Diffuse idiopathic skeletal hyperostosis may give the typical
postural abnormalities of advanced ankylosing spondylitis
I. Olivieri, S. D’Angelo, M. S. Cutro, A. Padula, G. Peruz, M. Montaruli, E. Scarano1, V. Giasi,
C. Palazzi2and M. A. Khan3
Objectives. To describe a case-series of patients who presented with the typical postural abnormalities of long-standing advanced
ankylosing spondylitis (AS) but were instead found to suffer from diffuse idiopathic skeletal hyperostosis (DISH).
Methods. We enrolled consecutive patients who showed postural abnormalities, which at first suggested to us the diagnosis of long-standing
advanced AS, although the diagnostic process led us to the correct diagnosis of DISH. Each patient had a complete physical examination and
radiographs of the spine and pelvis, and was investigated for HLA-B27 locus typing.
Results. From 15 June 1998 to 15 June 2006, 15 patients with DISH were seen who presented with the typical postural abnormalities of
long-standing advanced AS. All patients were males with a median age of 69yrs (range 51–91). All lacked HLA-B27 and denied personal
or family history of spondyloarthritis. All measurements assessing cervical, thoracic and lumbar spinal movement were abnormal.
Conclusions. Patients suffering from DISH can occasionally have severe limitations of spinal mobility, along with postural abnormalities that
resemble long-standing advanced AS. Thus, the differential diagnosis between DISH and advanced AS is not limited to the radiological
findings and can also extend to the clinical findings in the two diseases, as is highlighted by our report.
KEY WORDS: Diffuse idiopathic skeletal hyperostosis, Ankylosing spondylitis, Differential diagnosis.
Ankylosing spondylitis (AS) and diffuse idiopathic skeletal
hyperostosis (DISH) are two different diseases sharing the
involvement of axial skeleton and peripheral entheses [1, 2].
Symptoms of AS start at a young age, usually in late adolescence
and early adulthood, and consist of inflammatory spinal pain and
stiffness, decreasing range of spinal motion, and after many years
the illness can result in characteristic postural abnormalities
(‘Bechterew stoop’). In contrast, DISH, also known as ankylosing
hyperostosis, affects middle-aged and elderly persons and is
often asymptomatic, or is associated with mild dorso-lumbar pain
and/or some restriction of spinal mobility.
DISH has long been considered a radiographic entity with
minor and non-significant clinical manifestations. Till some years
ago, the differential diagnosis between AS and DISH was limited
to the radiological aspects since both diseases produce bone
proliferation (hyperostosis) in the spine and at extraspinal
In 1998, we came across a patient (patient # 1) with postural
abnormalities, which at first suggested to us the diagnosis of long-
standing advanced AS, although further evaluation led us to the
correct diagnosis of DISH. This observation led us to describe
a case-series of similar patients with the aim to better elucidation
of this under-recognized aspect of the differential diagnosis
between the two diseases.
Patients and methods
For the present study, we enrolled all consecutive patients seen for
the first time in our three out patient clinics, who showed the
postural abnormalities typical of long-standing advanced AS but
subsequently were diagnosed to be suffering from DISH. Patients
should have had forward stooping of the neck, high dorsal
kyphosis, rounding of the shoulders, obliteration of the normal
lumbar lordosis, wasting of the buttocks, flattening of the chest
and ‘ballooning’ of the abdomen.
The study was approved by the local ethics committees and
written consent was obtained from each enrolled patient accord-
ing to the Declaration of Helsinki.
Each patient was questioned about clinical symptoms of
spondyloarthritis (SpA) including inflammatory spinal pain,
buttock pain, peripheral arthritis, peripheral enthesitis, dactylitis,
chest wall pain, ocular symptoms of conjunctivitis and uveitis,
cutaneous and gastrointestinal symptoms, and urogenital or
enteric infections. Patients were also questioned about family
history of SpA and HLA-B27 associated diseases.
Each patient had a complete physical examination, including
peripheral joints, peripheral entheses and spine. Measures of
spinal mobility included:
(i) Schober test: the examiner marked a point midway along the
superior iliac spines. A second point was marked 10cm
vertically above when the patient was standing erect.
Following maximal forward flexion of the spine, the
normal if the difference was >5cm.
