Diffuse Idiopathic Skeletal Hyperostosis

The systemic disorder known as diffuse idiopathic skeletal hyperostosis (DISH) is characterized by distinctive ossification patterns that can affect the spine and peripheral entheses. DISH most frequently affects the spine and frequently manifests as stiffness and back discomfort.

The term DISH was first used to characterize this syndrome by Resnick et al. in 1975, and it is currently the most often-used word in the literature. The phrase both encompasses and characterizes the disease. In materials from a series of 200 patients, Forestier first identified the underlying disease in 1950 and gave it the name "senile ankylosing hyperostosis."

The ossifications in the spine are typically defined as running along the anterolateral aspect in at least three successive vertebral levels or four consecutive vertebrae.

Peripheral enthesopathy can develop in the shoulder, elbow, knee, or calcaneus, however, it is less frequent. The right side of the thoracic spinal segment is where DISH in the spine most frequently manifests.

Several risk factors, including gout, hyperlipidemia, and diabetes, have been discovered in the literature, even though the etiology is still poorly understood. In both DISH and diabetes mellitus, HLA-B8 is frequently seen. As a result, individuals with DISH have high rates of diabetic mellitus, hyperuricemia, and hyperlipidemia. Unlike other seronegative spondyloarthropathies, no connection between DISH and HLA-B27 appears to exist.

Diffuse Idiopathic Skeletal Hyperostosis: Causes

DISH is significantly associated with metabolic diseases such as diabetes mellitus, hyperinsulinemia, obesity, dyslipidemia, and hyperuricemia, according to several recent research. The pathophysiology and postulated mechanism behind these distinctive ossification patterns are still up for debate, despite the literature's suggestion of these clinical connections.

Several writers have made an effort to explain the underlying reasons, which include hereditary influences, exposure to harmful substances, mechanical stress, strain patterns, and others. Moreover, angiogenesis continues to be a prominent theme in research that, at least in principle, offers a plausible pathophysiologic relationship in a variety of clinical symptoms of DISH. For instance, people with metabolic syndrome had greater odds of correlation between carotid atherosclerosis and DISH.

Moreover, it has been discovered in the past that people with DISH had greater prevalence rates of aortic valve sclerosis, an independent risk factor for cardiovascular events.

Diffuse Idiopathic Skeletal Hyperostosis: Symptoms

Some DISH sufferers don't exhibit any symptoms. Upon studying X-rays obtained for a different purpose, doctors discover the problem.

When DISH symptoms do materialize, they consist of −

• Leg numbness or tingling

• Pain

• Diminished mobility

• Stiffness

• If DISH manifests in the neck, difficulty swallowing or hoarseness (abnormal voice changes) may result

Due to greater deforming pressures brought on by vertebral ankylosis and ligamentous calcification, patients with DISH who suffer from spine fractures are more likely to have instability. Longer instrumentation length is frequently required to account for the lever arms that are acting on the fracture site. Meyer showed the significance of rapid identification, examination, and therapy after trauma in patients with DISH by showing that surgical treatment of cervical fractures in older patients with DISH was associated with a 15% incidence of death compared to 67% following conservative treatment.

In individuals with DISH (30 to 56%), heterotopic ossification (HO) is a prevalent complication following total hip arthroplasty (THA). Patients without DISH had a 10 to 22% risk of HO in the reported study, in contrast.

Diffuse Idiopathic Skeletal Hyperostosis: Risk Factors

The major risk factors include −

• 50 years or older

• Men are more susceptible

• Fat or have diabetes

• Had long-term exposure to high vitamin A concentrations

Diffuse Idiopathic Skeletal Hyperostosis: Diagnosis

DISH frequently has normal laboratory results for erythrocyte sedimentation rate, C-reactive protein, rheumatoid factor, and antinuclear antibody. The non-marginal syndesmophytes that extend horizontally from the vertebrae and cause extra-articular ankylosis are described as "flowing candle wax" in radiographic evaluation with AP and lateral spine imaging in patients with DISH. This is distinct from the vertical "bamboo spine" that causes intra-articular disc space ossification in ankylosing spondylitis (AS).

The difference between DISH and AS, which may exhibit osteopenia and degenerative alterations, is further clarified by increased radiodensity, the preservation of facet joints, and disc gaps on spine imaging. In the literature, there is still debate on the link between DISH and poor bone density. Yet, there is a theoretical and clinical link between low-energy processes and a considerably higher incidence of vertebral fractures.

Vertebral fractures have been recorded in the literature in patients with DISH after elective, unrelated surgical operations, whereas individuals with osteoporosis might present with vertebral compression fractures while just laying in bed in a nursing home. A typical total hip replacement can result in postoperative partial paraplegia, according to one report from 2012.

Considering that the thoracic spine is frequently affected, the doctor should have a low barrier for ordering chest or thoracic radiographs, even in patients who have main neck or low back pain, stiffness, and scattered extremities symptoms. By establishing a DISH diagnosis based on thoracic imaging, other needless testing and surgical procedures could be avoided.

Increased uptake in the affected regions may be shown on a technetium bone scan in DISH, although this result may be misinterpreted as metastatic illness and is thus often ineffective in non-traumatic situations. As sacroiliac pathology may steer the diagnostic process towards other illnesses, such as seronegative spondyloarthropathies, lumbar spine involvement should be radiographically assessed at the lumbar spine and pelvis.

Patients with DISH are susceptible to fracture and instability following minor trauma. They might frequently lead to overlooked injuries that affect the nervous system and cause therapy to be delayed. Occult fractures in these individuals must be aggressively investigated with sophisticated imaging (CT, MRI, or CT myelogram). Plain radiographs can be used to examine extraspinal symptoms in individuals with DISH.

Diffuse Idiopathic Skeletal Hyperostosis: Treatment

The calcification or bone development linked to DISH cannot be stopped by treatment. Instead, treatment focuses on symptom management and delaying the progression of the illness (getting worse).

Options for DISH treatment include −

• Heat application − Warm compresses help relieve pain and stiffness.

• Medication − To treat pain, doctors may prescribe medications such as −

• Non-steroidal anti-inflammatory medications (NSAIDs) and over-the-counter painkillers

• Injections of corticosteroids

• Drugs that relax the muscles

• Physical therapy − Certain exercises can aid with mobility improvement.

• Surgery − When the bone overgrowth puts pressure on nerves or interferes with breathing, doctors may choose to operate to treat DISH.

Diffuse Idiopathic Skeletal Hyperostosis: Prevention

Maintaining a healthy weight and blood sugar levels can lower your risk of DISH. You may reduce your risk of developing DISH by limiting the amount of vitamin A-containing drugs you use.

Conclusion

There are still several crucial elements to the workup and care of these patients when they arrive, especially in the setting of small injuries, despite semantic differences about the absolute and universal agreement of DISH diagnostic criteria.

To obtain thorough histories and examinations (including required neurovascular examinations), and to have a low threshold for obtaining appropriate imaging, emergency medical services (EMS) providers, nurses, advanced practitioners, clinicians, and surgeons need efficient and coordinated care. This will help to ensure that underlying fractures are not missed. A rapid examination and management strategy are required in cases of clinical worsening.