Juvenile Idiopathic Arthritis

Question 1

JIA definition

Answer 1

• GROUP of SYSTEMIC INFLAMMATORY DISORDERS AFFECTING CHILDREN < 16 yrs
  
  • MOST COMMONLY DIAGNOSED RHEUMATIC DISEASE in CHILDREN
  • IMP. CAUSE of DISABILITY & BLINDNESS

Question 2

JIA criteria

Answer 2

1. AGE of ONSET: < 16 yrs
   
   2. DURATION of DISEASE: > 6 weeks
   3. PRESENCE of ARTHRITIS: JOINT SWELLING/2 of FOLLOWINGa. PAINFUL/LIMITED JOINT MOTION
      b. TENDERNESS
      c. WARMTH

Question 3

JIA subtypes

Answer 3

pauciarticular, polyarticular, systemic onset

enthesopathy related arthritis
juvenline psoriatic arthritis
others

helps to estimate = natural hx, complications, prognosis, decide strategy of rx

Question 4

Pauciarticular type 1 presentation, epidemiology, investigations

Answer 4

• MOST COMMON FORM (25%) of PAUCIARTICULAR JIA

• AGE: < 5yrs; PEAK 1 - 3yrs
• GIRLS > BOYS = 8 : 1

PRESENTATION:

* ASYMPTOMATIC in 50%
* LIMP > PAIN
* NO CONSTITUTIONAL MANIFESTATIONS e.g. NO FEVER

• MAINLY LOWER LIMB (LL) JOINTS

	○ KNEE > ANKLE > HAND/ELBOW; HIP V. RARE

* CHRONIC UVEITIS in 20% CASES (95% if FEMALE < 2yrs)
* IRREGULAR IRIS due to POSTERIOR SYNECHIAE

INVESTIGATIONS:

* MSK + EYE EXAMINATION
* +VE ANA in 40 - 75%

	○ NOT DIAGNOSTIC of ANYTHING; however, if +ve = MORE LIKELY to DEVLOP CHRONIC UVEITIS - BLINDNESS; SCREENING w/ OPTHALMOLOGIST w/ SLIT LAMP

Question 5

Pauciarticular type 2 presentation, epidemiology, investigations

Answer 5

• 15% of cases of PAUCIARTICULAR JIA

• AGE: > 8 - 9yrs
• GIRLS < BOYS = 1 : 7

PRESENTATION:

* LIMP due to LL being AFFECTED
* CONSTITUTIONAL RARE

• MAINLY LL JOINTS: KNEE, ANKLE, MID-FOOT (MID-TARSAL)

	○ HIP can be AFFECTED EARLY w/ RAPID DAMAGE req. THR early in life + ENTHESITIS + many have SI JOINTS & may evolve AS/SPONDYLOARTHRITIS

	○ 20% DIFFICULT to CLASSIFY to PARTICULAR SPONDYLOARTHROPATHY GROUP

* ACUTE IRIDOCYCLITIS in 10 - 20% = may notice BLURRY VISION
* Those w/ HLA-B27 + BACK INVOLVEMENT = categorised as JUVENILE ANKYLOSING SPONDYLITIS

Question 6

Pauciarticular type 3 presentation, epidemiology, investigations

Answer 6

• 15% of cases of PAUCIARTICULAR JIA

• AGE: ANY AGE DURING CHILDHOOD
• GIRLS > BOYS = 4 : 1

PRESENTATION:

* CONSTITUTIONAL RARE
* ASYMMETRIC UL & LL ARTHRITIS

	○ ARTHRITIS can be V. DESTRUCTIVE

* DACTYLITIS
* CHRONIC IRIDOCYCLITIS in 10 - 20%
* FHx of PSORIASIS in 40% ± NAIL PITTING

	○ These PT. may DEVELOP PSORIASIS LATER in LIFE

Question 7

Pauciarticular number of joints affected

Answer 7

4/less joints

Question 8

Polyarticular number of joints affected

Answer 8

5/more joints

Question 9

Polyarticular RF -ve presentation, epidemiology

Answer 9

• 15% of JIA

• AGE: ANY AGE, OFTEN EARLY
• GIRLS > BOYS = 9 : 1

PRESENTATION:

* CONSTITUTIONAL MANIFESTATIONS = LOW GRADE FEVER, MALAISE
* HEPATO-SPLENOMEGALY
* MILD ANAEMIA
* GROWTH ABNORMALITIES

* SYMMETRIC LARGE & SMALL JOINTS AFFECTED: KNEES, WRISTS, ANKLES, MCPs, PIPs, NECK, TMJ
* IRIDOCYCLITIS RARE = still need SOME DEGREE of SCREENING for UVEITIS

Question 10

Polyarticular RF +ve presentation, epidemiology

Answer 10

• 10% of JIA

• AGE: LATE CHILDHOOD (TEENS, 12 - 15yrs)
• GIRLS > BOYS = 7 : 1

PRESENTATION:

* CONSTITUTIONAL MANIFESTATIONS = LOW GRADE FEVER, MALAISE, WGT. LOSS
* ANAEMIA
* NODULES

* Can be COMPLICATED by SJOGREN'S, FELTY/VASCULITIS, AR, PULMONARY FIBROSIS, AAS, CTS
* SIMILAR to ADULT RA, but IN a CHILD
* EROSIONS in X-RAY OCCUR EARLY
* IRIDOCYCLITIS RARE = still need SOME DEGREE of SCREENING for UVEITIS

