Juvenile Idiopathic Arthritis - Rheumatology

Question 1

Differential diagnosis of joint pain in childhood?

Answer 1

The broad differential diagnosis can be remembered with the
mnemonic PRIME BONE PAN:
P—Pharmacologic: serum sickness; drug-induced lupus
R—Rheumatologic: juvenile idiopathic arthritis; systemic lupus erythematosus (SLE); Sjögren’s syndrome; systemic sclerosis/mixed connective tissue disease (MCTD); vasculitis; dermatomyositis; sarcoidosis
I—Infectious/postinfectious: bacterial (osteomyelitis, discitis, septic arthritis, rheumatic fever, reactive arthritis); viral (“toxic/transient” synovitis, human immunodeficiency virus [HIV], hepatitis B [Hep B] or hepatitis C [Hep C], parvo, Epstein–Barr virus [EBV], Herpes, rubella vaccination)
M—Metabolic/genetic: mucopolysaccharidoses; mucolipidoses; heritable collagen disorders (Marfan, etc.); pseudorheumatoid chondrodysplasia
E—Episodic: autoinflammatory syndromes (FMF and other periodic fever syndromes).
B—Blood/hematologic: sickle cell anemia; hemophilia
O—Orthopedic: chondromalacia patellae; Osgood–Schlatter disease; osteochondritis dissecans; Legg–Calve Perthes disease; slipped capital femoral epiphysis
N—Neoplastic: neuroblastoma; leukemia/lymphoma; bone tumors; metastases.
E—Endocrine: hypercortisolism; hypothyroidism; rickets; diabetes mellitus
P—Pain amplification syndromes/psychosomatic: complex regional pain syndrome (CRPS); fibromyalgia.
A—Accidental/trauma
N— “Normal variants”: “growing pains”; benign hypermobility

Question 2

the characteristics of an organic vs non-organic cause for joint pain

Answer 2

Organic:
» Occurs day and night
» Occurs during weekends and on vacation
» Severe enough to interrupt play and other pleasant activities
» Located in joint
» Unilateral
» Child limps or refuses to walk.
» Description fits with logical anatomic explanation

Nonorganic:
» Occurs only at night
» Occurs primarily on school days
» Child is able to carry out normal daily activities
» Located between joints
» Bilateral
» Child has unusual/bizarre gait
» Description is illogical, often dramatically stated, and not consistent with known anatomic or physical process.

Question 3

JIA definition and Types ?

Answer 3

Definition:
б is a heterogeneous group of idiopathic inflammatory arthritis affecting children younger than 16 years of age and lasting six weeks or longer.
б Juvenile idiopathic arthritis is the most common type of arthritis in children under the age of 16.
б Some types of juvenile idiopathic arthritis can cause serious complications, such as:
1. growth problems, 2. joint damage, 3. eye inflammation.

Types of JIA include the following:
1. Systemic-onset juvenile idiopathic arthritis (Still’s disease):
a. Arthritis of
» one or more joint with or preceded by a fever of at least a 2-week duration and accompanied by at least 1 of:
1. Evanescent erythematous rash,
2. Generalized lymph node enlargement,
3. Hepatomegaly and/or splenomegaly,
4. Or serositis (pericarditis and/or pleuritis and/or peritonitis, sore throat is common).
b. Must exclude:
1. infections,
2. Kawasaki disease,
3. periodic fever syndromes
4. malignancies.

2. Oligoarticular juvenile idiopathic arthritis:
3. Oligoarthritis
   » is defined as chronic arthritis affecting four joints or less during the first six months of disease.
4. Persistent oligoarthritis
   » is defined as the affected joints being four or less after the first six months
5. Extended oligoarthritis
   » is defined as more than four affected joints after the first six months.
6. Polyarticular juvenile idiopathic arthritis
7. RF negative polyarthritis
   » is defined as arthritis affecting five joints or more during the first six months of disease with a negative IgM RF.
8. RF positive polyarthritis
   » is arthritis affecting five joints or more during the first six months of disease with a positive IgM RF on at least two tests with three months apart
9. Psoriatic arthritis:
   б is defined as chronic arthritis with psoriasis (arthritis may precede the skin psoriasis)
   б or chronic arthritis with at least 2 of
10. dactylitis,
11. nail pitting,
12. or onycholysis
13. or psoriasis in a first-degree relative.
14. Enthesitis-related arthritis:
    б defined as arthritis with enthesitis [site of tendon insertion into the bone], or arthritis or enthesitis with at least 2 of SI joint tenderness and/or inflammatory lumbosacral pain,
    б a positive HLA-B27,
    б onset of arthritis in a male over six years of age,
    б acute anterior uveitis,
    б history of
15. ankylosing spondylitis,
16. sacroiliitis with inflammatory bowel disease,
17. reactive arthritis
18. or acute anterior uveitis in a first-degree relative
19. Undifferentiated arthritis:
    б Chronic arthritis,
    » which does not fulfill criteria in any subtype
    » or fulfills two or more subtypes

