Presentation
The patient will complain of back pain and spinal stiffness.
The patient may have other comorbidities such as gout or diabetes, and they need to get their hemoglobin A1c tested. Some patients may have high cholesterol levels.
DISH will present with large syndesmophytes, and if the condition occurs in the neck, it will cause dysphagia, hoarseness of the voice, and sleep apnea. The syndesmophytes are equal on the right and the left sides in the lumbar and cervical vertebrae.
Diagnosis
Diagnosis can be established by x-ray of the spine. On the lateral x-ray of the cervical spine, anterior bony fragments will be found and the discs will be preserved. When you look at the x-ray, ossification along the anterior aspect of the body, but separate from the vertebrae will be found, and will also be seen to have flowing ossification along the anterolateral aspect of at least four continuous vertebrae. Also, disc height will be preserved. There is no involvement of the discs and there is no facet or sacroiliac joint involvement.
Occult Fractures
Fractures in the spine of patients with DISH are usually due to hyperextension injury and can be occult, usually resulting from minor trauma, and may have major instability. If the patient has a history of trauma or a history of sudden neck or back pain, then the patient will be assumed to have an occult fracture. Therefore, a CT scan or an MRI are necessary, even if the pain is minimal or if x-ray appear normal.
Heterotopic ossification after total hip arthroplasty is seen more in patients with DISH. There is also an increased mortality in cervical spine trauma with DISH, especially in non-operative treatment.
Differential Diagnosis
DISH will have a “candle wax” appearance, while ankylosing spondylitis will appear more as a “bamboo spine”.
DISH will have large, flowing syndesmophytes, the disc space will be preserved, the sacroiliac joint will not be involved, it often occurs on older patients, and patients may have diabetes. On the other hand, ankylosing spondylitis will not have large flowing osteophytes, will have diffuse ossification of the disc space, the patient is usually young, the sacroiliac joint is involved, HLA-B27 is positive in most cases, and the patient will have limited chest expansion. For diagnosing DISH, focus on the large ossification with is separate from the vertebrae. It is truly challenging to differentiate between diffuse idiopathic skeletal hyperostosis and ankylosing spondylitis.