Question 11

Systemic onset JIA presentation, epidemiology

Answer 11

• EXTRA-ARTICULAR FEATURES DEFINE DISEASE = START EARLY & DISAPPEAR AFTER 2 - 5yrs
• 20% of JIA
• AGE: THROUGHOUT CHILDHOOD (4 - 6yrs)
• GIRLS > BOYS = 1.5 : 1

Fever:
• RISE to 39.5 C DAILY for ≥ 2 weeks
• LATE AFTERNOON/EVENING & RETURNS to NORMAL/SUBNORMAL in MORNING
• CHILD APPEARS TOXIC w/ FEVER ± CHILLS, but LOOKS NORMAL when FEVER GOES AWAY

Rash:
• 90%
• EVANESCENT SALMON RED ERUPTION
• On TRUNK & THIGHS
• ACCOMPANIES FEVER
• Can be BROUGHT ON by SCRATCHING = KOEBNER'S PHENOMENON

Lymph nodes:
• 50 - 75%
• GENERALISED LYMPHADENOPATHY
• NON-TENDER

Abdominal:
• HEPATOSPLENOMEGALY
• 50 - 75%
• ABDOMINAL PAIN
• ± TRANSAMINASES

Serositis:
• POLYSEROSITIS
• PERICARDITIS in 36%
• TEMPONADE & MI RARE

Pulmonary:
• RARE
• PLEURAL EFFUSION
• PULMONARY FIBROSIS

Arthritis:
• 75%
• W/I 3 - 14 months of ONSET of FEVER
• POLYARTICULAR = WRISTS, KNEES, ANKLES, CERVICAL SPINE, HIPS, TMJ

Question 12

JIA aetiology

Answer 12

• JIA = AUTOIMMUNE DISEASE
  
  • MULTIFACTORIAL (aetiology is also different to that of adult RA) = GENETIC, ENVIRONMENTAL, IMMUNOLOGIC
  • STRONG SUBSET-SPECIFIC GENETIC MARKERS may AFFECT IMMUNE RESPONSE

Question 13

Uveitis

Answer 13

• SIGNIFICANTLY HIGHER LVLS of UVEITIS in OLIGO-ARTICULAR & EXTENDED OLIGO GROUPS

	○ GLAUCOMA MOST COMMON in these GROUPS & ONLY occurred in pt. w/ PREVIOUS UVEITIS
	○ CATARACTS & EYE SURGERY MRE COMMON in EXTENDED OLIGO GROUP

* UVEITIS SIGNIFICANTLY RELATED to +VE ANA in PT. w/ EXTENDED OLIGO-JIA & RF -VE POLY-JIA
* UVEITIS HIGHER INCIDENCE RATES in OLIGO & PSORIATIC JIA
* SICCA SYNDROME SIGNIFICANTLY MORE COMMON in pt. w/ RF +VE JIA
* JIA MOST COMMON NON-INFECTIVE cause of UVEITIS = can AFFECT ALL JIA GROUPS

	○ COMPLICATIONS = POSTERIOR SYNECHIAE, CATARACT, BAND KERATOPATHY, GLAUCOMA, VISUAL LOSS

Screening - important for all JIA

Management - steroids (topical, can be intraocular, systemic), dilators (lift off inflamed tissues, mydriatic + cycloplegic agents), other agents (methotrexate, MMF, cyclosporin, anti-TNF)

Question 14

Growth failure

Answer 14

localised:
• LEG-LENGTH DISCREPANCIES - INFLAMMATION AFFECTS GROWTH PLATE

• SHORTENING of FINGERS, HANDS, FOREARMS, TOES, FEET
• MICROGNATHIA - INFLAMMATION in 1/BOTH TMJ = JAW RECEDES, has COSMETIC CONSEQUENCES, can AFFECT DENTITION, TREATED w/ INTRA-ARTICULAR INJECTIONS

generalised:
• RELATED to SEVERE SYSTEMIC DISEASE
• SHORT STATURE
• DELAYED PUBERTY
• SYSTEMIC STEROIDS

Question 15

JIA management

Answer 15

1st line:
• SIMPLE PAIN KILLERS

• NSAIDs

	○ Difference bwtn adults & children is half-life
	○ CAN CONTROL DISEASE
	○ Doses different, compounds same

2nd line:
• NO RESPONSE to NSAIDs/JOINT STEROID INJECTIONS
• RARELY REQ. in OLIGOARTICULAR JIA

• SHORT-TERM STEROIDS can be used; but if req. for a while then move onto IMMUNOSUPPRESSANTS

1. METHOTREXATE = pharmacokinetics is age-related
2. ANTI-TNF Rx (all 3) = in methotrexate failure/cannot tolerate methotrexate
3. IL-1 R-ANTAGONIST (ANAKINRA) = in refractory systemic arthritis IL-6 ANTAGONIST (TOCILIZUMAB) = for refractory systemic disease

Others: rehabilitation - physio, OT

Local steroids:
• INTRA-ARTICULAR MAINLY in OLIGO-ARTICULAR JIA
• EYE DISEASE (ANA +VE OLIGOARTICULAR DISEASE)

Systemic steroids:
• LIMITED INDICATIONS due to SERIOUS SIDE-EFFECTS

• USED IN:

	○ SYSTEMIC JIA = CONTROL PAIN + FEVER
	○ SERIOUS DISEASE COMPLICATIONS w/ ANY SUBTYPE e.g. pericardial effusion, tamponade, vasculitis, severe autoimmune anaemia, severe eye disease
	○ As a BRIDGE bwtn DMARDs
	○ CHILDREN UNDERGOING SURGERY

• RISK of OSTEOPOROSIS, INFECTIONS, GROWTH ABNORMALITIES

Surgery: synovectomy, reconstructive/joint replacement surgery