Juvenile Idiopathic Arthritis (JIA)

Question 1

JIA: Basics

Answer 1

• Formerly called Juvenile Rheumatic Arthritis
• Includes psoriatic arthritis and enthesis related arthritis (inflammation where tendons and ligaments insert in bones)
• Autoimmune disorder characterized by polyarthritis and extra-articular involvement
• Strong genetic component
• Smoking increases risk
• Results in joint destruction deformity, disability, and premature death

Question 2

JIA: Definitions

Answer 2

• Autoimmune disease that represents a group of conditions with onset of Sx in children at or <16yo that causes chronic inflammation of 1+ synovial joints for 6+wk

Question 3

JIA: 4 Subtypes

Answer 3

1) Oliogoarticular: 1-4 joints involved; affects med-to-lg joints
2) Polyarticular: 5+ joints involved; Lg and Sm joints; low grade fever; fatigue; rheumatoid nodules; anemia (resembles RA in adults)
3) Systemic: rash, high fever, serositis, hepatosplenomegaly
4) Enthesis-associated: Lower extremity, lg. joint pain w/inflammation of tendon insertions like the tibial terberosity and heel or sacrolitis

Question 4

JIA: Arthritis

Answer 4

• Inflammation, of T and B lymphocytes, occurs in synovial lining of joints
• Synovial membrane becomes thicker and forms granulation tissue called pannus
• Pannus invades the cartilage and bone and destroys joints
• Immune complexes form in the synovial fluid involving many cells leading to bone erosion and destruction of cartilage w/inflammation of tendons and ligaments

Question 5

JIA: Clinical Presentation

Answer 5

• Weakness
• Weight loss
• Malaise
• Fatigue
• Anorexia
• Aching
• Stiffness
• Localized painful, tender, swollen joints
• Morning stiffness lasting 1-2hr
• Small joints of wrists, hands, feet are commonly affected first; bilateral and symmetric
• Hips, knees, ankles, shoulders, and cervical spine later involved

Question 6

JIA: PE (Articular Manifestations)

Answer 6

• Examine every joint for pain, tenderness, degree of swelling, ROM, and deformity
• Joint feels warm, tender, thickened, and boggy
• Skin may look shiny and have ruddy color over joint

Question 7

JIA: PE (Extra-Articular Manifestations)

Answer 7

• Subcutaneous nodules over pressure areas such as elbows
• Nodules can sometimes be found on cardiac valves, pleura, lung, and spleen
• Signs of vasculitis (skin infarcts, ulcerations)
• Ocular signs (*** Think -itis)
• Respiratory symptoms (interstitial lung disease)
• Cardiac involvement (valve disease, pericarditis)
• Peripheral nerve entrapment
• May be associated with Sjogren’s syndrome: dry eyes, xerostomia from destruction of salivary and lacrimal glands
• Felty’s syndrome: Skin ulcers, leukopenia, splenomegaly, and increased risk for bacterial infections (more common in long-standing RA)

Question 8

JIA: Dx

Answer 8

• Imaging
• CBC, ESR, CRP, CMP, UA
• HBV, HCV (drugs used in treatment are harsh on liver and kidney)
• Rheumatoid factor (RF)
• ANA
• Anticitrullinated peptide (anti-ccp) antibodies: an autoantibody that is marker for RA
• Synovial fluid analysis: high WBC count

Question 9

JIA: Differential

Answer 9

• All causes of inflammatory arthritis
• Lupus
• Seronegative spondyloarthropathies
• Fibromyalgia
• Connective tissue disorders

Question 10

JIA: Pharmacology

Answer 10

• NSAIDs
• Cox-2 Inhibitors (Mobic)
• Disease modifying antirheumatic drugs (DMARDs): mainstay of treatment; targets interleukins, B and T cells; methotrexate is used first
• Glucocorticoid
• Biologics if DMARDs not effective: etanercept, infliximab, adalimumab