Arthritis Flashcards
How common is Juvenile Idiopathic Arthritis? Increased or decreased in recent years?
13.9 cases per 100,000 per year, but incidence has decreased in recent years.
How many cases of JIA in the US?
70k to 100k
What is the affected female to male ratio?
2-3:1 but in children under 8 years old the ratio is 8:1 (female:male). Occasional seasonal variance.
Is there any family involvement in JIA?
no consistent Mendelian or monogenic patterns, but slight family involvement. families w/ multiple affected members isn’t common (if multiple family members have it in family, most have the same type).
What type of foci are associated in the development of JIA?
Multiple HLA foci are associated, but some HLA class II alleles can be protective possibly
What are environmental factors that increase the risk for JIA?
Infections (rubella virus and immunization, EBV, flu, parvovirus B19, chlamydia, mycoplasma), maternal tobacco use, and HLA-B27+ (can be triggered by bacterial infections in kids and adults
What are environmental factors that can decrease the risk for JIA?
Breastfeeding, vitamin D/sun exposure
What is the major clinical manifestation of JIA? What does this result in?
persistent joint swelling due to synovial fluid volume and synovial thickening (membrane).
Results in deformities bc periarticular ligaments and tendons stretch and activity of osteoclasts. Osteoclasts are stimulated bc of increased levels of cytokines (produced by inflammatory cells/tissue)
How is synovial fluid affected in JIA?
It’s increased in volume, decreased in viscosity. The synovial fluid is filled with inflammatory cells (PMNs, plasma cells, DCs, T cells)
What is pannus in synovial tissue?
Abnormal layer of synovial tissue. This layer causes joint damage bc they’re filled with inflammatory cells. It’s almost a tumor-like expansion of pannus, which adheres to intraarticular cartilage. (pannus/cartilage junction is where cartilage is degraded/destroyed bc increased blood supply and increased inflammatory cell infiltration).
What is chronic synovitis?
villous hypertrophy and hyperplasia with edema and hyperemia (excess of blood in supplying vessels) of subsynovial tissues
What does pannus formation in synovial tissue lead to in JIA?
destruction of cartilage and bone as disease advances
What do parents often relate JIA symptoms to?
sports injuries, though usually not
What are some molecular targets of biologis in the pathogenesis of JIA?
B cells (CD20), TNF alpha, IL-1, IL-1 receptor, IL-6 receptor, APC (CD80/86)
What does JIA lead to in the joint?
excess fluid in joint cavity, swollen/inflamed synovial membrane, thinning cartilage, bone erosion
What symptoms lead to clinical manifestation? Is it subtle or very acute?
morning stiffness, joint pain, fatigue, fever, swollen/non-erythematous/warm to touch joints.
Can either be subtle or very acute.
What are the 3 major types of JIA?
Systemic onset JIA (Still’s Disease), Pauciarticular JIA (4 or fewer joints at 6 months), Polyarticular JIA (5 or more joints affected at 6 months.
When is systemic onset JIA referred to as adult-onset Still’s?
if onset is after 16 yo
Does Systemic Onset JIA affect males or females more? How do patients appear?
Trick question, only form that affects males and females equally.
Patients appear ill (fever, rash, elevated WBC, anemic) and is often mistaken for infectious or neoplastic disease
What’s the most common early sign of systemic onset JIA? Which joints do it affect? What’s the joint it affects that is not seen in other types?
arthralgias (not joint pain/arthritis).
can affect any joint (most often wrist, knee, ankles).
Will invlove hip (not seen in other types).
What can be present in chronic version of Systemic Onset JIA after years of disease?
Micrognathia (undersized jaw) and cervical spine fusion.
What are extra-articular manifestations of Systemic Onset JIA?
Intermittent fever (>39 degrees C), rash (most often axilla and waist). The rash can disappear when temp returns to normal, may reappear w/ stroking of skin (KOEBNER PHENOMENON) or other trauma.
