Monday, June 14, 2010

Disease that mimic Ankylosing Spondylitis- DISH (Diffuse idiopathic skeletal hyperostosis)




I. Recent findings in DISH

The diagnosis of DISH or Forestier's disease is based solely on radiographic abnormalities defined using the Resnick criteria. DISH is a condition characterized by calcification and/or ossification of soft tissues, mainly entheses, ligaments and joint capsules. Its prevalence increases with age and, therefore, DISH is a relatively common entity in the elderly. Witnessing the present increase in lifespan, obesity, DM and metabolic syndrome in the Western population, the prevalence of DISH should be expected to rise.

Recent findings: Recent studies confirm that patients with DISH have

a. Strong association with obesity: DISH patients have a greater body mass index, increased waist circumference
b. Strong association with metabolic disturbances: DISH patients have disturbed lipid profile (dyslipidaemia), hypertension, , diabetes mellitus (DM), hyperuricaemia, metabolic syndrome and an increased risk for cardiovascular diseases.
c. In addition, DISH is most probably related to abnormal bone cell growth/activity reflecting the influence of metabolic factors that lead to new bone formation. Serum matrix Gla protein may be a marker of osteometabolic syndromes, such as DISH, that cause hyperostosis.

II. Extra-skeletal manifestation of DISH

The classical site of involvement is the spinal column with right anterolateral soft tissue ossification being the most characteristic feature. However, DISH is not limited to the spine, and may affect multiple peripheral sites independently. Extraspinal entheseal ossifications are common and observing their isolated presence may lead to the diagnosis of DISH. Furthermore, hypertrophic or atypical OA observed in joints usually not affected by primary OA has frequently been reported in DISH.

III. Following are few facts that is important for a clinician to know about DISH & AS:

1. a. Diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS) share involvement of the axial skeleton and peripheral entheses.
b. Both diseases produce bone proliferations in the later phases of their course. Patterns of these bone proliferations are dissimilar.
c. Both advanced DISH and advanced AS may cause the same limitations of spinal mobility and postural abnormalities.
c. However, the radiologic spinal findings are so different that changes due to each disease can be recognized even in patients in whom both diseases occur.

Radiologic differential diagnosis between the two diseases exists mostly as a consequence of a lack of awareness of their characteristic clinical and radiographic features.

Two characteristic radiographic features include:

a. The predominantly horizontal nature of the enthesiophyte in DISH.

b. Right preponderance in the thoracic region due to the presence of the thoracic aorta located in the left thoracic side.

The differentiating point radiologically is

A midthoracic notch in DISH which seemed to be confined to noninflammatory conditions, but was not found in ankylosing spondylitis.

2. Postural differentiation is also some times difficult between DISH & AS. In a study of 15 patients form the age of 51-91 years all seronegetive for HLA-B27 & diagnosed DISH showed that DISH can occasionally have severe limitations of spinal mobility, along with postural abnormalities that resemble long-standing advanced AS.

3. AS & DISH can occur in the same patient with their respective peculiar clinical & investigative feature. SI joint CT scan is an invaluable diagnostic aid in this case.
DISH is also found to co-exist with OA. But DISH differ from patients with primary OA in several aspects i.e. prevalence in the general population, gender distribution, anatomic site of primary involvement, magnitude and distribution in the spine and the peripheral joints.

IV. Options in management in DISH

Little is known about the pathogenesis of the disease and possible therapeutic interventions.

a. Treatment should be aimed at the symptomatic relief of pain and stiffness; the prevention, retardation or arrest of progression; the treatment of associated metabolic disorders and the prevention of spontaneous or induced complications.

b. Change of lifestyle, nutrition and therapeutic options to alleviate pain and stiffness are measures that might improve quality of life in patients affected by DISH. Control of associated metabolic disorders such as hypertension, hyperinsulinaemia with or without hyperglycaemia, hyperlipidaemia and hyperuricaemia may reduce the morbidities associated with these disorders and prevent further progression of the condition.

Chiropractic approach to management of DISH:

Though only one research mentioned 3 patients benefited a little out of 15 selected Troyanovich et al claimed in a case study that Chiropractic approach to management of DISH.

Following procedures are found to be effective in that case study- chiropractic manipulation and drop table adjustments, along with range-of-motion exercise, extension exercise, and standing lumbar extension traction.

Physiotherapeutic approach to management of DISH

According to Al-Herz et al who evaluated the effect of exercise therapy on back pain, spinal range of motion (ROM), and disability in persons with DISH exercise program designed for DISH led to small improvements in physical measures which achieved significance only for lumbosacral flexion. Out of only 16, 14 people completed this study 8 (53.3%) participants rated their status as improved, 3 (20%) as unchanged, and four (27%) were unsure about the benefit.

Exercise program included mobility, stretching, and strengthening exercises for the cervical, thoracic, and lumbar spine.

Final words:

Recent developments in our understanding of the molecular basis of the ligamentous and entheseal changes that lead to the development of DISH might pave the way to future, more targeted and effective therapies.

Readers are advised to refer my previous article on DISH on this blog

References:

1. Olivieri I et al; Curr Rheumatol Rep. 2009 Oct;11(5):321-8. (Diffuse idiopathic skeletal hyperostosis: differentiation from ankylosing spondylitis.)
2. Olivieri I et al; Rheumatology (Oxford). 2007 Nov;46(11):1709-11. Epub 2007 Oct 15. (Diffuse idiopathic skeletal hyperostosis may give the typical postural abnormalities of advanced ankylosing spondylitis.)
3. Maertens M et al; J Rheumatol. 1992 Dec;19(12):1978-83. (Simultaneous occurrence of diffuse idiopathic skeletal hyperostosis and ankylosing spondylitis in the same patient.)
4. Maertens M et al; Clin Rheumatol. 1992 Dec;11(4):551-7. (Evaluation of the involvement of axial entheses and sacroiliac joints in relation to diagnosis: comparison among diffuse idiopathic skeletal hyperostostis (DISH), osteoarthrosis and ankylosing spondylitis.)
5. Sarzi-Puttini P et al; Curr Opin Rheumatol. 2004 May;16(3):287-92. New developments in our understanding of DISH (diffuse idiopathic skeletal hyperostosis).
6. Mader R et al; Rheumatology (Oxford). 2009 Dec;48(12):1478-81. Epub 2009 Sep 25. (Extraspinal manifestations of diffuse idiopathic skeletal hyperostosis.)
7. Mader R; Expert Opin Pharmacother. 2005 Jul;6(8):1313-8. (Current therapeutic options in the management of diffuse idiopathic skeletal hyperostosis.)
8. Troyanovich SJ et al; J Manipulative Physiol Ther. 2003 Mar-Apr;26(3):202-6. (A structural chiropractic approach to the management of diffuse idiopathic skeletal hyperostosis.)
9. Al-Herz A et al; Clin Rheumatol. 2008 Feb;27(2):207-10. Epub 2007 Sep 21. (Exercise therapy for patients with diffuse idiopathic skeletal hyperostosis.)





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