may result. This is another indication to perform surgical removal of bony spurs.
Even if this condition is slowly progressive, the prognosis for diffuse idiopathic skeletal hyperostosis is excellent. Complications and mortality are not common and symptoms may be relieved by conservative measures.
References
eMedicine, “Diffuse Idiopathic Skeletal Hyperostosis” accessed 1/25/11
https://emedicine.medscape.com/article/1258514-overview
Mayo Clinic, “Diffuse Idiopathic Skeletal Hyperostosis (DISH)” accessed 1/25/11
https://www.mayoclinic.com/health/diffuse-idiopathic-skeletal-hyperostosis/DS00740
