Arthritis in A Teenager
B. J. Manaster, MD, PhD, FACR
DIFFERENTIAL DIAGNOSIS
Common
Juvenile Idiopathic Arthritis (JIA)
Ankylosing Spondylitis (AS)
Psoriatic Arthritis
Septic Joint
Pigmented Villonodular Synovitis (PVNS)
Femoral Acetabular Impingement (FAI)
Developmental Dysplasia of Hip
Less Common
Hemophilia: MSK Complications
Synovial Osteochondromatosis
Legg-Calvé-Perthes, Secondary Changes
Chronic Reactive Arthritis
Inflammatory Bowel Disease Arthritis
Osteoid Osteoma of Hip, 2° Changes
Rare but Important
Congenital Insensitivity/Indifference to Pain
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
Surprising number of arthridities originate during childhood or teenage years
Early and accurate diagnosis is important to initiate treatment and avoid later debilitating joint disease
Helpful Clues for Common Diagnoses
Juvenile Idiopathic Arthritis (JIA)
May have 1 of several manifestations
5% appear indistinguishable from adult rheumatoid arthritis (RA); most become seropositive
40% are pauciarticular, affecting knee, elbow, and ankle most frequently; seronegative; 25% develop iridocyclitis
20% have Still disease: Acute systemic disease with fever, anemia, hepatosplenomegaly; 25% of these have polyarticular destructive arthritis, affecting small and large joints alike
25% have seronegative polyarticular disease, symmetric & widespread in adult distribution; no systemic complaints & seronegative
Specific features generally distinguishing JIA from other teenage arthridities
Enlarged metaphyses and epiphyses (“balloon joints”) due to overgrowth, secondary to hyperemia from inflammatory process
Cartilage narrowing & widened notches related to pannus formation & erosion
Often asymmetric
Other distinguishing features
Periostitis may be 1st manifestation in young child
Fusion frequently occurs in carpals
Interbody fusion in cervical spine limits growth of vertebral bodies, giving “waisted” appearance
Ankylosing Spondylitis (AS)
Earliest manifestations (clinical and radiographic) occur during teenage years
Spinal manifestations initiate radiographic disease process
Osteitis at anterior corners of vertebral bodies
SI joint widening and erosions; may be asymmetric initially
Teenagers normally have wide SI joints with indistinct cortices; do not overcall!
Appendicular disease most frequently is in large proximal joints, particularly hips; may be erosive or productive
Psoriatic Arthritis
30-50% of psoriatic patients develop spondyloarthropathy
Bilateral asymmetric erosive disease; may eventually fuse
20% of psoriatic patients develop arthropathy prior to skin and nail changes
Distinguishing features
May have “sausage” digit with periostitis
DIP disease predominates; hands > feet
Aggressive erosive disease (“pencil-in-cup”) and eventual fusion
Septic Joint
Monostotic; cartilage damage and osseous deformity eventually leads to secondary osteoarthritis
If longstanding & slow process in child (especially tuberculous or fungal septic joint), hyperemia leads to overgrowth of epiphyses & metaphyses: “Balloon” joint
Pigmented Villonodular Synovitis (PVNS)
Monoarticular; nodular mass or nodules lining synovium
Causes erosion if longstanding
Large effusion; iron deposition results in foci of low signal, which bloom on GRE
Femoral Acetabular Impingement (FAI)
Often bilateral abnormalities, though complaints usually begin unilaterally
Morphologic abnormalities of femoral head, neck, or acetabulum → impingement
Lateral femoral neck “bump,” limiting normal head/neck cutback: Cam type
Acetabular rim overgrowth or retroversion: Pincer type
Multiple etiologies: Trauma, DDH, SCFE
→ labral tear and cartilage damage → early osteoarthritis
Onset of complaints 2nd or 3rd decade
Developmental Dysplasia of Hip
Multiple types of dysplasia
Shallow acetabulum
Femoral varus or valgus
Acetabular or femoral retroversion
Develop labral hypertrophy; with shear stress, labrum tears; eventual cartilage damage and early osteoarthritis
Helpful Clues for Less Common Diagnoses
Hemophilia: MSK Complications
Similar appearance to JIA, with “balloon” overgrowth of epiphyses/metaphyses due to hyperemia
Pauciarticular; knee > elbow > ankle
Hemosiderin deposits lead to low signal on MR, “blooming” on GRE sequence
Chronic Reactive Arthritis
Rare compared with psoriatic arthritis; appendicular manifestations usually foot/ankle
Inflammatory Bowel Disease Arthritis
Less frequent, but manifestations are similar to AS
Osteoid Osteoma of Hip, 2° Changes
Intraarticular OO elicits synovitis → subluxation of joint → altered weight bearing & development of osteophytesStay updated, free articles. Join our Telegram channel
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