Enrico Scarano

Fast spin echo-T2-weighted sequences with fat saturation in toe dactylitis of spondyloarthritis

We aimed to establish by using fast spin echo (FSE)-T2-weighted sequences with fat saturation if flexor tendon enthesitis is the primary lesion in spondyloarthritis (SpA) toe dactylitis. Consecutive patients showing toe dactylitis and meeting Amor criteria for the classification of SpA were enrolled. Dactylitic toes and their corresponding normal contralateral digits were studied by FSE-T2-weighted sequences with fat saturation. Twelve dactylitic toes belonging to ten SpA patients were studied. All dactylitic toes showed mild-to-moderate fluid collection in the synovial sheaths of flexor digitorum brevis and longus. Involvement of joint cavity was simultaneously seen in at least one joint of eight (66.6%) out of the 12 toes. A mild-to-severe peritendinous soft tissue edema was observed in all but one of the affected toes. In no dactylitic toe was bone edema observed either near the insertions of the flexor digitorum brevis and longus tendons or in other sites of the phalanges. No lesions were observed in the 12 contralateral clinically normal toes. In SpA toe dactylitis there is no evidence of enthesitis of the flexor digitorum brevis and longus tendons and joint capsules.

Involvement of an inconstant bursa under the head of the second metatarsal bone in spondyloarthritis

We recently reported the case of a patient suffering from psoriatic arthritis and showing the involvement of an inconstant bursa between the head of the 5th metatarsal bone and the insertion of the tendon of abductor digiti minimi [1]. We have now seen a further case of a spondyloarthropathy patient with an inflamed synovial bursa in the forefoot. The patient was a 37-year-old man, referred to the Rheumatology Department of Lucania for evaluation of a 1-month history of severe pain in his feet which was resistant to adequate administration of non-steroidal anti-inflammatory drugs. His medical history was otherwise unremarkable and his family was negative for spondyloarthritis. Physical examination disclosed swelling, warmth and tenderness of the left ankle and along the tendons of tibialis anterior and posterior of both sides. He also complained of pain over the base of the fifth metatarsal bone of both feet, the calcaneal attachment of the plantar fascia in the left foot, and both lateral epicondyles. There was no limitation of spinal movement and no restriction of chest expansion. Laboratory evaluation revealed only an erythrocyte sedimentation rate of 28 mm/h and a C-reactive protein level of 30.1 mg/l (normal <5). HLA typing showed A3, A29, B51, B35, Cw4, DR7 and DR13. Radiographs of the feet revealed only soft tissue swelling of the left ankle. Pelvic X-rays were normal. A diagnosis of undifferentiated spondyloarthropathy was made and sulfasalazine at a dose of 2 g/day was given. In the following months, the patient returned to the clinic with a painful swelling under the second metatarsophalangeal (MTP) joint of the left foot. Ultrasonography (US), performed with a 10 Mhz linear transducer, revealed a hypoechoic oval area adjacent to the second left MTP joint and the flexor tendons of the second left toe (Fig. 1). MRI performed using fast spin echo (FSE) and gradient echo (GRE) sequences with and without fat suppression showed a 2 cm diameter, T2 hyperintense soft-tissue mass next to the plantar surface of the second left MTP joint (Fig. 2). Both US and MRI findings suggested bursitis, and this was confirmed by a biopsy from the mass showing an inflamed synovial lining. Anatomical considerations suggest that the bursa is likely to be one of the intermetatarsophalangeal bursae that are often present in the interdigital clefts in association with the insertions of the small tendons of the interossei [2, 3].

Lateral epicondylitis with marked soft tissue swelling in spondyloarthritis

Peripheral enthesitis is a clinical hallmark of spondyloarthritis (SpA) [1]. The insertions of the lower limbs are more frequently involved than those of the upper ones [1, 2]. When deep-seated insertions are involved, pain revealed by palpation is the only finding on physical examination. On the contrary, when superficial entheses like the Achilles tendon and those on the humeral epicondyles are involved, a visible soft tissue swelling is present. We have recently come across a patient with SpA showing enthesitis of the lateral epicondyle with a marked soft tissue swelling. We studied this enthesitis using different imaging techniques and observed the typical findings of SpA enthesitis seen in other sites, that is to say, bone erosion at the insertion, swelling of the insertion and bone oedema [1, 3, 4]. The patient was a 50-year-old woman with undifferentiated elderly onset B27-positive SpA lacking axial involvement [5]. The disease began in July 1999 with peripheral arthritis involving the second and third proximal interphalangeal (PIP) joints of the right hand together with enthesitis of the ulnar extensor of the right wrist and of the lateral left epicondyle without any evident swelling. In November 2000 she developed dactylitis of the second left toe and a painful swelling over the left lateral epicondyle (Fig. 1A). Radiographs of the left elbow showed erosion at the lateral epicondyle (Fig. 1B). Ultrasonography performed with a 10-MHz linear transducer showed thickening of the insertions on the epicondyle together with the interruption of the bone surface (Fig. 1C). Magnetic resonance imaging showed swelling of the insertions of the extensor brevis and of the collateral radial ligament together with bone oedema (Fig. 1D). There was also a small amount of fluid in the joint. The present report emphasizes that lateral epicondylitis of SpA is characterised by the same imaging findings observed in enthesitis of the lower limbs such as Achilles enthesitis and plantar fasciitis.

Terapia E Imaging Follow-Up

Il trattamento delle SpA in generale si basa sull’associazione di farmaci diversi ed include di norma un antinfiammatorio non steroideo ed un trattamento immunosoppressore cosiddetto “di fondo” o “modificante l’evoluzione della malattia”. In questa classe di farmaci sono inclusi sulfasalazina, ciclosporina, metotressato e leflunomide. Questi ultimi non hanno, comunque, un ruolo centrale come nell’AR.