RHEUMATOLOGY
SERONEGATIVE SPONDYLOARTHRITIS
Classification system (Curr Opin Rheumatol 2010;22:375)
• 5 subtypes: ankylosing spondylitis (most common), reactive arthritis, psoriatic arthritis, IBD-associated arthritis and undifferentiated
• All subtypes share common clinical manifestations: inflammatory spine disease, peripheral arthritis, enthesitis and extra-articular manifestations (primarily ocular and skin disease)
Epidemiology & pathogenesis (Semin Arthritis Rheum 2008;38:83)
• ↑ prevalence of HLA-B27; HLA-B27 accounts for ~30% of attributable genetic risk
• Environmental factors likely critical for disease, esp. reactive arthritis (eg, infection)
• Prevalence of 0.5–2% of population, worldwide
Major clinical manifestations (Lancet 2011;377:2127)
• Inflammatory back pain: SI joints (sacroiliitis), apophyseal joints of spine
characterized by IPAIN (Insidious onset, Pain at night, Age of onset <40 y, Improves w/ exercise/hot water, No improvement w/ rest), a.m. stiffness, responsive to NSAIDs
• Peripheral arthritis: typically asymmetric, oligoarticular, large joints, lower > upper limb; however, can be symmetric & polyarticular (thus, mimic RA), esp. in psoriatic arthritis
• Enthesitis: inflammation at site of tendon/ligament insertion into bone, esp. Achilles, pre-patellar, elbow epicondyles, plantar fasciitis. Rigidity of spine (bamboo spine by X-ray, ankylosis due to progressive growth of bony spurs which bridge intervertebral disc).
• Dactylitis (“sausage digit”): inflammation of entire digit (joint + tenosynovial inflamm)
• Uveitis: anterior uveitis most common extra-articular manifestation; p/w pain, red eye, blurry vision, photophobia, usually unilateral
Descriptions of skin manifestations
• Psoriasis: erythematous plaques with sharply defined margins often w/ thick silvery scale
• Circinate balanitis: shallow, painless ulcers of glans penis and urethral meatus
• Keratoderma blennorrhagica: hyperkeratotic lesions on soles of feet, scrotum, palms, trunk, scalp
• Erythema nodosum: red tender nodules due to panniculitis, typically on shins; Ddx incl. idiopathic, infxn, sarcoid, drugs, vasculitis, IBD, lymphoma
• Pyoderma gangrenosum: neutrophilic dermatosis → painful ulcers w/ violaceous border; Ddx incl. idiopathic, IBD, RA, myelogenous leukemia
Psoriatic arthritis subtypes (Lancet 2011;377:2127)
• Monoarticular/oligoarticular (eg, large joint, DIP joint, dactylitic digit): most common initial manifestation
• Polyarthritis (small joints of the hands/feet, wrists, ankles, knees, elbows): indistinguishable from RA, but often asymmetric
• Arthritis mutilans: severe destructive arthritis with bone resorption, esp. hands
• Axial disease: similar to ankylosing spondylitis ± peripheral arthritis
• DIP-Limited: good correlation with nail pitting and onycholysis
Clinical assessment (Nat Rev Rheumatol 2012;8:253)
• Axial disease assessment
Severity of lumbar flexion deformity assessed by modified Schober’s test (
if <5 cm ↑ in distance between a point 5 cm below the lumbosacral jxn and another point 10 cm above, when going from standing to maximum forward flexion)
T-spine mobility (extension) and kyphosis severity measured by occiput-to-wall distance
• Seronegative: notable for absence of rheumatoid factor or autoantibodies; ± ↑ ESR
• HLA-B27: nonspecific, as common in general population (6–8%); most useful when high clinical suspicion but nl imaging; 90% of Pts w/ AS, but only 20–80% in other SpA
• Radiology
MRI preferred for early detection of inflammation (sacroiliitis)
Plain films detect late structural changes (SI erosions/sclerosis)
calcification of spinal ligaments w/ bridging symm syndesmophytes (“bamboo spine”)
squaring and generalized demineralization of vertebral bodies (“shiny corners”)
• Infectious evaluation for reactive arthritis (
studies do not r/o)
U/A, PCR of urine and/or genital swab for Chlamydia; urethritis usually due to Chlamydia infxn preceding arthritis, but also can see sterile urethritis post dysentery
stool Cx, C. diff toxin
consider HIV in workup of reactive or psoriatic arthritis
Treatment approach (Lancet 2011;377:2127; Rheumatology 2012;51:1378)
• Untreated disease may lead to irreversible structural damage and associated ↓ function
• Early physiotherapy beneficial
• NSAIDs: 1st line; rapidly ↓ stiffness and pain; prolonged, continuous administration may modify disease course but associated w/ GI and CV toxicity
• Intra-articular corticosteroids in mono- or oligoarthritis; limited role for systemic steroids, esp. for axial disease
• Conventional DMARDs (eg, MTX and SAS): no efficacy for axial disease or enthesitis; may have role in peripheral arthritis, uveitis and other extra-articular manifestations
• Anti-TNFs: effective for both axial and peripheral manifestations; improves function (Ann Rheum Dis 2006;65:423) and may slow progression of structural changes (Curr Rheumatol Rep 2012;14:422); unclear role of other biologics
• Other
Abx in reactive arthritis if evidence of active infxn; consider prolonged abx for refractory Chlamydia ReA (Arthritis Rheum 2010;62:1298)
Involve ophthalmologist for any evidence of inflammatory eye disease (may benefit from steroid eye drops or intravitreal steroid injections)
Treat underlying IBD when appropriate