What are some other clinical findings/signs of Systemic Onset JIA?
organomegally (liver/spleen), lymphadenopathy, pleural & pericardial effusions (small), vasculitis, ill appearance (anemia/systemic effect), headaches and other neurological complaints.
What are lab findings of Systemic onset JIA?
WNO specific lab/diagnosis of exclusion.
See elevated WBC (up to 60k, granulocytes predominate), profound anemia, elevated sedimentation rate, elevated C-reactive protein.
What’s a rare lab finding in systemic onset JIA that should lead you to look at other types of JIA?
Rheumatoid Factor and ANA+, should prompt further exploration
What is sedimentation rate (sed rate)? What happens when sed rate is higher?
Blood test that measures how quickly RBCs settle in a test tube in one hour. The more that fall to the bottom of the test tube in one hour, the higher the sed rate.
Inflammation causes certain proteins in RBCs to stick together and fall quicker than normal.
What is ANA test?
Detects antinuclear Ab’s in blood, positive test indicates that your immune system has launched misdirected attack on your own tissue (autoimmune rxn).
How can you diagnose Systemic Onset JIA?
Combination of intermittent daily fever & arthritis. Fever present for 6 wks or more. Arthritis doesn’t need to be constant but must be noted.
What’s the clinical course of Systemic Onset JIA?
Highly variable, usually 4-6 months of spiking fever, rash, arthralgia, arthritis. Often after initial onset, an asymptomatic period. 40-50% of kids have complete resolution of the arthritis. 1/3 of patients have very bad/long course, some w/ little progression of joint disease but others w/ progressive/destructive arthritis (w/ acquired leg-length discrepancies and TMJ restriction).
How many joints does pauciarticular onset JIA affect? Which area of the body does it primarily affect?
Involves 4 or fewer joints at 6 months. predominantly involves the lower extremity.
What is the most common type of JIA? How many cases does it account for?
Pauciarticular onset JIA. Accounts for approximately half of all cases.
Does pauciarticular onset JIA involve the hips?
No
When is pauciarticular onset JIA incidence highest? Affect females or males more?
Peak incidence is 2nd and 3rd yr of life, rare after age 10. Females more often than males, typically limps or walks funny in the morning but symptoms improve during the day. Family will usually seek medical help due to joint swelling.
Which joints are affected by pauciarticular JIA? Are there any systemic symptoms?
Large joints (knee, ankle, wrist, elbow) but usually spares the hip. The only systemic symptoms are only the eye, positive ANA means could have eye involvement.
What is the presentation of the joints during pauciarticular JIA?
swollen, tender, and warm, but not erythematous (skin redness). ROM is decreased on affected side.
What’s the diagnosis of pauciarticular JIA?
- 4 or fewer joints involved at 6 mos.
- if single joint involved, involved constantly for 6 wks.
- ANA often present (homogeneous pattern is most common) EYE INVOLVEMENT.
- inflammatory markers normal to near normal.
- normal WBC and platelet counts.
What is the course and prognosis of Pauciarticular JIA?
many cases are “benign” and resolve in 6 mos.
Up to 54% remit completely in time (mos to yrs).
Progression of joint involvement signals worse prognosis.
systemic complications other than eye are rare.
What is Uveitis or iridocyclitis? What positive test makes it more likely?
inflammation of the anterior uveal tract and ciliary body.
ANA test, if symptomatic at diagnosis of pauciarticular JIA then permanent eye damage likely present (pain is a poor prognosis). If patient is younger than 6 at diagnosis and ANA positive, then worse prognosis (needs early evaluation by ophthalmologist)
What is a possible consequence of pauciarticular JIA?
Leg length discrepancy bc of increased blood flow to affected leg (knee) carries increased nutrients, increased inflammatory changes, and more active osteoclasts. This can be avoided w/ early therapy (especially joint/intra-articular injections).
What are some characteristics of polyarticular onset JIA?
More than four affected joint in first six months, comprises 20-30% of cases of JIA, bi-modal age distribution (peak at years 2-5, 10-14).
It may be two or more distinct diseases.
What is the clinical presentation of polyarticular onset JIA in the 2-5 age range?
