JUVENILE IDIOPATHIC ARTHRITIS

Question 1

DEFINITION

Answer 1

a group of a heterogenous forms of chronic arthritis of unknown etiology that have their onset before the age of 16 years.

Question 2

There are other diseases (beside of rheumatologic ones) that can present with arthritis in a child:

Answer 2

• Diseases with a single inflamed joint e.g. septic arthritis or osteomyelitis, Lyme disease, reactive arthritis (bacterial or viral infections), hemarthrosis (e.g. due to trauma or bleeding diseases) and even malignancies (such as ALL).
• Diseases with more than one inflamed joint and/or systemic features:
  o Connective tissue diseases: systemic lupus erythematosus, juvenile dermatomyositis, sarcoidosis, Sjogren’s syndrome, mixed connective tissue disease, Henoch Schoenlein Purpura
  o Reactive arthritis/Septic arthritis
  o Lyme disease
  o Malignancy
  o Immunodeficiency associated arthritis
  o Inflammatory bowel disease associated arthritis (enteropathic arthritis)
  o Other: chronic recurrent multifocal osteomyelitis, chronic infantile neurological cutaneous and arthritis syndrome (CINCA, also known as NOMID (Neonatal-Onset Multisystem Inflammatory Disease)

Question 3

Alert symptoms that can guide us to the diagnosis of idiopathic juvenile arthritis:

Answer 3

1. Constitutional symptoms:
   o without spontaneous improvement
   o Lack of response to simple drug treatment
   o Diurnal (GÜNLÜK) variation to symptoms severity
2. Or: fever, rash, irritability, fatigue, weakness, anorexia, non-specific musculoskeletal pain
   + Joint swelling accompanied with pain with movement of the joint.

Question 4

DIAGNOSTIC CRITERIA

Answer 4

all 3 conditions must be met:
1. Arthritis persisting for over 6 weeks
2. Age at the onset of symptom must be <16 years of age
3. Exclusion of all other conditions associated with or mimicking arthritis

Question 5

CLINICAL PRSENTATION

Answer 5

1. Pain, inconsistent feature of JIA
2. Parents are likely to note limping or joint swelling if one or more large peripheral joints are involved.
3. Rare isolated small joint arthritis or axial joint involvement
4. Early morning stiffness that improves with movement and is helped by a warm bath or shower - this could be a useful parameter in monitoring the treatment during the follow up.

Question 6

The Formal Examination of the Musculoskeletal System in Children examination:

Answer 6

• Inspection - always compare both sides and inspect the position of the joint at rest, its surface anatomy, contours, color, scars, limb length, foot and size and muscle bulk. Children with this disease do not develop in a linear manner, both in terms of skeletal alignment and growth velocity. This means that joints of the 2 sides can have important differences we always have to consider both sides of each joints. We inspect the position of the joint at rest.
• Palpation - looking for swelling and warmth of the joint, as well as any skin abnormalities of the skin over the joint. Note particularly the presence of enthesitis.
• Observing movement - observing both passive and active movements, assess joint range of movement in all directions (should be pain-free even at end of range). This is meant to check the range of motion.
• Imaging - asking for ultrasound and other imaging techniques to further investigate the characteristics of the arthritis (edema inside the joints).

Question 7

Clinical patterns of JIA

Answer 7

All these conditions will be defined as JIA with systemic arthritis, oligoarthritic and so on.

Question 8

1. Systemic arthritis

Answer 8

An arthritis in one or more joints with, or preceded by, a fever of at least 2 weeks duration that can be documented daily for at least 3 days. Along with one of the following:
 Evanescent, non-fixed, erythematous rash - has a pinkish pattern (‘salmon-macular’) that worsens with fever spikes. It is usually found in the axillary region, anterior chest wall and inner thighs. This is an ‘evanescent rash’ meaning that it is fast to come and fast to go.
 Generalized lymphadenopathy
 Hepatomegaly and/or splenomegaly
 Serositis (e.g. pleuritis, pericarditis)

Question 9

Prominent extra-articular features are also present: quotidian fever, rash, myalgia, arthralgia and irritability. The arthritis pattern is variable, ranging from several swollen joints to a widespread polyarticular pattern (difficult to control). The polyarticular pattern is associated with worse prognosis, because of early erosions, loss of joint motion, severe growth delay. ‘Macrophage activation syndrome’ is a life-threatening complication that can be seen in 10-15% of these patients and is very difficult to treat

Answer 9

Laboratory analysis:
o High WB, Severe anemia, thrombocytosis
o High acute phase reactant - such as ERS, CRP, and ferritin.
o Positive d-dimers or fibrin split products.

Question 10

2.Oligoarthritis

Answer 10

An arthritis that involves 1 to 4 joints during the first 6 months of the disease. This form could be ‘persistent’ or ‘extended’:

Question 11

Persistent Oligoarthritis

Answer 11

affects no more than 4 joints throughout the disease course.

females

The joints most affected include large joints such as knee, ankle and wrist, which are associated with growth disturbances, because the affected leg grows longer. This could be a result of a chronic hyperemia in the affected leg which results in discrepancy of leg strength. Mostly asymmetrical.

The arthritis can result in a knee flexion contracture (inability to fully straighten the knee) or atrophy of muscles above the knee

An important systemic manifestation is chronic asymptomatic anterior uveitis that is insidiously progressive and can lead to loss of visual acuity and blindness (20% of cases).

Laboratory analysis:
o Acute phase reactant
o Anti-nuclear antibodies (ANA)

Question 12

 Extended Oligoarthritis

Answer 12

the first 6 months are characterized by an involvement of <4 joints, but later on more joints could be involved. It can affect both large and small joints.
o Also, here there is an important association with anterior uveitis.
o Laboratory data and prognosis are similar to those with polyarthritis.