Question 4

Signs and symptoms of JIA

Answer 4

A. History findings in children with JIA may include the following:
1. Arthritis
» present for at least 6 weeks before diagnosis (mandatory for diagnosis of JIA)
2. Either
» insidious or abrupt disease onset,
» often with morning stiffness.
3. Complaints of
a. joint pain,
b. swelling,
c. limited range of motion.
4. History of
a. school absences
b. or limited ability to participate in physical education classes
5. Spiking fevers
» occurring once or twice each day at about the same time of day
6. Evanescent rash (transient and disappears rapidly) on the trunk and extremities
7. Psoriasis, dactylitis, enthesitis, or inflammatory back pain

B. Physical findings include the following:
1. Arthritis:
» Defined either as intra-articular swelling on examination
» or as limitation of joint motion in association with pain.

2. Iridocyclitis
   » The most common comorbidity.
   » (inflammation of the anterior chamber and anterior vitreous) that is typically asymptomatic but sometimes causes blurring of vision and miosis.
   » Rarely, in enthesitis related arthritis, there are also the more common uveitis manifestations of conjunctival injection, pain, and photophobia.
   » Iridocyclitis can result in scarring (synechia),
3. cataracts,
4. glaucoma,
5. or band keratopathy.
   » Iridocyclitis is most common in oligoarticular JIA, developing in nearly 20% of patients, especially if patients are positive for antinuclear antibodies (ANA).
   » It may occur in the other forms but is exceedingly rare in
6. polyarticular RF-positive JIA
7. and systemic JIA.
8. Skin abnormalities
   » present mainly in psoriatic JIA, in which psoriatic skin lesions, dactylitis, and/ or nail pits may be present, and in systemic JIA, in which a typical transient rash often appears with fever.
9. Systemic abnormalities
   б in systemic JIA include
10. high fever, 2. rash, 3. splenomegaly,
11. generalized adenopathy (especially of the axillary nodes),
12. serositis with pericarditis or pleuritis.
    б These symptoms may precede the development of arthritis.
    б Fever occurs daily (quotidian) and is often highest in the afternoon or evening and may recur for weeks.
    б In 7 to 10% of patients, systemic JIA may be complicated by macrophage activation syndrome, a life threatening cytokine storm syndrome.

Question 5

JIA diagnosis and ttt?

Answer 5

Diagnosis of JIA is based on the history and physical examination findings.
1. Laboratory studies that may be considered include the following:
1. Inflammatory markers:
a. Erythrocyte sedimentation rate (ESR)
b. or CRP level
2. Complete blood count (CBC).
3. Antinuclear antibody (ANA) testing
4. Rheumatoid factor (RF) and anti–cyclic citrullinated peptide (CCP) antibody
5. Additional studies to exclude other causes of joint pain:
1. Total protein,
2. albumin,
3. fibrinogen,
4. ferritin,
5. D-dimer,
6. angiotensin-converting enzyme
(ACE),
7. antistreptolysin O (ASO),
8. lactate dehydrogenase (LDH),
9. EBV and hepatitis markers.
» When only a single joint is affected, radiography is important to exclude other diseases (septic arthritis and trauma).
2. Basic radiographic changes in JIA include the following:
1. Soft tissue swelling
2. Osteopenia or osteoporosis
3. Joint space narrowing
4. Bony erosions
5. Intra-articular bony
ankylosis
6. Periostitis

Management:
1. Pharmacologic therapy:
1. Nonsteroidal anti-inflammatory drugs (NSAIDs), like
a. ibuprofen, b. naproxen c. indomethacin
2. Disease-modifying antirheumatic drugs (DMARDs), like
a. methotrexate,
b. leflunomide,
c. sulfasalazine,
d. cyclosporine.
3. Biologic agents, like
a. tumor necrosis factor inhibitors [infliximab and adalimumab],
b. and non-TNF inhibitors like [IL 1 inhibitor anakinra and IL 6 inhibitor
tocilizumab]
4. Intra-articular steroids like
» Triamcinolone hexacetonide in oligoarticular or monoarticular cases.
2. Measures to enhance school performance (e.g., academic counseling)
3. Improved nutrition
4. Physical therapy
5. Occupational therapy