(ii) Finger-to-floor distance: distance between the tip of the
middle finger and the floor following maximal forward
flexion with knees extended.
(iii) Lumbar lateral flexion: distance between the tip of ipsilateral
middle finger and the floor following maximal lumbar lateral
flexion, with both feet on the floor, knees extended and
(iv) Chest expansion: the difference in centimetres between full
expiration and full inspiration, measured at the 4th inter-
(v) Occiput-to-wall distance: horizontal distance between occi-
put and wall while patient stands with heel and buttock
against the wall.
(vi) Flexion and extension of the cervical spine: distance between
the chin and the jugular notch of manubrium sterni in full
flexion and in full extension, respectively.
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Rheumatology Department of Lucania, San Carlo Hospital and Madonna delle
Grazie Hospital, Potenza and Matera,1Radiology Department, San Carlo Hospital,
Western Reserve University, Division of Rheumatology, Cleveland, OH, USA.
2Division of Rheumatology of ‘‘Villa Clinic’’, Chieti, Italy and
Submitted 26 February 2007; revised version accepted 27 July 2007.
Lucania, San Carlo Hospital, Contrada Macchia Romana, 85100 Potenza, Italy.
to: DrI.Olivieri,MD,Rheumatology Departmentof
Rheumatology 2007; 1 of 3doi:10.1093/rheumatology/kem227
? The Author 2007. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: email@example.com
Rheumatology Advance Access published October 15, 2007
by guest on June 2, 2013
Each patient was also studied for complete blood count,
erythrocyte sedimentation rate (ESR), C-reactive protein (CRP),
uric acid, glucose, urinalysis and tested for HLA-B27.
Each patient had a pelvic radiograph (an anteroposterior
view) and also radiographs of the spine. The diagnosis of
DISH was made according to the criteria suggested by Resnick
et al. [3, 4]:
(i) the presence of flowing ossification along the anterolateral
aspect of at least four contiguous vertebral bodies;
(ii) the presence of relative preservation of the intervertebral
disc height in the involved vertebral segment and the
absence of radiographic changes of degenerative disc
(iii) the absence of apophyseal joint bone ankylosis and sacroiliac
joint sclerosis, erosion and fusion.
In order to obtain reference values for spinal mobility
measures, a control group of age- and sex-matched healthy
subjects was enrolled. In all control subjects radiographs of the
spine and pelvis were performed.
In the period extending from 15 June 1998 to 15 June 2006,
15 patients with the typical postural abnormalities of AS due
to DISH were seen. All enrolled patients suffered from mild
mechanical spinal pain. The reason for the consultation was long-
standing limitation of spinal mobility.
All patients had four or more contiguous vertebrae bridged as
a minimum criterion of DISH. No patient presented radiological
evidence of sacroiliitis, squaring of vertebral bodies, syndesmo-
phytes, spondylodiscitis, apophyseal joint sclerosis and ankylosis,
or prominent reduction of intervertebral disc spaces. All patients
showed ‘flowing mantles’ of ossification of the anterior long-
itudinal ligament (Figs 1 and 2).
All patients were males with a median age of 69yrs (range
51–91). Acute phase reactants were normal in all patients except
one. All lacked HLA-B27 and denied personal or family history
The control subjects, all males with a median age of 69yrs
(range 47–84), did not show any DISH features but only signs
of spondylosis on radiographs of the spine and pelvis.
In DISH patients,all measurements
thoracic and lumbar spinal movements were abnormal in
comparisonwith control subjects
P<0.05). In particular, the median values of spinal measures,
recorded in DISH patients and controls, respectively, were as
follows: cervical flexion (jugular notch to chin distance) 7.0cm
(range 0.0–10.0) vs 3.0cm (range 0.0–5.0); cervical extension
(jugular notch to chin distance) 15.0cm (range 13.0–22.0)
vs 19.0cm (range 16.0–24.0); occiput-to-wall distance 10.0cm
(range 3.0–19.0) vs 3.0cm (range 0.0–9.5); Schober test 1.5cm
(range 0.5–5.0) vs 5.0cm (range 4.0–5.5); right lateral flexion
58.0cm (range 53.0–65.0) vs 52.0cm (range 41.0–60.0); left
lateral flexion 56.0cm (range 52.0–65.0) vs 53.0cm (range
37.0–58.0); chest expansion 2.0cm (range 1.0–4.0) vs 4.5cm
(range 4.0–6.0); and finger-to-floor distance 32.0cm (range
15.0–40.0) vs 12.0cm (range 0.0–28.0).
