Characteristic X ray findings of the different arthritides
What are the characteristic radiographic features of the different arthritides
• RA: Symmetric, erosive arthritis, uniform joint space narrowing (especially weight-bearing joints). Most common sites are small joints of hands and feet (MCPs, PIPs, wrists, MTPs) and cervical spine. Soft tissue nodules that do not calcify. Swan neck deformities and ulnar deviation.
• JIA: Periarticular osteoporosis, but joint space narrowing and erosions typically absent until late. Periosteal reaction and bony fusion (carpus, facets in cervical spine) may distinguish it from RA. Overgrowth of bone at the margins of a joint suggests JIA.
• AS: Bilateral, symmetric sacroiliitis with ankylosis. Bilateral, thin, marginal syndesmophytes in the spine may cause spinal fusion (bamboo spine). Peripheral arthropathy affects large axial joints (shoulders, hips).
• Chronic reactive arthritis (formerly Reiter’s syndrome): Can be bilateral or unilateral, asymmetric sacroiliitis. Peripherally, there is a predilection for lower extremities (especially the interphalangeal joint of great toe), with erosions and fluffy periostitis. Enthesopathy with erosions and calcifications at tendon insertions into calcaneus. Frequently, asymmetric joint involvement. Large, asymmetric, nonmarginal (jug-handle) bridging syndesmophytes.
• Psoriatic arthritis: Axial arthropathy similar to chronic reactive arthritis. Peripherally, it has an upper extremity predilection; DIP or PIP fusion. “Pencil-in-cup” deformity. Enthesopathy and periostitis. Erosions of several joints of a single digit (MCP, PIP, and DIP of one finger). Frequently, asymmetric joint involvement. Acroosteolysis. Jug-handle (chunky) bridging syndesmophytes in the spine.
• Gout: Erosions with overhanging edge and sclerotic margins. Preserved joint space. Soft tissue tophi that can contain calcium.
• CPPD: Osteoarthritic changes at sites atypical for DJD (MCPs, elbow, radiocarpal, ankle, shoulder).
• Osteoarthrosis (OA): Nonuniform joint space narrowing, sclerosis, osteophytosis, cysts. Most common sites include the DIPs, PIPs, thumb CMC, knees, hips, acromioclavicular joint, and spine.
• Neuropathic joint (Charcot arthropathy): Destruction, disorganization, density (i.e., sclerosis), debris, dislocation (the five Ds).
• SLE: Reversible swan neck and ulnar deviation deformity and subluxation, but absence of erosions.
• Scleroderma: Tapered, atrophic soft tissues (sclerodactyly) with soft tissue calcifications. Acroosteolysis of terminal phalanges.
• Hemochromatosis: Chondrocalcinosis. Degenerative changes at MCPs with “hook-like” spurs. Cystic changes of radiocarpal joint of wrist.
• Ochronosis: Vertebral disc calcification, chondrocalcinosis, OA in multiple joints (especially spine) at young age.
• Acromegaly: Widened joint and disc spaces. Large spurs at bases of distal phalanges (spade phalanges).
• Hyperparathyroidism: Subperiosteal resorption at the radial side of middle phalanges. Soft tissue calcifications, chondrocalcinosis, “salt and pepper” skull, ligament, and tendon ruptures.
• Avascular necrosis: Crescent sign of subchondral sclerosis and lucency. Hips and shoulders are most commonly affected
• Hypertrophic osteoarthropathy (periosteal reaction): Intrathoracic pathology such as primary lung cancer. Less likely causes include thyroid acropachy, voriconazole treatment, or pachydermoperiostosis. Other causes of periosteal reaction include venous stasis and infection.