Clinical History
A 25-year-old male patient was admitted because of severe back pain and inability to stand. Physical examination showed severe tenderness of the spine. The Mantoux skin test was positive. Past medical history included a back pain syndrome 5 years prior to current admission and weight loss and diarrhoea 1 year ago.
Imaging Findings
Lumbar spine radiographs were obtained and showed no findings. MR imaging of the lumbar spine (1.5T, T1w, T2w, STIR and fat suppressed contrast enhanced T1w sequences) showed extensive oedema in the bone marrow of the posterior elements and the para-vertebral soft tissues. Focal oedema was depicted at the posterosuperior corner of the L3 vertebral body and anterior corners of the lower lumbar vertebral bodies (Fig. 1-2). All oedematous areas exhibited enhancement after contrast medium administration (Fig. 3). The AP radiograph of the pelvis showed subchondral sclerosis and erosions in the sacroiliac joints (Fig. 4).
Discussion
A. Patients with inflammatory bowel disease (IBD) may demonstrate, from 21% to 40%, extra-intestinal manifestations (EIM), most commonly from the joints, skin, eyes and biliary tract [1, 2]. Musculoskeletal is the most common location of EIM (6%-46%) [1]. Based on the type of involvement in IBD, EIMs are classified as peripheral arthropathies (5%-20%) further classified as type I and II, and IBD-related spondyloarthropathy (SpA) (3%-12%) [1, 3]. Approximately 10% of IBD patients develop SpA, clinically identical to ankylosing spondylitis, and most of them are HLA-B27 positive [2]. Isolated sacroiliitis may be asymptomatic [3]. Asymptomatic IBD, detected only by endoscopy, may coexist with SpA in 60% of patients. IBD-related SpA runs an independent course related to the activity of bowel disease [4].
B. Symptoms from peripheral or axial articular involvement can precede, be synchronous to IBD (usually of less than 6 months duration), or develop later, often as late as 10 years following the diagnosis of IBD [1]. In about 5%, arthritis occurs before IBD and sacroiliitis is the most common manifestation.
In our case, the EIM musculoskeletal manifestation of Crohn’s disease manifested prior to the bowel inflammation. Sacroiliitis was clinically mild and was obvious only on radiograph, probably preceding IBD for at least 5 years. MRI diagnosis of an inflammatory spondylitis had a great influence on changing the clinicians planned treatment towards an infectious spondylodiscitis.
C. As far as MRI findings are concerned, what makes this case unique is that lesions were observed mainly in the posterior elements of the lumbar spine, as opposed to the expected anterior enthesitis and resulting bone marrow oedema in SpA. Although symptoms of Chron's were not typical, in our case the diagnosis was established with endoscopy and biopsy.
D. MRI is the most recent imaging milestone in the diagnosis of the preradiographic phase of AS whether or not it is related to IBD. In this way it contributes in the early diagnosis and treatment of SpA which is important regarding the efficiency of the currently available anti-TNF agents.
Despite the fact that medical or surgical therapy of the underlying IBD does not usually alter the course of the axial involvement, in this case there was a significant improvement of the symptoms after medical treatment [4] .
E. Extra-intestinal manifestations of IBD could be present prior to disease, manifest in the posterior elements of spine, while MR is the gold standard for pre-radiographic detection of IBD-related spondylarthropathy.
Differential Diagnosis List
Extra-intestinal musculoskeletal manifestation, prior to Crohn’s disease
Myositis
Ankylosing spondyloarthritis
Lymphoma
Final Diagnosis
Extra-intestinal musculoskeletal manifestation, prior to Crohn’s disease