With regard to comorbid conditions, five patients (# 3, 5, 9, 10,
12) had diabetes mellitus, five (# 6, 7, 8, 12, 15) had dyslipidaemia,
one (# 4) had severe obesity (body mass index¼35), two (# 2, 15)
had coronary artery disease and one (# 7) had multinodular
One patient (# 1) suffered from dysphagia caused by large
pharynx and the oesophagus.
DISH has for a long time been considered a radiographic entity
with less importance given to clinical signs and symptoms than
other spinal diseases. In general this is true. However, patients
with DISH may have spinal pain and marked decrease of
spinal mobility. Occurrence in DISH patients of marked
reduction in spinal mobility and greater physical disability when
compared with healthy subjects has recently been emphasized
by Mata et al. .
Spinal involvement of DISH is characterized by ‘flowing’
ossification of the anterior longitudinal ligament typically
separated from the anterior aspect of the vertebral body by a
thin radiolucent line . The thoracic region is predominantly
FIG. 2. Lateral view of the cervical spine from patient # 5 showing a radiolucent line
(arrow) between the ossified anterior longitudinal ligament and the anterior aspect
of the vertebral bodies together with the ossification of the posterior longitudinal
FIG. 1. Lateral view of the lumbar spine from patient # 6 showing flowing
ossification on the anterior aspect of the vertebrae. A radiolucent line (arrow)
between the ossified anterior longitudinal ligament and the anterior aspect of the
vertebral bodies is evident.
2 of 3 I. Olivieri et al.
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affected but any or all levels may be involved. To differentiate Download full-text
DISH from other spinal disorders including AS, spondylosis
deformans and intervertebral osteochondrosis, Resnick et al. [3, 4]
suggested the aforementioned criteria for the diagnosis of DISH.
According to Arlet and Mazie ` rez , the involvement of three
contiguous vertebral bodies at the lower thoracic level is sufficient
for the diagnosis of DISH. Sacroiliac capsular bridging has been
described in patients with DISH [7, 8]. This may give the false
appearance of obliteration of the sacroiliac joint space that occurs
in patients with AS on the pelvic X-ray anteroposterior view.
In these cases, computed tomography shows intact sacroiliac joint
space and presence of anterior capsular bridging due to capsular
On the contrary, axial involvement in AS is characterized
by vertebral body squaring, Romanus lesion, syndesmophytes,
spondylodiscitis, apophyseal joint sclerosis and ankylosis, and
sacroiliitis . The radiological findings of axial involvement of
AS and DISH are so different that in patients with the coexistence
of the two diseases it is possible to identify the changes due to each
disease at any level [10–12].
Clinical presentation of DISH patients with severe spinal
limitation and postural abnormalities resembling long-standing
advanced AS that we have highlighted in this report have not
been previously reported to the best of our knowledge. All
patients enrolled in the present study showed clinical and
postural abnormalities that initially made us suspect the
presence of AS. However, none of the reported patients
had sacroiliac joint changes compatible with AS. This was the
prime indication that AS was not the correct diagnosis; the
presence of changes more characteristics of DISH (i.e. ossifi-
cation at the anterior longitudinal ligament with a radiolucent
line between the new bone and the adjacent vertebral body)
andthe absence ofvertebral
In conclusion, our study suggests that patients suffering from
DISH can have severe limitation of spine mobility and associated
postural abnormalities typical of long-standing advanced AS.
Our report suggests that the differential diagnosis between DISH
and long-standing advanced AS is not limited to the radiological
findings and can also extend to the clinical aspects.
Funding: This work was supported by a grant from the
Government of Basilicata (Lucania) Region of Italy.
Disclosure statement: The authors have declared no conflicts of
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another report.J Rheumatol
Rheumatology key messages
? Patients suffering from DISH can occasionally have postural
abnormalities that resemble long-standing advanced AS.
? The differential diagnosis between DISH and long-standing
advanced AS is not limited to the radiological findings and can
also extend to the clinical aspects.
DISH may give postural abnormalities of AS 3 of 3
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