Seronegative spondyloarthropathies

Seronegative spondyloarthropathies in Radiology

1. -DR SAJAN VARMA SERONEGATIVE SPONDYLOARTHROPATHIES

2. introduction Seronegative spondyloarthropathies are a group of musculoskeletal syndromes linked by common clinical features and common immunopathologic mechanisms. Negative to rheumatoid factor and mostly involve the axial skeleton. Most have positivity to the HLAB27 gene.

3. CLASSIFICATION Ankylosing spondylitis Psoriatic arthritis Reactive arthritis ( Reiter syndrome ) Enteropathic arthritis ( i.e. extra-intestinal manifestation of IBD)

4. Ankylosing spondylitis Ankylosing spondylitis  (also known as Bechterew disease  and Marie Strümpell disease)  is a spondyloarthropathy,   which, as the name suggests, results in fusion (ankylosis) of the spine and sacroiliac (SI) joints, although involvement is also seen in large and small joints . There is a male predilection of 3:1 and it usually manifests in young adults The axial skeleton is predominantly affected, although in ~20% of cases the peripheral joints are also involved .

5. Imaging Sacroiliitis  is usually the first manifestation  and is symmetrical and bilateral T he sacroiliac (SI) joints first widen before they narrow S ubchondral erosions, sclerosis and proliferation on the iliac side of the SI joints A t end-stage, the SI joint may be seen as a thin line.

6. Imaging (CONTINUED) Spine - early spondylitis is characterized by small erosions at the corners of vertebral bodies with reactive sclerosis: Romanus lesions of the spine ( shiny corner sign) Vertebral body squaring D iffuse syndesmophytic ankylosis can give a " bamboo spine " appearance Interspinous ligament ossification can give a " dagger spine " appearance on frontal radiographs Ossification of spinal ligaments, joints and discs (with fatty marrow within the ossified disc, best seen on MRI) Apophyseal and costovertebral arthritis and ankylosis

7. Other findings There can be bridging or fusion of the pubic symphysis. Knees demonstrate uniform joint space narrowing with bony proliferation . Hands are generally involved asymmetrically, with smaller, shallower erosions and marginal periostitis. Shoulder joint involvement is not uncommon and demonstrates a large erosion of the anterolateral aspect of the humeral head, producing a ' hatchet ' deformity .

8. RADIOGRAPH OF THE SACRO-ILIAC JOINT SHOWING FUSION OF THE JOINT IN A CASE OF ANKYLOSING SPONDYLOARTHROPATHY

9. BAMBOO SPINE

10. DAGGER SIGN -DENSE LINE CAUSED BY OSSIFICATION OF SUPRASPINOUS AND INTERSPINOUS LIGAMENTS IN ANKYLOSING SPONDYLITIS

11. Psoriatic arthritis Etiology is considered to be a combination of environmental and hereditary factors . 60% of patients being HLA-B27 positive . Approx . 10%–15% of patients with skin manifestations of psoriasis will develop psoriatic arthritis. Usually such manifestations will precede the development of arthritis.

12. RADIOLOGIC FINDINGS The hallmarks of psoriatic arthritis are signs of inflammatory arthritis combined with bone proliferation , periostitis and enthesitis. In the hands, wrists, and feet, a distal distribution is characteristic . Findings may be bilateral or unilateral and symmetric or asymmetric. “ Sausage digit” Diffuse fusiform swelling of a digit due to involvement of several joints in a single digit . “Fuzzy” appearance or “whiskering” Bone proliferation produces an irregular and indistinct appearance to the marginal bone about the involved joint.

13. RADIOLOGIC FINDINGS (continued...) The erosions can cause a "pencil in cup" deformity where one articular surface is eroded creating a pointed appearance; the other articulating bone becomes concave, resembling an upside down cup. “ Ivory phalanx” Involvement of the distal phalanges (especially in the first digit) in the foot with sclerosis, enthesitis, periostitis, and soft-tissue swelling. Periostitis may appear as a thin periosteal layer of new bone adjacent to the cortex, a thick irregular layer, or irregular thickening of the cortex itself. Joint subluxation may also be present .

14. PSORIATIC ARTHRITIS Radiograph (PA) Hand. Note the asymmetrical but predominantly distal distribution. Prominent periarticular swelling ( S ), uniform loss of joint space ( J ), marginal erosions ( E ), and fluffy periostitis ( P ) complete the radiologic picture .

15. PENCIL IN A CUP DEFORMITY IN PSOARIATIC ARTHRITIS

16. IVORY PHALANX IN THE GREAT TOE IN A CASE OF PSOARIATIC ARTHRITIS

17. Difference between normal and psoriatic arthritis in hip joint

18. REACTIVE ARTHRITIS Also called Reiter’s syndrome, is a sterile inflammatory arthritis . It follows enteric or urogenital infection . Associated with urethritis and conjunctivitis.80 % positive for the HLA-B27 antigen. It is most common in young men aged 25–35 years . The features allowing differentiation between reactive arthritis and psoriatic arthritis relate to clinical history, patient sex and age, and distribution of joint involvement .

19. Radiographic features In appendicular skeleton, distribution may be unilateral or bilateral and symmetric or asymmetric. Affects feet more commonly than hands and also in more severe form. Findings seen in the hands, wrists, and feet include joint inflammation, bone proliferation, periostitis , and enthesitis, Calcaneal enthesitis and spur formation occurs in 35-40 %. Sausage digit and pencil-and-cup deformities may also occur. In the feet, an ivory phalanx may be seen .

20. Radiographic features(continued…) Axial involvement may also occur, leading to bilateral symmetric or asymmetric sacroiliitis. Large , comma-shaped, paravertebral ossification may also be seen. Other peripheral joints are less commonly involved. Erosions & bony proliferation of the 1st to 4th MTP Joints with subluxation. Fluffy bony proliferation along the medial malleolus, navicular & sesamoid bones of the 1st metatarsal head.

21. Erosions and bone formation at the posterior calcaneus in a case of reactive arthritis

22. The radiograph shows a periosteal reaction at the plantar fascia insertion (black arrow) and early erosion at the Achilles tendon insertion ( white arrow) on the calcaneus

23. X ray foot showing thin layer of periosteal new bone at the phalangeal base at 3 rd metatarsophalengeal joint and diminished density in metatarsal head (arrowhead)

24. Enteropathic arthritis ( EA )   is a form of chronic, inflammatory arthritis associated with the occurrence of an inflammatory bowel disease (IBD), in approximately 20% of patients of IBD . A least three forms of joint abnormalities are recognised in patients with inflammatory bowel diseases according to location : peripheral joint arthritis sacroiliitis spondylitis identical to Ankylosing spondylitis

25. Lead pipe appearance of the colon (red arrows). Ankylosis of the left sacroiliac joint and partial ankylosis on the right (yellow arrow). 

26. Ct scan showing bilateral sacroiliac joint ankylosis due to enteropathic arthritis   

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