- indolent (lazy appearance) presentation, 1 or 2 joints at first then spreads to involve 5 or more joints w/in 6 mos.
- often unrecognized until intercurrent infection brings about increase in severity of symptoms.
- Relentless march of disease w/ periods of apparent response to treatment followed by relapse (joint involvement).
- Symmetrical joint involvement is common
- dactylitis (single digit- sausage digit, may be associated w/ family history of psoriatic arthritis)
- Uveitis less common, but if ANA+ there’s increased risk.
What’s the clinical presentation of polyarticular onset JIA in the 10-14 age range?
Relatively rapid onset, often involves multiple joints in hands and feet, pain out of proportion w/ apparent disease, seems to be two groups (Rheumatoid Factor negative and RF positive)
What’s the difference in polyarticular onset JIA between RF+ and RF-?
RF+ is more likely female, may be HLA-DR4 positive and/or have anti-cyclic citrullinated peptide (anti-CCP) Ab’s, which suggest aggressive disease w/o appropriate therapy (mimics adult onset disease)
RF- is much more common, rare to have in combo w/ positive anti-CCP, less severe initial course
How do you diagnose polyarticular onset JIA?
> 4 joints involved during first 6 mos.
Elevated erythrocyte sedimentation rate (>40 mm/hr)
Elevated anemia (Hb 11g/dl or less)
Many of the young age group are ANA+ (increases risk of eye involvement)
Other markers aren’t present and are suggestive of connective tissue disease (Ab’s to dsDNA, Sm, Ro, La, or RNP aren’t expected, think SLE or other CT diagnosis).
What percentages of people are affected by each different type of JIA?
Systemic Onset JIA (10-15%) Pauciarticular JIA (50%) Polyarticular JIA (20-30%)
What are the proportions of incidence in sexes affected in the different types of JIA?
Systemic onset affects more females than males.
Pauciarticular and polyarticular JIA affect males and females evenly.
What are the age of onset ranges for each of the JIA?
Systemic Onset JIA = 10
Polyarticular JIA = 2-5 and 10-14
What joints are affected by the different JIAs?
systemic onset JIA joints = any
pauciarticular JIA joints = large, rarely hips
Polyarticular JIA joints = any, rare to start at hip
Which type of JIA has fever, nodes, rash, organomegaly?
Systemic onset JIA
How common is Uveitis in the different types of JIA?
systemic onset JIA = rare
pauciarticular JIA = 20% (esp, ANA+)
polyarticular JIA = less frequent
Which form of JIA has marked leukocytosis and anemia?
Systemic JIA has marked leukocytosis and anemia. Polyarticular JIA has mild anemia.
In order from highest to lowest amount of ESR (erythrocyte sedimentation rate), list the types of JIA
systemic onset, polyarticular, pauciarticular (none)
How strong is the titer for the various JIAs for ANA?
Systemic onset = ANA-
pauciarticular = low titer
Polyarticular = low titer in young
how common is rheumatoid factor in the JIAs?
systemic onset = rare
pauciarticular = absent
polyarticular = 10-20% if > 10 yo
how common is destructive arthritis in each of the JIAs?
systemic = >50% pauciarticular = rare polyarticular = > 50%
How often are disease modifying drugs used in each of the JIAs?
systemic = commonly used pauciarticular = rarely used polyarticular= commonly used
What else can bring on acute onset arthritis?
trauma, infections, hemophilia, malignancy, sickle crisis
What other diseases can have multiple joint involvement?
-any chronic arthritis, systemic autoimmune states, reactive arthritis (post-viral, etc), IBS, infectious arthritis, psoriasis, metastatic malignancy.
Diagnosis of JIA
16 yo or less symptoms for >6 wks exclude other causes JIA subtype determined at 6 mos referrals (eye, cardiac, orthopod, rheumatologist) baseline radiographic studies
treatment of JIA
initially NSAIDS methotrexate or cyclophosphamide (second line) Etanercept 2x wk SQ injection joint injections treat anemia PT and exercise OMM counseling/education
