Diffuse Idiopathic Skeletal Hyperostosis (DISH)
Diffuse = spread out, not confined to a single location
Idiopathic = with a cause that is not known
Skeletal = having to do with the skeleton
Hyperostosis = too much growth of bony tissue
Diffuse idiopathic skeletal hyperostosis (DISH) is a form of arthritis that involves the tendons and ligaments around the spine. Also known as Forestier’s disease, this condition occurs when these tendons and ligaments become hardened, a process known as calcification. Once the tendons and ligaments harden, parts of these tissues can turn into bone. This usually occurs where the tissue connects with the bone. As a result, bone spurs develop, which is an outgrowth of bone that develop along the edges of a bone.
DISH commonly affects the upper part of the back and neck, known as the thoracic and cervical spine. However, DISH can also affect the shoulders, elbows, hands, knees, hips, heels, and/or ankles.
DISH may or may not cause symptoms.
If DISH causes symptoms, these may include:
- Stiffness (most noticeable in the morning or in the evening)
- Pain in the back, especially in the upper back
- Pain in the shoulders, elbows, knees, or heels
- Pain when pressure is applied to the affected area
- Difficulty swallowing or a hoarse voice (if DISH has affected the neck)
- Loss of range of motion (difficulty moving neck or back)
- Tingling, numbness, and/or weakness in the legs
Symptoms usually develop when the bone spurs begin to compress the nearby nerves of the spine.
If a patient presents with symptoms associated with DISH, the doctor may perform a physical examination of the spine. The doctor can often make a diagnosis based on signs and symptoms.
To confirm a diagnosis of DISH, an X-ray is often performed, which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
To rule out other conditions, the doctor may order the following diagnostic procedures:
- X-ray (also known as plain films): test that uses invisible electromagnetic energy beams (X-rays) to produce images of bones. Soft tissue structures such as the spinal cord, spinal nerves, the disc and ligaments are usually not seen on X-rays, nor on most tumors, vascular malformations, or cysts. X-rays provide an overall assessment of the bone anatomy as well as the curvature and alignment of the vertebral column. Spinal dislocation or slippage (also known as spondylolisthesis), kyphosis, scoliosis, as well as local and overall spine balance can be assessed with X-rays. Specific bony abnormalities such as bone spurs, disc space narrowing, vertebral body fracture, collapse, or erosion can also be identified on plain film X-rays. Dynamic, or flexion/extension X-rays (X-rays that show the spine in motion) may be obtained to see if there is any abnormal or excessive movement or instability in the spine at the affected levels.
- Computed tomography scan (CT scan): a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce detailed images of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.
- Magnetic resonance imaging scan (MRI): a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
Although the cause of DISH is unknown, there are certain risk factors that are thought to increase the risk for DISH. These include:
- Certain endocrine disorders: Conditions such as diabetes mellitus (a condition marked by high blood sugar) and acromegaly (a hormone disorder marked by too much growth hormone in the body) affect the metabolism of cartilage, and as a result, may lead to DISH.
- Older age: Since DISH is a type of arthritis, DISH typically affects an older population.
- Male gender
- Certain medications: Retinoids, including medications used to treat severe acne, can increase a person’s risk for developing DISH.
Usually, treatment involves anti-inflammatory drugs, including non-steroid anti-inflammatory drugs (NSAIDS). Treatment will also typically include physical therapy to help reduce stiffness.
Since there is a connection between endocrine disorders such as diabetes mellitus and DISH, addressing the underlying condition can help stop the progression of DISH.
In some cases, surgery may be needed to correct structural problems in the spine. Surgery may also be an option for those patients who have difficulty swallowing as a result of bone spurs in the neck.
If DISH has resulted in bone spurs in and around the spine, and if these bony growths begin to compress the spinal cord and/or nerve roots, surgery to decompress the spinal cord may be required. In addition, if DISH has resulted in fractures, surgery is required to repair the fracture. If these fractures begin to compress the spinal cord and/or nerve roots, surgery to decompress the spinal cord may be necessary.
The surgeon may elect to perform any of the following surgical procedures to remove the pressure on the spinal cord and/or nerve roots:
In some cases, the surgeon may perform a spinal fusion to ensure the spinal column is stable after surgery. During a spinal fusion, the surgeon may place a bone in the open space and allow the bones to fuse together (fusion).
The surgeon will tailor treatment to each patient and each situation.