JIA

Question 1

Define the term Juvenile Chronic Arthritis.

Answer 1

A collection of joint disorders characterised by arthritis that is:

• non-infective
• > 3 months duration
• inflammatory
• in children <16 years of age

Question 2

Discuss the pathological features of JIA.

Answer 2

• primary synovial inflammation
• fibrosis and ankylosis
• flexion deformities are common
• retardation of growth & local bone deformities → is due to chronic inflammation and alteration in blood supply to eg growth plates

NB: cartilage erosion is as not marked as in RA → severe joint instability is uncommon

Question 3

Briefly describe the clinical features of the following forms of JIA; in your answer, you must highlight the distinguishing features of each form of JIA:

Answer 3

a. Systemic JIA

• initially: episodes of fever/ macular rashes/malaise
o these episodes occurs daily
• the episodes last for a few hours during which the child appears quite ill.
o between episodes the child seems well
• +/- lymphadenopathy splenomegaly hepatomegaly
• joint swelling
o occurs weeks/months after onset
o usually resolves when the condition subsides
o may become progressive seronegative polyarthritis

b. Pauciarticular JIA

•	no systemic illness
•	only a few joints are affected 
•	presenting ssx:
o	swelling of medium sized joints (knee/ankle/elbow/wrist)
o	swelling of only a single joint
o	chronic iridocyclitis
•	remission occurs after a few years; the child may have permanent:
o	growth defects   
o	sight problems 
o	asymmetrical deformities

c. Polyarticular JIA

• polyarticular arthritis
o TMJ
o Cx Spine
o Hands / wrists
• Classic RA-like deformities usually absent
• the condition may however present as an RA-like condition with a positive RF, in which case it is described as “JUVENILE RA”.

Question 4

Briefly discuss the main laboratory investigations which are employed in JIA. Comment on the typical findings for each investigation.

Answer 4

• ESR / CRP: incr. (systemic condition)
• WBC count: incr. (systemic condition)
• RF: +ve in Juvenile RA only
• HLAB27: +ve in Juvenile AS.
• Joint aspiration and synovial fluid examination will exclude infection/septic arthritis (comparatively non-developed immune system wrt adult Pt) and haemarthrosis (because of young age of Pt chance that haemophillia may not have been previously diagnosed)

Question 5

Comment briefly on the diagnostic problems encountered in JIA.

Answer 5

• systemic JIA may resemble a viral infection

• systemic JIA with single joint involvement may be confused with:
o Reiter’s
o septic arthritis
o tuberculous arthritis (if manifestations are less acute)

• Always need to consider the possible presence of:
o leukemia
o rheumatic fever
o bleeding disorders (dt age of Pts)

Question 6

List the main complications of JIA.

Answer 6

Ankylosis
o good function is the rule
o some loss of movement is common

Growth defects:
o	growth retardation
o	damage to growth plate eg.
•	external torsion of tibia
•	dysplasia of distal ulna
•	shortness of neck etc

Fractures:
o mainly in children < 5 years
o is due to osteoporosis (d/t incr. presence of inflammatory mediators around joints / bones → affects bone deposition) that may occur.

Iridocyclitis
o is common in pauciarticular disease
o if untreated, it may cause blindness

Amyloidosis
o occurs in long standing disease
o can be fatal