Diffuse Idiopathic Skeletal Hyperostosis (DISH)

What happens in DISH

In DISH, calcium deposits form and turn into bone at entheses, the points where ligaments and tendons attach to bone. In the spine, the anterior longitudinal ligament running down the front of the vertebrae ossifies, producing a thick, flowing "candle wax" layer of bone that can bridge several vertebrae. It usually starts in the thoracic (mid back) spine on the right side, and can extend to the neck and lower back.

Unlike arthritis, the discs between vertebrae and the small facet joints are usually preserved, and there is little inflammation.

DISH can also affect joints and tendon attachments outside the spine: heels (spurs at the Achilles and plantar fascia attachments), elbows, knees, shoulders, hips and pelvis.

Who gets DISH

DISH is common in older adults, found on X-rays in a substantial minority of people over 60, and more often in men. Risk factors include:

• age over 50
• male sex
• type 2 diabetes and insulin resistance
• obesity and metabolic syndrome
• high blood pressure and gout
• long-term use of retinoid medicines (vitamin A derivatives)

The cause is not fully understood; metabolic and growth factors that stimulate bone formation are thought to play a role.

Symptoms

Many people with DISH have no symptoms, and it is found on an X-ray taken for another reason. When symptoms occur:

• stiffness of the mid back, neck or lower back, often worse in the morning and in cold weather
• reduced ability to bend or turn
• mild back or neck pain
• pain and tenderness at tendon attachments: heel, elbow, knee or shoulder
• difficulty swallowing, a lump feeling, hoarseness or, rarely, breathing problems if large bone spurs in the neck press on the esophagus or airway
• rarely, numbness or weakness if bone growth narrows the spinal canal

DISH vs ankylosing spondylitis

DISH is also different from spondylosis (degenerative arthritis of the spine), which narrows discs and forms smaller, horizontal bone spurs. The two often coexist.

Diagnosis

• X-rays: show flowing bone along the front and side of at least four consecutive vertebrae, with preserved disc heights and normal sacroiliac joints (the Resnick criteria).
• CT or MRI: to assess fractures, spinal canal narrowing or neck spurs affecting swallowing.
• Swallow studies or endoscopy: when swallowing difficulty is present, to confirm the bone spur as the cause and exclude other problems.
• Blood tests: usually normal; used to check blood sugar and rule out inflammatory arthritis.

Treatment

There is no treatment that removes the extra bone or stops DISH, so care focuses on symptoms and complications:

• Exercise and physical therapy: stretching and range-of-motion exercises maintain flexibility; strengthening and aerobic activity help weight and metabolic health.
• Pain relief: acetaminophen (paracetamol) or anti-inflammatory medicines at the label dose, if safe for you; heat for stiffness.
• Injections at painful tendon attachments, such as the heel or elbow.
• Managing metabolic risk factors: blood sugar, weight, blood pressure and cholesterol.
• Swallowing problems: diet changes and swallowing therapy; surgery to remove large neck bone spurs if symptoms are severe.
• Spinal surgery: for fractures or spinal cord compression.

Complications

• Fractures: a fused spine behaves like a long, rigid bone and can break with minor trauma, such as a fall from standing. These fractures can be unstable and injure the spinal cord. Any new back or neck pain after a fall needs prompt imaging, often CT.
• Dysphagia and airway problems from neck spurs.
• Spinal stenosis from ossification of other spinal ligaments.
• Difficulty with intubation for anesthesia in people with neck involvement.
• Heterotopic bone formation after hip replacement surgery.

Outlook

DISH progresses slowly over years. Most people manage well with exercise and symptom treatment. Awareness of fracture risk and prompt assessment after injuries are important.

Frequently asked questions

What is DISH disease?

DISH, or diffuse idiopathic skeletal hyperostosis, is a condition in which ligaments and tendons turn to bone, mainly along the spine. It causes stiffness and reduced flexibility, mostly in people over 50. It is also called Forestier disease and is often linked to type 2 diabetes and obesity.

What are the symptoms of DISH?

Many people have no symptoms. Others notice stiffness and mild pain in the mid back or neck, reduced movement, heel or elbow pain, and sometimes difficulty swallowing or hoarseness. Symptoms usually develop slowly over years.

Is DISH the same as arthritis?

No. DISH is not a true arthritis, because it does not mainly damage the joints or cause much inflammation. It affects ligaments and tendon attachments. It is often confused with osteoarthritis of the spine and with ankylosing spondylitis, which have different features.

Can DISH cause trouble swallowing?

Yes. Large bone spurs at the front of the neck vertebrae can press on the esophagus, causing food to stick, choking or a lump feeling. Rarely they affect the voice or breathing. Swallowing therapy helps, and surgery to remove the spurs is an option for severe cases.

Is DISH serious?

Usually it is not, and many people never have symptoms. The main serious risk is that a stiff, fused spine can fracture after minor trauma, potentially injuring the spinal cord. Severe swallowing problems are another complication that may need treatment.