Department of Rheumatology and 1 Department of Radiology, Norfolk and Norwich University Hospital, Norwich, UK
Correspondence to: Anita Lim, Department of Rheumatology, Norfolk and Norwich University Hospital, Colney Lane, Norwich, NR4 7UZ. Email: anita.lim{at}nnuh.nhs.uk
SIR, Spondylodiscitis is an uncommon presentation of ankylosing spondylitis (AS). TNF- blockade has previously been shown to be markedly effective in controlling the clinical manifestations of AS with improvement in enthesitis and osteitis, as demonstrated by magnetic resonance imaging (MRI) [1]. We report dramatic improvement, both clinically and radiologically, in an adolescent with unusually florid signs of spondylodiscitis as the initial manifestation of AS, following treatment with infliximab.
A 14-yr-old male presented to his general practitioner with a 4-week history of severe back pain and stiffness in 1999. Clinical examination revealed scoliosis concave to the left. Plain thoracolumbar spine radiographs showed endplate irregularity and early sclerosis at D7/8; the sacroiliac joints were normal. An orthopaedic opinion was requested. MRI of the thoracolumbar spine showed loss of height of the D10/11 disc (disc space narrowing) and sclerosis of the vertebral endplates at several levels, with focal endplate collapse consistent with Scheuermann's disease. He was referred to physiotherapy and advised to use NSAIDs as required; nevertheless his symptoms persisted.
Three years later, he represented to rheumatology with constant spinal pain, prolonged early morning stiffness, intermittent retrosternal chest pain and kyphosis. He was struggling to remain in full-time employment. Blood investigations revealed haemoglobin 11.9 g/dl (range 13.518 g/dl), platelets 450 x 109 per litre (range 150450 x 109), ESR 31 mm/h (range 110 mm/h), C-reactive protein (CRP) 28 mg/l (normal range 010 mg/l) and serum albumin 37 (range 3550 g/l). HLA B 27 tissue typing was positive. There was no history of psoriasis, enthesopathy or acute uveitis. MRI showed unusually florid multilevel inflammatory endplate changes that were most pronounced at T11/12, manifest as oedema, endplate irregularity and disc space narrowing (Fig. 1A). A diagnosis of inflammatory spondyloarthropathy was raised, particularly as there was also focal oedema at a number of the vertebral entheses. Radiographic evidence of bilateral sacroiliitis (grade 3) supported this diagnosis. Refractory spinal pain improved with phenylbutazone 100 mg three times a day. One year later, he developed an irritable left hip. Ultrasound demonstrated synovitis with an effusion which responded well to an intra-articular injection of 80 mg methylprednisolone and 1 ml of bupivacaine.
|
While awaiting approval, he was admitted with severe diarrhoea. Blood investigations showed haemoglobin 11.6 g/dl, platelets 574 x 109 per litre, ESR 41 mm/h and CRP 101 mg/l. Colonoscopy and barium follow-through confirmed Crohn's disease, which improved on steroids (40 mg prednisolone daily tapering regime over 7 weeks) and mesalazine (800 mg three times a day). Spinal symptoms were unchanged: ESR 50 mm/h, CRP 94 mg/l.
Infliximab (3 g/kg) was commenced at a 0-, 2- and 6-week loading regime and maintained 6-weekly thereafter. By 2 weeks, AS disease activity and Crohn's disease had improved significantly (ESR 15 mm/h, CRP <7 mg/l, BASDAI 2.56, BASFI 3.28, BASMI 4.7). MRI evaluation following the fifth infusion of infliximab showed considerable resolution of the endplate and entheseal oedema with residual inflammatory change confined to the L3/4 disc level (Fig. 1B).
The estimated incidence of juvenile-onset spondyloarthropathy (SpA) is between 1.44 and 2.10 per 100 000 children in Canada [2] and 2.0 per 100 000 children in the USA [3]. The diagnosis fulfils European Spondyloarthropathy Study Group (ESSG) criteria, which have been validated in children [4]. Enthesitis-related arthritis (ERA) is the International League of Associations for Rheumatology (ILAR) classification equivalent for juvenile idiopathic arthritis [5]. Psoriasis and the presence of systemic arthritis (as defined in the criteria) are exclusions, as are reactive arthritis and inflammatory bowel disease arthropathy. Extra-articular manifestations of ERA are enthesitis and acute uveitis. These children usually present with oligoarthritis of the lower extremities and enthesopathy. Spinal and sacroiliac joint involvement develops most frequently between 5 and 10 yr of disease.
Spondylodiscitis, although an uncommon manifestation of AS [6, 7], is usually asymptomatic unless it affects the lumbar or lower thoracic spine. Previously thought to be a late manifestation of AS [8]; it may be an early, and even the first, radiological sign of AS. Radiographic characteristics include proliferative entheseal erosions and sclerosis of the vertebral endplate adjacent to the disc with eventual progression to ankylosis of the spine. Early inflammatory lesions are common at the vertebral entheses, notably at the junction of the annulus fibrosus with the periosteum of the vertebra. Although not usually visualized on radiographs, these early changes are identifiable on MRI as focal areas of bone oedema.
Spondylodiscitis associated with Crohn's disease has been reported twice [9, 10]. The association of juvenile-onset SpA with Crohn's disease may only emerge later in the course of the disease [11]. Spondylodiscitis can be the initial manifestation of AS and lead to diagnostic confusion. This case illustrates the dramatic MRI changes in the presence of minor plain radiographic features at initial diagnosis and the prompt clinical, laboratory and MRI improvement following infliximab therapy.
|
The authors have declared no conflicts of interest.
References
|