Seronegative: AS, PsA, ReA, IBD-associated Flashcards
ASAS Criteria
Only apply if: >3 mo back pain + onset <45y
- Sacroilitis on imaging (definite radiographic by NY or active inflammation on MRI) plus 1 SpA feature
- OR
- HLAB27 + 2 SpA features
New york classification criteria
Clinical criteria
- LBP and stiffness >3 mo (improves w/ exercise not rest)
- Limited L-spine ROM in lateral flexion (expect >10cm) and frontal planes (schober - expect increase of 10—>14cm)
- Limited chest expansion relative to normal values correlated with age + sex
Radiological criteria (based on X-ray pelvis AP)
- ≥ Gr II bilaterally or ≥ Gr III unilaterally
- Definite = 1 of each
ASAS SpA features
- Inflamm back pain
- Arthritis
- Enthesitis (heel)
- Uveitis
- Dactylitis
- Psoriasis
- CD/UC
- NSAID response
- Fam Hx SpA
- HLAB27
- Elevated CRP
IBP vs Mech LBP
-Age
- Onset
- Duration
- AM stiffness
- Nocturnal
- Effect of exercise vs rest
- Back mobility
- Alternating buttock pain
-Age: <40 vs any age
-Onset: insidious vs acute s/p injury
-Duration: >3mo vs <4wks
-AM stiffness: >60min vs <30min
-Nocturnal: Freq vs absent
-Effect of exercise vs rest:
-Back mobility: lost in all planes vs flexion abnormal
-Alternating buttock pain: present in early vs not present
Px tests
- Good and Bad
Good:
-Occiput to wall, chest expansion (abN <2.5, N>5), Schober (at least 4.5cm)
-Bad: pelvic compression, Gaenslens, Patricks/FABER
Sites of enthesitis
-Supraspinatous
-Patellae
-Clavicles
-Calcanei (achilles or plantar)
-Epicondyle - lateral, medial
-ASIS, PSIS
-Greater trochanter
-SI joints
-Ligamentous structures of intervertebral disks
-Manubriosternal joints
-Symphysis pubis
-Attachment in spinous process
Peripheral joints of axSpA
-TMJ
-Cricoarytenoid
-Shoulders
-Sternoclavicular, sternocostal, manubriosternal, costovertebral,
-Hips, Symphysis pubis
DDx costochondritis
-Tietze syndrome
-Infxn
-Spondyloarthropathy
-SAPHO
-Relapsing polychondritis
Extraarticular manifestations AxSpa
-Skin
-Neuro
-Ocular
-Cardiac
-Pulmonary
-GI
-Renal
-Discitis or spondylodiscitis (Andersson lesions)
Cardiac manifestations AxSpa
-Aortopathy: regurg, aortitis, root dilation
-Conduction abnormalities: AV block
-Diastolic dysfcn,
-Pericarditis,
-CAD
Neuro manifestations AxSpa
-C1-C2 subluxation,
-Cauda equina from spinal arachnoiditis,
-Traumatic spinal fractures w myelopathy (C5-6, C6-7),
-Ossification of posterior longitudinal ligament with spinal stenosis
Renal manifestations AxSpa
-2ndary amyloid
-IgA nephropathy
-chronic prostatitis
Skin manifestations AxSpa
-Psoriasis,
-Erythema nodosum,
-Keratoderma blennorhagicum,
-Pyoderma gangrenosum
Pulmonary manifestations AxSpa
-ILD
-Chest wall restriction
-Spontaneous PTX
-Sleep Apnea (Cspine disease compresses oropharyngeal airway and respiratory centres in medulla)
C spine involvement in Ank Spond
-C1-C2 subluxation —> spinal stenosis
-Cervical ossification, facet ankylosis, fracture, kyphosis
Ocular manifestations AxSpa
Acute anterior uveitis
Conjunctivitis
Cataracts
Glaucoma
GI manifestations AxSpa
-Asymptomatic microscopic colitis
-Crohn’s like lesions in ileum and colon
HLA B27 pathogenesis of Ank Spond
-Arthritogenic peptide: microbial peptides bind HLA B27 → CD8+ cytotoxic T cells
-Molecular mimicry: shared epitopes on infecting organisms and HLAB27 or other self peptides
-Homodimer formation: HLAB27 form stable homodimers without associated beta 2 microglobulin on cell surface → activate NK, T, and B cells via TLR
-Misfolding protein: HLA B27 misfolds –> unfolded protein stress response and autophagy –> IL23 activates Th17 cells
XR view for SI joints
AP and ferguson view (AP w tube angled 25-40degrees cephalad)
MRI order for AS
MRI pelvis w/ T1 sequence (for ankylosis, erosions, backfill, fatty metaplasia) and STIR sequence (for osteitis/inflam)
-Include semi coronal views
**seroneg XR features pelvis **
Bilateral, symmetric sacroiliitis (lower ⅔)
-NY grading
– Gr 0: normal
– Gr 1: suspicious changes
– Gr 2: Sclerosis or minimal iliac erosion
– Gr 3: erosions, sclerosis, WIDENING, narrowing, partial ankylosis
– Gr 4: complete ankylosis/fusion
Enthesopathy: Iliac crest, greater tuberosities of the humerus, ischial tuberosities, femoral trochanters, calcaneus, vertebral spinous processes
**XR features Spine (and what causes it) **
Early: Romanus lesion / shiny corners
Moderate: Squaring of vertebral bodies
Late:
-Andersson lesions (inflamm destructive spondylodiscitis)
-Flowing syndesmophytes (ossification of annulus fibrosis)
-Bamboo spine (fusion of facet joints and calcification of spinal ligaments) → chalk stick fracture
-Dagger sign (supraspinous ligament calcification)
SASSS stoke ankylosing spondylitis spine score
Anterior/posterior changes in L spine T12-S1
-Gr 0: normal
-1: erosion, sclerosion, squaring
-2: syndesmophytes (NONBRIDGING)
-3: ankylosis (bridging between upper and lower vertebrae)
Romanus lesion
Enthesitis of annulus fibrosis @ corner of vertebrae