Pediatric Rheumatic Disorders: Imaging Across the Autoinflammatory–Autoimmune Continuum
A practical radiology review of Pediatric Rheumatic Disorders: Imaging Across the Autoinflammatory–Autoimmune Continuum, focused on imaging findings, differential diagnosis,...
RadPhrases Editorial Team3 min read
A practical radiology review of Pediatric Rheumatic Disorders: Imaging Across the Autoinflammatory–Autoimmune Continuum, focused on imaging findings, differential diagnosis, reporting points, and high-yield teaching pearls.
Big Picture: The New Concept
- Rheumatic diseases are no longer viewed as purely autoimmune or autoinflammatory.
Instead, they exist on an
- Autoinflammatory ⟷ Autoimmune Continuum
- Innate immunity dominant → FMF, TRAPS, CAPS
- Mixed diseases→ Takayasu, IBD, ERA, Interferonopathies
- Adaptive immunity dominant→ SLE, Dermatomyositis, RF+ JIA
- Radiologists should understand imaging findings through this immunologic spectrum.
- Imaging Approach = Exam Favorite
- US = First-line
- Synovitis,Tenosynovitis, Enthesitis
- Disease activity with Doppler
- Best for: Hands Feet
- MRI = Problem Solver
- Sacroiliitis Spondylitis Large jointsBone marrow edema
- CT: Vasculitis Serositis Pulmonary disease Bowel involvement
- Whole-body MRI
- CRMO Systemic inflammatory disease mapping
Monogenic Autoinflammatory Diseases
FMF (Familial Mediterranean Fever)
- Very relevant in Türkiye
Imaging
- Ascites
- Pericardial effusion
- Pleural effusion
- Bowel wall thickening
- Mesenteric fat stranding
- MSK Enthesitis, Sacroiliitis, Monoarthritis
Buzzwords
- Recurrent fever Sterile peritonitisDramatic colchicine response
TRAPS Imaging
- Bowel wall thickening
- Intraperitoneal fluid
- Fasciitis on MRI
- Clues
- Periodic fever
- Periorbital edema
- Abdominal pain
Blau Syndrome
Characteristic Imaging
- Marked tenosynovitis
- Synovial thickening
- "Boggy arthritis"
- Helpful Differentiators
- No erosions
- No destructive arthritis
- Early carpal ossification
- Prominent tendon sheath disease
- Think: Uveitis
- Arthritis Dermatitis
CAPS / CINCA
- Radiology Pearl
Very characteristic skeletal findings
- Growth plate widening
- Irregular calcification
- Bulbous knees
- Epiphyseal enlargement
- If you see bizarre epiphyseal overgrowth + inflammation → think CINCA.
CRMO (Chronic Recurrent Multifocal Osteomyelitis)
Imaging Hallmarks
- Multifocal lesions
- Metaphyses
- Pelvis
- Vertebrae
- Highly Specific Sites
- Clavicle Mandible
MRI
- Bone marrow edema
- Whole-body MRI = modality of choice
- Helpful Differential Point
- Usually no diffusion restriction
- Helps separate from infection
- Multiple symptomatic + asymptomatic lesions are common.
Systemic JIA (Still Disease)
Systemic Findings
- Fever Rash Pericarditis Serositis Lymphadenopathy Hepatosplenomegaly
Imaging
- US excellent initially
- MRI for arthritis burden
- Late Findings
- Abnormal ossification
- Osteoporosis
- Cervical ankylosis
- Macrophage Activation Syndrome = life-threatening complication
Mixed Diseases
Takayasu Arteritis
- Best Imaging Findings
- Circumferential vessel wall thickening
- Wall enhancement
- Stenosis
- Aneurysm
- Modalities
MRA CTA FDG-PET
Think
- Aorta + major branches
IBD
- Extraintestinal Imaging
- Sacroiliitis Spondylitis UveitisAortitis
- Cross-sectional Imaging
- Wall thickening
- Hyperemia
- Fistulas
- Strictures
- Abscesses
ERA (Enthesitis-Related Arthritis)
- Key Association
HLA-B27
Imaging
- Enthesitis, SacroiliitisSpondylitis
- MRI Findings
- Bone marrow edema
- Early SI joint inflammation
- MRI is essential because radiographs may be normal.
Autoimmune Diseases
Juvenile SLE
Imaging Findings
- Pericarditis Pneumonitis Alveolar hemorrhage Enteropathy Cerebral vasculitisIschemia
- MSK Nonerosive arthritis
- Important Complication
- Femoral head osteonecrosis (steroids)
Juvenile Dermatomyositis (JDM)
MRI Findings
- Symmetric proximal myositis
- T2/STIR hyperintensity
- Fascial inflammation
- Panniculitis
- Classic Radiology Pearl
- Calcinosis cutis
Especially
- Periarticular soft tissues
- Whole-body MRI
- Disease activity
- Biopsy targeting
Juvenile Idiopathic Arthritis (JIA)
ANA+ JIA
Typical patient
- Young girl (<6 years)
Imaging
- Juxta-articular osteopenia
- Megaepiphysis
- Limb overgrowth initially
- Growth arrest later
MRI
- Synovial enhancement
- Bone marrow edema
- High risk of uveitis
RF+ JIA
- Closest pediatric equivalent of adult RA.
- Imaging
- Joint space narrowing
- Bone erosions
- Ankylosis
- Bone marrow edema
- Common Sites
- MCP PIP FeetCervical spine TMJ
- Much more destructive than ANA+ JIA.
Pediatric Sjögren Disease
- Pediatric Clue
- Dry mouth often absent
- Instead: Fever Parotitis Myositis Arthritis
Imaging
- US → heterogeneous hypoechoic glands
- MR sialography → "salt-and-pepper" appearance
Exam Pearls
- FMF → serositis + recurrent fever + Mediterranean populations
- CRMO → clavicle/mandible involvement + whole-body MRI
- Blau syndrome → massive tenosynovitis with little erosion
- CINCA → epiphyseal overgrowth + bizarre calcifications
- Takayasu → concentric aortic wall thickening
- ERA → HLA-B27 + sacroiliitis + enthesitis
- JDM → calcinosis cutis + proximal muscle edema
- ANA+ JIA → megaepiphysis & limb overgrowth
- RF+ JIA → erosions and destructive arthritis
- US = synovitis king | MRI = sacroiliitis king
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